JP7514377B1 - Manufacturing method of additionally processed parts - Google Patents

Abstract

[Problem] To suppress cracking of a processed member formed by applying additional processing to a member by directed energy deposition. [Solution] A method for manufacturing a processed member includes a first lamination step of supplying a first material 2211 having a higher hardness or linear expansion coefficient than the member 21 and melting the first material by irradiating with a laser 181 to laminate a first layer 221 on the member, and a second lamination step of supplying a second material 2221 having a higher hardness or linear expansion coefficient than the first material on the first layer and melting the second material 2221 by irradiating with a laser 181 to laminate a second layer 222 on the first layer. [Selected Figure] Figure 5

Description

The present invention relates to a method for manufacturing additionally processed components.

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

Patent Document 1 discloses a composite member made up of multiple layers with different mixture ratios of ceramic powder and metal. The multiple layers are formed by alternately stacking high-hardness layers and low-hardness layers. Such a composite member is applied to a mold to form a tool having a predetermined shape. With this tool, even if a crack occurs in the high-hardness layer, the crack is prevented from progressing in the low-hardness layer.

JP 2016-108668 A

Patent Document 1 lists directed energy deposition as an example of a method for forming high and low hardness layers. In directed energy deposition, a 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 and low hardness layer formed by directed energy deposition is used as a tool material. Meanwhile, directed energy deposition is also used in additive processing, which forms an additive processing layer of a specified thickness and shape on the surface of the base material of the tool.

In additively processed components that have been subjected to additive processing, the additive processing layer may wear over time. In this case, the old additive processing layer may be removed, and a new additive processing layer may be laminated on the component to repair the worn additive processing layer. Here, in the directed energy deposition method, a laser is used to melt the component and the material powder when the additive processing layer is laminated on the component. The heat of this laser may change the material of the component and harden the component. In additively processed components used in tools, a material with high hardness is used for the additive processing layer. In such cases, in additively processed components whose additive processing layer has been repaired by directed energy deposition, a hard additive processing layer is provided on the surface of the hardened component. Generally, materials with high hardness have low toughness and are difficult to expand and contract. As a result, when the repaired additively processed component is cooled, a difference occurs between the amount of thermal contraction of the component and the amount of thermal contraction of the additive processing layer, which may cause cracks or deformation in the additive processing layer.

The present invention aims to suppress cracking of processed components formed by applying additional processing to components using directed energy deposition.

The method for producing an additively processed member of the present invention comprises the steps of:
a first lamination step of supplying a first material having a hardness or a linear expansion coefficient higher than that of 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;
and a second lamination process for supplying a second material having a higher hardness or linear expansion coefficient than the first material onto the first layer and melting the second material by irradiating it with a laser, thereby laminating a second layer on the first layer.

In the manufacturing method of the additively processed member described above, a first layer having a hardness or linear expansion coefficient intermediate between the member and the second layer is provided between the member and the second layer made of the second material. The first layer absorbs the difference in the amount of thermal contraction between the member and the second layer when the member is cooled after the first and second layers are laminated on the member. Therefore, according to the manufacturing method of the additively processed member described above, it is possible to suppress cracking of the additively processed member formed by applying additive processing to the member using directed energy deposition.

The manufacturing method of the additively processed component of the present invention can suppress cracking of the additively processed component formed by applying additive processing to the component using the directed energy deposition method.

FIG. 1 is a schematic diagram of a machine tool used in a method for manufacturing an additionally processed member. FIG. 2 is a flow chart of a method for manufacturing an additionally processed member. FIG. 3 is a diagram for explaining the removing step. FIG. 4 is a diagram for explaining the first lamination step. FIG. 5 is a diagram for explaining the second lamination step.

The following describes an embodiment of the present invention with reference to the drawings.

<Machine tools>
FIG. 1 is a schematic diagram of a machine tool used in a manufacturing method for additively processed members. Referring to FIG. 1 (A), the machine tool 1 is an AM/SM hybrid machine tool capable of additive machining (AM) and subtractive machining (SM) of members. The machine tool 1 has a turning function using a fixed tool and a milling function using a rotating tool as SM processing functions. The machine tool 1 is a numerically controlled (NC) machine tool in which various operations for machining members are automated by numerical control by a computer. In this specification, an axis that is parallel to the left-right direction (width direction) of the machine tool 1 and extends horizontally is referred to as the "Z axis", an axis that is parallel to the front-rear direction (depth direction) and extends horizontally is referred to as the "Y axis", and an axis that extends vertically is referred to as the "X axis".

