JP3633504B2 - Casting product cast by mold formed using sampling model and vanishing model and casting method thereof - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a casting that is cast by a mold formed by using a sampling model such as a wooden mold and a disappearance model, and a casting method thereof.
[0002]
[Prior art]
For castings such as machining centers, NC machine tools, machine tool beds, work tables, etc., in general, for general-purpose products with a fixed shape, cast a mold with a wooden mold, and for special products that have a shape change. The mold was cast with a disappearance model made of foamed resin. In addition, several types of castings such as a bed for an NC-dedicated machine are prepared as standard specifications for the size of the lower base part, and the upper part changed according to the user's request to the lower base part selected by the user from the standard specifications We designed a bed with, and cast it into a mold made of wood for the bed.
[0003]
An oil pan for recovering chips, coolant, lubricating oil and the like is provided on the outer peripheral side surface of the upper portion of the bed so as to project outward in a bowl shape. This oil pan is installed in the mold so that the inner peripheral part protrudes into the casting space of the mold made of wood, and the inner peripheral part is cast and attached to the outer peripheral side of the upper part of the bed It was.
[0004]
Furthermore, since the bed upper surface on which the table is slidably mounted needs to be hardened and not worn, it has been hardened by induction hardening or the like.
[0005]
[Problems to be solved by the invention]
It is costly to cast a large casting such as a bed of a machine tool by casting a mold with a vanishing model one by one. In addition, it has been impossible to manufacture a bed model having a part that may be changed according to a user's request from the viewpoint of cost and storage of the wooden pattern. In addition, although the shape of the lower part of the bed has been determined, the upper part may actually be manufactured in a plurality of shapes to determine the optimum shape. Even in such a case, it is costly to mold a plurality of types of bed molds having different shapes only in the upper part using only a wooden pattern or a vanishing model.
[0006]
Casting the inner peripheral part of the oil pan that protrudes into the casting space of the mold made of wooden molds, and attaching the oil pan to the outer peripheral side of the upper part of the bed Since it is molded and the inner peripheral portion protrudes into the casting space and is easily oxidized, defective welding and peeling partially occur, causing coolant leakage and oil leakage. In order to improve the adhesion, it is expensive to plate a metal with good compatibility such as nickel on the inner peripheral portion of the oil pan. Dividing the oil pan into multiple parts, bolting to the outer peripheral side of the upper part of the bed, and filling the joint with putty to prevent coolant leaks and oil leaks can complicate operations and increase costs. there were. In addition, induction hardening of the portion on which the table is placed has a problem of requiring time and cost.
[0007]
The present invention was made in order to solve such conventional problems, in which the casting space is formed with a sampling model for a part for which the specification of the casting is determined, and the uncertain part with a specification change is a disappearance model. It is to make a mold.
[0008]
[Means for Solving the Problems]
In order to solve the above-mentioned problem, the structural feature of the invention described in claim 1 is that, with respect to a definite part where the specification of the casting is fixed, a casting space is formed using a sampling model, and the fixed part is connected to the fixed part. For unconfirmed parts that are connected at the part and that have a specification change, an erasure model with a shape corresponding to the unconfirmed part is placed in a mold that is placed and placed so that the end part appears in the casting space at the connected part It is a casting that is cast and cast.
[0009]
The structural feature of the invention according to claim 2 is that, with respect to a definite part where the specification of the casting is fixed, a casting space is formed using a sampling model, and the specification part is connected to the fixed part and the specification is not changed. For the definite part, the disappearance model of the shape corresponding to the undetermined part is placed and molded so that the end part appears in the casting space at the joint part, and a mold is formed, and the mold is cast into the mold. The casting is cast.
[0010]
The structural feature of the invention according to claim 3 is that there is a specification change for a general-purpose part of a casting forming a machine tool by forming a casting space using a sampling model and connecting the general-purpose part and the connection part. For the dedicated part, the disappearance model of the shape corresponding to the dedicated part is placed and molded so that the end part appears in the casting space at the connection part, and a mold is formed, and the mold is cast into the mold. It is to cast a casting.
