Method for manufacturing additional machining member

Abstract

To suppress cracks in an additional machining member formed by performing additional machining on a member through directional energy deposition.SOLUTION: This method for manufacturing the additional machining member comprises: a first lamination step of supplying, onto a member 21, a first material 2211 having hardness or a linear expansion coefficient higher than that of the member, melting the first material through irradiation with a laser 181, and laminating a first layer 221 on the member; and a second lamination step of supplying, onto the first layer, a second material 2221 having hardness or a linear expansion coefficient higher than that of the first material, melting the second material 2221 through irradiation with the laser 181, and laminating a second layer 222 on the first layer.SELECTED DRAWING: Figure 5

Description

Technical Field

[0001] The present invention relates to a method for manufacturing an additional processing member.

Background Art

[0002] As a means for suppressing tool cracking, it is known to use a composite material composed of multiple layers. Such a composite material is disclosed in, for example, Patent Document 1.

[0003] Patent Document 1 discloses a composite member composed of multiple layers with different mixing ratios of ceramic powder and metal. The multiple layers are formed by alternately laminating a high-hardness layer with high hardness and a low-hardness layer with low hardness. By applying such a composite member to a mold, a tool having a predetermined shape is formed. According to this tool, even if cracks occur in the high-hardness layer, the progression of cracks is suppressed in the low-hardness layer.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] Patent Document 1 gives the directed energy deposition method as an example of a method for forming the high-hardness layer and the low-hardness layer. In the directed energy deposition method, material powder is melted by a laser to form a layer composed of the material powder. In Patent Document 1, a composite member having a high-hardness layer and a low-hardness layer formed by the directed energy deposition method is used as a material for a tool. On the other hand, the directed energy deposition method is also used for additional processing to form an additional processing layer with a predetermined thickness and shape on the surface of a member that serves as the base of the tool.

[0006] In an additive member to which additive working has been performed, the additive working layer may wear over time. In this case, after removing the old additive working layer, a new additive working layer may be laminated on the member to repair the worn additive working layer. Here, in the directed energy deposition method, when laminating the additive working layer on the member, the member and the material powder are melted by a laser. Due to the heat of this laser, the material of the member may change and the member may harden. In an additive member used for a tool, a high-hardness material is used for the additive working layer. In such a case, in an additive member in which the additive working layer is repaired by the directed energy deposition method, a hard additive working layer is provided on the surface of the hardened member. Generally, a high-hardness material has low toughness and is difficult to expand and contract. As a result, when cooling the repaired additive member, a difference may occur between the thermal contraction amount of the member and the thermal contraction amount of the additive working layer, which may cause cracks or deformation in the additive working layer.

[0007] An object of the present invention is to suppress cracking of an additive member formed by performing additive working on a member by a directed energy deposition method.

Means for Solving the Problem

[0008] The method for manufacturing an additive member of the present invention comprises: a first lamination step of supplying a first material having a higher hardness or linear expansion coefficient than the member onto the member, melting the first material by irradiating with a laser, and laminating a first layer on the member; a second lamination step of supplying a second material having a higher hardness or linear expansion coefficient than the first material onto the first layer, melting the second material by irradiating with a laser, and laminating a second layer on the first layer.

[0009] In the manufacturing method of the above-mentioned additional processing member, a first layer having a hardness or a linear expansion coefficient intermediate between the member and the second layer composed of the second material is provided between the member and the second layer. The first layer absorbs the difference in thermal shrinkage between the member and the second layer when the member is cooled after the first layer and the second layer are laminated on the member. Therefore, according to the manufacturing method of the above-mentioned additional processing member, cracking of the additional processing member formed by performing additional processing on the member by the directed energy deposition method can be suppressed.

Advantages of the Invention

[0010] According to the manufacturing method of the additional processing member of the present invention, cracking of the additional processing member formed by performing additional processing on the member by the directed energy deposition method can be suppressed.

Brief Description of the Drawings

[0011]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Embodiments for Carrying Out the Invention

[0012] Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[0013] <Machine Tool> FIG. 1 is a schematic view of a machine tool used in a method for manufacturing an additional processing member. Referring to (A) in the figure, the machine tool 1 is an AM / SM hybrid machine tool capable of performing additional processing (AM) and removal processing (SM) of a member. The machine tool 1 has, as a function of SM processing, a turning function using a fixed tool and a milling function using a rotary tool. The machine tool 1 is an NC (Numerically Control) machine tool in which various operations for processing a member are automated by numerical control by a computer. In this specification, an axis parallel to the left-right direction (width direction) of the machine tool 1 and extending in the horizontal direction is referred to as the "Z axis", an axis parallel to the front-rear direction (depth direction) and extending in the horizontal direction is referred to as the "Y axis", and an axis extending in the vertical direction is referred to as the "X axis".

