System and method for manufacturing an enhanced cast iron workpiece having increased lubricant storage

Abstract

The present disclosure provides a method for manufacturing an enhanced cast iron workpiece with increased oil storage. The method includes providing a laser tool, the laser tool being configured to emit a laser to perform carbon burnout from the cast iron workpiece. The cast iron workpiece includes cast iron and has a first surface having a carbon microstructure on the first surface. The method also includes selectively laser burning out the carbon microstructure from the first surface of the workpiece to form a pattern on the first surface. The pattern has separate recesses by laser burning out the carbon microstructure on the first surface. Each separate recess is separated from any other recess relative to the first surface and is not fluidically connected to provide a higher lubricant storage rate in each recess of the first surface. The method also includes heating the workpiece to about 200°C to about 400°C to temper the first surface and then cooling the workpiece to ambient temperature.

Description

Technical Field

[0001] The present invention relates to workpieces capable of storing lubricant, and more particularly to systems and methods for producing enhanced cast iron workpieces having increased oil storage. Background Art

[0002] Many traditional workpieces such as cast iron cylinder bores rely on the honing process. The honing process provides a high-platform cross-hatch honing surface for oil reservoirs and reduced friction of counter bodies (such as piston rings) on the workpiece. Due to the nature of the cross-hatch, the oil reservoir paths are often interconnected, which is contrary to tribology. Summary of the invention

[0003] Therefore, while current methods serve their intended purpose, a need exists for a new and improved system and method for producing enhanced cast iron workpieces having increased lubricant storage.

[0004] According to one aspect of the present invention, a method for manufacturing an enhanced cast iron workpiece having increased oil storage is disclosed. The method includes configuring a laser tool that is configured to emit a laser to perform carbon burn-off from a cast iron workpiece. The cast iron workpiece includes cast iron and has a first surface having a carbon microstructure thereon. The method also includes cleaning the workpiece to remove contaminants thereon.

[0005] In addition, the method also includes selectively laser ablating carbon microstructures from a first surface of the workpiece to form a pattern on the first surface. The pattern has individual pockets by laser ablating the carbon microstructures on the first surface. Each individual pocket is isolated from and not in fluid communication with any other pocket relative to the first surface to obtain a higher lubricant storage rate in each pocket of the first surface. The method also includes heating the workpiece to about 200° C. to about 400° C. to temper the first surface. In addition, the method includes cooling the workpiece to ambient temperature to obtain an enhanced cast iron workpiece with higher lubricant storage.

[0006] In one example of this aspect, the method further includes preheating the workpiece to about 200°C to about 400°C to reduce the risk of cracking. In another example, the method further includes preheating the workpiece to about 250°C to about 350°C to reduce the risk of cracking. In yet another example of this aspect, the method further includes preheating the workpiece to about 350°C to reduce the risk of cracking.

[0007] In one example of this aspect, the heating step includes heating the workpiece to about 200°C to about 400°C to temper the first surface when the hardness of the cast iron workpiece is greater than about 600 Hv (Vickers hardness scale) after selectively laser burning away the carbon microstructure. In another example, the method further includes heating the workpiece to about 250°C to about 350°C to temper the first surface. In yet another example of this aspect, the method further includes preheating the workpiece to about 350°C to temper the first surface.

[0008] In another example of this aspect, the step of laser ablating includes a laser output of about 4000 W to about 9000 W. In yet another example, the laser output is 4800 W.

[0009] In yet another example of this aspect, the carbon microstructure is graphite.

[0010] In another aspect of the present disclosure, a system for manufacturing an enhanced cast iron workpiece with increased oil storage is also disclosed. In one embodiment, the system includes a cast iron workpiece, the cast iron workpiece including cast iron and having a first surface having a carbon microstructure thereon. The system also includes a laser tool configured to emit a laser on the cast iron workpiece to selectively laser ablate the carbon microstructure from the first surface of the cast iron workpiece to form a pattern on the first surface. In this embodiment, the pattern has individual recesses formed by the laser on the first surface. In addition, each individual recess is separated from any other recess relative to the first surface and has no fluid communication to obtain a higher lubricant storage rate in each recess of the first surface.

