A process for preventing burns during EDM cutting of titanium alloys

Abstract

This invention discloses a process for preventing burns during electro-discharge (EDM) cutting of titanium alloys, relating to the field of EDM special processing technology. Specifically, it involves applying a protective paint layer to the area of ​​the titanium alloy workpiece to be cut before performing EDM cutting. This invention pre-forms a protective paint layer on the area of ​​the titanium alloy workpiece to be cut, blocking stray discharges during EDM cutting, suppressing arc generation, and dispersing localized high temperatures. This ensures that only the electrode wire and the workpiece's cutting location undergo controlled discharge erosion, fundamentally preventing EDM burn marks on the titanium alloy workpiece at the cutting location. This effectively improves the surface quality of the titanium alloy workpiece after EDM cutting. Furthermore, this process requires no modification to the EDM cutting equipment, has a simple operation procedure, strong versatility, and is applicable to EDM cutting of titanium alloy workpieces, significantly reducing post-processing costs such as grinding.

Description

Technical Field

[0001] This invention relates to the field of electrical discharge machining technology, and in particular to a process for preventing burns during electrical discharge cutting of titanium alloys. Background Technology

[0002] Electrical discharge machining (EDM) is a widely used processing method in the field of special machining. It relies on the instantaneous high temperature generated by high-frequency pulse discharge to remove metal materials, enabling the machining of complex-shaped workpieces that are difficult to achieve with conventional cutting. It occupies an irreplaceable position in industries such as aerospace, medical devices, and precision manufacturing. Titanium alloys, due to their high specific strength, good corrosion resistance, and excellent biocompatibility, have become the core material in the aforementioned high-end fields. However, their poor thermal conductivity and high chemical reactivity make them more susceptible to stray discharges and arcing phenomena generated by high-frequency pulse discharges during EDM, resulting in severe burns to the workpiece at the cutting location. Furthermore, titanium alloys are prone to chemical reactions with the surrounding medium at high temperatures, further exacerbating the burn defects.

[0003] However, in actual EDM machining of titanium alloys, due to the inherent material properties of titanium alloys and the characteristics of high-frequency pulsed discharge, stray discharge and arcing are easily generated. These uncontrollable discharge forms cause the area around the cut position of the titanium alloy workpiece to be affected by high temperature, resulting in obvious burns and blackening marks. At the same time, a recast layer and microcracks will also form on the workpiece surface, which not only seriously affects the appearance quality of the titanium alloy workpiece, but also reduces its core properties such as corrosion resistance and fatigue strength, adversely affecting subsequent assembly and use. In order to solve the burn problem of EDM, existing technologies mostly adopt methods such as optimizing discharge parameters, increasing the working fluid flushing pressure, and calibrating the electrode wire to try to reduce the generation of stray discharge. However, these methods can only alleviate the degree of burns to a certain extent, and cannot eliminate burn marks at the root. Moreover, there is a lack of special anti-burn solutions for titanium alloys, and existing general solutions have poor adaptability to titanium alloys, making it difficult to meet the high-precision machining requirements of titanium alloy workpieces.

[0004] Furthermore, titanium alloy workpieces generally require high machining precision. After electrical discharge machining (EDM), if burn marks remain at the cut location, fine grinding and polishing are necessary post-processing steps to remove the burn marks and recast layer. However, titanium alloys have high hardness and toughness, making post-processing difficult and inefficient. This not only increases the number of processing steps and production cycle but also raises processing costs. Moreover, grinding can easily cause deviations in workpiece dimensional accuracy, affecting the machining precision of titanium alloy workpieces. Therefore, those skilled in the art are dedicated to developing an EDM process that can fundamentally prevent workpieces from being burned during titanium alloy EDM, and that is simple to implement, requires no equipment modification, and is adapted to the material properties of titanium alloys, in order to solve the aforementioned problems in the existing technology. Summary of the Invention

[0005] In view of the above-mentioned defects in the prior art, the technical problem to be solved by the present invention is that in the existing electric discharge cutting process, titanium alloy workpieces are more prone to burn marks due to stray discharge, electric arc, etc. due to the material characteristics of poor thermal conductivity and high chemical activity. At the same time, defects such as recast layer and microcracks are also present, which seriously affect the core performance and surface quality of titanium alloy workpieces. Existing improvement methods cannot completely eliminate the burn problem of titanium alloy workpieces, and there is a lack of dedicated adaptation solutions. The post-burning post-processing is difficult and costly, and it is easy to cause deviations in the dimensional accuracy of the workpiece.