[0014] The machine tool 1 includes a bed 11, a first spindle headstock 12, a second spindle headstock 13, and a tool spindle 14.

[0015] The bed 11 is a base for supporting the first spindle headstock 12, the second spindle headstock 13, and the tool spindle 14. The bed 11 is installed on the floor surface of a factory or the like. The first spindle headstock 12, the second spindle headstock 13, and the tool spindle 14 are provided in a machining area partitioned by a splash guard. The machining area is sealed.

[0016] The first spindle headstock 12 and the second spindle headstock 13 are provided facing each other in the Z-axis direction. The first spindle headstock 12 includes a first work spindle 121 for holding and rotating the member 21. The first work spindle 121 is rotatably provided about a central axis A121 parallel to the Z axis. Similarly, the second spindle headstock 13 includes a second work spindle 131 for holding and rotating the member 21. The second spindle headstock 13 is provided so as to be movable in the Z-axis direction by various feed mechanisms, guide mechanisms, motors, and the like. The second work spindle 131 is rotatably provided about a central axis A131 parallel to the Z axis. The central axis A121 and the central axis A131 are located on the same straight line. Chucks for detachably gripping the member 21 are provided on the first work spindle 121 and the second work spindle 131, respectively.

[0017] The member 21 has a cylindrical shape. However, the shape of the member 21 is not particularly limited. The member 21 may have a solid structure or a hollow structure. The member 21, when attached to the first workpiece spindle 121 and the second workpiece spindle 131, has a central axis that coincides with the extension line of the central axis A121 (A131) of the first workpiece spindle 121. One end of the member 21 in the central axis direction is gripped by the chuck of the first workpiece spindle 121, and the other end is gripped by the chuck of the second workpiece spindle 131. The first workpiece spindle 121 and the second workpiece spindle 131 rotate synchronously with each other, causing the member 21 to rotate around the central axis A121 (A131).

[0018] The tool spindle 14 is configured to be rotatable about a central axis included in the X - Z plane of the attached tool. The tool spindle 14 is supported on the bed 11 by a column or the like (not shown). The tool spindle 14 is provided to be movable in the X - axis direction, Y - axis direction, and Z - axis direction by various feed mechanisms, guide mechanisms, motors, etc. provided on the column or the like. With such a configuration, the tool spindle 14 moves three - dimensionally. The tool spindle 14 is further provided to be rotatable about a turning central axis parallel to the Y - axis (B - axis turning).

[0019] The machine tool 1 further includes an additional processing head 15. The additional processing head 15 supplies material to the member 21 and irradiates it with a laser. That is, the additional processing head 15 performs additional processing on the member 21 by the directed energy deposition method.

[0020] The additional processing head 15 is configured to be detachable from the tool spindle 14. When the tool spindle 14 moves in the X - axis direction, Y - axis direction, and Z - axis direction, the additional processing head 15 also moves in the X - axis direction, Y - axis direction, and Z - axis direction. Further, when the tool spindle 14 turns around the turning central axis (B - axis), the additional processing head 15 also turns around the B - axis integrally with the tool spindle 14.

[0021] The machine tool 1 further includes a control device 16. The control device 16 controls the machine tool 1. The control device 16 is composed of a computer including a CPU, a RAM, a ROM, etc. The control device 16 controls the operations of each part of the machine tool 1 by executing a computer program stored in a recording medium.

[0022] Referring to (B) in the figure, the machine tool 1 further includes a powder feeder 17, a laser oscillator 18, and a cable 19.

[0023] The powder feeder 17 supplies the material powder used for additive processing to the processing position. Although not shown, the powder feeder 17 includes a powder hopper and a mixing section. The powder hopper forms a sealed space for accommodating the material powder used for additive processing. The mixing section mixes the material powder accommodated in the powder hopper and the gas for the carrier of the material. In this embodiment, the case where the material is in powder form is described, but the material may be in wire form.