[0011]
The structural feature of the invention according to claim 4 is the casting method using the sampling model and the disappearance model according to claim 2 or claim 3, wherein the disappearance model is formed of a dissimilar metal material different from the casting. Inserting a part of the forming member and casting a part of the forming member.
[0012]
The structural feature of the invention according to claim 5 corresponds to a desired surface portion of the casting desired to be hardened in the casting method using the sampling model and the disappearance model according to any one of claims 2 to 4. Applying a chilling agent to the surface portion of the disappearance model to cast a gray cast iron casting in which the desired surface portion is cured.
[0013]
The constitutional feature of the invention according to claim 6 is the desired surface to change the mechanical properties of the casting in the casting method using the sampling model and the disappearance model according to any one of claims 2 to 4. A casting of a foreign material having a mechanical property different from that of the metal material of the casting is adhered to the surface portion of the disappearance model corresponding to the portion, and the casting of the foreign material is dispersed on the desired surface portion. That is.
[0014]
[Operation and effect of the invention]
In the invention according to claim 1 configured as described above, with respect to the fixed part where the specifications of the casting are fixed, a casting space is formed using a sampling model, and the fixed part and the connecting part are connected to change the specification. Because the uncertain site is a casting that is cast by casting into a mold that is placed and placed so that the end portion of the disappearance model corresponding to the uncertain site appears in the casting space at the connection site For the confirmed part, many molds are made with a sampling model such as a wooden mold to reduce the cost per piece. For the unconfirmed part, the specification change due to the user's request or design change by using the disappearance model Can respond quickly.
[0015]
In the invention according to claim 2 configured as described above, with respect to the fixed part where the specifications of the casting are fixed, a casting space is formed using a sampling model, and the fixed part and the connecting part are connected to change the specification. For the undefined part, place the disappearance model of the shape corresponding to the uncertain part so that the end part appears in the casting space at the connection part, mold it and mold it, cast it into the mold Since castings are cast, a large number of molds are made with a sampling model such as a wooden mold for the confirmed part to reduce the cost per piece. It can quickly respond to specification changes due to design changes, etc., and can cast many types of castings in a short time at low cost. In addition, it is possible to reduce the management cost for storing models by minimizing the types of sampling models such as wooden molds.
[0016]
In the invention according to claim 3 configured as described above, for the general-purpose part of the casting constituting the machine tool, a casting space is formed using a sampling model, and the shape is changed by connecting the general-purpose part and the connection part. For a dedicated part, the disappearance model of the shape corresponding to the dedicated part is arranged so that the end part appears in the casting space at the connecting part, and the mold is cast and cast into the mold. Since castings were made, for general-purpose parts that are standard dimensions of machine tools, many molds were made with sampling models such as wooden molds to reduce the cost per piece, and dedicated parts disappeared By using the model, it is possible to easily and quickly respond to the user's request or the specification change due to the design change, etc., and it is possible to cast many kinds of workpieces in a short time and at a low cost. In addition, it is possible to reduce the management cost for storing models by minimizing the types of sampling models such as wooden molds.
[0017]
In the invention according to claim 4 configured as described above, a part of the forming member formed of a different metal material different from the casting is inserted into the disappearing model to form the disappearing mold, and a part of the forming member In addition to the effects of the invention described in claim 2 or claim 3, it is possible to easily cope with a change in the mounting position of the forming member of the dissimilar metal material due to a user request or a design change. I can do it. In addition, a part of the forming member is inserted into the disappearing model and the contact with air is cut off and oxidation is prevented, so that a part of the forming member is cast into the casting without causing poor welding and peeling. .
[0018]
In the invention according to claim 5 configured as described above, the desired surface portion is cured by applying a chilling agent to the surface portion of the vanishing model corresponding to the desired surface portion of the gray cast iron casting to be cured. Therefore, in addition to the effects of the invention described in claim 2 or claim 3, it is possible to easily cope with a change in the position of the surface portion of the casting desired to be hardened due to a user request or a design change.
[0019]
In the invention according to claim 6 configured as described above, the dissimilar material having a mechanical property different from that of the metal material of the casting is formed on the surface portion of the disappearance model corresponding to the desired surface portion where the mechanical property of the casting is to be changed. In addition to the effects of the invention according to claim 2 or 3, in addition to the effect of the invention according to claim 2, the powder of a different material is dispersed on the desired surface portion to change the mechanical properties of the surface portion. Even if the position of the surface portion where the mechanical properties of the casting are to be changed is changed due to the requirement or design change, it can be easily handled.