[0006] To achieve the above objectives, the present invention provides a process for preventing burns during electrical discharge machining (EDM) of titanium alloys, comprising the following steps:

[0007] S10. Pre-treat the area to be cut of the titanium alloy workpiece;

[0008] S20. Apply protective paint to the pre-treated titanium alloy workpiece's area to be cut to form a protective coating.

[0009] S30. Clamp the titanium alloy workpiece coated with protective coating onto the electrical discharge cutting equipment and complete the cutting path positioning.

[0010] S40. Start the electrical discharge cutting equipment and perform electrical discharge cutting on the titanium alloy workpiece along the positioned cutting path;

[0011] S50. After cutting, remove any residual protective paint from the titanium alloy workpiece and perform a final cleaning.

[0012] Preferably, the pretreatment in step S10 is to remove oil, scale and dust from the area of ​​the titanium alloy workpiece to be cut, and to keep the area of ​​the titanium alloy workpiece to be cut dry.

[0013] Preferably, the protective paint in step S20 is an insulating and high-temperature resistant paint, the protective coating is a uniformly applied continuous coating, and the protective coating covers the preset areas on both sides of the cutting line.

[0014] Preferably, the protective paint does not carbonize or stick in high-temperature environments and does not chemically react with titanium alloy materials. The protective paint has moderate adhesion, making it easy to peel off after cutting without leaving any residue.

[0015] Preferably, after applying the protective paint in step S20, the protective coating is cured by air drying at room temperature or drying at low temperature. Air drying at room temperature means that the coating is cured naturally in a clean and ventilated environment at room temperature, while drying at low temperature means that the coating is cured rapidly in a constant temperature environment at low temperature.

[0016] Preferably, the positioning in step S30 is to align the electrode wire of the electrical discharge cutting device with the center line of the area covered by the protective coating.

[0017] Preferably, the processing parameters for electrical discharge cutting in step S40 are low-energy, high-frequency, and small-pulse-width discharge parameters, and working fluid is continuously supplied to the processing area for flushing and cooling during the cutting process.

[0018] Preferably, the working fluid is continuously purged and cooled in such a way that the working fluid fully covers the discharge contact area between the electrode wire and the titanium alloy workpiece.

[0019] Preferably, in step S50, residual protective paint is removed by wiping or peeling, and the titanium alloy workpiece after paint removal is cleaned with a cleaning solution. After cleaning, the workpiece is allowed to air dry or dried by baking.

[0020] The present invention also provides a workpiece processing method that applies the above-mentioned anti-burn process for titanium alloy EDM cutting. The anti-burn process for titanium alloy EDM cutting is applied to the wire EDM cutting of titanium alloy workpieces. By using a protective coating to block stray discharge, suppress electric arc, and disperse local high temperature, the electrode wire and the position to be cut of the titanium alloy workpiece can be controlled to discharge and erode.

[0021] Compared with the prior art, the technical effects of the present invention are as follows:

[0022] (1) In view of the material characteristics of titanium alloy with poor thermal conductivity and high chemical activity, the present invention forms a protective coating by pre-coating the area to be cut with a protective paint with a thickness of less than 0.2 mm. The protective paint has insulation and high temperature resistance, which blocks stray discharge during the electric spark cutting process and suppresses the generation of electric arc. At the same time, it can disperse the local high temperature generated by the discharge, so that the discharge process only occurs between the electrode wire and the position to be cut of the titanium alloy workpiece. This achieves controllable discharge erosion, which avoids the electric spark burn marks on the titanium alloy workpiece at the cutting position from the root. It completely solves the problems of burning, blackening, recasting layer and micro cracks after cutting titanium alloy workpieces in the prior art, and greatly improves the surface quality and core performance of titanium alloy workpieces.

