JP4064210B2 - Machining method with rotary tool and cutter path generation method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a machining method for cutting an integrated object in which a complete body is integrated with a rotating tool from a workpiece through a support, and a cutter path generation method for generating a cutter path used for machining.
[0002]
[Prior art]
For example, a mock-up or part (finished product) having a complicated shape used in the development of a product design is processed using a rotary tool such as an end mill from a hexahedral workpiece such as a rectangular body. In the method, there is a case where the part of the finished body itself cannot be fixed directly to the machine tool when processing.
[0003]
In those cases, usually, as shown in FIG. 7A, first, a portion 52 to be a frame of the workpiece 51 is fixed to a machining table 53 of a machine tool. Next, as shown in FIG. 7 (b), the workpiece 51 is cut at a predetermined location by the rotary tool 54, and the one surface 56 of the finished body 58 is cut out and supported as an integrated object. Cut out one side of 55. Next, as shown in FIG. 7C, the workpiece 51 is reversed and a predetermined portion is cut by the rotary tool 54 to cut the other surface 57 of the finished body 58 and the support 55. Complete the monolith.
[0004]
Thereafter, the finished body 58 is separated from the support 55 (including the frame 52), and finish processing is performed by manual work or the like, thereby completing the finished body 58.
[0005]
[Problems to be solved by the invention]
However, it is difficult to avoid the following problems with the processing method using a rotary tool such as an end mill as described above.
[0006]
(1) When machining with a rotating tool, the entanglement of the rotating tool due to entanglement of chips or cutting load causes interference between the neck of the rotating tool and the wall of the frame, leading to tool breakage, It may cause a deterioration in the quality of the design surface (surface).
[0007]
(2) Further, in the case of the above-described component, after processing one surface (the other surface), when processing the other surface (one surface) by reversing, it is already processed to form a gap. When cutting the workpiece, if the strength of the support and the finished body is not sufficient, the workpiece will vibrate or deform due to the cutting load during machining, and the quality of the machined surface may be reduced. May cause an error in the dimensions.
[0008]
(3) When cutting a curved surface shape, a ball end mill is used as a rotary tool, but when machining one surface (the other surface), if machining to a parting surface that separates one surface from the other surface, Because of the ball end mill, uncut residue along the R shape of the cutting edge occurs. In order to avoid this, it is conceivable to use a flat tool or to cut the uncut portion using a ball end mill having a smaller diameter. In the former case, depending on the shape of the curved surface, a flat end mill is not good because the processed parts have steps. On the other hand, in the latter case, the use of a small-diameter tool may cause tool breakage due to a cutting load.
[0009]
(4) When processing one surface (the other surface) and then reversing to process the other surface (the one surface), the entire area is generally gradually changed from roughing to finishing from the top to the bottom. It cuts out through. In this method, since the part holding the part is only the support part, the holding force is weak. For this reason, a processing method of finishing from one side in order to maintain the holding force can be considered, but there is no cutter path calculation system that embodies it.
[0010]
(5) In the three-axis control (XYZ axis) machining using a general rotary tool, an uncut region is generated in the undercut portion 59 as shown in FIG. In the past, machining such an undercut with a small diameter tool (diameter: 6 mm or less) was not possible because the tool itself was not found and the machining method was not established. For this reason, it has been dealt with by setting up the workpiece in the direction in which machining can be performed. However, due to the change in the setup, an error due to the deviation of the machining standard has occurred, and the machining accuracy is inevitably lowered.
[0011]
The present invention has been made on the basis of these circumstances, and a processing method for cutting a finished body having a good surface finish and a good dimensional accuracy, and a cutter path for use in the processing. An object is to provide a cutter path generation method.
