Method and apparatus for pulse fusion surfacing
First Claim
1. A system for electrically fusing a conductive material into a substrate, comprising:
- an electrode extending longitudinally about a central axis and comprising a conductive material;
a current source connected to the electrode including a trigger/discharge circuit for discharging a series of short-duration electrical pulses to the electrode for melting and fusing a quantity of electrode material into the substrate;
a reversible stepper motor drivably connected to the electrode, the stepper motor oscillating the electrode radially back and forth in a semi-circular path about the central axis while at the same time rotating the electrode about the same central axis thereby super-imposing a rotation into the semi-circular oscillatory movement of the electrode; and
a processor coupled to the current source and to the stepper motor, the processor for controlling the discharge of the series of short-duration electrical pulses from the trigger/discharge circuit to the electrode, and for controlling the stepper motor to oscillate and rotate the electrode in a predetermined pattern and at a predetermined rate.
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Accused Products
Abstract
The invention both rotates and oscillates the electrode at the same time to increase the quality of materials deposited onto a substrate during an pulse fusion surfacing process. The PFS spark rate is also varied to further increase the quality and effectiveness of the PFS process. Electrode oscillation keeps the electrode from welding to the substrate surface and electrode rotation maintains even wear on the electrode work surface. An evenly worn electrode surface allows the PFS process to generate more consistent substrate surfaces. In addition, electrode oscillation neutralizes "run away" conditions and varying spark torque that occur with electrodes that are only rotated. The spark rate is varied according to various PFS process parameters (e.g., substrate material) to further improve the quality of the PFS deposition layer. The pulse fusion surfacing process according to the invention is utilized to create knife blades that remain sharp even after extended use due to differential wear between the blade substrate material and the PFS material.
49 Citations
46 Claims
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1. A system for electrically fusing a conductive material into a substrate, comprising:
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an electrode extending longitudinally about a central axis and comprising a conductive material; a current source connected to the electrode including a trigger/discharge circuit for discharging a series of short-duration electrical pulses to the electrode for melting and fusing a quantity of electrode material into the substrate; a reversible stepper motor drivably connected to the electrode, the stepper motor oscillating the electrode radially back and forth in a semi-circular path about the central axis while at the same time rotating the electrode about the same central axis thereby super-imposing a rotation into the semi-circular oscillatory movement of the electrode; and a processor coupled to the current source and to the stepper motor, the processor for controlling the discharge of the series of short-duration electrical pulses from the trigger/discharge circuit to the electrode, and for controlling the stepper motor to oscillate and rotate the electrode in a predetermined pattern and at a predetermined rate. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A system for transferring metallic conductive materials between an electrode and a substrate, the rate at which material is transferred between the electrode and the substrate varying according to as set of system parameters and a set of substrate parameters, the system comprising:
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a power supply for supplying energy to the electrode; a bank of variable sized capacitors coupled to the power supply, each capacitor storing a different amount of energy from the power supply; a switch coupled between the capacitors and the electrode for initiating the discharge of energy from the capacitors to the electrode; and a control circuit coupled to the switch for automatically varying the rate at which energy is discharged from the capacitors into the electrode according to the speed at which the electrode is moved over the substrate. - View Dependent Claims (12, 13, 14, 15, 16, 17)
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18. A method for melting and fusing a conductive material into a substrate, comprising:
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providing an electrode formed of a conductive material; discharging a series of discrete short-duration current pulses through the electrode to the substrate for melting and fusing a predetermined amount of the conductive material into the substrate; oscillating the electrode radially back and forth at a predetermined rate and in a predetermined semi-circular pattern about an electrode longitudinal axis; rotating the electrode about the same longitudinal axis super-imposing an electrode rotation into the radial oscillatory movement of the electrode; and controlling the rate of current pulses to the electrode, the oscillation frequency of the electrode, and the rotational speed of the electrode to form a layer of conductive material having a predetermined surface morphology. - View Dependent Claims (19, 20, 21, 22, 23, 24)
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25. A method of forming a self-sharpening cutting blade, comprising the steps of:
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providing a metallic substrate having a first and second side joined together at a top end by a top face; depositing a thin layer of wear-resistant material from an electrode onto the substrate only on the first side and a first portion of the top face of the substrate while the second side and a second portion of the top face remain uncovered by the wear-resistent material, the wear-resistant material being substantially harder than the substrate; and beveling the blade from the first side of the substrate down toward the second side of the substrate forming a cutting edge between the wear-resistant material on the first side of the substrate and the top face of the substrate formed of two materials of different wear resistances; and cutting with the cutting edge so that the second portion of the top face wears at a faster rate than the first portion of the top face thereby increasing the sharpness of the cutting edge formed between the first side and top face of the substrate. - View Dependent Claims (26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38)
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39. A self-sharpening knife, comprising:
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a metallic substrate having a first side and a second side joined together by a top face; a thin layer of wear-resistant material pulse fused only to the first side of the substrate and on an adjacent portion of the top face, the wear-resistant layer having a width, a length, and a thickness, the wear-resistant material being harder than the substrate; the substrate being beveled along the top face from a top end of the first side down to the second side forming a sharpened cutting edge between the first side and the top face of the substrate, the top face forming a composite including the wear-resistant material in the adjacent portion adjacent to the first side of the substrate and the substrate located between the adjacent portion of the top face and the second side of the substrate; and the metallic substrate of the cutting edge wearing at a faster rate than the wear-resistant material thereby maintaining a sharpened cutting edge as the knife is used. - View Dependent Claims (40, 41, 42, 43, 44, 45, 46)
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Specification