[0024] The laser oscillator 18 oscillates a laser 181 used for additive processing. The cable 19 is composed of an optical fiber for guiding the laser from the laser oscillator 18 to the additive processing head 15, a pipe for guiding the material powder from the powder feeder 17 to the additive processing head 15, an air pipe serving as an air flow path, a gas pipe serving as an inert gas flow path, a cooling pipe serving as a refrigerant flow path, electrical wiring, and a pipe member for accommodating these.

[0025] <Method for manufacturing an additive processing member> Subsequently, the method for manufacturing an additive processing member according to this embodiment will be described. In this embodiment, the case of repairing the additive processing layer of a die cutter by the method for manufacturing an additive processing member will be described.

[0026] FIG. 2 is a flowchart of a method for manufacturing an additional processing member. The method for manufacturing the additional processing member includes, in the order of execution, a removal step S11, a first lamination step S12, a second lamination step S13, and a cooling step S14. Each step (process) is executed by the control device executing various programs.

[0027] FIG. 3 is a diagram for explaining the removal step. In the figure, (A) is a schematic diagram of the configuration of the die cut roll. In the removal step S11, the additional processing layer 20 previously applied to the member 21 is removed. Specifically, first, a cutter 2 is prepared. The cutter 2 constitutes a die cut roll together with the opposing anvil roll 3. The cutter 2 is configured such that an additional processing layer 20 is provided on the surface of a member 21 having a cylindrical shape. The additional processing layer 20 includes a blade portion 201 and a sliding portion 202. The blade portion 201 constitutes the blade of the cutter 2. In the figure, the case where the blade portion 201 has a square shape is shown, but the shape of the blade portion 201 is not particularly limited. The blade portion 201 has a shape corresponding to the shape of the product to be processed by the cutter. The sliding portion 202 is provided at both ends of the member 21. The sliding portion 202 is pressed against the anvil roll 3 and slides with the anvil roll 3 as the cutter 2 rotates.

[0028] In the figure, (B) is a cross-sectional view of a part of the cutter cut along a plane including the central axis of the cutter. In the present embodiment, the previously provided additional processing layer 20 is made of high-speed steel. The additional processing layer 20 is made of the same material as the second layer described later. However, the material of the additional processing layer 20 is not particularly limited. The additional processing layer 20 may be made of a material different from that of the second layer. The method of previously attaching the additional processing layer 20 to the member 21 is not particularly limited. The additional processing layer 20 may be formed, for example, by a directed energy deposition method, or may be formed by a method other than the directed energy deposition method. The additional processing layer 20 may be formed by cutting a layer formed by, for example, a powder bed method.

[0029] The sliding part 202 of the cutter wears over time. When the wear amount of the sliding part 202 exceeds a predetermined value, repair of the sliding part 202 becomes necessary. Therefore, in the removal step S11, the sliding part 202 of the cutter is removed by, for example, cutting or grinding. When the removal step S11 is completed, the surface of the member 21 is exposed at the portion where the sliding part 202 was provided. The material of the member 21 is not particularly limited. The member 21 is, for example, steel. More specifically, the member 21 is, for example, carbon steel. The structure of the member 21 changes by heat treatment. The hardness or coefficient of linear expansion of the member 21 changes by heat treatment. In short, the member 21 is made of a material capable of phase transformation by heat treatment.

[0030] Figure 4 is a cross-sectional view for explaining the first lamination step. In the first lamination step S12, the first layer 221 is laminated on the member 21 by the directed energy deposition method. The first layer is provided at a position corresponding to the sliding part 202 of the cutter described above in the member 21. Specifically, referring to (A) in the figure, in the first lamination step S12, the powdered first material 2211 is supplied from the powder feeder 17 to the surface of the member 21 and irradiated with the laser 181. The laser 181 melts both the member 21 and the first material 2211. When the member 21 is irradiated with the laser 181, the member 21 melts and a melt pool 211 is formed on the surface of the member 21. The melted first material 2211 spreads so as to overlap the melt pool 211. As a result, referring to (B) in the figure, the first layer 221 made of the first material is laminated on the surface of the member 21.

[0031] The first material 2211 has a higher hardness or coefficient of linear expansion than the member 21. That is, the first layer 221 has a higher hardness or coefficient of linear expansion than the member 21. The hardness and coefficient of linear expansion of the member 21 referred to here are the hardness and coefficient of linear expansion before being irradiated with the laser. If this condition is satisfied, the first material 2211 is not particularly limited. The first material 2211 is, for example, stainless steel.