[0011] In this embodiment, the system further includes a power source for powering the laser tool and a controller for controlling the powering of the laser tool to burn away the carbon microstructure from the first surface of the cast iron workpiece.

[0012] In another embodiment of this aspect, the system further comprises a first furnace for preheating the workpiece to about 200°C to about 400°C to reduce the risk of cracking. In yet another embodiment, the system further comprises a first furnace for preheating the workpiece to about 250°C to about 350°C to reduce the risk of cracking. In yet another embodiment, the system further comprises a first furnace for preheating the workpiece to about 350°C to reduce the risk of cracking.

[0013] In one embodiment of this aspect, the system further comprises a second furnace for preheating the workpiece to about 200°C to about 400°C to temper the first surface when the hardness of the cast iron workpiece is greater than about 600 Hv after selectively laser burning off the carbon microstructure. In another embodiment, the system further comprises a second furnace for preheating the workpiece to about 250°C to about 350°C to temper the first surface when the hardness of the cast iron workpiece is greater than about 600 Hv after selectively laser burning off the carbon microstructure. In yet another embodiment, the system further comprises a second furnace for preheating the workpiece to about 350°C to temper the first surface when the hardness of the cast iron workpiece is greater than about 600 Hv after selectively laser burning off the carbon microstructure.

[0014] In one embodiment of this aspect, the laser tool is configured to emit a laser having an output of about 4000 W to about 9000 W. In another embodiment, the laser output is 4800W.

[0015] In another aspect, the present disclosure also provides a method for manufacturing an enhanced cast iron workpiece with increased oil storage. The method includes configuring a laser tool that is configured to emit a laser to perform carbon burnout from a cast iron workpiece. The cast iron workpiece includes cast iron and has a first surface having a carbon microstructure thereon. The method also includes cleaning the workpiece to remove contaminants thereon.

[0016] In addition, the method also includes selectively laser ablating carbon microstructures from a first surface of the workpiece to form a pattern on the first surface. The pattern has individual recesses formed by laser ablating the carbon microstructures on the first surface. Each individual recess is isolated from and has no fluid communication with any other recess relative to the first surface to obtain a higher lubricant storage rate in each recess of the first surface.

[0017] In this aspect, the method further includes heating the workpiece to about 200° C. to about 400° C. to temper the first surface after selectively laser burning away the carbon microstructure when the hardness of the cast iron workpiece is greater than about 600 Hv. Additionally, the method includes cooling the workpiece to ambient temperature to obtain an enhanced cast iron workpiece with higher lubricant storage.

[0018] Further areas of applicability will become apparent from the description provided herein.It should be understood that the description and specific examples are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The drawings described herein are for illustration purposes only and are not intended to limit the scope of the present disclosure in any way.

[0020] Figure 1 FIG. 1 is a schematic diagram of a system for manufacturing an enhanced cast iron workpiece with increased oil storage according to one embodiment of the present invention.

[0021] Figure 2 Reason Figure 1 Conceptual perspective view of an enhanced cast iron workpiece with increased oil storage implemented with a system.

[0022] Figure 3 A conceptual cross-sectional side view of the enhanced workpiece.

[0023] Figure 4 According to an example of the present invention, Figure 1 A flow chart of a method for manufacturing an enhanced cast iron workpiece with increased oil storage implemented by a system.

[0024] Figure 5 Reason Figure 1 A flow chart of another method for manufacturing an enhanced cast iron workpiece with increased oil storage implemented by a system. DETAILED DESCRIPTION

[0025] The following detailed description is merely exemplary in nature and is not intended to limit the invention, its application, or uses.

