JP7736072B2 - Multi-purpose grinder - Google Patents

Description

The present disclosure relates to a composite grinding machine.

In the technology described in Patent Document 1, a cylindrical substrate is built up using laser metal deposition (LMD), and the built-up portion is then ground. As a result, a hard metal coating composed of tungsten carbide and chromium is formed on the surface of the cylindrical substrate.

In the technology of Patent Document 1, the following processes are performed in order: A cylindrical substrate is attached to an apparatus that performs LMD. LMD is performed on the substrate while the cylindrical substrate is rotated. The cylindrical substrate is removed from the apparatus that performs LMD. The cylindrical substrate is attached to a grinding machine. While the cylindrical substrate is rotated in the grinding machine, grinding is performed on the surface of the buildup portion of the substrate. As a result, the outer shape of the cylindrical substrate provided with a hard metal coating is formed with high precision.

JP 2017-110239 A

The inventors of the present invention have developed a processing device that can perform both additive manufacturing and grinding without multiple mounting and dismounting of the cylindrical substrate. Such a processing device eliminates mounting errors in the cylindrical substrate, allowing for smaller machining allowances in the hard metal coating.

However, the inventors of the present invention have discovered the following problem with such processing equipment. Immediately after additive manufacturing, the substrate and the coating on its surface are at high temperatures. As a result, the substrate and coating contain thermal strain. Furthermore, the heat contained in the substrate and coating is conducted to the processing equipment, causing thermal expansion of the processing equipment. As a result, the machining accuracy during subsequent grinding may be reduced.

In additive manufacturing, even if the machining accuracy of the processing equipment is slightly reduced, as long as high-precision shaping is performed during subsequent grinding, it is unlikely to affect the accuracy of the shape and dimensions of the finished product. However, if high-precision shaping is not performed during grinding, it will affect the accuracy of the shape and dimensions of the finished product.

This disclosure can be realized in the following forms:

(1) According to one aspect of the present disclosure, there is provided a multi-purpose grinding machine including: a holding unit capable of holding and rotating a workpiece; an additive manufacturing unit movable relative to the holding unit that supplies material to a surface of the workpiece held by the holding unit while melting the material to adhere the material to the surface; a grinding unit movable relative to the holding unit that includes a grinding wheel and rotates the grinding wheel; and a thermal strain reduction unit that enables the grinding unit to grind the material adhered to the surface in a state where the influence of heat generated in the adhesion of the material to the surface is reduced.
In this embodiment, the material attached to the surface of the workpiece is ground while reducing the influence of heat generated during the attachment of the material to the surface of the workpiece. This not only allows the machining allowance of the material layer attached to the surface of the workpiece to be set small, but also allows for more accurate grinding by the grinding unit compared to an embodiment that does not include a thermal distortion reduction unit. As a result, the accuracy of the shape and dimensions of the finished workpiece can be improved.
(2) In the above-described composite grinding machine, the thermal strain reduction unit may supply a fluid to the surface of the workpiece after the material has adhered to the surface and before grinding by the grinding unit.
In this embodiment, the workpiece, which has a material adhering to its surface and is heated to a high temperature, is cooled by the fluid supplied to the surface before grinding by the grinding unit. This allows for high-precision grinding by the grinding unit. As a result, the accuracy of the shape and dimensions of the finished workpiece can be improved.
(3) In the above-described form of the composite grinding machine, a control unit that controls the composite grinding machine is provided, and functions as the thermal distortion reduction unit by performing standby control to keep the grinding unit on standby after the additive manufacturing unit has attached the material to the surface and before the grinding unit has ground the material, and the standby control can be performed for a time period determined according to the process of attaching the material to the surface.
With this configuration, the workpiece, which has a material adhered to its surface and is at a high temperature, is cooled during standby control prior to grinding by the grinding unit. This allows high-precision grinding by the grinding unit. As a result, the accuracy of the shape and dimensions of the finished workpiece can be improved. Furthermore, because the time during which standby control is performed is determined depending on the process of adhering material to the surface, the time required from the start of adhering material to the surface to the completion of grinding is not unnecessarily extended due to standby control.
(4) In the above-described form of the composite grinding machine, the additive manufacturing unit may include a beam irradiation unit that irradiates a light beam that melts the material, and the composite grinding machine may further include a detection unit that can acquire the state of the workpiece irradiated with the light beam, and the control unit may function as the thermal distortion reduction unit by limiting the output of the light beam irradiated by the beam irradiation unit in accordance with the state of the workpiece acquired by the detection unit.
In this embodiment, the time required for standby control can be shortened compared to an embodiment in which the output of the light beam is not limited according to the state of the workpiece.
(5) In the above-described form of the composite grinding machine, the thermal strain reduction section can receive heat directly or indirectly from the holding section, and can have at least one of a function of holding liquid and a function of circulating liquid.
In this embodiment, heat generated during the deposition of material on the workpiece surface can be diffused to the thermal strain reduction unit via the holding unit. Furthermore, because the liquid flows, heat is efficiently diffused throughout the liquid in the thermal strain reduction unit. Therefore, even when heat is conducted from the workpiece, which has become hot due to the deposition of material, to other parts of the multi-purpose grinding machine via the holding unit, the temperature rise in parts of the multi-purpose grinding machine that may affect machining accuracy can be reduced. As a result, the amount of thermal strain in parts of the multi-purpose grinding machine that may affect machining accuracy can be reduced, and a decrease in grinding accuracy can be suppressed.
(6) In the above-described form of the composite grinding machine, the holding portion may be a center attached to the holding portion and in contact with the workpiece, and the workpiece may be held via the center functioning as the thermal distortion reduction portion, and the center may be made of a material having a lower thermal conductivity than the material of the portion of the holding portion to which the center is attached.
This configuration makes it difficult for heat to be conducted from the workpiece, which has a material attached to its surface and is at a high temperature, to the holder and further to other parts of the combined grinding machine, thereby reducing the possibility of thermal expansion of the combined grinding machine and a decrease in its machining accuracy.
(7) In the above-described form of the composite grinding machine, the holding portion may be a chuck attached to the holding portion and holding the outer periphery of the workpiece at three or more points, and the workpiece is held via the chuck that functions as the thermal distortion reduction portion, and the chuck may be made of a material having a lower thermal conductivity than the material of the portion of the holding portion to which the chuck is attached.
This configuration makes it difficult for heat to be conducted from the workpiece, which has a material attached to its surface and is at a high temperature, to the holder and further to other parts of the combined grinding machine, thereby reducing the possibility of thermal expansion of the combined grinding machine and a decrease in its machining accuracy.
The present disclosure can be realized in various forms other than a composite grinding machine, such as a processing device, a manufacturing method for a processing device, a control method for a processing device, a computer program for implementing the control method, a non-transitory recording medium on which the computer program is recorded, etc.