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

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

The first headstock 12 and the second headstock 13 are arranged opposite each other in the Z-axis direction. The first headstock 12 includes a first work spindle 121 that holds and rotates the member 21. The first work spindle 121 is arranged to be rotatable around a central axis A121 parallel to the Z-axis. Similarly, the second headstock 13 includes a second work spindle 131 that holds and rotates the member 21. The second headstock 13 is arranged to be movable in the Z-axis direction by various feed mechanisms, guide mechanisms, motors, etc. The second work spindle 131 is arranged to be rotatable around a central axis A131 parallel to the Z-axis. The central axes A121 and A131 are located on the same straight line. The first work spindle 121 and the second work spindle 131 are each provided with a chuck for detachably holding the member 21.

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. When the member 21 is attached to the first work spindle 121 and the second work spindle 131, the member 21 has a central axis that coincides with an extension of the central axis A121 (A131) of the first work spindle 121. One end of the member 21 in the central axis direction is held by the chuck of the first work spindle 121, and the other end is held by the chuck of the second work spindle 131. The first work spindle 121 and the second work spindle 131 rotate synchronously with each other, causing the member 21 to rotate around the central axis A121 (A131).

The tool spindle 14 is configured so that the attached tool can rotate around a central axis included in the X-axis-Z-axis plane. The tool spindle 14 is supported on the bed 11 by a column or the like (not shown). The tool spindle 14 is provided so that it can move in the X-axis, Y-axis, and Z-axis directions by various feed mechanisms, guide mechanisms, motors, etc. provided on the column or the like. With this configuration, the tool spindle 14 moves three-dimensionally. The tool spindle 14 is further provided so that it can rotate around a central axis of rotation parallel to the Y axis (B-axis rotation).

The machine tool 1 further includes an additional processing head 15. The additional processing head 15 supplies material to the member 21 and irradiates the member 21 with a laser. In other words, the additional processing head 15 performs additional processing on the member 21 by the directed energy deposition method.

The additional processing head 15 is configured to be detachable from the tool spindle 14. As the tool spindle 14 moves in the X-axis, Y-axis, and Z-axis directions, the additional processing head 15 also moves in the X-axis, Y-axis, and Z-axis directions. Furthermore, as the tool spindle 14 rotates around the central axis of rotation (axis B), the additional processing head 15 also rotates together with the tool spindle 14 around axis B.

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, RAM, ROM, etc. The control device 16 controls the operation of each part of the machine tool 1 by executing a computer program stored in a recording medium.

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

The powder feeder 17 supplies the material powder used in the additional processing to the processing position. Although not shown, the powder feeder 17 includes a powder hopper and a mixing section. The powder hopper forms an enclosed space for storing the material powder used in the additional processing. The mixing section mixes the material powder stored in the powder hopper with a gas that carries the material. Note that, although the material is in powder form in this embodiment, the material may be in wire form.

The laser oscillator 18 emits a laser 181 used for additional processing. The cable 19 is composed of an optical fiber for guiding the laser from the laser oscillator 18 to the additional processing head 15, a pipe for guiding the material powder from the powder feeder 17 to the additional processing head 15, an air pipe as an air flow path, a gas pipe as an inert gas flow path, a cooling pipe as a refrigerant flow path, electrical wiring, and a tube member that houses these.

<Method of manufacturing additionally processed member>
Next, a method for manufacturing an additively processed member according to the present embodiment will be described. In the present embodiment, a case in which an additively processed layer of a die cutter is repaired by the method for manufacturing an additively processed member will be described.

Figure 2 is a flow chart of the method for manufacturing an additionally processed component. The method for manufacturing an additionally processed component includes, in order of execution, a removal process S11, a first lamination process S12, a second lamination process S13, and a cooling process S14. Each process (process) is performed by the control device executing various programs.