[0026] The present invention provides a method and system for manufacturing an enhanced cast iron workpiece with increased oil storage. A laser burns and vaporizes carbon microstructures on a first surface of the workpiece. Burning and vaporizing such carbon microstructures leaves voids, pockets, or pressurized chambers on the first surface of the workpiece. The friction performance lubricant can be more effectively retained in these voids to enhance its lubricity within the friction performance range of the workpiece. When the opposing body passes through the first surface during operation, the pressure in the voids containing the lubricant accumulates and supports the hydrodynamic lubrication mechanism. These voids prevent (or reduce) the movement of the lubricant therein. Therefore, these voids provide a surface texture on the first surface to store the lubricant between the first surface and the opposing body.

[0027] According to one embodiment of the present disclosure, Figure 1 A system 10 for manufacturing an enhanced cast iron workpiece with increased oil storage is shown. As shown, the system 10 includes a cast iron workpiece 12 containing cast iron. The cast iron workpiece 12 can be a crankshaft, a bore cylinder, or any other suitable workpiece having a carbon microstructure formed thereon. In addition, the cast iron workpiece 12 has a first surface 14 having a carbon microstructure 16 disposed on the upper surface and within the subsurface thereof.

[0028] In this embodiment, the system 10 also includes a laser tool 20 configured to emit a laser 22 at the cast iron workpiece 12 to selectively laser ablate the carbon microstructure 16 from the first surface 14 of the cast iron workpiece 12. In one embodiment, the laser tool 20 is configured to emit a laser 22 having an output of about 4000 W to about 9000 W. In another embodiment, the laser tool 20 is configured to emit a laser 22 having an output of preferably about 4800 W.

[0029] Preferably, the laser 22 burns and vaporizes the carbon microstructure 16, such as graphite, at the first surface 14 to form a customized area or pattern 24 on the first surface 14 and subsurfaces of the workpiece 12, such as Figure 2 and Figure 3 As shown. In this embodiment, the pattern 24 has individual lubricating recesses, voids or micro pressure chambers 26 formed by the laser 22 on the first surface 14, from which the carbon microstructure 16 is removed. When an opposing body (such as a piston ring) passes through the first surface 14 of the workpiece 12 (such as a bore cylinder) during operation, such recesses 26 on the first surface 14 can be used for lubricant storage or oil storage within the range of friction performance.

[0030] Furthermore, the location of such lubricating dimples 26 can be customized to areas of the workpiece 12, such as cylinder bores (such as top dead center and bottom dead center) where increased oil storage is desired, and can also be distributed in a pattern. When the carbon microstructures 16 are laser ablated and vaporized, these patterns will not alter the entire first surface 14, but only the selected areas where the carbon microstructures 16 are located. Therefore, when extreme tribological events occur during operation of the workpiece 12, a large portion of the first surface 14 will act as a solid lubricant.

[0031] In addition, each individual dimple is isolated and not in fluid communication with any other dimple relative to the first surface 14. A higher lubricant storage rate is achieved in each dimple of the first surface 14 within the friction performance range of the workpiece 12. In addition, each dimple 26 does not have any oil storage path and connection to other dimples 26, nor does it have any connection between other dimples 26. That is, each dimple does not include a path connected to any other dimple 26.

[0032] Thus, each lubrication pocket 26 is separated from the other lubrication pockets. Thus, when the opposing body 28 passes through the first surface 14 during operation, the movement of lubricant between the lubrication pockets 26 is prevented (or reduced) so that the lubricant 18 (e.g., oil) is retained therein to promote a higher oil reserve. When the opposing body 28 (e.g., a piston ring) movably slides across the first surface 14 of the workpiece 12 (e.g., a cylinder bore), the higher oil reserve forms a micro-pressurized chamber.

[0033] For example, laser graphite ablation can be performed at selected locations or patterns 24 within the inner diameter of the cylinder bore workpiece. Laser graphite ablation can be performed on loose liners using a fixed laser head and a rotating liner fixture. Alternatively, laser ablation can be performed with a rotating laser head and a fixed liner / hole, such as in the case of a cast iron liner preformed into an engine block or a monolithic / linerless cast iron engine block. Laser ablation can be performed on other suitable cast iron workpieces without departing from the scope or spirit of the present disclosure.