1 is an explanatory diagram showing a multi-purpose grinding machine 1 according to a first embodiment; FIG. 2 is a diagram showing in detail the configuration of a portion of the additive manufacturing unit 300. 1 is an explanatory diagram showing the configuration and operation of a protection unit 500 and an additive manufacturing unit 300. FIG. An explanatory diagram showing the state of the protective unit 500 and the additive manufacturing unit 300 when the workpiece WP held by the holding unit 100 is being ground by the grinding wheel 21 of the grinding unit 200. An explanatory diagram showing the state of the protective unit 500 and the additive manufacturing unit 300 when the additive manufacturing unit 300 adheres material Mx to the surface Sw of the workpiece WP. FIG. 2 is a flow chart showing the processing of the workpiece WP. 1 is a flow chart showing a conventional process for machining a workpiece WP. FIG. 10 is a flowchart showing a process for machining a workpiece WP in a second embodiment. FIG. 10 is an explanatory diagram showing a multi-purpose grinding machine 3 according to a third embodiment.

A. First embodiment:
FIG. 1 is an explanatory diagram showing a multi-purpose grinding machine 1 according to a first embodiment. FIG. 1 corresponds to a plan view. However, FIG. 1 does not accurately represent the dimensions and shapes of the components of each part. In addition, in order to facilitate understanding of the technology, some components of the multi-purpose grinding machine 1 are not shown in FIG. 1.

The multi-purpose grinding machine 1 is capable of performing additive manufacturing (AM) and subtractive grinding on cylindrical workpieces (WP). The multi-purpose grinding machine 1 includes a holding unit 100, a grinding unit 200, an additive manufacturing unit 300, a coolant supply unit 400, a protection unit 500, a detection unit 38, a bed 800, and a control unit 900.

The holding unit 100 can hold and rotate the workpiece WP (see the bottom of Figure 1). The holding unit 100 is arranged to be movable horizontally relative to the bed 800. The holding unit 100 includes a table 12, a headstock 13, and a tailstock 14.

The table 12 is mounted on the bed 800. The table 12 is mounted so as to be movable horizontally relative to the bed 800. The direction in which the table 12 moves is referred to as the X-axis direction in this specification. In Figure 1, the movement of the holding unit 100 is indicated by the arrow Ax1 (see the lower right part of Figure 1).

The headstock 13 is mounted on the table 12. The headstock 13 holds the workpiece WP via a chuck 15 attached to the headstock 13. That is, the chuck 15 holds one end of the cylindrical workpiece WP by holding the outer periphery of the cylindrical workpiece WP at three points. The headstock 13 can rotate the chuck 15.

The chuck 15 is made of a material with a lower thermal conductivity than the material of the portion 18 of the holding part 100 to which the chuck 15 is attached. Specifically, the chuck 15 is made of porous ceramic. The portion 18 to which the chuck 15 is attached is made of steel.

The tailstock 14 is mounted on the table 12. The tailstock 14 holds the workpiece WP via a center 16 attached to the tailstock 14. In other words, the center 16 comes into contact with the workpiece WP and supports the other end of the cylindrical workpiece WP.

The center 16 is made of a material with a lower thermal conductivity than the material of the portion 17 of the holding part 100 where the center 16 is attached. Specifically, the center 16 is made of porous ceramic. The portion 17 where the center 16 is attached is made of steel.

This configuration makes it difficult for heat to be conducted from the workpiece WP, which has material Mx attached to its surface Sw and is at a high temperature, to the holding part 100 and further to other parts of the multi-purpose grinding machine 1. This reduces the possibility of significant thermal expansion of each component of the multi-purpose grinding machine, which could lead to a decrease in the machining accuracy of the multi-purpose grinding machine.

The workpiece WP is supported at both ends by the chuck 15 of the headstock 13 and the center 16 of the tailstock 14, and is rotated by the headstock 13 around a rotation axis parallel to the X-axis direction. The rotation axis of the headstock 13 is shown by a dashed line parallel to the X-axis direction in Figures 1, 3 to 5, and 9.

The grinding unit 200 functions to grind the surface of the workpiece WP (see the middle right part of Figure 1). The grinding unit 200 includes a grinding wheel head 20, a grinding wheel 21, a grinding wheel drive motor 22, a grinding wheel spindle 23, and a belt transmission mechanism 24.

The grinding wheel head 20 is mounted on the bed 800. The grinding wheel head 20 is mounted so that it can move horizontally relative to the bed 800. The direction in which the grinding wheel head 20 moves is perpendicular to the direction in which the table 12 moves. In this specification, the direction in which the grinding wheel head 20 moves is referred to as the Z-axis direction. In Figure 1, the movement of the grinding unit 200 is indicated by arrow Az2 (see the middle right part of Figure 1). In this specification, the vertically upward direction is defined as the positive Y-axis direction. Figure 1 shows a Cartesian coordinate system consisting of the X-axis, Y-axis, and Z-axis.

The grinding wheel spindle 23 is supported by the grinding wheel head 20 so that it can rotate around a direction parallel to the X-axis direction. The grinding wheel 21 is a circular grinding wheel. The grinding wheel 21 is connected to the grinding wheel spindle 23 so that the central axis of the disc coincides with the central axis of the grinding wheel spindle 23. The grinding wheel 21 has a cylindrical grinding surface 21a on the outer peripheral surface of the disc that is parallel to the X-axis direction.

The grinding wheel drive motor 22 is supplied with power and outputs a rotational output. The grinding wheel drive motor 22 is fixed to the grinding wheel head 20. The belt transmission mechanism 24 transmits the rotational output of the grinding wheel drive motor 22 to the grinding wheel spindle 23. In other words, the grinding unit 200 rotates the grinding wheel 21 using the grinding wheel drive motor 22 via the belt transmission mechanism 24.

While the workpiece WP is rotated by the holding unit 100, the cylindrical grinding surface 21a of the rotating grinding wheel 21 is pressed against the surface Sw of the workpiece WP by the grinding unit 200, thereby grinding the surface Sw of the cylindrical workpiece WP.

The grinding unit 200 can move in the Z-axis direction relative to the holding unit 100 by means of the grinding wheel head 20 (see Az2 in the middle right part of Figure 1). Meanwhile, the holding unit 100 can move in the X-axis direction while rotating the workpiece WP (see Ax1 in the bottom right part of Figure 1). Therefore, the grinding unit 200 and holding unit 100, controlled by the control unit 900, can perform traverse grinding as a removal process on the workpiece WP held by the holding unit 100.

The coolant supply unit 400 supplies coolant CL to the contact point CP where the workpiece WP held in the holder 100 and the grinding wheel 21 come into contact (see the lower right part of Figure 1). The coolant supply unit 400 is fixed to the grinding unit 200. However, in Figure 1, to facilitate understanding of the technology, the coolant supply unit 400 is shown independent of the grinding unit 200. The coolant supply unit 400 includes a tank that stores coolant CL and a pump that delivers the coolant CL from the tank to the contact point CP where the workpiece WP and the grinding wheel 21 come into contact.