[0020]
[Embodiment]
DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, a first embodiment of the invention will be described with reference to the drawings. In FIG. 1, reference numeral 11 denotes an NC dedicated machine, which is an integral casting 15 in which a table guide portion 13 that is an upper portion is connected to a base portion 12 that is a lower portion by a connecting portion 14. The bed 11 is prepared with several types of dimensions of the base portion 12 as standard specifications. The table guide portion 13 having a dimension and shape suitable for the application is placed at a desired arrangement position on the base portion 12 having specifications selected by the user from the standard specifications. The specifications are provided. That is, the base portion 12 is a fixed portion where the shape of the bed 11 is fixed, in other words, a general-purpose portion, and the table guide portion 13 is connected to the fixed portion and the connecting portion 14, and the shape and arrangement according to the user's request or design change, etc. It is an undetermined part whose specifications such as position are changed, in other words, a dedicated part.
[0021]
For the base part 12 whose specification has been determined, a casting space is formed using a sampling model such as a wooden mold, and for the table guide part 13 whose specification has not yet been determined, a disappearance model having a shape corresponding to the table guide part 13 is used. The bed 11 is cast by casting in a mold that is arranged and molded so that the end portion appears in the casting space at the connecting portion 14. Reference numeral 16 denotes a bowl-shaped oil pan for collecting chips, coolant, lubricating oil, and the like, and its inner peripheral surface is cast on the outer peripheral side surface of the table guide portion 13 and protrudes outward.
[0022]
When developing new models for general-purpose machine tools such as NC general-purpose machines and machining centers, the shape of some parts of cast components such as beds, pallet changers, and tables are determined at the design stage, but other parts In some cases, it is not possible to determine specifications such as the optimum shape and arrangement position without actually making a prototype and testing it in a plurality of shapes and arrangement positions. A second embodiment in which the present invention is applied to such a casting will be described. In FIG. 2, reference numeral 21 denotes an NC general-purpose machine table, which is an integral casting 25 in which a rotary table support portion 23, which is another part, is connected at a connecting part 24 on a slide part 22 that is a partial position. The slide portion 21 can be determined at the design stage to have the same shape and dimension as the slide portion of a similar table from past results. Various tables 21 integrally formed on the slide portion 21 with the pair of rotary table support portions 23 being changed in shape and pitch are designed and prototyped, and an optimum specification is determined. In this case, the slide part 22 is a fixed part where the specification of the table 21 is fixed, and the pair of rotary table support parts 23 are connected to the fixed part and the connecting part 24, and the specification is changed by a design change or the like. is there.
[0023]
For the slide part 22 whose specification has been determined, a casting space is formed using a sampling model such as a wooden mold, and for the rotary table support part 23 whose specification has not been determined, a disappearance model having a shape corresponding to the rotary table support part 23 The table 21 is cast by casting it into a mold that has been placed and molded so that its end portion appears in the casting space at the connecting portion 24. 26 is a bowl-shaped oil pan for collecting chips, coolant, lubricating oil, and the like, and its inner peripheral surface is cast on the outer peripheral side surface of the rotary table support portion 23 and protrudes outward.
[0024]
A steel pipe 28 is cast in the center hole 27 of each rotary table support portion 23, and the inner peripheral surface is quenched after casting. The rotary table 20 is rotatably supported by a cross roller bearing on the upper surface of the rotary table support portion 23, and the engaging portion of the clamp device that fixes the rotary table 20 in the index position is engaged with and disengaged from the inner peripheral surface of the steel pipe 28. It is like that.
[0025]
In addition, the present invention is not limited to the component parts of machine tools, and is not limited to the components of machine tools, as long as it is a casting having a fixed part with a fixed specification and an unfixed part connected with the fixed part and the connected part. The present invention can be applied to a casting that is a component or a single unit.