[0034] It is important to note that the geometry (thickness) of the workpiece or target material, the desired oil storage properties (such as volume, depth, density or amount), and the required hardness will determine the laser performance and parameters (such as spot size, intensity, energy, jitter, frequency). The following provides an example of laser parameters made on a cast iron workpiece.

[0035] In order to reduce or prevent mass quenching after graphite burnout, the workpiece 12 may be preheated before laser burnout. Therefore, the system 10 may further include a first furnace 30. That is, before laser burnout, the workpiece 12 may be preheated in the first furnace 30 to about 200°C to about 400°C to reduce the risk of cracking after laser burnout. Preferably, the workpiece 12 may be preheated in the first furnace 30 to about 250°C to about 350°C, and more preferably, preheated to about 350°C to reduce the risk of cracking after laser burnout. In addition, preheating may increase throughput by reducing the laser exposure time required for graphite burnout. Preheating may also reduce the risk of cracking of thin pads during laser graphite burnout.

[0036] After laser ablation, the workpiece 12 may be tempered to reduce surface hardening. After selectively ablation of the carbon microstructure 16, the workpiece 12 may be tempered when the hardness of the cast iron workpiece 12 is greater than about 600 Hv (Vickers hardness scale). Figure 1 As shown, the system 10 may further include a second furnace 32 for heating the workpiece 12 to about 200° C. to about 400° C. to temper the first surface 14 when the hardness of the cast iron workpiece 12 is greater than 600 Hv after selectively laser burning away the carbon microstructure 16. In another embodiment, the second furnace 32 may heat the workpiece 12 to about 250° C. to about 350° C., more preferably to about 300° C., to temper the first surface 14.

[0037] like Figure 1 As shown, the system 10 further includes a power supply 34 for powering the laser tool 20, a first furnace 30, a second furnace 32, and a controller 36. In this embodiment, the controller 36 is configured to control the operation and power supply of the laser tool 20, the first furnace 30, and the second furnace 32. In addition, the pad can be finely machined and / or honed to achieve a desired surface finish (e.g., a mirror finish, a cross-hatch finish).

[0038] According to an example of the present disclosure, Figure 4 A method 110 for manufacturing an enhanced cast iron workpiece having increased oil storage is depicted. In this example, the method 110 comprises the steps described above and as follows: Figure 1 The illustrated system 10 implements . However, any other suitable system may be used without departing from the spirit or scope of the present disclosure.

[0039] As shown, the method 110 includes providing a laser tool 20 in block 112, which is configured to emit a laser 22 to perform carbon burnout on a cast iron workpiece 12. The cast iron workpiece 12 has cast iron and a first surface 14, with a carbon microstructure 16 disposed on and within a subsurface of the upper surface. In this example, the cast iron workpiece 12 may be a crankshaft, a bore cylinder, or any other suitable workpiece formed with a carbon microstructure 16. In one embodiment, the laser tool 20 is configured to emit a laser 22 having an output of about 4000 W to about 9000 W. In another embodiment, the laser tool 20 is configured to emit a laser 22 having an output of preferably about 4800 W.

[0040] The method 110 also includes cleaning the workpiece 12 in frame 114 to remove contaminants thereon. The cleaning step of the workpiece 12 can be completed by an industrial washing machine and dried by air or an oven. In one example, the industrial washing machine can be a water-based cleaning machine known in the art, which uses lower pressure and higher pressure for cleaning.

[0041] In addition, the method 110 includes selectively laser ablating the carbon microstructures 16 from the first surface 14 of the workpiece 12 to form a pattern 24 on the first surface 14 in frame 116. Preferably, the laser burns and vaporizes the carbon microstructures 16, such as graphite, from the first surface 14 to form customized areas or patterns 24 on the first surface 14 and subsurfaces of the workpiece 12. In this embodiment, the pattern 24 has individual lubrication pockets, voids, or micro-pressure chambers 26 formed by the laser 22 on the first surface 14, with the microstructures 16 located on and removed from the first surface 14. Such pockets 26 on the first surface 14 can be used for lubricant storage or oil storage within the range of friction properties when an opposing body passes through the first surface 14 during operation.