Figure 2 is a diagram showing in detail the configuration of a portion of the additive manufacturing unit 300. The additive manufacturing unit 300 functions to perform additive manufacturing on the surface Sw of the workpiece WP (see the center part of Figure 1). The additive manufacturing unit 300 can move in the Z-axis direction relative to the holding unit 100. In Figure 1, the movement of the additive manufacturing unit 300 is indicated by arrow Az3 (see the left part of the interruption in Figure 1). The additive manufacturing unit 300 comprises a beam irradiation unit 32 and a material supply unit 33.

The beam irradiation unit 32 emits a light beam LB that melts the material Mx outside the additive manufacturing unit 300. The beam irradiation unit 32 includes an oscillator 34 and an optical system 35. The oscillator 34 emits a light beam. The optical system 35 converges the light beam emitted by the oscillator 34 to a focal point at a predetermined position relative to the beam irradiation unit 32. To facilitate understanding of the technology, the optical system 35 is shown in the shape of a single convex lens in Figure 2. The beam irradiation unit 32, which includes the optical system 35, is an optical device used to deposit material on the surface Sw of the workpiece WP.

The material supply unit 33 supplies cemented carbide powder Mf to the outside of the additive manufacturing unit 300. The direction of emission of the light beam LB by the beam irradiation unit 32 and the direction of emission of the cemented carbide powder Mf by the material supply unit 33 intersect at the focus of the light beam LB. As a result, the cemented carbide powder Mf supplied by the material supply unit 33 is melted by the light beam LB. That is, the additive manufacturing unit 300 supplies cemented carbide powder Mf as material to the surface Sw of the workpiece WP held in the holding unit 100 while melting the material, thereby adhering the material to the surface Sw of the workpiece WP. That is, the additive manufacturing unit 300 performs directed energy deposition (DED). More specifically, the additive manufacturing unit 300 performs laser metal deposition (LMD).

In this specification, the powdered material is referred to as "powder Mf." The structure formed by melting the powder Mf and adhering it to the surface Sw of the workpiece WP is referred to as the "additional portion Md" or "additional layer Md." When the materials constituting the powder Mf and the additional layer Md are collectively referred to as "material Mx."

While the workpiece WP is rotated by the holding unit 100, the additive manufacturing unit 300 applies material Mx to the surface Sw of the workpiece WP, thereby forming an annular additive portion Md centered on the central axis of the workpiece WP on the surface Sw of the cylindrical workpiece WP.

The additive manufacturing unit 300 can move in the Z-axis direction relative to the holding unit 100 (see Az3 in the middle left of Figure 1). Meanwhile, the holding unit 100 can move in the X-axis direction while rotating the workpiece WP (see Ax1 in the bottom right of Figure 1). Therefore, the additive manufacturing unit 300 and holding unit 100, controlled by the control unit 900, deposit cemented carbide on the surface Sw of the workpiece WP held and rotated by the holding unit 100, thereby forming an additive layer Md on the surface Sw of the workpiece WP. However, the surface of the additive layer Md is not flat, but has peaks and valleys that are approximately parallel to the circumferential direction of the cylindrical workpiece WP.

This configuration allows the formation of an additional layer of material Md on the surface Sw of the workpiece WP and the grinding of that additional layer Md to be performed on the multi-purpose grinding machine 1 without removing and reinstalling the workpiece WP from the multi-purpose grinding machine 1. Therefore, misalignment of the center of rotation when the workpiece WP is attached multiple times does not affect the accuracy of the shape and dimensions of the additional layer of material Md formed on the surface Sw of the workpiece WP. Therefore, compared to an embodiment in which the formation of the additional layer of material Md on the surface Sw of the workpiece WP and the grinding of that additional layer Md are performed using different devices, the portion of the additional layer of material Md formed on the surface Sw of the workpiece WP that exceeds the thickness required for the product, known as the machining allowance, can be made smaller.

The detection unit 38 is an infrared camera (see the center of Figure 1). The detection unit 38 is fixed to the additive manufacturing unit 300. The detection unit 38 can acquire the state of the workpiece WP. For example, the detection unit 38 can detect the coolant CL attached to the surface Sw of the workpiece WP. The detection unit 38 can also acquire the state of the workpiece WP irradiated with the light beam LB. The detection unit 38 is an optical device used for attaching material to the surface Sw of the workpiece WP.

The bed 800 supports the holding unit 100, the grinding unit 200, the additive manufacturing unit 300, the coolant supply unit 400, the protection unit 500, and the detection unit 38. The holding unit 100 can move in the X-axis direction on the bed 800 (see Ax1 in the lower right part of Figure 1). The additive manufacturing unit 300 and the detection unit 38 fixed to the additive manufacturing unit 300 can move together in the Z-axis direction on the bed 800 (see Az3 in Figure 1). The grinding unit 200 and the coolant supply unit 400 fixed to the grinding unit 200 can move together in the Z-axis direction (see Az2 in the lower right part of Figure 1).

The control unit 900 controls the holding unit 100, grinding unit 200, additive manufacturing unit 300, coolant supply unit 400, protection unit 500, and detection unit 38. The control unit 900 is a computer equipped with a display 970 that functions as an output device and a keyboard 980 that functions as an input device (see Figure 1). The control unit 900 further includes a processor, a CPU 940, a RAM 950, and a ROM 960. The CPU 940 loads computer programs stored in the ROM 960 into the RAM 950 and executes them, thereby causing the holding unit 100, grinding unit 200, additive manufacturing unit 300, coolant supply unit 400, protection unit 500, and detection unit 38 to perform the various functions described below.

Figure 3 is an explanatory diagram showing the configuration and operation of the protection unit 500 and additive manufacturing unit 300. Figures 3 to 5 are plan views. Note that Figures 3 to 5 do not accurately represent the dimensions and shapes of the components of each part. Also, to facilitate understanding of the technology, some components of the composite grinding machine 1 are omitted from the illustration in Figures 3 to 5.

The protective unit 500 prevents the coolant CL from adhering to the beam irradiation unit 32 and the detection unit 38 (see the upper center part of Figure 3). The protective unit 500 has a cover 51 and a pressure unit 57.

The cover 51 covers the beam irradiation unit 32 and the detection unit 38. The cover 51 has an opening 53 and a lid unit 52. The lid unit 52 can open and close the opening 53. The protective unit 500 can selectively position the lid unit 52 in an open position Po or a closed position Pc.

Figure 4 is an explanatory diagram showing the state of the protective unit 500 and the additive manufacturing unit 300 when the workpiece WP held by the holding unit 100 is being ground by the grinding wheel 21 of the grinding unit 200. When the workpiece WP held by the holding unit 100 is being ground by the grinding wheel 21 of the grinding unit 200, the grinding unit 200 moves to a position closer to the rotation axis of the headstock 13 than in the state shown in Figure 3 (see Az2 in Figure 4).

When the workpiece WP held by the holding unit 100 is ground by the grinding wheel 21 of the grinding unit 200, the lid unit 52 is positioned in the closed position Pc (see the center of Figure 4). In this state, the additive manufacturing unit 300 is located within the cover 51. That is, the beam irradiation unit 32 and the detection unit 38 are covered by the cover 51. Therefore, the beam irradiation unit 32 cannot irradiate the light beam LB onto the surface Sw of the workpiece WP. The detection unit 38 cannot acquire the state of the workpiece WP.