[0026]
Next, the case where the bed 11 which is the casting 15 of the first embodiment is cast by the casting method using the mold formed using the sampling model and the disappearance model according to the present invention based on FIGS. explain. For the base part 12 which is a fixed part where the shape of the bed 11 is fixed, a sampling model such as a wooden mold for the base part 12 is placed in the lower mold frame 29 and molded, and then the model is released and cast. The lower mold 33 in which the space 32 is formed is formed (step 51). For the table guide part 13 that is connected to the base part 12 at the connection part 14 and is an uncertain part having a shape change, a disappearance model 34 having a shape corresponding to the table guide part 13 is manufactured with a foaming resin or the like. 34 is placed at a predetermined position of the upper mold frame 30 and molded, and the upper mold 35 is formed (step 52). As the resin, polystyrene, polymethyl methacrylate, or the like is used. In the vanishing model 34, an inner peripheral portion of an oil pan 16 as a forming member formed of a steel plate made of a different metal material different from the bed 12 is inserted.
[0027]
As shown in FIG. 4, the lower mold 33 and the upper mold 35 are matched with each other to create a mold 36 (step 53). When the lower mold 33 and the upper mold 35 are matched with each other, the vanishing model 34 is arranged so that the end of the vanishing model 34 appears in the casting space 32 at a position corresponding to the connecting portion 14. When molten molten iron, which is cast iron, is cast through the gate 37 and the runner 38 provided in the mold 36, the molten metal is filled in the casting space 32 to form the base portion 12, and the resin disappearance model 34 burns. Then, the molten metal is replaced and flows into the space to form the table guide portion 13 (step 54). In the middle of the replacement of the molten metal with the disappearance model 34, the inner peripheral portion inserted into the disappearance model 34 of the oil pan 16 is cast into the molten metal, and the oil pan 16 projects outwardly on the outer peripheral side surface of the table guide portion 13. Attached. Since the inner peripheral part of the oil pan 16 is inserted into the vanishing model 34 and contact with air is cut off and cast without oxidization, poor welding and peeling between the table guide 13 and the oil pan inner peripheral part. Will not occur. The casting mold 15 of the bed 12 is taken out from the casting mold 36 (step 55), and a necessary portion is machined (step 56) to create the bed 12.
[0028]
When the upper surface portion 19 of the table guide portion 13 is to be chilled and hardened, gray cast iron is used as cast iron, and a chilling agent is applied to the surface portion 39 of the disappearance model 34 corresponding to the upper surface portion 19 of the table guide portion 13 to be hardened. Then, the upper surface portion is cured. For this purpose, first, as shown in FIG. 5, a solution of a chilling agent containing tellurium (Te) as a main component is prepared (step 61). As the chilling agent, for example, commercially available tellurite 150 (trade name) is used. The solution is prepared by diluting tellurite 150 with water and diluting tellurite 150 to water weight ratio 4: 1 to 1: 1, preferably 3: 1 in terms of flowability and concentration. In addition, the component of tellurite 150 is a weight%, Silica aggregate: 40-50%, Metal tellurium: 14-16%, Organic binder: 2% or less, Inorganic binder: 3% or less, Additive: Trace amount, moisture: remaining. A chilling agent is applied to the surface portion 39 of the disappearance model 34 corresponding to the upper surface portion of the table guide portion 13 to be hardened (step 62). Therefore, the chilling agent solution is applied to the corresponding surface portion 39 of the disappearance model 34 with a brush and dried. A sufficient amount of the chilling agent can be applied to the surface portion 39 by repeating the application and drying of the chilling agent solution about three times.
[0029]
A coating agent is applied to the entire surface of the disappearance model 34 in which the chilling agent is applied to the surface portion 39 (step 63), and the disappearance model 34 to which the coating agent is applied is placed in the upper mold frame 30. The upper mold 35 is formed by molding. When the molten cast iron is cast into the mold 36 in which the upper mold 35 and the lower mold 33 are combined, the chilling agent applied to the corresponding surface portion 39 of the disappearance model 34 comes into contact with the molten cast iron. Then, the upper surface portion 39 of the table guide portion 13 is chilled and cured.