[0023] (2) The anti-burn process for titanium alloy EDM cutting of the present invention only adds pretreatment, coating of protective paint and removal of residual paint to the existing EDM cutting process. No modification is required to the EDM cutting equipment. The process is simple to operate and has low technical requirements for operators. It is specially adapted to EDM cutting of titanium alloy materials.

[0024] (3) By precisely controlling the thickness of the protective coating to be less than 0.2mm, the present invention not only ensures the anti-burn protection effect, but also avoids the coating being too thick and affecting the cutting accuracy. At the same time, the optimized curing method realizes the efficient and stable film formation of the coating, which is suitable for the high-precision processing requirements of titanium alloy workpieces.

[0025] (4) The present invention eliminates the burn marks on titanium alloy workpieces, and eliminates the need for complex grinding, polishing and other post-processing procedures on the cut titanium alloy workpieces. This greatly reduces the difficulty and cost of titanium alloy post-processing, shortens the production cycle, and avoids the workpiece size accuracy deviation that may be caused during post-processing, thus ensuring the processing accuracy of titanium alloy workpieces.

[0026] (5) The protective paint selected in this invention does not react chemically with titanium alloy materials, and is easy to peel off after cutting without leaving any residue. It will not have any adverse effects on the material and performance of titanium alloy. At the same time, the protective paint has a low cost, which further reduces the overall processing cost of titanium alloy workpieces. Detailed Implementation

[0027] The following description, with reference to the specification, introduces several preferred embodiments of the present invention to make its technical content clearer and easier to understand. The present invention can be embodied in many different forms, and the scope of protection of the present invention is not limited to the embodiments mentioned herein.

[0028] Example 1

[0029] This embodiment provides a specific implementation of a process for preventing burns during EDM cutting of titanium alloys. Taking the EDM wire cutting of TC4 titanium alloy precision aerospace parts as an example, the process steps, operation methods, and working principles of this invention are explained in detail. In this embodiment, the workpiece is made of TC4 titanium alloy, and the area to be cut is the irregular contour cutting area of ​​the workpiece. After cutting, the cut surface is required to be free of burns and blackening marks, with a surface roughness Ra≤1.6μm, and the thickness of the protective coating is strictly controlled within the range of less than 0.2mm.

[0030] S10. Pre-treat the area to be cut of the titanium alloy workpiece.

[0031] Select the TC4 titanium alloy precision aerospace parts to be processed. First, use fine-grit sandpaper to gently sand the irregular contour area of ​​the workpiece to be cut, removing the oxide scale and raised dust particles from the surface. After sanding, use a lint-free cloth soaked in anhydrous ethanol to repeatedly wipe the sanded area to be cut, wiping in the same direction to ensure that oil stains, residual dust and sanding debris are completely removed from the surface of the workpiece. At the same time, avoid excessive wiping force to scratch the titanium alloy surface. After wiping, place the workpiece in a clean and ventilated environment at 25°C to air dry naturally for 10 minutes, so that the area of ​​the titanium alloy workpiece to be cut is completely dry, with no moisture or cleaning fluid residue, to ensure the effect of subsequent protective paint coating.

[0032] The working principle of this step is as follows: removing impurities such as oil, scale, and dust from the area of ​​the titanium alloy workpiece to be cut can prevent impurities from affecting the adhesion between the protective paint and the titanium alloy surface, and prevent problems such as peeling or missed coating of the protective coating. At the same time, keeping the area to be cut dry can prevent moisture from causing defects such as pinholes and bubbles after the protective paint has cured, ensuring the continuity and uniformity of the protective coating. It also prevents impurities from reacting chemically with the highly chemically active titanium alloy at the high temperature of cutting, which would aggravate the burning of the workpiece.

[0033] S20. Apply protective paint to the pre-treated titanium alloy workpiece's area to be cut to form a protective coating.