Figure 5 is an explanatory diagram showing the state of the protection unit 500 and the additive manufacturing unit 300 when the additive manufacturing unit 300 adheres material Mx to the surface Sw of the workpiece WP. When the additive manufacturing unit 300 adheres material Mx to the surface Sw of the workpiece WP, the grinding unit 200 moves to a position farther from the rotation axis of the headstock 13 than in the state shown in Figure 4 (see Az2 in Figure 5).

When the additive manufacturing unit 300 applies material Mx to the surface Sw of the workpiece WP, the lid unit 52 is positioned in the open position Po (see the center of Figure 5). When the lid unit 52 is in the open position Po, the opening 53 of the cover 51 is opened. At this time, the lid unit 52 moves upward, i.e., in the positive direction of the Y axis, from the position blocking the opening of the cover 51 shown in Figure 4. Note that Figure 5 does not show the lid unit 52 retracted upward. The additive manufacturing unit 300 moves through the opening of the cover 51 to a position closer to the rotation axis of the headstock 13 than in the state shown in Figure 4 (see Az3 in the middle left of Figure 5). In other words, the beam irradiation unit 32 and the detection unit 38 are not covered by the cover 51.

In this state, the beam irradiation unit 32 emits a light beam LB onto the surface Sw of the workpiece WP through the opening 53. The material supply unit 33 supplies cemented carbide powder Mf onto the surface Sw of the workpiece WP through the opening 53 (see Figure 2). The detection unit 38 captures the light reflected by the workpiece WP through the opening 53. To facilitate understanding of the technology, the material supply unit 33 is not shown in Figures 3 to 5.

This configuration reduces the possibility that the coolant CL scattered by the rotating grinding wheel 21 and the rotating workpiece WP in the multi-purpose grinding machine 1 equipped with the grinding unit 200 and additive manufacturing unit 300 will adhere to the beam irradiation unit 32 and the detection unit 38, reducing the accuracy with which the additive manufacturing unit 300 applies material Mx to the surface Sw. It also reduces the possibility that the coolant CL will adhere to the beam irradiation unit 32 and the detection unit 38, causing the beam irradiation unit 32 and the detection unit 38 to malfunction.

More specifically, even if droplets of coolant CL scattered by the rotating grinding wheel 21 and the rotating workpiece WP fly toward the beam irradiation unit 32 and the detection unit 38, the droplets will adhere to the cover 51, which is closed with the lid 52 covering the beam irradiation unit 32 and the detection unit 38. This reduces the possibility of coolant CL adhering to the beam irradiation unit 32 and the detection unit 38.

The pressurizing unit 57 can increase the pressure in the space inside the cover 51 that houses the beam irradiation unit 32 and the detection unit 38. Specifically, the pressurizing unit 57 is a compressor. The pressurizing unit 57 compresses external air and supplies it into the cover 51, thereby maintaining the pressure in the space inside the cover 51 with the opening 53 closed higher than the pressure around the cover 51.

By using this configuration, even if there are tiny droplets of coolant CL floating around the composite grinding machine 1, the possibility of those droplets entering the space inside the cover 51 through the gaps around the lid portion 52 and adhering to the beam irradiation portion 32 and detection portion 38 can be reduced.

Figure 6 is a flow diagram showing the process of machining a workpiece WP. First, a cylindrical workpiece WP before processing is prepared as the material to be processed (see the right part of Figure 6). Note that in this specification, both the object before the processing of Figure 6 and the object after the processing of Figure 6 are referred to as workpiece WP.

In step S10, the workpiece WP is transported to a cutting machine other than the multi-purpose grinding machine 1 and attached to the chuck of the cutting machine.

In step S20, turning and drilling are performed on the workpiece WP using a cutting machine. In step S30, the workpiece WP is removed from the cutting machine. The workpiece WP is then transported to the multi-purpose grinding machine 1 of the first embodiment and attached to the headstock 13 of the multi-purpose grinding machine 1 (see the lower part of Figure 1).

In step S40, additive manufacturing and subtractive grinding are performed on the workpiece WP using the multi-purpose grinding machine 1. Step S40 includes steps S42, S44, S45, S46, and S48. While steps S42, S44, S45, S46, and S48 are performed, the workpiece WP is not removed from the headstock 13 and tailstock 14, but continues to be held by the headstock 13 and tailstock 14.

In step S42, rough grinding is performed on the workpiece WP. More specifically, the grinding unit 200 rotates and brings the grinding wheel 21 into contact with the workpiece WP, which is being rotated by the holding unit 100, thereby performing rough grinding. The coolant supply unit 400 supplies coolant CL to the contact point CP between the workpiece WP held by the holding unit 100 and the grinding wheel 21. At this time, the grinding wheel 21 used for rough grinding in step S42 is attached to the grinding unit 200. The lid unit 52 of the protection unit 500 is positioned in the closed position Pc (see the center of Figure 4). The beam irradiation unit 32 and detection unit 38 are covered by the cover 51 of the protection unit 500. The functional unit of the CPU 940 that controls each unit to perform rough grinding in step S42 is shown in Figure 1 as the first rough grinding unit 942.

After rough grinding is completed, the grinding unit 200 moves to a position farther from the rotation axis of the headstock 13 than in the state shown in Figure 4 (see Az2 in Figure 5). The lid unit 52 of the protective unit 500 is positioned in the open position Po (see the center of Figure 5). Then, under the control of the control unit 900, the additive manufacturing unit 300 moves through the opening of the cover 51 to a position closer to the rotation axis of the headstock 13 than in the state shown in Figure 4 (see Az3 in Figure 5).

Then, the rough grinding wheel attached to the grinding unit 200 in step S42 is replaced with a rough grinding wheel in step S46.

In step S44, build-up processing of a hard material is performed. More specifically, the additive manufacturing unit 300 forms an additional layer Md of cemented carbide on the surface Sw of the workpiece WP (see Figure 2). In build-up processing of a hard material, the control unit 900 first detects the coolant CL adhering to the surface Sw of the workpiece WP using the detection unit 38. Then, based on the detection result by the detection unit 38, the control unit 900 controls the output of the light beam LB when the material Mx is adhering to the surface Sw.

By performing this process, if coolant CL remains on the surface Sw of the workpiece WP manufactured by the additive manufacturing unit 300, the output of the light beam LB can be increased to take into account the effects of the coolant CL. This reduces the possibility that the accuracy of the application of material Mx to the surface Sw by the additive manufacturing unit 300 will be reduced due to coolant CL adhering to the workpiece WP.

The control unit 900 also limits the output of the light beam LB emitted by the beam irradiation unit 32 so that it does not become excessive, depending on the state of the workpiece WP acquired by the detection unit 38. More specifically, the control unit 900 acquires the temperatures of the surface Sw and the additional layer Md of the workpiece WP based on information from the detection unit 38, which is an infrared camera, and limits the output of the light beam LB so that it does not become excessive based on those temperatures.