Figure 3 is a diagram for explaining the removal process. In the figure, (A) is a schematic diagram of the configuration of the die cut roll. In the removal process S11, the additional processing layer 20 previously applied to the member 21 is removed. Specifically, first, the die cutter 2 is prepared. The die cutter 2 constitutes a die cut roll together with the anvil roll 3 that is paired with it. The die cutter 2 is constituted by providing the additional processing layer 20 on the surface of the 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 die cutter 2. In the figure, the blade portion 201 is shown to have a square shape, but the shape of the blade portion 201 is not particularly limited. The blade portion 201 has a shape according to the shape of the product to be processed by the die 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 against the anvil roll 3 as the die cutter 2 rotates.

In the figure, (B) is a cross-sectional view of a part of the die cutter cut by a plane including the central axis of the die cutter. In this embodiment, the pre-formed 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 below. 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 pre-forming the additional processing layer 20 on 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, for example, by a powder bed method.

The sliding part 202 of the die cutter wears over time. When the amount of wear of the sliding part 202 reaches a certain level or more, the sliding part 202 needs to be repaired. Therefore, in the removal process S11, the sliding part 202 of the die cutter is removed by, for example, cutting or grinding. When the removal process S11 is completed, the surface of the member 21 is exposed in 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 due to heat treatment. The hardness or linear expansion coefficient of the member 21 changes due to heat treatment. In short, the member 21 is made of a material that can undergo phase transformation due to heat treatment.

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 on the member 21 at a position corresponding to the sliding part 202 of the die cutter described above. Specifically, referring to (A) in the figure, in the first lamination step S12, the surface of the member 21 is supplied with the powdered first material 2211 from the powder feeder 17 and irradiated with the laser 181. The laser 181 melts both the member 21 and the first material 2211. When the laser 181 is irradiated to the member 21, the member 21 melts and a melt pool 211 is formed on the surface of the member 21. The molten first material 2211 spreads so as to overlap with 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.

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

Figure 5 is a diagram for explaining the second lamination step. In the second lamination step S13, the second layer 222 is laminated on the first layer 221 by directed energy deposition. The second layer 222 is provided at the position where the first layer 221 is provided, i.e., at the position corresponding to the sliding part 202 of the die cutter. The second layer 222 is provided on the outermost surface of the die cutter. In other words, the second layer 222 essentially functions as the sliding part of the die cutter.

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

The second material 2221 has a higher hardness or linear expansion coefficient than the first material 2211. That is, the second layer 222 has a higher hardness or linear expansion coefficient 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 Vickers hardness of 600 Hv or more.

In the cooling step 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 step S14 is completed, an additionally processed member is manufactured in which the first layer 221 and the second layer 222 are laminated on the member 21. In other words, the previously provided additionally processed layer 20 is replaced with a new additionally processed layer 22, and the repair of the die-cut roll is completed.

As described above, in the manufacturing method of the additively processed member of this embodiment, the first layer 221 made of the first material is provided between the member 21 and the second layer 222 made of the second material. The first material has a hardness or linear expansion coefficient intermediate between that of the second material and the member. Therefore, the first layer 221 absorbs the difference between the amount of thermal contraction of the member 21 and the amount of thermal contraction of the second layer 222 in the cooling process. Therefore, according to the manufacturing method of the additively processed member described above, it is possible to suppress cracking of the additively processed member formed by applying additive processing to the member by the directed energy deposition method.

In particular, the above-mentioned manufacturing method for the additionally processed member is effective when using a member whose hardness or linear expansion coefficient changes due to the heat of the laser. That is, when the additionally processed layer of the product (the die cutter in the above-mentioned embodiment) is repaired using the directed energy deposition method, the member is heat-treated by the heat of the laser, and the hardness or linear expansion coefficient 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 hardened by the heat of the laser. In such a case, if the second layer is directly laminated on the surface of a member with high hardness, a material with low toughness is provided on a material with low toughness. As a result, the member is less likely to absorb the amount of thermal contraction of the second layer with high hardness, and the second layer is more likely to crack. In contrast, in the above-mentioned manufacturing method for the additionally processed member, the first layer 221 is provided between the member 21 and the second layer 222, and the difference in the amount of thermal contraction between the member 21 and the second layer 222 is absorbed. Therefore, the manufacturing method for the additively processed component described above is particularly effective when using a component 21 whose hardness or linear expansion coefficient changes due to the heat of the laser.

The above-described embodiments are illustrative in all respects and are not restrictive. Those skilled in the art may make appropriate modifications and variations. The scope of the present invention is defined by the claims, not the above-described embodiments. Furthermore, the scope of the present invention includes modifications from the embodiments within the scope of the claims and the scope equivalent thereto.