[0030]
In order to change mechanical properties such as increasing the wear resistance of the desired surface portion of the casting 15, a method of dispersing powder of a different material different from the metal material of the casting 15 in the desired surface portion will be described. A case where the wear resistance of the upper surface portion 19 which is a desired surface portion is increased will be described. As shown in FIG. 6, a gel-like dissimilar material made of a plurality of dissimilar materials having different mechanical properties from the metal material of the molten metal is created (step 65). For example, different materials that increase wear resistance include tungsten compounds such as tungsten (W) and tungsten carbide (WC), titanium nitride (TiN), silicon carbide (SiC), and aluminum oxide (Al2O2) as high-hardness materials. is there. Examples of the hardness adjusting material used for adjusting the hardness of the high-hardness material include iron-based compounds such as cobalt (Co) and cast iron stainless steel, nickel (Ni), and copper (Cu). As the high hardness material and the hardness adjusting material, a powder having a particle size of several μ to 0.1 mm is suitable. As the binder for gelling the powders of a plurality of different kinds of materials, a starch paste that gasifies or carbonizes quickly during casting is suitable. These powders of high hardness material and hardness adjusting material are mixed at a ratio so as to obtain the desired hardness, and are mixed with starch paste to form a gel. For example, a tungsten material as an abrasion resistant material is added with an arbitrary amount of cobalt powder to adjust the abrasion resistance, and a dissimilar material gelled with starch paste is appropriately thickened on the corresponding surface portion 39 of the disappearance model 34. (Step 66). The disappearance model 34 coated with the gelled dissimilar material is put in the upper mold frame 30 and molded, and the upper mold 35 is formed. When, for example, molten flake graphite cast iron (FC300) is cast into the mold 36 in which the upper mold 35 and the lower mold 33 are combined, the dissimilar material applied to the corresponding surface portion 39 of the vanishing model 34 is removed from the table guide. The tungsten powder of the dissimilar material dispersed in the upper surface portion 19 of 16 is chemically bonded to carbon (C), phosphorus (P), manganese (Mn), etc. contained in flake graphite cast iron, and tungsten carbide (WC) is Fine segregation as a main component is formed, and the wear resistance of the upper surface portion 19 of the table guide portion 13 is improved.
[0031]
Next, a method for casting the casting 25 of the second embodiment will be described based on the mold 50 shown in FIG. A wooden mold having the same outer shape as the outer peripheral surface shape of the slide portion 22 which is a specification-determining portion of the table 21 which is a casting 25 is mounted on the model surface plate with the rotary table support portion 23 side up, and a lower mold casting frame. 40.
[0032]
A pair of disappearance models 42 having a shape corresponding to the rotary table support portion 23 which is an unspecified part is made of a foaming resin or the like. Each vanishing model 42 is formed with a stepped hole 43 having a small diameter equal to the inner diameter of the steel pipe 28 and a large diameter equal to the outer diameter at the shaft center, and the steel pipe 28 is fitted to the shoulder of the stepped hole 43, Between the opening end of the large-diameter hole of the stepped hole 43 and the end surface of the steel pipe 28, a ring 44 made of foamed resin having the same inner and outer diameter as the steel pipe 28 is fixed. The pair of vanishing models 42 are fitted into holes formed in a predetermined position at a predetermined pitch in a dish-shaped oil pan 45, and the fitting portions are filled with an adhesive 46 for foamed resin without any gaps. The pair of vanishing models 42 to which the oil pan 45 is attached are positioned and placed on a wooden mold having the same outer shape as the outer peripheral surface shape of the slide portion 22, and the lower mold is released from the wooden mold. 47 is formed (step 51).
[0033]
A mold such as a sprue and a runner is placed in the upper mold frame 41, and the upper mold 49 is formed (step 52). A core 48 having the same outer shape as the inner peripheral surface shape of the slide portion 22 is fixed to the lower surface of the upper die 49, and the lower die 47 and the upper die 49 are combined with each other to produce the mold 50 (step 53). When the lower mold 47 and the upper mold 49 are combined, the inner peripheral surface of the space formed by the wooden mold having the same outer shape as the outer peripheral surface shape of the slide portion 22 of the lower mold 47 and the outer peripheral surface of the core 48 A casting space 58 is formed between them, and the end portion of the disappearance model 41 appears in the casting space 58 at a position corresponding to the connecting portion 24.