By performing this processing, the temperature rise of the workpiece WP can be kept to the minimum necessary. As a result, the time for performing standby control in the subsequent step S45 can be set shorter than in a configuration in which the output of the light beam LB is not limited according to the state of the workpiece WP.

The functional part of the CPU 940 that controls each part in step S44 to perform the deposition processing is shown as deposition part 944 in Figure 1.

After the additive manufacturing process, the additive manufacturing unit 300 is controlled by the control unit 900 to move into the cover 51 (see Az3 in Figure 4). The lid unit 52 of the protective unit 500 is then placed in the closed position Pc (see the center of Figure 4). When the lid unit 52 is in the closed position Pc, the opening 53 of the cover 51 is closed by the lid unit 52. The grinding unit 200 moves to a position closer to the rotation axis of the headstock 13 than in the state shown in Figure 5 (see Az2 in Figure 4).

In step S45, standby control is performed. Specifically, the control unit 900 causes the grinding unit 200 to wait for a time determined in accordance with the process of adhering the material Mx to the surface Sw of the workpiece WP executed in step S44. During this time, the process of step S46 is not started. The time for which the grinding unit 200 is kept waiting is associated with the process of adhering the material Mx to the surface Sw of the workpiece WP executed in step S44 and is stored in advance in the RAM 950 of the control unit 900. The RAM 950 stores multiple combinations of the process of adhering the material Mx to the surface Sw of the workpiece WP executed in step S44 and the time for which the grinding unit 200 is kept waiting.

In this manner, the workpiece WP, which has material Mx adhering to its surface Sw and is at a high temperature, is cooled by heat dissipation to the surroundings while standby control is performed prior to grinding by the grinding unit 200. This allows high-precision grinding by the grinding unit 200 to be performed in subsequent steps S46 and S48. As a result, the accuracy of the shape and dimensions of the finished workpiece WP can be improved.

The time for which standby control is performed is determined according to the process of adhering material Mx to surface Sw executed in step S44. Therefore, the time required from the start of adhering material Mx to surface Sw in step S44 to the completion of grinding in step S48 is not unnecessarily extended due to standby control. The functional part of the CPU 940 that controls each part in step S45 to perform the process of rough grinding is shown as standby control unit 945 in Figure 1.

In step S46, rough grinding is performed on the workpiece WP. More specifically, the grinding unit 200 rotates and brings the grinding wheel 21 into contact with the workpiece WP, which is being rotated by the holding unit 100, thereby performing rough grinding on the additional layer Md formed on the workpiece WP. The coolant supply unit 400 supplies coolant CL to the contact point CP where the workpiece WP held by the holding unit 100 and the grinding wheel 21 come into contact. As a result, the ridges formed on the surface of the additional layer Md are roughly removed. At this time, the grinding wheel 21 for rough grinding in step S46 is attached to the grinding unit 200. The lid unit 52 of the protective unit 500 is positioned in the closed position Pc (see the center of Figure 4). The beam irradiation unit 32 and the detection unit 38 are covered by the cover 51 of the protective unit 500 (see Figure 4). The functional part of the CPU 940 that controls each part to perform the rough grinding process in step S46 is shown as a second rough grinding part 946 in FIG.

After rough grinding is completed, the grinding unit 200 moves to a position farther from the rotation axis of the headstock 13 than in the state shown in Figure 4 (see Az2 in Figure 5). The grinding wheel used for rough grinding in step S46, which is attached to the grinding unit 200, is replaced with a grinding wheel used for finish grinding in step S48. The grinding unit 200 then moves to a position closer to the rotation axis of the headstock 13 than in the state shown in Figure 5 (see Az2 in Figure 4).

In step S48, finish grinding is performed on the workpiece WP. More specifically, the grinding unit 200 rotates and brings the grinding wheel 21 into contact with the workpiece WP being rotated by the holding unit 100, thereby performing finish grinding on the additional layer Md formed on the workpiece WP. The coolant supply unit 400 supplies coolant CL to the contact point CP where the workpiece WP held by the holding unit 100 and the grinding wheel 21 come into contact. As a result, the surface of the additional layer Md is machined to be flat. At this time, the grinding wheel 21 for finish grinding in step S48 is attached to the grinding unit 200. The lid unit 52 of the protective unit 500 is positioned in the closed position Pc (see the center of Figure 4). The beam irradiation unit 32 and the detection unit 38 are covered by the cover 51 of the protective unit 500 (see Figure 4). The functional part of the CPU 940 that controls each part in step S48 to perform the finish grinding process is shown as a finish grinding part 948 in FIG.

After finish grinding is completed, the grinding section 200 moves to a position farther from the rotation axis of the headstock 13 than in the state shown in Figure 4 (see Az2 in Figure 5).

In step S50, the workpiece WP is removed from the headstock 13 of the multi-purpose grinding machine 1 (see the bottom of Figure 1) and transported to a designated finished product storage area. This completes the processing of the workpiece WP.

Figure 7 is a flow chart showing conventional processing for machining a workpiece WP. In conventional processing for machining a workpiece WP, the processing from preparation of the material to be processed to step S120 is the same as the processing from preparation of the material to be processed to step S20 in Figure 6 of this embodiment.

In step S130, the workpiece WP is removed from the cutting machine. The workpiece WP is then transferred to a conventional grinding machine and attached to the grinding machine's headstock.

In step S142, rough grinding is performed on the workpiece WP in a grinding machine. At this time, a grinding wheel 21 for rough grinding in step S142 is attached to the grinding machine.

After rough grinding, the grinding wheel for rough grinding attached to the grinding machine in step S142 is replaced with a grinding wheel for rough grinding in step S146.

In step S143, the workpiece WP is removed from the grinding machine. The workpiece WP is then transported to the DED processing machine and attached to the DED processing machine.

In step S144, hard material build-up processing is performed. More specifically, an additional layer Md of cemented carbide is formed on the surface Sw of the workpiece WP using a DED processing machine (see Figure 2).

In step S145, the workpiece WP is removed from the DED machine. The workpiece WP is then transferred to a conventional grinding machine and attached to the headstock of the grinding machine (see the bottom of Figure 1).

In step S146, rough grinding is performed on the workpiece WP. At this time, the grinding wheel 21 for rough grinding in step S146 is attached to the grinding machine.

In step S147, the grinding wheel used for rough grinding in step S146 attached to the grinding machine is replaced with a grinding wheel used for finish grinding in step S148.

In step S148, finish grinding is performed on the workpiece WP. At this time, the grinding wheel 21 for finish grinding in step S48 is attached to the grinding unit 200.

In step S150, the workpiece WP is removed from the grinding machine's headstock and transported to a designated finished product storage area. This completes the conventional processing of the workpiece WP.

In conventional processing, while steps S142 to S148 are being performed, the workpiece WP is sequentially mounted on a grinding machine, a DED machine, and a grinding machine. When the workpiece WP is first mounted on the grinding machine, then mounted on the DED machine, and then mounted on the grinding machine a second time, the mounting position of the workpiece WP on each machine, and the resulting center of rotation of the workpiece WP on each machine, are misaligned. For this reason, when processing a workpiece WP using conventional grinding machines and DED machines, it is necessary to set a large machining allowance.