[0032] FIG. 5 is a diagram for explaining the second lamination process. In the second lamination process S13, the second layer 222 is laminated on the first layer 221 by a directed energy deposition method. The second layer 222 is provided at the position where the first layer 221 is provided, that is, at the position corresponding to the sliding portion 202 of the die cutter. The second layer 222 is provided on the outermost surface of the die cutter. That is, the second layer 222 substantially functions as the sliding portion of the die cutter.

[0033] Specifically, referring to (A) in the figure, while supplying the powdery second material 2221 from the powder feeder 17 to the surface of the laminated first layer 221, the laser 181 is irradiated. The laser 181 melts both the first layer 221 and the second material 2221. When the laser 181 is irradiated on the first layer 221, the first layer melts, and a melt pool 2212 is formed on the surface of the first layer. The melted second material 2221 spreads so as to overlap the melt pool 2212. As a result, referring to (B) in the figure, the second layer 222 made of the second material is laminated on the surface of the first layer 221.

[0034] The second material 2221 has a higher hardness or coefficient of linear expansion than the first material 2211. That is, the second layer 222 has a higher hardness or coefficient of linear expansion than the first layer 221. As long as this condition is satisfied, the second material 2221 is not particularly limited. The second material 2221 is, for example, high-speed steel. Preferably, the second material 2221 has a hardness of 600 Hv or more in terms of Vickers hardness.

[0035] In the cooling process S14, the member 21 on which the first layer 221 and the second layer 222 are laminated is cooled. The cooling method is not particularly limited. The cooling method may be natural cooling or may use a cooling medium. When the cooling process S14 is completed, an additional processed member in which the first layer 221 and the second layer 222 are laminated is manufactured on the member 21. That is, the previously provided additional processing layer 20 is replaced with a new additional processing layer 22, and the repair of the die cut roll is completed.

[0036] As described above, in the method for manufacturing the additional processing member of the present embodiment, a first layer 221 made of a first material is provided between the member 21 and a second layer 222 made of a second material. The first material has a hardness or a coefficient of linear expansion intermediate between those of the second material and the member. Therefore, the first layer 221 absorbs the difference between the amount of thermal shrinkage of the member 21 and the amount of thermal shrinkage of the second layer 222 in the cooling process. Accordingly, according to the method for manufacturing the additional processing member described above, cracking of the additional processing member formed by performing additional processing on the member by the directed energy deposition method can be suppressed.

[0037] In particular, the method for manufacturing the additional processing member described above is effective when using a member whose hardness or coefficient of linear expansion changes due to the heat of a laser. That is, when repairing the additional processing layer of a product (a die cutter in the above-described embodiment) using the directed energy deposition method, heat treatment may be performed on the member by the heat of the laser, and the hardness or coefficient of linear expansion of the member may change. For example, when the member is made of iron or an alloy mainly composed of iron, at least a part of the member may be quenched by the heat of the laser. In such a case, if the second layer is directly laminated on the surface of the member having a high hardness, a material having low toughness is provided on a material having low toughness. As a result, it becomes difficult for the member to absorb the amount of thermal shrinkage of the second layer having a high hardness, and the second layer is likely to crack. On the other hand, in the method for manufacturing the additional processing member described above, the first layer 221 is provided between the member 21 and the second layer 222, and absorbs the difference between the amount of thermal shrinkage of the member 21 and the amount of thermal shrinkage of the second layer 222. Therefore, the method for manufacturing the additional processing member described above is particularly effective when using a member 21 whose hardness or coefficient of linear expansion changes due to the heat of a laser.

[0038] The description of the above embodiment is illustrative in all respects and not restrictive. Modifications and changes are appropriately possible for those skilled in the art. The scope of the present invention is indicated not by the above embodiment but by the claims. Furthermore, the scope of the present invention includes modifications from the embodiments within the scope equivalent to the scope of the claims.

[0039] For example, in the above-described embodiment, the case where the product to be processed is a die cutter was described. However, the product is not limited to a die cutter. The product may be any product that laminates an additional processing layer on a member using a directed energy deposition method.

[0040] Also, in the above-described embodiment, the case of repairing the additional processing layer in a product in which the additional processing layer is laminated in advance was described. However, when laminating the additional processing layer on the member in advance, the manufacturing method of the additional processing member of the present invention may be applied. That is, when manufacturing a new product, the additional processing layer may be formed by the manufacturing method of the additional processing member of the present invention.