[0034] A high-temperature resistant, insulating epoxy protective paint suitable for titanium alloy materials is selected. This paint has a high breakdown voltage, excellent high-temperature resistance, and does not carbonize or stick under the high-temperature environment of EDM cutting. It also does not chemically react with TC4 titanium alloy materials, exhibits moderate adhesion, facilitates subsequent peeling, and leaves no residue. The protective paint is applied evenly to the pre-treated irregular contour area of ​​the workpiece to be cut using a spraying method. During spraying, the paint output and movement speed of the spray gun are precisely controlled to ensure a continuous and uniform protective coating, free from defects such as missed areas, runs, and pinholes. The thickness of the protective coating is strictly controlled to 0.15mm (less than 0.2mm), covering the pre-defined areas on both sides of the cutting line to form a complete protective layer. After spraying, the protective coating is cured by natural air drying at room temperature. The workpiece is placed in a clean, well-ventilated environment at 25℃ and 60% relative humidity for 20 minutes to allow natural film formation and curing through air convection, resulting in a fully cured protective layer with good insulation and high-temperature resistance.

[0035] The working principle of this step is as follows: Utilizing the insulating properties of the protective paint, an insulating layer is formed on the surface of the titanium alloy workpiece to be cut, which can block stray discharges during the electric spark cutting process and prevent stray discharges from burning the titanium alloy surface. The high-temperature resistance of the protective paint ensures that it will not carbonize or stick under the high-temperature environment generated by the discharge, maintaining its protective performance at all times, and it does not chemically react with the titanium alloy, avoiding aggravating material damage. Controlling the thickness of the protective coating to less than 0.2mm ensures both the density and protective effect of the protective layer, while avoiding an excessively thick coating that would obstruct the discharge path of the electrode wire and affect cutting accuracy. The uniform and continuous protective coating can fully cover the area to be cut and its surroundings, ensuring no blind spots in protection. At the same time, the moderate adhesion ensures that the protective coating will not fall off during the cutting process and is easy to remove after cutting. The room temperature natural air drying curing method achieves gentle film formation of the coating, ensuring the adhesion between the coating and the titanium alloy surface.

[0036] S30. Clamp the titanium alloy workpiece coated with a protective coating onto the EDM equipment and complete the cutting path positioning.

[0037] Precision aerospace parts made of TC4 titanium alloy, coated with a protective layer, are clamped onto the worktable of an EDM wire cutting machine using a flexible special fixture. During clamping, the workpiece position is adjusted to ensure that the workpiece's machining datum coincides with the machine's worktable positioning datum. Appropriate clamping force is applied, utilizing the buffering characteristics of the flexible fixture to ensure the workpiece remains stable and does not shift, while avoiding excessive clamping force that could damage the titanium alloy workpiece surface and protective coating, and preventing workpiece displacement during cutting that could affect cutting accuracy. After clamping, the cutting path parameters are input into the EDM wire cutting machine's CNC system, and the machine's positioning function is activated. This allows the machine's electrode wire to slowly move to the workpiece's cutting area, precisely aligning with the center line of the area covered by the protective coating. Once positioning is complete, the electrode wire's position is locked to ensure that it moves along the center line of the protective coating during cutting.

[0038] The working principle of this step is as follows: The reliable clamping of the flexible special fixture ensures that the position of the titanium alloy workpiece is fixed during the cutting process, avoiding deviations in the cutting path and damage to the protective coating due to workpiece loosening or offset. At the same time, it is adapted to the characteristic that titanium alloy material is susceptible to stress damage. The electrode wire is aligned with the center line of the protective coating, so that the discharge process only occurs at the contact point between the electrode wire and the titanium alloy workpiece to be cut, ensuring that the protective coating can effectively protect the surrounding area, while ensuring the cutting accuracy of the titanium alloy workpiece.

[0039] S40. Start the electrical discharge cutting equipment and perform electrical discharge cutting on the titanium alloy workpiece along the positioned cutting path.