In contrast, in steps S42, S44, S45, S46, and S48 of this embodiment, additive manufacturing and subtractive grinding are performed on the workpiece WP using the multi-purpose grinding machine 1 (see S40 in Figure 6). Therefore, the workpiece WP is not removed from or attached to the multi-purpose grinding machine 1 during this time. This allows the so-called machining allowance to be set small. Furthermore, the multi-purpose grinding machine 1 eliminates the need to transport the workpiece WP between processing devices and the need for setup work at each processing device. Therefore, the time required to process the workpiece WP can be shortened compared to the process in Figure 7. As a result, the cost of processing the workpiece WP can also be reduced.

In this embodiment, additive manufacturing and subtractive grinding are performed using a single multi-purpose grinding machine 1 (see S40 in Figure 6). Therefore, the space required for these processes within a factory can be reduced compared to the configuration shown in Figure 7, which uses a grinding machine and a DED processing machine.

In embodiments where the workpiece WP is plated rather than DED, hexavalent chromium is used. However, in this embodiment, an additional layer Md is formed on the surface Sw of the workpiece WP by DED rather than plating. Therefore, there is no need to treat or manage hexavalent chromium.

In this embodiment, the center 16 is made of porous ceramic (see the lower right part of Figure 1). This makes it difficult for heat to be conducted from the workpiece WP to the holding unit 100 and further to other parts of the composite grinding machine 1. Also, in this embodiment, in step S45 of Figure 6, standby control is performed by the standby control unit 945 of the control unit 900. As a result, in step S44, the influence of heat generated in the deposition of material Mx on the surface Sw of the workpiece WP is reduced, and in steps S46 and S48, the grinding unit 200 can grind the additional layer Md deposited on the surface Sw.

For this reason, the composite grinding machine 1 not only allows the machining allowance of the additional layer Md attached to the surface Sw of the workpiece WP to be set small, but also allows for more accurate grinding by the grinding unit 200 compared to an embodiment that does not have a center 16 and standby control unit 945 of such a configuration. As a result, the accuracy of the shape and dimensions of the finished workpiece WP can be improved.

In this embodiment, the center 16 and standby control unit 945 are also referred to as the "thermal distortion reduction unit." The grinding wheel 21 is also referred to as the "grinding wheel." The beam irradiation unit 32 is also referred to as the "optical equipment."

B. Second embodiment:
In the second embodiment, the process of step S45b is performed instead of the process of step S45 in Fig. 6. Other points of the second embodiment are the same as those of the first embodiment.

Figure 8 is a flow diagram showing the processing of the workpiece WP in the second embodiment. In the processing of Figure 8, after the material Mx is adhered to the surface Sw of the workpiece WP in step S44, coolant CL is supplied to the surface Sw of the workpiece WP in step S45b prior to grinding by the grinding unit 200 in steps S46 and S48. Specifically, while the workpiece WP is rotated by the holding unit 100, coolant CL is supplied to the surface Sw of the workpiece WP by the coolant supply unit 400.

The coolant supply unit 400, together with the grinding unit 200, can be moved in the Z-axis direction relative to the holding unit 100 by the wheel head 20 (see Az2 in the middle right part of Figure 1). Meanwhile, the holding unit 100 can be moved in the X-axis direction while rotating the workpiece WP (see Ax1 in the bottom right part of Figure 1). Therefore, the coolant supply unit 400 and holding unit 100, controlled by the control unit 900, can sequentially pour coolant CL onto the entire cylindrical side surface of the workpiece WP held by the holding unit 100.

By performing this process, the workpiece WP, which has material Mx adhering to its surface Sw and is heated to a high temperature, is cooled by the coolant CL supplied to the surface Sw prior to grinding by the grinding unit 200. In other words, the heat of the workpiece WP is carried away by the coolant CL before the holding unit 100 and grinding unit 200 of the multi-purpose grinding machine 1 are heated by the heat of the workpiece WP. This reduces the amount of thermal deformation of the workpiece WP, as well as the holding unit 100 and grinding unit 200, enabling high-precision grinding by the grinding unit 200. As a result, the accuracy of the shape and dimensions of the finished workpiece WP can be improved. The functional part of the CPU 940 that controls each part to perform rough grinding in step S45b is shown in Figure 1 as the workpiece cooling unit 945b.

The coolant supply section 400 and workpiece cooling section 945b in this embodiment are also referred to as the "thermal distortion reduction section."

C. Third embodiment:
The multi-purpose grinding machine 3 of the third embodiment includes an equipment cooling unit 600. Furthermore, the holding unit 103 of the multi-purpose grinding machine 3 has an additional function in addition to the function of the holding unit 100 of the multi-purpose grinding machine 1. Other points of the multi-purpose grinding machine 3 of the third embodiment are the same as those of the multi-purpose grinding machine 1 of the first embodiment.

Figure 9 is an explanatory diagram showing a multi-purpose grinding machine 3 of the third embodiment. Figure 9 corresponds to Figure 1. In Figure 9, components that perform the same functions as those shown in Figure 1 are indicated by the same reference numerals. Figure 9 corresponds to a plan view. Figure 9 does not accurately represent the dimensions and shapes of the components of each part. Also, to facilitate understanding of the technology, Figure 9 omits the illustration of some of the components of the multi-purpose grinding machine 3.

The holding unit 103 has components corresponding to those of the holding unit 100 of the multi-purpose grinding machine 1 of the first embodiment, and performs the same functions as the holding unit 100. The holding unit 103 also has the function of circulating a coolant inside. The heat generated by the holding unit 103 is carried away from the holding unit 103 by the circulating coolant.

The equipment cooling unit 600 receives heat from the holding unit 103. The equipment cooling unit 600 has a coolant tank 61, a circulation flow path 62, and a circulation pump 63. The coolant tank 61 holds the coolant. The circulation pump 63 circulates the coolant between the coolant tank 61 and the holding unit 103 via the circulation flow path 62. As a result, the heat held by the holding unit 103 is transferred to the coolant circulating within the holding unit 103 and stored in the coolant in the coolant tank 61.

The control unit 900 controls the equipment cooling unit 600 to circulate the coolant while the grinding unit 200 or the additive manufacturing unit 300 is operating. The functional units of the CPU 940 that control each unit to circulate the coolant in step S40 are the first rough grinding unit 942, the build-up unit 944, the second rough grinding unit 946, and the finish grinding unit 948 (see Figure 1).

With this configuration, heat generated during the adhesion of material Mx to the surface Sw of the workpiece WP can be diffused to the equipment cooling unit 600 via the holding unit 100. Furthermore, because the coolant flows, heat is efficiently diffused throughout the entire coolant in the equipment cooling unit 600. Therefore, even when heat is conducted from the workpiece WP, which has become hot due to the adhesion of material Mx, to other parts of the multi-purpose grinding machine 3 via the holding unit 103, the temperature rise in parts of the multi-purpose grinding machine 3 that could affect machining accuracy, such as the holding unit 103 and grinding unit 200, can be minimized. Furthermore, the workpiece WP can be cooled in a short time. As a result, the amount of thermal distortion in parts of the multi-purpose grinding machine 3 that could affect machining accuracy can be reduced, suppressing a decrease in grinding accuracy.