[0034]
When molten molten iron, which is cast iron, is cast into the mold 50 from the gate and runner, the molten metal is filled into the casting space 58 to form the slide portion 22, and the resin disappearance model 42 burns and disappears. The molten metal is exchanged and flows into the rotary table support portion 23 (step 54). In the middle of the replacement of the molten metal with the disappearance model 42, the adhesive 46 for the foaming resin that fixes the oil pan 45 to the disappearance model 42 is replaced with the molten metal, and the inner peripheral portion of the hole of the oil pan 45 is cast into the molten metal. Is integrally attached to the outer peripheral side surface of the rotary table support 23 so as to protrude outward. A steel pipe 28 is also cast in the center hole 27 of the rotary table support 23. Thereafter, the casting mold 25 is taken out and the casting 25 is taken out from the casting mold 50 (step 55), and a necessary portion is machined (step 56) to create the table 22.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing a bed of a machine tool.
FIG. 2 is a cross-sectional view showing a table.
FIG. 3 is a diagram showing a process of a casting method using a sampling model and a lost mold according to the present invention.
FIG. 4 is a cross-sectional view showing a bed mold.
FIG. 5 is a diagram showing a process of chilling a desired surface portion of a casting.
FIG. 6 shows the steps of a method for dispersing a powder of a different material on a desired surface portion in order to change the mechanical properties of the desired surface portion of the casting.
FIG. 7 is a cross-sectional view showing a table mold.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 11 ... Bed, 12 ... Base part (specification determined part), 13 ... Table guide part (specification undefined part), 14, 24 ... Connection part, 15, 25 ... Casting, 16 , 26 ... oil pan, 21 ... table, 22 slide part (specification determined part), 23 ... rotary table support part (specification unconfirmed part), 28 ... steel pipe, 29, 40 ... Lower mold casting frame, 30, 41 ... Upper mold casting frame, 32, 58 ... Casting space, 33, 47 ... Lower mold, 34, 42 ... Disappearing model, 35, 49 ... -Upper mold, 36, 50 ... mold, 48 ... core.

Claims (6)

For the confirmed part for which the specifications of the casting are confirmed, a casting space is formed using a sampling model, and for the uncertain part that is connected with the confirmed part and the connected part and has a specification change, the shape corresponding to the uncertain part A casting obtained by casting a casting model into a cast mold in which the end portion is arranged so that the end portion appears in the casting space at the connecting portion. For the confirmed part for which the specifications of the casting are confirmed, a casting space is formed using a sampling model, and for the uncertain part that is connected with the confirmed part and the connected part and has a specification change, the shape corresponding to the uncertain part The extraction model is characterized in that the disappearance model is arranged and molded so that the end portion appears in the casting space at the connecting portion, and a mold is formed, and the casting is cast by casting into the mold. And casting method using disappearance model. For general-purpose parts of castings constituting the machine tool, a casting space is formed using a sampling model, and for a special part that is connected with the general-purpose part and the connection part and has a specification change, a shape corresponding to the special part is formed. An extraction model characterized in that an extinguishment model is placed and molded so that an end portion appears in the casting space at the connection site, a mold is formed, and the casting is cast by casting into the mold. Casting method using disappearance model. 4. The casting method using the sampling model and the disappearance model according to claim 2 or 3, wherein a part of a forming member formed of a different metal material different from the casting is inserted into the disappearing model, and the forming member is inserted. A casting method using a sampling model and a disappearing model, wherein a part of the casting is cast. The casting method using the sampling model and the disappearance model according to any one of claims 2 to 4, wherein a chilling agent is applied to a surface portion of the disappearance model corresponding to a desired surface portion of the casting to be cured. A casting method using a sampling model and a vanishing model, characterized by casting a cast product of gray cast iron in which the desired surface portion is hardened. 5. The casting method using the sampling model and the disappearance model according to claim 2, wherein the casting is formed on a surface portion of the disappearance model corresponding to a desired surface portion where the mechanical properties of the casting are to be changed. Using a sampling model and a disappearance model characterized in that a powder of a different material having a mechanical property different from that of the metal material is adhered, the powder of the different material is dispersed on the desired surface portion, and the casting is cast. Casting method.

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