For example, in the above embodiment, the product to be processed is a die cutter. However, the product is not limited to a die cutter. The product may be any product in which an additive processing layer is laminated onto a component using directed energy deposition.

In the above embodiment, a case has been described in which an additional processing layer is repaired in a product on which the additional processing layer has already been laminated. However, the manufacturing method of the additional processing member of the present invention may be applied when the additional processing layer is laminated on the member in advance. In other words, 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.

In the above embodiment, the first layer and the second layer are each a single layer. However, multiple first layers may be stacked. Multiple second layers may be stacked. By stacking multiple first layers or multiple second layers, the thickness of the additional processing layer can be adjusted. The thickness of the first layer and the second layer may be set appropriately according to the product specifications.

When a plurality of first layers are stacked, each of the plurality of first layers may be made of the same material or different materials. A portion of the plurality of first layers may be made of the same material. When a plurality of first layers are stacked, the first layer stacked on the upper side in the stacking direction may have a higher hardness or linear expansion coefficient. When a plurality of first layers are stacked, the first layer closer to the second layer may have a higher hardness or linear expansion coefficient. When a plurality of first layers are stacked, the upper first layer stacked on the upper side in the stacking direction may have a hardness or linear expansion coefficient equal to or higher than the hardness or linear expansion coefficient of the lower first layer provided one layer below the upper first layer. When a plurality of first layers are stacked, the uppermost first layer provided at the top in the stacking direction may have a higher hardness or linear expansion coefficient than the lowermost first layer provided at the bottom.

In the above embodiment, the manufacturing method of the additionally processed member includes a removing step and a cooling step. However, the manufacturing method of the additionally processed member does not have to include these steps. That is, the manufacturing method of the additionally processed member of the present invention may be applied to a member on which no additional processing layer has been laminated in advance. The manufacturing method of the additionally processed member of the present invention may be applied to a member from which an additional processing layer that has been laminated in advance at a different location has been removed. In addition, in the case of a product that does not require forced cooling, the cooling step may be omitted. Furthermore, the manufacturing method of the additionally processed 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, etc.

In the above embodiment, the second layer is provided on the outermost surface of the additionally processed member. However, the second layer does not have to be provided on the outermost surface of the additionally processed member. The additionally processed member may include a third layer laminated on the second layer. There is no particular limitation on the material of the third layer.

1: Machine tool 11: Bed 12: First headstock 13: Second headstock 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: Blade portion 202: Sliding portion 21: Member 211, 2221: Melt pool 3: Anvil roll

Claims (6)

a first lamination step of supplying a first material having a hardness or linear expansion coefficient higher than that of a member from which a previously applied additional processing layer has been removed , and irradiating a laser to melt the first material and a part of the member , thereby laminating a first layer on the member;
a second lamination step of supplying a second material having a hardness or a linear expansion coefficient higher than that of the first material onto the first layer and melting the second material by irradiating the second material with a laser, and laminating a second layer on the first layer ;
the additive processing layer is provided on the member and is made of the second material;
A method for manufacturing an additively processed member , wherein in the first lamination step, the hardness or linear expansion coefficient of the member is changed by the heat of the laser. A method for producing an additively processed member according to claim 1,
The method for producing the additively processed member further comprises:
A removal step of removing an additive processing layer that has been laminated on the member in advance,
In the first lamination step,
A method for manufacturing an additively processed member, comprising laminating the first layer on the member from which the additively processed layer has been removed in the removing step. A method for producing an additively processed member according to claim 1,
A method for manufacturing an additively processed member, wherein in the first lamination step, at least one first layer is laminated on the member, or in the second lamination step, at least one second layer is laminated on the first layer. A method for producing an additively processed member according to claim 1,
The second material has a Vickers hardness of 600 Hv or more. A method for producing an additively processed member according to claim 1,
The method for manufacturing the component further comprises:
A method for manufacturing an additively processed member, comprising a cooling step of cooling the member on which the second layer is laminated. A method for producing an additively processed member according to claim 1,
In the first lamination step,
A plurality of the first layers each having a different hardness or linear expansion coefficient are laminated on the member;
A method for manufacturing an additively processed member, wherein the first layers stacked on the upper side in a stacking direction have a higher hardness or linear expansion coefficient among the plurality of first layers.

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