The equipment cooling section 600 in this embodiment is also called the "thermal strain reduction section."

D. Other Embodiments:
D1. Other embodiment 1:
(1) In the first embodiment, the temperatures of the surface Sw of the workpiece WP and the additional layer Md are obtained based on information from the detector 38, which is an infrared camera, and the output of the light beam LB is limited based on the temperatures so as not to become excessive (see S44 in FIG. 6 ). However, the control unit 900 may obtain information on the properties of the additional layer Md, such as the presence or absence of cracks in the additional layer Md and the spacing between adjacent cracks in the additional layer Md, via the detector 38, and determine the output of the light beam LB based on the information.

(2) In the first embodiment described above, the time for which the grinding unit 200 is kept on standby is associated with the process of adhering material Mx to the surface Sw of the workpiece WP executed in step S44 and is stored in advance in the RAM 950 of the control unit 900 (see the upper center of Figure 1). However, the time for executing standby control may be determined by the control unit 900, for example, by acquiring the temperatures of the surface Sw of the workpiece WP and the additional layer Md based on information from the detection unit 38, which is an infrared camera. Furthermore, the control unit 900 may acquire information on the properties of the additional layer Md, such as the presence or absence of cracks in the additional layer Md and the spacing between adjacent cracks in the additional layer Md, via the detection unit 38, and determine the time for executing standby control based on this information.

(3) In the first embodiment described above, the center 16 is made of porous ceramic (see the lower right part of Figure 1). However, the material making up the center may be brick, non-porous ceramic, or a metal with lower thermal conductivity than the portion 17 to which the center 16 is attached.

(4) In the second embodiment described above, in step S45b, coolant CL is supplied to the surface Sw of the workpiece WP (see Figure 8). However, instead of supplying coolant CL, air may be blown onto the surface Sw of the workpiece WP using a compressor or blower. Even in such a configuration, the workpiece WP can be cooled in a shorter time than in a configuration in which no fluid is supplied to the workpiece WP.

(5) In the above third embodiment, the circulation pump 63 of the equipment cooling unit 600 circulates the coolant between the coolant tank 61 and the holding unit 103 via the circulation flow path 62. However, the equipment cooling unit may also circulate the coolant between, for example, the bed. In other words, the thermal strain reduction unit may be capable of receiving heat directly or indirectly from the holding unit.

(6) In the above-described third embodiment, the equipment cooling unit 600 includes a coolant tank 61, a circulation flow path 62, and a circulation pump 63 (see the lower left part of Figure 9). However, the equipment cooling unit can also be configured, for example, to include a coolant tank 61 without including a circulation pump. Even in such a configuration, the coolant tank 61 increases the thermal capacity of the multi-purpose grinding machine, thereby lowering the temperature of the workpiece WP and each part of the multi-purpose grinding machine. In addition, the heat of the workpiece WP can be diffused throughout the liquid in the coolant tank 61 and the circulation flow path 62 through convection and conduction.

The equipment cooling unit can also be configured to include, for example, a circulation flow path 62, a circulation pump 63, and a radiator, without a coolant tank. In such a configuration, the heat from the workpiece WP can be transferred to the radiator via the coolant, and the heat can be dissipated into the surrounding environment by the radiator. As a result, the workpiece WP can be cooled, and the temperature rise of the multi-purpose grinding machine can be suppressed.

(7) In the above embodiment, the material supply unit 33 supplies cemented carbide powder Mf to the outside of the additive manufacturing unit 300. However, various materials can be used as the material for the additive layer Md, such as Fe-based alloys, Ni-based alloys, Co-based alloys, Cu-based alloys, Al-based alloys, and ceramics. These alloys can be alloys with added chromium, cobalt, vanadium, etc.

In addition, various materials can be used for the workpiece, including carbon steel, bearing steel, stainless steel, and aluminum.

(8) In the above embodiment, the material supply unit 33 supplies cemented carbide powder Mf to the outside of the additive manufacturing unit 300. However, the material supply unit can also supply the material in the form of wire. Furthermore, the material supplied by the material supply unit can be high-speed steel in addition to cemented carbide.

(9) In the above embodiment, the grinding unit 200 and the additive manufacturing unit 300 move in the Z-axis direction, and the holding unit 100 moves in the X-axis direction. However, either the grinding unit or the holding unit may be configured to be able to move in two directions that are perpendicular to each other. In other words, the multi-purpose grinding machine may be configured so that the grinding unit can assume any position in a plane relative to the holding unit. Also, either the additive manufacturing unit or the holding unit may be configured so that it can move in two directions that are perpendicular to each other. In other words, the multi-purpose grinding machine may be configured so that the additive manufacturing unit can assume any position in a plane relative to the holding unit.

(10) In the above embodiment, the detection unit 38 is an infrared camera. However, the detection unit may have other configurations, such as a digital still camera that records visible light or a camera that can record video. The detection unit may be any device that can detect coolant adhering to the surface of a workpiece.

(11) In the above embodiment, the beam irradiation unit 32 of the additive manufacturing unit 300 irradiates a laser beam. However, the additive manufacturing unit may heat and melt the material by irradiating arc plasma or an electron beam instead of a laser beam.

(12) The multi-purpose grinding machine 1 can also be configured to further include a sizing device. The sizing device includes a pair of contacts and an amplifier. The pair of contacts are arranged on either side of the central axis of the cylindrical workpiece WP, and each contacts the surface of the workpiece WP. The amplifier outputs a signal corresponding to the distance between the pair of contacts. This signal represents the outer diameter of the workpiece WP.

In this embodiment, the control unit 900 can perform the following control during grinding in steps S42, S46, and S48 of Figures 6 to 8. The control unit 900 receives a signal representing the size of the outer diameter of the workpiece WP from the sizing device. The control unit 900 acquires the temperature of the surface of the workpiece WP from the detection unit 38. At this time, the additive manufacturing unit 300 is located farther from the rotation axis of the headstock 13 than when additive manufacturing is performed, and the lid portion 52 of the cover 51 is in the open position Po.

Based on this information, the control unit 900 performs real-time feedback control of the rotational speed of the grinding wheel 21, the position of the cylindrical grinding surface 21a in the Z-axis direction, the feed rate of the table 12 in the Z-axis direction, etc. As a result, high-precision machining can be performed in a shorter time than in a configuration without such feedback control. The multi-purpose grinding machine 1 can also be equipped with a radiation thermometer, and the control unit 900 can obtain the surface temperature of the workpiece WP from the radiation thermometer.

D2. Alternative embodiment 2:
In the second embodiment, after the material Mx is attached to the surface Sw of the workpiece WP in step S44, and prior to grinding by the grinding unit 200 in steps S46 and S48, the coolant CL is supplied to the surface Sw of the workpiece WP in step S45b (see FIG. 8 ). However, an embodiment may also be adopted in which the coolant CL is not supplied to the surface Sw of the workpiece WP before grinding by the grinding unit 200. In such an embodiment, for example, the circulation of the coolant by the equipment cooling unit 600 may be performed at a higher speed than during grinding.