[0042] Furthermore, the location of such lubricating dimples 26 can be customized to areas of the workpiece 12, such as cylinder bores (such as top dead center and bottom dead center) where increased oil storage is desired, and can also be distributed in a pattern. When the carbon microstructures 16 are laser ablated and vaporized, these patterns will not alter the entire first surface 14, but only the selected areas where the carbon microstructures 16 are located. Therefore, when extreme tribological events occur during operation of the workpiece 12, a large portion of the first surface 14 will act as a solid lubricant.

[0043] In addition, each individual dimple is isolated and not in fluid communication with any other dimple relative to the first surface 14. A higher lubricant storage rate is achieved in each dimple of the first surface 14 within the friction performance range of the workpiece 12. In addition, each dimple 26 does not have any oil storage path and connection communicating with other dimples 26, nor any connection between other dimples 26. That is, each dimple does not include a path connecting to any other dimple 26.

[0044] Therefore, each lubricating recess is separated from the other lubricating recesses. Thus, when the opposing body 28 passes through the first surface 14 during operation, the movement of lubricant between the lubricating recesses 26 is prevented (or reduced) so that the lubricant 18 (such as oil) is retained therein to promote a higher oil reserve. When the opposing body 28 (such as a piston ring) movably slides across the first surface 14, the higher oil reserve forms a micro-pressurized chamber.

[0045] like Figure 4 As shown, the method 100 also includes preheating the workpiece 12 to about 200° C. to about 400° C. in frame 118 to temper the first surface 14. After laser ablation, the workpiece 12 may preferably be tempered to reduce surface hardening. After selectively burning away the carbon microstructure 16, when the hardness of the cast iron workpiece 12 is greater than about 600 Hv (Vickers hardness scale), the workpiece 12 may be tempered. The example of tempering discussed above is heating by the second furnace 32 (e.g., Figure 1 That is, the second furnace 32 may heat the workpiece 12 to about 200° C. to about 400° C. to temper the first surface 14 when the hardness of the cast iron workpiece 12 is greater than 600 Hv after selectively laser burning away the carbon microstructure 16. In another example, the second furnace 32 may heat the workpiece 12 to about 250° C. to about 350° C., more preferably to about 300° C., to temper the first surface 14.

[0046] Furthermore, method 110 includes cooling workpiece 12 to ambient temperature in block 120, resulting in an enhanced cast iron workpiece with increased lubricant storage. Additionally, the liner may be finish machined and / or honed to achieve a desired surface finish (eg, mirror finish, cross-hatch finish).

[0047] In one example, the method 110 further includes preheating the workpiece 12 to about 200° C. to about 400° C. to reduce the risk of cracking. The preheating step may be performed before the step of selectively laser burning the carbon microstructure 16 from the first surface 14. Preheating the workpiece 12 may reduce or prevent mass quenching after graphite burnout. The preheating step may be accomplished by the first furnace discussed above.

[0048] Therefore, before laser ablation, the workpiece 12 may be placed in the first furnace 30 and preheated to about 200° C. to about 400° C. to reduce the risk of cracking after laser ablation. Preferably, the workpiece 12 may be placed in the first furnace 30 and preheated to about 250° C. to about 350° C., and more preferably, preheated to about 350° C. to reduce the risk of cracking after laser ablation. In addition, preheating may increase throughput by reducing the laser exposure time required for graphite ablation. Preheating may also reduce the risk of cracking of thin pads during laser graphite ablation.

[0049] It is important to note that the geometry (thickness) of the workpiece or target material, the desired oil storage properties (such as volume, depth, density or amount), and the required hardness will determine the laser performance and parameters (such as spot size, intensity, energy, jitter, frequency). The following provides an example of laser parameters made on a cast iron workpiece.