[0040] After positioning, the wire EDM machine is started, and the EDM processing parameters are set to low energy, high frequency, and small pulse width discharge parameters, specifically high-frequency pulse discharge. The ratio of pulse interval to pulse width is set reasonably to ensure low-energy discharge erosion, adapting to the poor thermal conductivity of titanium alloy and reducing heat accumulation. During the cutting process, a special EDM emulsion is continuously supplied as the working fluid to the discharge contact area between the electrode wire and the titanium alloy workpiece. The supply pressure of the working fluid is kept stable to ensure that the working fluid fully covers the discharge contact area and achieves continuous flushing cooling. The machine tool drives the electrode wire to perform irregular contour cutting on the titanium alloy workpiece along the positioned cutting path. During the processing, a controllable high-frequency pulse discharge is generated between the electrode wire and the titanium alloy workpiece at the cutting position. The high temperature generated by the discharge only erodes the metal material at the electrode wire contact position. The protective coating with a thickness of less than 0.2 mm effectively blocks stray discharge, suppresses the generation of arc, and disperses the local high temperature generated by the discharge, preventing the high temperature from spreading to the surrounding area and preventing severe burns and chemical reactions of the titanium alloy due to high temperature accumulation.

[0041] The working principle of this step is as follows: Low-energy, high-frequency, and small-pulse-width discharge parameters can reduce the heat generated by the discharge, reduce the impact of high temperature on titanium alloy workpieces with poor thermal conductivity, and ensure cutting efficiency; continuous flushing and cooling of the working fluid can promptly remove metal debris generated by the discharge, and further reduce the temperature of the discharge area, reduce high temperature accumulation, and avoid chemical reactions such as oxidation of titanium alloy due to high temperature; the insulating and high-temperature resistant properties of the protective coating block stray discharge and arc from the source, so that the discharge process is always under control, and only the electrode wire can accurately erode the position to be cut on the titanium alloy workpiece, avoiding burns on the surface of the titanium alloy workpiece, and the precisely controlled coating thickness will not affect the discharge and cutting accuracy of the electrode wire.

[0042] S50. After cutting, remove any residual protective paint from the titanium alloy workpiece and perform a post-cleaning process.

[0043] After the wire EDM machine completes the preset cutting path, shut down the machine and the working fluid supply system. Once the titanium alloy workpiece has cooled to room temperature, remove it from the flexible fixture. Use a lint-free cloth dampened with a special paint remover to repeatedly wipe away any remaining protective paint from the workpiece surface. Apply gentle pressure during wiping to ensure complete removal of the protective paint without scratching the surface of the titanium alloy workpiece. After removing the residual paint, rinse the workpiece in clean water to remove the paint remover and paint debris. After rinsing, allow the workpiece to air dry in a clean, well-ventilated environment. Once dry, inspect the cut areas to ensure there is no paint residue, burn marks, or blackening.

[0044] The working principle of this step is as follows: using a paint stripping and cleaning solution that matches the protective paint can quickly and effectively remove residual protective paint without corroding the titanium alloy material; rinsing with clean water can remove the cleaning solution and debris from the surface, preventing residual impurities from affecting the surface quality and corrosion resistance of the titanium alloy workpiece; natural air drying can avoid the impact of high-temperature drying on the precision of the titanium alloy workpiece, ensuring the machining accuracy and surface performance of the workpiece, while preventing oxidation of the titanium alloy during the drying process.

[0045] After this embodiment was completed, the cutting position of the TC4 titanium alloy precision aerospace part was inspected. The results showed that the cut surface was bright, without any electrical spark burns, blackening marks, recast layer and microcracks, the residual thickness of the protective coating was 0, and the surface roughness Ra reached 1.2μm, which met the high precision machining requirements of titanium alloy aerospace parts. Moreover, the dimensional accuracy of the workpiece was consistent with the preset parameters and there was no deviation.

[0046] Example 2

[0047] This embodiment provides a specific implementation method for workpiece processing using a titanium alloy EDM anti-burn process. Taking the EDM wire cutting of TA2 pure titanium medical precision parts as an example, TA2 pure titanium has excellent biocompatibility and is a core titanium alloy material used in medical device manufacturing. After EDM cutting, the cut surface must be free of burns, recast layers, and have a smooth surface to ensure the biocompatibility and safety of the medical parts. In this embodiment, the titanium alloy EDM anti-burn process of this invention is applied to the processing of this TA2 pure titanium workpiece, and the protective coating thickness is controlled within the range of less than 0.2 mm. The application method, process adjustment, and working principle are explained in detail.