D3. Other embodiment 3:
In the first embodiment, standby control is performed in step S45 (see FIG. 6 ). However, instead of standby control in which the workpiece WP is on standby while natural heat dissipation is occurring, active cooling of the workpiece WP may be performed as in the second and third embodiments. Active cooling of the workpiece WP may be performed, for example, by supplying a fluid to the surface of the workpiece WP or by circulating a coolant through the equipment cooling unit 600.

D4. Alternative embodiment 4:
In the first embodiment, the control unit 900 limits the output of the light beam LB emitted by the beam irradiation unit 32 so as not to be excessive, depending on the state of the workpiece WP acquired by the detection unit 38 (see S44 in FIG. 6 ). However, the control unit may maintain the output of the light beam constant regardless of the state of the workpiece.

D5. Alternative embodiment 5:
The equipment cooling unit 600 holds and circulates a coolant (see the lower left part of Figure 9). However, as shown in the first embodiment, the multi-purpose grinding machine may be configured not to have the equipment cooling unit 600 but to cool the workpieces WP by natural heat dissipation. The multi-purpose grinding machine may also be configured to have a configuration other than a liquid tank to increase the heat capacity of the multi-purpose grinding machine. For example, the multi-purpose grinding machine may be configured to hold multiple workpieces WP before processing and to diffuse heat among the multiple workpieces WP.

D6. Other embodiment 6:
In the first embodiment, the center 16 is made of a material having a lower thermal conductivity than the material of the portion 17 of the holding unit 100 where the center 16 is attached (see the lower right part of FIG. 1 ). However, for example, in the multipurpose grinding machine 3 of the third embodiment equipped with the equipment cooling unit 600, the center 16 may have thermal conductivity equivalent to or higher than that of the portion 17 where the center 16 is attached. In such an embodiment, the heat of the workpiece WP is conducted to the tailstock 14 via the center 16 and is cooled by the coolant flowing through the holding unit 103.

D7. Other embodiment 7:
In the first embodiment, the chuck 15 is made of a material having a lower thermal conductivity than the material of the portion 18 of the holding part 100 to which the chuck 15 is attached (see the lower left part of FIG. 1 ). However, for example, in a multipurpose grinding machine 3 of a third embodiment equipped with an equipment cooling part 600, the chuck 15 may have thermal conductivity equivalent to or higher than that of the portion 18 to which the chuck 15 is attached. In such an embodiment, the heat of the workpiece WP is conducted to the headstock 13 via the chuck 15 and is cooled by the coolant flowing through the holding part 103.

The present disclosure is not limited to the above-described embodiments and can be realized in various configurations without departing from its spirit. For example, the technical features of the embodiments corresponding to the technical features in each aspect described in the Summary of the Invention section can be replaced or combined as appropriate to solve some or all of the above-described problems or achieve some or all of the above-described effects. Furthermore, if a technical feature is not described as essential in this specification, it can be deleted as appropriate.

1...Multi-purpose grinding machine, 3...Multi-purpose grinding machine, 12...Table, 13...Headstock, 14...Tailstock, 15...Chuck, 16...Center, 17...Portion where center 16 is attached, 18...Portion where chuck 15 is attached, 20...Grinding wheel head, 21...Grinding wheel, 21a...Cylindrical grinding surface, 22...Grinding wheel drive motor, 23...Grinding wheel spindle, 24...Belt transmission mechanism, 32...Beam irradiation unit, 32w...Window unit, 33...Material supply unit, 34...Oscillator unit, 35...Optical system, 38...Detection unit, 51...Cover, 52...Lid unit, 53...Opening, 57...Pressure unit, 61...Coolant tank, 62...Circulation flow path, 63...Circulation pump, 100...Holding unit, 103...Holding unit, 200...Grinding unit, 300...Additive manufacturing unit, 400...Coolant supply unit, 500...Protection unit, 600...equipment cooling unit, 800...bed, 900...control unit, 940...CPU, 942...first rough grinding unit, 944...build-up unit, 945...standby control unit, 945b...workpiece cooling unit, 946...second rough grinding unit, 948...finish grinding unit, 950...RAM, 960...ROM, 970...display, 980...keyboard, Ax1...arrow indicating movement of holding unit 100, Az2...arrow indicating movement of grinding unit 200, Az3...arrow indicating movement of additive manufacturing unit 300, CL...coolant, CP...area where workpiece WP and grinding wheel 21 come into contact, LB...light beam, Md...additive layer, Mf...powder material, Mx...material, Pc...closed position of lid unit 52, Po...open position of lid unit 52, Sw...surface of workpiece WP, WP...workpiece

Claims (6)

A composite grinding machine,
a holding part capable of holding and rotating a workpiece;
an additive manufacturing unit movable relative to the holding unit, the additive manufacturing unit supplying material to a surface of the workpiece held by the holding unit while melting the material, thereby depositing the material on the surface;
a grinding unit that is movable relative to the holding unit, the grinding unit having a grinding stone and rotating the grinding stone;
a thermal strain reduction unit that enables the grinding unit to grind the material attached to the surface in a state where an influence of heat generated in the attachment of the material to the surface is reduced,
The thermal strain reduction portion is
capable of receiving heat directly or indirectly from the holding portion;
A composite grinding machine having at least one of a function for retaining liquid and a function for circulating liquid. 2. The composite grinding machine according to claim 1,
The thermal strain reduction unit supplies a fluid to the surface of the workpiece after the material is deposited on the surface and prior to grinding by the grinding unit. 2. The composite grinding machine according to claim 1,
a control unit that controls the composite grinding machine, the control unit functioning as the thermal strain reduction unit by performing standby control to cause the grinding unit to wait after the additive manufacturing unit has attached the material to the surface and before the grinding unit has ground the material;
The standby control is executed for a time period determined according to the process of attachment of the material to the surface. 4. The composite grinding machine according to claim 3,
The additive manufacturing unit includes a beam irradiation unit that irradiates a light beam that melts the material,
The composite grinding machine further comprises:
a detection unit capable of acquiring a state of the workpiece irradiated with the light beam;
A composite grinding machine in which the control unit functions as the thermal distortion reduction unit by limiting the output of the light beam emitted by the beam irradiation unit in accordance with the state of the workpiece obtained by the detection unit. 2. The composite grinding machine according to claim 1,
the holding portion holds the workpiece via a center that is attached to the holding portion and comes into contact with the workpiece, and that functions as the thermal strain reducing portion;
The center is made of a material having a lower thermal conductivity than a material of a portion of the holding part to which the center is attached. 6. The composite grinding machine according to claim 1 or 5,
the holding portion is a chuck attached to the holding portion and holding the outer periphery of the workpiece at three or more points, and the workpiece is held via the chuck that functions as the thermal strain reduction portion;
The chuck is made of a material having a lower thermal conductivity than a material of a portion of the holding part to which the chuck is attached.