[0041] Also, in the above-described embodiment, the case where the first layer and the second layer are each one layer was described. However, a plurality of first layers may be laminated. A plurality of second layers may be laminated. By laminating a plurality of the first layer or the second layer, the thickness of the additional processing layer can be adjusted. The thicknesses of the first layer and the second layer may be appropriately set according to the specifications of the product.

[0042] When a plurality of the first layers are laminated, the plurality of first layers may each be composed of the same material or different materials. A part of the plurality of first layers may be composed of the same material. When a plurality of the first layers are laminated, the first layer laminated on the upper side in the lamination direction may have a higher hardness or coefficient of linear expansion. When a plurality of the first layers are laminated, the first layer closer to the second layer may have a higher hardness or coefficient of linear expansion. When a plurality of the first layers are laminated, the upper first layer laminated on the upper side in the lamination direction may have a hardness or coefficient of linear expansion equal to or higher than that of the lower first layer provided one below the upper first layer. When a plurality of the first layers are laminated, the uppermost first layer provided in the uppermost layer in the lamination direction may have a higher hardness or coefficient of linear expansion than the lowermost first layer provided in the lowermost layer.

[0043] In the above-described embodiment, the case where the manufacturing method of the additional processing member includes a removal step and a cooling step has been described. However, the manufacturing method of the additional processing member may not include these steps. That is, the manufacturing method of the additional processing member of the present invention may be applied to a member on which the additional processing layer is not laminated in advance. Further, the manufacturing method of the additional processing member of the present invention may be applied to a member from which the additional processing layer laminated in advance at another location has been removed. Further, in the case of a product that does not require forced cooling, the cooling step may be omitted. Furthermore, the manufacturing method of the additional processing member may include other steps in addition to the first lamination step and the second lamination step. The other steps are a surface treatment step, a grinding step, and the like.

[0044] In the above-described embodiment, the case where the second layer is provided on the outermost surface of the additional processing member has been described. However, the second layer may not be provided on the outermost surface of the additional processing member. The additional processing member may include a third layer laminated on the second layer. The material of the third layer is not particularly limited.

Explanation of Reference Numerals

[0045] 1 : Machine tool 11 : Bed 12 : First spindle head 13 : Second spindle head 14 : Tool spindle 15 : Additional processing head 16 : Control device 17 : Powder feeder 18 : Laser oscillator 181 : Laser 19 : Cable 2 : Die cutter 20,22: Additional processing layer 221 : First layer 2211 : First material 222 : Second layer 2221 : Second material 201 : Cutting edge 202 : Sliding part 21 : Member 211,2221: Melt pool 3: Anvil roll

Claims

1. A first lamination step of supplying a first material having a higher hardness or coefficient of linear expansion than the member onto the member and irradiating the first material with a laser to melt the first material and laminate a first layer on the member; A second lamination step of supplying a second material having a higher hardness or coefficient of linear expansion than the first material onto the first layer and irradiating the second material with a laser to melt the second material and laminate a second layer on the first layer. A method for manufacturing a processed member.

2. The method for manufacturing a processed member according to Claim 1, The method for manufacturing the processed member further includes A removal step of removing a processed layer pre-laminated on the member, In the first lamination step, The first layer is laminated on the member from which the processed layer has been removed in the removal step. A method for manufacturing a processed member.

3. The method for manufacturing a processed member according to Claim 1, In the first lamination step, at least one layer of the first layer is laminated on the member, or In the second lamination step, at least one layer of the second layer is laminated on the first layer. A method for manufacturing a processed member.

4. The method for manufacturing a processed member according to Claim 1, The second material has a hardness of 600 Hv or more in terms of Vickers hardness. A method for manufacturing a processed member.

5. The method for manufacturing a processed member according to Claim 1, The method for manufacturing the member further includes A cooling step of cooling the member on which the second layer is laminated. A method for manufacturing a processed member.

6. The method for manufacturing a processed member according to Claim 1, In the first lamination step, A plurality of the first layers having different hardnesses or coefficients of linear expansion are respectively laminated on the member, Among the plurality of first layers, the first layer laminated on the upper side in the lamination direction has a higher hardness or coefficient of linear expansion. A method for manufacturing a processed member.

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