[0050] As an example, the following data provides laser parameters that can be used for the cast iron workpiece detailed below. For a workpiece having gray cast iron grade 250, 250 MPa min (tensile strength), 207 to 255 HBW 10 / 3000 (hardness), 3.2 to 3.3% carbon, up to 5.0% ferrite, up to 1.0% carbide, type A minimum 50% type B, type D and type E (graphite flake type), and 4 to 6 (flake size), a laser tool with the following parameters can be used: YAG solid state (laser type), 4 mm (laser spot size), 4800 W (power), 50 Hz (pattern frequency), 9000 mm / s (laser beam speed), and 1020°C (temperature).

[0051] According to another example of the present disclosure, Figure 5 A method 210 for making an enhanced cast iron workpiece with increased oil storage is depicted. In this example, the method 210 is implemented by the system 10 described above. However, any other suitable system may be used without departing from the spirit or scope of the present invention.

[0052] As shown, the method 210 includes providing a laser tool 20 in frame 212, which is configured to emit a laser 22 to perform carbon burnout on a cast iron workpiece 12. The cast iron workpiece 12 has cast iron and a first surface 14, and a carbon microstructure 16 is disposed on and in a subsurface of the upper surface. In this example, the cast iron workpiece 12 can be a crankshaft, a bore cylinder, or any other suitable workpiece formed with a carbon microstructure 16. In one embodiment, the laser tool 20 is configured to emit a laser 22 having an output of about 4000 W to about 9000 W. In another embodiment, the laser tool 20 is configured to emit a laser 22 having an output of preferably about 4800 W.

[0053] The method 210 also includes cleaning the workpiece 12 to remove contaminants thereon in frame 214. The cleaning step of the workpiece 12 can be completed by an industrial washing machine and dried by air or an oven. In one example, the industrial washing machine can be a water-based washing machine known in the art, which uses lower pressure and higher pressure for cleaning.

[0054] like Figure 5 As described, the method 210 includes selectively laser ablating the carbon microstructures 16 from the first surface 14 of the workpiece 12 in block 216 to form a pattern 24 on the first surface 14. Preferably, the laser 22 burns and vaporizes the carbon microstructures 16, such as graphite, on the first surface 14 to form customized areas or patterns 24 on the first surface 14 and subsurfaces of the workpiece 12. In this embodiment, the pattern 24 has individual lubricating pockets, voids or micro-pressure chambers 26 formed by the laser 22 on the first surface 14, and the microstructures 16 are located on the first surface 14 and removed therefrom. When the counterbody passes through the first surface 14 during operation, such pockets 26 on the first surface 14 can be used for lubricant storage or oil storage within the range of tribological properties. When the carbon microstructures 16 are laser ablated and vaporized, these patterns do not change the entire first surface 14, but only the selected areas where the carbon microstructures 16 are located. Therefore, when extreme tribological events occur during operation of the workpiece 12, most of the first surface 14 will act as a solid lubricant.

[0055] In addition, each individual dimple is isolated and has no fluid communication with any other dimple relative to the first surface 14. A higher lubricant storage rate is achieved in each dimple of the first surface 14 within the friction performance range of the workpiece 12. In addition, each dimple 26 does not have any oil storage path and connection communicating with other dimples 26, nor any connection between other dimples 26. That is, each dimple does not include a path connecting to any other dimple 26.

[0056] Therefore, each lubrication pocket 26 is separated from the other lubrication pockets. Thus, when the opposing body 28 passes through the first surface 14 during operation, the movement of lubricant between the lubrication pockets 26 is prevented (or reduced) so that the lubricant 18 (such as oil) is retained therein to promote a higher oil reserve. When the opposing body 28 (such as a piston ring) movably slides across the first surface 14, the higher oil reserve forms a micro-pressurized chamber.