[0048] Step 1: Pre-treatment of the area to be cut on the titanium alloy workpiece

[0049] Select a TA2 pure titanium medical precision part to be processed. The area to be cut is the micropore contour area of ​​the workpiece. First, sandblasting is used to remove the dense oxide scale and surface oil stains in the area to be cut. Fine sand particles are used in the sandblasting process, and the pressure is moderate to avoid excessive damage to the titanium alloy surface. After sandblasting, compressed air is used to blow the sandblasted area to remove residual sand particles and dust. Then, a lint-free cloth soaked in acetone is used to repeatedly wipe the area to be cut after blowing to remove residual oil stains and fine dust that was not removed by compressed air. After wiping, the workpiece is placed in a clean and ventilated place at 22°C to air dry naturally for 15 minutes to ensure that the area to be cut is completely dry and free of any impurities and moisture residue. To meet the high precision and high surface quality requirements of TA2 pure titanium medical parts, the pretreatment in this step adopts sandblasting + acetone wiping. Compared with simple sandpaper polishing, sandblasting can more thoroughly remove the dense oxide scale on the surface of pure titanium. At the same time, the fine sand particles will not cause excessive damage to the titanium alloy surface, ensuring effective adhesion between the protective paint and the titanium alloy workpiece surface, while preventing impurities from affecting the safety of subsequent use of medical parts.

[0050] Step 2: Coating and curing of protective paint

[0051] A silicone-based insulating high-temperature protective paint with superior high-temperature resistance, specifically formulated for pure titanium, is selected. This paint boasts higher temperature resistance, making it suitable for the slightly higher heat generated during electrical discharge cutting due to the poor thermal conductivity of titanium alloys. Furthermore, this paint exhibits no chemical reaction with TA2 pure titanium, exhibits moderate adhesion, and is easy to remove subsequently, fully meeting the material requirements for medical parts. Since the micropore contour area of ​​medical parts is a small, irregular curved surface, this step employs a microneedle dot coating + light brushing method to apply the protective paint. Precise control of the coating amount ensures uniform application of the protective coating to the surface to be cut along the micropore contour, forming a continuous, seamless, and uniform protective coating. The coating thickness is strictly controlled to 0.1mm (less than 0.2mm), covering the pre-defined areas on both sides of the cutting line and completely enveloping the area to be cut along the micropore contour. After coating, considering the high precision requirements of medical parts, a low-temperature drying method was used to cure the protective coating. The workpiece was placed in a low-temperature constant-temperature drying equipment, and the drying temperature was set to 50℃ to achieve rapid film formation and curing of the coating. The workpiece was dried at this constant temperature for 30 minutes. After drying, the workpiece was removed and allowed to cool to room temperature. The cured protective coating showed no cracking or peeling and exhibited good insulation and high-temperature resistance. For the micro-complex structure of the micropores in TA2 pure titanium, a microneedle dot coating + light brushing method was used to precisely control the coating amount and thickness, preventing excessive coating thickness from clogging the micropores. Simultaneously, the low-temperature drying curing method accelerated the coating curing speed while achieving rapid film formation at a constant temperature. This avoided the impact of high temperatures on the pure titanium metallographic structure, ensuring the material properties and biocompatibility of the workpiece, while also improving production efficiency and meeting the batch processing requirements of medical parts.

[0052] Step 3: Clamping and cutting path positioning of titanium alloy workpieces

[0053] The TA2 pure titanium medical precision parts coated with a protective coating are clamped onto the worktable of an EDM wire cutting machine using a vacuum adsorption fixture. The adsorption surface of the vacuum adsorption fixture is a non-machined area to avoid damage to the protective coating and the area to be cut. During clamping, the workpiece's level is adjusted using a level to ensure that the workpiece remains parallel to the machine's worktable. The vacuum adsorption pressure is stable to ensure that the workpiece does not loosen or shift, while also preventing the fixture from causing mechanical damage to the tiny medical parts. After clamping, the CAD drawing of the micro-hole contour is imported into the CNC system of the EDM wire cutting machine to generate a fine cutting path. The machine's positioning function is activated to precisely align the electrode wire with the center line of the area covered by the protective coating. For the tiny and complex structure of the micro-hole contour, a micron-level segmented positioning method is used to calibrate key positions such as corners and arcs of the contour one by one, ensuring that the electrode wire remains aligned with the center line of the protective coating throughout the entire cutting path. After positioning, the machine's motion axis is locked.