[0012]
[Means for Solving the Problems]
According to the means of the first aspect of the present invention, a completed body having a three-dimensional shape having an opening, a plurality of supports extending outward from the outer wall surface of the three-dimensional shape of the completed body, and tips of the respective supports A processing method using a rotary tool that is formed by cutting a single object formed of a frame formed on a part and held and fixed by a jig of a processing device from a workpiece with the rotary tool of the processing device ,
A portion of the workpiece to be a frame is held and fixed at both ends, and one side of a plurality of supports connected to the frame is formed on the inner surface of the solid shape with respect to the workpiece, and the support and support During the formation of the inside of the solid body of the finished body, to support a load from the rotary tool, and the inside of the solid body having an opening of the finished body of the workpiece A first surface processing step of forming a comb-like sub-support extending to a tip of the frame that is flush with the holding and fixing surface of the frame ;
After the first surface processing step, the workpiece subjected to the first surface processing step is removed from the processing apparatus, and the other surface of the frame is placed in the state where the front and back sides of the workpiece are reversed. machining device is held fixed, the form the other surface of the plurality of support for continuous and the other surface of the frame of the workpiece, further between the support and support, is the other surface of the finished body And a second surface machining step of forming the three-dimensional outer surface while supporting a load from the rotary tool by the plurality of sub-supports .
[0013]
According to the means of the invention of claim 2, the sub-support is a machining method using a rotary tool, wherein a plurality of sub-supports are formed.
[0014]
According to the means according to the invention of claim 3, surface facing the three-dimensional shape of the frame around the contact portion with the support, the gradient as the frame becomes thinner toward the end portion of the frame The machining method using a rotary tool according to claim 1, wherein the machining method is provided.
[0015]
According to a fourth aspect of the present invention, in the machining method using a rotary tool according to the third aspect, the gradient is 1 to 10 degrees.
[0018]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the processing method by the rotary tool which is embodiment of this invention is demonstrated with reference to drawings.
[0019]
FIG. 1 is a perspective view of a mockup that is an example of a finished product manufactured according to the present embodiment. The mock-up 1 is formed by extending a main body 1a having an arch-shaped cross section in the longitudinal direction, and an opening end of the main body 1a extends horizontally inside the arch, and is formed by processing an undercut portion described later. A plurality of legs 2 are provided.
[0020]
As shown in the perspective view of FIG. 2, when the mock-up 1 is cut out from the hexahedron by machining, the frame 8, the support 9, and the main body 1a of the mock-up 1 are connected and integrated. It is in the form of a unitary object.
[0021]
FIGS. 3A to 3D are schematic views showing the main parts of the processing steps of the mockup 1 described above. Note that the cutter path of the rotary tool when the undercut portion is processed in the following processing is controlled by software generated by a cutter path generation method described later.
[0022]
First, as shown in FIG. 3A, for example, a hexahedral workpiece 3 such as a resin material (PC, ABS, etc.) or a metal material (carbon steel, Al, Cu, etc.) is machine tool (not shown). ) Is fixed on the processing table 4, and a part 8 to be a frame is clamped with a jig 6 in the integrated object to be machined.
[0023]
Next, as shown in FIG. 3B, one surface is cut out by cutting with a ball end mill 7 which is a rotary tool. In this cutting process, a plurality of sub-supports 11 that support the load from the tool when cutting one side of the support 9 that extends from the frame 8 and cutting the other surface at the center of the workpiece 3 are provided. Form. The tip of the sub support 11 is formed flush with the surface of the frame 8. (First surface processing step)
Next, as shown in FIG.3 (c), the leg part 2 is processed. Leg 2 forms Ri by that cut out the undercut portion 2a. For this reason, since it is difficult to perform processing by the ball end mill 7 at the position where the workpiece 3 is fixed, the rotary tool is replaced with the slot cutter 12 shown in FIGS. 4A and 4B for processing. Then, the undercut portion 2a is cut out.