[0057] In this example, the method 210 also includes heating the workpiece 12 to about 200° C. to about 400° C. in block 218 to temper the first surface 14 when the hardness of the cast iron workpiece 12 is greater than about 600 Hv after the step of selectively laser ablating the carbon microstructure 16. After laser ablating, the workpiece 12 may preferably be tempered to reduce surface hardening. After selectively laser ablating the carbon microstructure 16, when the hardness of the cast iron workpiece 12 is greater than about 600 Hv (Vickers hardness scale), the workpiece 12 may preferably be tempered. The example of tempering discussed above is heating by the second furnace 32 (e.g., Figure 1 That is, the second furnace 32 may heat the workpiece 12 to about 200° C. to about 400° C. to temper the first surface 14 when the hardness of the cast iron workpiece 12 is greater than about 600 Hv after selectively laser burning away the carbon microstructure 16. In another example, the second furnace 32 may heat the workpiece 12 to about 250° C. to about 350° C., more preferably to about 300° C., to temper the first surface 14.

[0058] Additionally, method 210 includes cooling workpiece 12 to ambient temperature in block 220, resulting in an enhanced cast iron workpiece 12 with increased lubricant storage. Additionally, the liner may be finish machined and / or honed to achieve a desired surface finish (eg, mirror finish, cross-hatch finish).

[0059] In one example of this aspect, the method 210 further includes preheating the workpiece 12 to about 200° C. to about 400° C. to reduce the risk of cracking. The preheating step may be performed before the step of selectively laser burning the carbon microstructure 16 from the first surface 14. Preheating the workpiece 12 may reduce or prevent mass quenching after graphite burnout. The preheating step may be accomplished by the first furnace discussed above.

[0060] Therefore, before laser ablation, the workpiece 12 may be placed in the first furnace 30 and preheated to about 200° C. to about 400° C. to reduce the risk of cracking after laser ablation. Preferably, the workpiece 12 may be placed in the first furnace 30 and preheated to about 250° C. to about 350° C., and more preferably, preheated to about 350° C. to reduce the risk of cracking after laser ablation. In addition, preheating may increase throughput by reducing the laser exposure time required for graphite ablation. Preheating may also reduce the risk of cracking of thin pads during laser graphite ablation.

[0061] The description of the present disclosure is merely exemplary in nature, and variations that do not depart from the gist of the present disclosure are within the scope of the present disclosure. Such variations should not be regarded as departing from the spirit and scope of the present disclosure.

Claims

1. A method for producing an enhanced cast iron workpiece having increased oil storage, comprising: providing a laser tool configured to emit a laser to perform carbon burn-off from a cast iron workpiece, the cast iron workpiece comprising cast iron and having a first surface having a carbon microstructure on the first surface; cleaning the workpiece to remove contaminants thereon; selectively laser ablating a carbon microstructure from a first surface of the workpiece to form a pattern on the first surface, the pattern having individual recesses formed by laser ablating the carbon microstructure on the first surface, each individual recess being isolated from and not in fluid communication with any other recess relative to the first surface to achieve a higher lubricant storage rate in each recess of the first surface; heating the workpiece to 200° C. to 400° C. to temper the first surface; The workpiece is cooled to ambient temperature, resulting in a reinforced cast iron workpiece with increased lubricant storage.

2. The method of claim 1, further comprising preheating the workpiece to 200°C to 400°C to reduce the risk of cracking.

3. The method of claim 1, further comprising preheating the workpiece to 250°C to 350°C to reduce the risk of cracking.

4. The method of claim 1, further comprising preheating the workpiece to 350°C to reduce the risk of cracking.

5. The method of claim 1, wherein: The heating the workpiece to 200° C. to 400° C. to temper the first surface includes: heating the workpiece to 200° C. to 400° C. to temper the first surface when the hardness of the cast iron workpiece is greater than 600 Hv after selectively laser burning away the carbon microstructure.

6. The method of claim 5, further comprising heating the workpiece to 250°C to 350°C to temper the first surface.

7. The method of claim 6, further comprising heating the workpiece to 350°C to temper the first surface.

8. The method of claim 1, wherein: The laser ablation step includes a laser output of 4000W to 9000W.

9. The method of claim 8, wherein: The laser output is 4800W.

10. The method of claim 1, wherein: The carbon microstructure is graphite.

Images