[0054] Step 4: Electrical Discharge Cutting

[0055] After positioning, the wire EDM machine is started. Based on the material characteristics of TA2 pure titanium, the discharge parameters are appropriately adjusted to reduce the energy of a single discharge, ensuring sufficient energy to effectively remove the pure titanium while maintaining low-energy discharge to avoid excessive heat accumulation, thus adapting to the poor thermal conductivity of pure titanium. During the cutting process, a micro-flow, high-pressure flushing method continuously supplies EDM-specific deionized water to the machining area of ​​the micro-hole contour. The working fluid is precisely supplied from the micro-flushing port, ensuring that it fully penetrates the small, complex area of ​​the micro-hole contour, completely covering the discharge contact area between the electrode wire and the titanium alloy workpiece, achieving sufficient flushing cooling and chip removal. During the processing, the electrode wire performs electrical discharge cutting on the micro-hole contour of the TA2 pure titanium medical parts along the preset cutting path. The 0.1mm thick protective coating effectively blocks stray discharge and suppresses the generation of electric arc due to its good insulation and high temperature resistance. Even when the heat of pure titanium cutting is slightly high, the protective coating can still maintain its complete protective performance, disperse local high temperature, and make the discharge process only occur between the electrode wire and the titanium alloy workpiece to be cut, so as to achieve controllable erosion processing and avoid burn marks on the micro-hole cutting surface of the TA2 pure titanium medical parts. At the same time, the ultra-thin protective coating does not affect the cutting accuracy of the micro-hole.

[0056] Step 5: Residual paint removal and post-cleaning

[0057] After the micro-pore contour cutting of the TA2 pure titanium medical parts is completed, the machine tool and working fluid supply system are turned off. Once the workpiece has cooled to room temperature, it is removed from the vacuum suction fixture. First, a soft cotton swab dipped in a special paint stripping cleaning solution is used to gently wipe away any residual protective coating on and inside the micro-pore contour. For minor paint residue in the corners and crevices of the micro-pores, a fine soft brush is used to gently scrub, ensuring no paint residue remains. Avoid using hard brushes during the scrubbing process to prevent scratching the pure titanium surface and to maintain the surface smoothness of the medical parts. After the residual paint is completely removed, the workpiece is placed in an ultrasonic cleaner and ultrasonically cleaned for 10 minutes with medical-grade pure water to remove the paint stripping cleaning solution, paint debris, and metal fragments generated during cutting. After ultrasonic cleaning, the workpiece is removed and rinsed again with medical-grade pure water. Then, the workpiece is placed in a low-temperature drying oven and dried at 60°C for 20 minutes to achieve rapid drying. After drying, it is removed and cooled to room temperature. For the microporous microstructure and high surface quality requirements of TA2 pure titanium medical precision parts, the method of wiping with cotton swabs and brushing with ultra-fine soft brushes can thoroughly remove residual paint without damaging the workpiece surface. Ultrasonic cleaning with medical-grade pure water can effectively clean the fine impurities in the corners and gaps of the micropores, ensuring the cleanliness and biocompatibility of the workpiece surface. Low-temperature drying can quickly dry the workpiece while avoiding the impact of high temperature on the pure titanium material.

[0058] After this embodiment was completed, the micro-hole cutting surface of the TA2 pure titanium medical precision parts was inspected. The results showed that the micro-hole cutting surface had no burns, blackening marks, recast layer and microcracks. The surface roughness Ra of the cutting surface reached 1.0μm. The dimensional accuracy and contour accuracy of the microholes met the design requirements of medical parts. There were no paint residues or impurities on the workpiece surface. The biocompatibility met the standards and fully met the processing and use requirements of medical titanium alloy parts.