[0024]
FIG. 4A is an external view of the slot cutter 12 for processing the undercut portion 2a, and FIG. 4B is an explanatory diagram for the processing. The slot cutter 12 has an inverted T-shaped side section, and a cutting edge 13 having a diameter larger than that of the shank 12a is formed at the tip of the shank 12a. When machining the undercut portion 2a of the workpiece 3 due to the shape of the cutting edge 13, the tool escape amount 14 is a dimension of a depth of 15 or more of the undercut portion, and the blade length 13a of the cutting edge 13 is: The undercut portion has a dimension that is less than 16 in height.
[0025]
Next, as shown in FIG. 3D, the workpiece 3 processed on one side is reversed and positioned on the processing table 4 of the machine tool, and the frame 8 is fixed by the jig 6. In this state, the sub-support 11 is on the lower side and comes into contact with the surface of the work table 4, so that the sub-support 11 can also receive the cutting load when processing the main body 1a as the other surface. High-precision machining is possible by suppressing vibrations. In this state, the support 9 is cut by cutting with a rotary tool 7 such as a ball end mill, and the support 9 is shaped to hold the portion that becomes the main body 1a of the mockup 1.
[0026]
In this case, as shown in FIGS. 3C and 3D, in order to avoid mechanical interference between the rotary tool and the wall surface 8a of the frame 8 during processing, the rotary tool is placed on the wall surface 8a of the frame 8. A gradient is provided in the direction of escape. In addition, although the angle of the gradient is a practical value of 1 degree to 10 degrees, an angle in the vicinity thereof can be appropriately used according to the processing conditions.
[0027]
Next, although not shown, the mock-up 1 is cut out integrally with the frame 8 through the support 9 by a rotary tool. (Second surface processing step)
Thereafter, the mockup 1 is separated from the support 9 (including the frame 8), and the portion to which the support 9 is connected and the vicinity thereof are finished by manual work or the like to complete the mockup 1.
[0028]
In the above case, since the shape of the mock-up 1 is arched, the sub-support 11 is provided. However, when processing the mock-up 1 in which a portion performing the same function as the sub-support 11 exists. The sub-support 11 need not be provided.
[0029]
Next, calculation of the cutter path in the above-described undercut processing will be described.
[0030]
FIG. 5 is a flowchart showing the procedure for calculating the cutter path. FIGS. 6A to 6C are explanatory views showing a design model for calculating a cutter path when the undercut portion is processed. 6A is a plan view, FIG. 6B is a side view at the time of processing, and FIG. 6C is a side view of processing by a flat end mill for explaining the process of cutter path calculation.
[0031]
As shown in FIGS. 6A and 6B, the undercut portion 2 a is cut out on the workpiece 3 to form the necessary leg portion 2.
[0032]
In order to process the undercut portion 2a, as shown in FIG. 6 (a), it is necessary to process using the slot cutter 12 whose side surface is inverted T-shaped, but in general CAM, FIG. As shown in c), software intended for the flat end mill 7 and the ball end mill is used as the rotary tool. Therefore, by applying it to software that is used in the CAM, it is difficult to perform the calculation of the cutter path of the slot cutter 12.
[0033]
Using the software for generating the cutter path of the normal flat end mill 7 as shown in FIG. 6C, the cutter path for the slot cutter 12 whose side section has an inverted T shape can be calculated. First, as shown in FIG. 6 (b), the leg portion 2 is processed by cutting out the undercut portion 2 a from the main body 1 a with the slot cutter 12. When the slot cutter 12 is lifted upward from the leg portion 2 after the processing, as shown in FIG. 6A, the outer contour of the leg portion 2 is defined as a region where the leg portion 2 and the slot cutter 12 do not interfere with each other. A boundary line 21 is set by offsetting the radius of the rotating part of the slot cutter 12 from 20 and the boundary line 21 is read by CAM to set an interference boundary region 22. (S1)
Next, a virtual body 23 is calculated by removing the leg 2 by CAD. (S2)
Subsequently, a cutter path of the normal tool 7 (for example, a flat end mill) for the virtual body 23 is generated by CAM. (S3) (Cutter path generation process)
The cutter path 25 is edited so that the slot cutter 12 is not pulled up within the boundary line 21 with respect to the generated cutter path 25. (S3a) (Cutter path editing process)
Note that, depending on the CAM, if the boundary line 21 is defined, the creation area of the cutter path 25 is automatically calculated, and the cutter path 25 is generated so that the tool (slot cutter 12) is not pulled up in the creation area. Is also present.