[0059] This invention provides a burn-proof process for EDM cutting of titanium alloys, specifically designed for EDM machining of titanium alloys. Addressing the core material characteristics of titanium alloys—poor thermal conductivity and high chemical reactivity—it achieves burn-free cutting of titanium alloy workpieces by precisely controlling the protective coating thickness to less than 0.2mm, combined with optimized curing methods and process steps. This process can be widely applied to EDM wire cutting of precision parts made of various titanium alloys such as TC4, TA2, and TA15. For different grades of titanium alloy workpieces with varying shapes and precision requirements, only the coating method and discharge parameters of the protective paint need to be adjusted according to the actual situation to achieve excellent burn-proof performance. The process is highly versatile, flexible in operation, and fully adaptable to the high-precision machining requirements of titanium alloy workpieces in aerospace, medical devices, and precision manufacturing fields.

[0060] The preferred embodiments of the present invention have been described in detail above. It should be understood that those skilled in the art can make numerous modifications and variations based on the concept of the present invention without creative effort. Therefore, all technical solutions that can be obtained by those skilled in the art based on the concept of the present invention through logical analysis, reasoning, or limited experimentation on the basis of existing technology should be within the scope of protection defined by the claims.

Claims

1. A process for preventing burns during electro-discharge cutting of titanium alloys, characterized in that, Includes the following steps: S10. Pre-treat the area to be cut of the titanium alloy workpiece; S20. Apply protective paint to the pre-treated titanium alloy workpiece's area to be cut to form a protective coating. S30. Clamp the titanium alloy workpiece coated with protective coating onto the electrical discharge cutting equipment and complete the cutting path positioning. S40. Start the electrical discharge cutting equipment and perform electrical discharge cutting on the titanium alloy workpiece along the positioned cutting path; S50. After cutting, remove any residual protective paint from the titanium alloy workpiece and perform a final cleaning.

2. The anti-burn process for titanium alloy EDM cutting as described in claim 1, characterized in that, The pretreatment in step S10 is to remove oil, scale and dust from the area of ​​the titanium alloy workpiece to be cut, and to keep the area of ​​the titanium alloy workpiece to be cut dry.

3. The anti-burn process for titanium alloy EDM cutting as described in claim 1, characterized in that, The protective paint in step S20 is an insulating and high-temperature resistant paint, and the protective coating is a uniformly applied continuous coating that covers the preset areas on both sides of the cutting line.

4. The anti-burn process for titanium alloy EDM cutting as described in claim S30, characterized in that, The protective paint does not carbonize or stick in high-temperature environments and does not chemically react with titanium alloy materials. The protective paint has moderate adhesion, making it easy to peel off after cutting without leaving any residue.

5. The anti-burn process for titanium alloy EDM cutting as described in claim 1, characterized in that, In step S20, after applying the protective paint, the protective coating is cured by air drying at room temperature or drying at low temperature. Air drying at room temperature means that the coating is naturally cured in a clean and ventilated environment at room temperature. Drying at low temperature means that the coating is rapidly cured in a constant temperature environment at low temperature.

6. The anti-burn process for titanium alloy EDM cutting as described in claim 1, characterized in that, The positioning in step S30 is to align the electrode wire of the electrical discharge cutting equipment with the center line of the area covered by the protective coating.

7. The anti-burn process for titanium alloy EDM cutting as described in claim 1, characterized in that, In step S40, the electrical discharge cutting parameters are low energy, high frequency, and small pulse width discharge parameters, and working fluid is continuously supplied to the processing area for flushing and cooling during the cutting process.

8. The anti-burn process for titanium alloy EDM cutting as described in claim 7, characterized in that, The working fluid is continuously flushed and cooled to ensure that it fully covers the discharge contact area between the electrode wire and the titanium alloy workpiece.

9. The anti-burn process for titanium alloy EDM cutting as described in claim 1, characterized in that, In step S50, residual protective paint is removed by wiping or peeling, and the titanium alloy workpiece after paint removal is cleaned with cleaning fluid. After cleaning, the workpiece is allowed to air dry or dried by baking.

10. A workpiece processing method using the anti-burn process for titanium alloy EDM cutting according to any one of claims 1-9, characterized in that, The aforementioned anti-burn technology for EDM of titanium alloy workpieces is applied to the wire EDM process of titanium alloy workpieces. By using a protective coating to block stray discharge, suppress electric arc, and disperse local high temperature, the electrode wire and the position to be cut of the titanium alloy workpiece can be controlled to discharge and erode.