[0034]
Thus, according to the slot cutter 12 using conventional Sofutoue A may create an undercut machining possible machining cutter path 25.
[0035]
The edited (or generated) cutter path 25 for processing is output to a processing device (not shown) (S4), thereby performing predetermined processing on the undercut portion.
[0036]
By these procedures, it is possible to easily process a workpiece requiring undercut using a special tool such as the slot cutter 12.
[0037]
As described above, according to the above-described embodiment, even when a complex shape is machined on both surfaces of the workpiece by the rotary tool, vibration of the workpiece during machining can be prevented. Therefore, high-precision processing can be performed.
[0038]
【The invention's effect】
ADVANTAGE OF THE INVENTION According to this invention, the process of the complicated shape where the quality of a process surface is favorable and dimensional accuracy is favorable can be performed.
[Brief description of the drawings]
FIG. 1 is a perspective view of a mockup.
FIG. 2 is a perspective view of an integrated object.
FIGS. 3A to 3D are schematic views showing the main parts of the processing steps of the present invention.
4A is an external view of a special tool, and FIG. 4B is an explanatory diagram at the time of processing.
FIG. 5 is a flowchart showing a procedure for calculating a cutter path according to the present invention.
FIGS. 6A to 6C are explanatory views showing a design model for calculating a cutter path when processing an undercut portion. FIGS.
FIGS. 7A to 7C are schematic views showing a main part of a conventional processing step.
FIG. 8 is an explanatory diagram of an undercut portion.
[Explanation of symbols]
1 ... mockup, 1a ... body, 2 ... leg, 3 ... workpiece, 7 ... rotary tool, 8 ... frame, 8a ... wall surface, 9 ... support, 11 ... sub-support, 12 ... slot cutter (special tools , 13 ... Cutting edge, 14 ... Escape amount, 15 ... Depth of undercut part , 16 ... Height of undercut part , 22 ... Interference boundary region, 23 ... Virtual body.

Claims (4)

A completed body having a three-dimensional shape having an opening, a plurality of supports extending outward from the outer wall surface of the three-dimensional shape of the completed body, and a jig formed on the tip of each support by a jig of a processing device It is a processing method by a rotary tool that forms an integrated object composed of a frame to be held and fixed by cutting out from a workpiece with the rotary tool of the processing device ,
A portion of the workpiece to be a frame is held and fixed at both ends, and one side of a plurality of supports connected to the frame is formed on the inner surface of the solid shape with respect to the workpiece, and the support and support During the formation of the inside of the solid body of the finished body, to support a load from the rotary tool, and the inside of the solid body having an opening of the finished body of the workpiece A first surface processing step of forming a comb-like sub-support extending to a tip of the frame that is flush with the holding and fixing surface of the frame ;
After the first surface processing step, the workpiece subjected to the first surface processing step is removed from the processing apparatus, and the other surface of the frame is placed in the state where the front and back sides of the workpiece are reversed. machining device is held fixed, the form the other surface of the plurality of support for continuous and the other surface of the frame of the workpiece, further between the support and support, is the other surface of the finished body A processing method using a rotary tool , comprising: a second surface processing step of forming the outer surface of the three-dimensional shape while supporting a load from the rotary tool with the plurality of sub-supports .   The processing method using a rotary tool according to claim 1, wherein the support forms a plurality. Surface facing the three-dimensional shape of the frame around the contact portion with the support, according to claim 1, wherein the frame is provided with a gradient that becomes thinner toward the end portion of the frame Machining method with a rotating tool.   The machining method using a rotary tool according to claim 3, wherein the gradient is 1 to 10 degrees.

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