Water-jet guided laser composite drilling device and method

Abstract

The invention belongs to the technical field of precision non-traditional machining, and relates to a water-jet-guided laser composite drilling machining device and method, which comprises a control system, a water-jet-guided laser electric spindle, a water jet device, a laser module and a three-axis motion platform. In-situ laser heating pretreatment is utilized, materials are subjected to thermal modification, the hardness of the materials is reduced, an initial guide hole is formed, then water jet and a drill bit are coupled for synchronous machining, the hardness of the materials is reduced, meanwhile, microcracks are inhibited, the surface of a tool and the inner wall of the hole are prevented from being coated with slag, and real-time removal of cuttings is promoted; the problems that in the cutting process, the heat affected zone is large, the hole wall quality is poor, cuttings are difficult to remove, and a tool is seriously abraded are solved, and high-precision, high-efficiency and low-damage drilling machining of metal-based, ceramic-based and other difficult-to-machine composite material thick plate holes is met.

Description

Technical Field

[0001] This invention belongs to the field of precision special machining technology, and in particular relates to a water-guided laser composite drilling processing device and method. Background Technology

[0002] Metal-based and ceramic-based composite materials, which are difficult to machine, possess excellent properties such as high strength, low density, and wear resistance. Components produced from these materials are widely used in aerospace, defense, and electronics industries (e.g., tubular supports, stator blades, combustion chamber flame tubes, and high-temperature connectors). However, during conventional machining, the high hardness and brittleness of these composite materials result in poor hole wall quality, high roughness, difficult chip removal, and severe tool wear, making it difficult to meet the high-efficiency, high-quality machining requirements of high-end equipment components. Water-guided laser machining technology uses high-pressure water to guide the laser beam, effectively cooling the machining area and flushing away molten slag. However, due to uneven laser energy distribution, water jet stability, and the characteristics of the processed materials, the machined holes often deviate from the designed diameter, resulting in holes that are too large or too small, roundness exceeding allowable limits, high hole wall roughness, and residue adhesion, making it difficult to meet the application requirements of high-end equipment components. Existing technologies, such as patent CN 109676380 B, use laser-assisted material softening, but lack the simultaneous cooling and chip removal capabilities of water jets, resulting in high residual thermal stress and poor hole wall quality in the machined parts. Patent CN 114406449 B employs a step-by-step processing method, first using water-guided lasers and continuous lasers to perform spiral scanning processing on the upper and lower surfaces, and then using a drill bit to complete the final processing step, solving the problem of low processing efficiency for holes larger than 6mm in complex and difficult-to-machine materials. However, its fixed water jet nozzle cannot achieve dynamic parameter matching in deep hole processing, leading to energy attenuation and chip accumulation, and the processing method is complex, requiring frequent process switching.

[0003] Therefore, there is an urgent need for a high-efficiency precision machining device and method with low-damage processing characteristics to improve the machining accuracy and efficiency of holes in thick plates of difficult-to-machine composite materials such as metal matrix and ceramic matrix, reduce the processing cost of composite materials, and meet the high reliability and long service life requirements of difficult-to-machine composite material parts such as metal matrix and ceramic matrix. Summary of the Invention

[0004] The technical problem to be solved by this invention is to provide a water-guided laser composite drilling device and method, which utilizes in-situ laser heating pretreatment to thermally modify the material, reduce its hardness, and form an initial guide hole. Then, a water jet is coupled with the drill bit for synchronous processing, which reduces the material hardness while inhibiting microcracks and slag coating on the tool surface and the inner wall of the hole, and promotes real-time chip removal. This solves the problems of large heat-affected zone, poor hole wall quality, difficulty in chip removal, and severe tool wear during the cutting process, and meets the requirements of high-precision, high-efficiency, and low-damage drilling of thick plates of difficult-to-machine composite materials such as metal matrix and ceramic matrix.

[0005] A water-guided laser composite drilling device is disclosed. The device is installed on a marble platform and includes a control system, a water-guided laser electric spindle, a water jet device, a laser module, and a three-axis motion platform. The water-guided laser electric spindle includes a water-guided laser rotary joint, a hollow spindle, a channel connector, an ER tool holder, and an ER chuck. The chuck fixes a drill bit with micro-holes onto the ER tool holder. The drill bit with micro-holes has a micro-hole array structure with a diameter of 50-200μm. The micro-hole array structure is centrally symmetrical on the chip removal groove, with the included angle between the micro-hole axes being 15°-30° and the included angle between the micro-hole axes and the drill bit axis being 15°-30°. The coaxiality error is ≤5μm. Under high-pressure jet conditions, the micro-hole array structure forms a vortex jet field through the micro-holes, utilizing the Bernoulli effect to remove chips.

[0006] The water-guided laser rotary connector includes a water-guided laser rotary connector end cap, a focusing lens, a sapphire optical window, and a water-guided laser channel.

[0007] The water jet device includes a pressure tank and a hydraulic tank, which are connected to the water-guided laser electric spindle via a water-guided laser rotary joint.

[0008] The laser module includes a reflector, a laser, a focusing lens, and a water-cooled box volume laser controller. The laser emitted from the laser enters the water-guided laser electric spindle through the reflector and hits the workpiece through the water-guided laser channel.

[0009] The three-axis motion platform includes a Z-axis slide, an X-axis slide, and a Y-axis slide, with a stage equipped with a pressure sensor mounted on the Z-axis slide.

[0010] The control system integrates a pressure sensor, an infrared temperature measurement module, and an adaptive control algorithm unit to dynamically adjust laser power, water pressure, and spindle speed according to the processing depth.

[0011] A water-guided laser composite drilling method, employing a water-guided laser composite drilling device, includes the following steps, which are performed sequentially:

[0012] Step 1: Use ANSYS Workbench finite element simulation software to perform laser heating simulation and water-guided laser composite cutting simulation.

[0013] Step 2: Install and fix the workpiece onto the stage with pressure sensor, select the corresponding micro-hole drill bit according to the size of the hole to be processed, and fix it on the water-conducting laser electric spindle through the ER chuck;

[0014] Step 3: Control the X, Y, and Z axes through the control system to return the machine tool to zero, activate the laser's infrared positioning, and confirm the machining position;

[0015] Step 4: Open the machining program in the control system, set the parameters based on the parameters in Step 1, and perform water-guided laser composite drilling.

[0016] 1) First, perform continuous laser irradiation for 10-30 seconds to heat the material surface to the softening point and form a 0.1-0.3mm guide hole;

[0017] 2) Then, the water jet coupled laser and the drill bit are turned on for synchronous processing. The drilling and the water-guided laser beam work together, the water pressure is increased according to the gradient, and the laser power is linearly reduced.

[0018] Step 5: After the hole is machined, the control system first turns off the laser and then retracts the tool. During the retraction process, the high-pressure jet forms a spiral scouring effect through the microhole. Finally, the water jet is turned off.

[0019] Through the above design scheme, the present invention can bring the following beneficial effects:

[0020] 1. The water-guided laser composite drilling method of the present invention uses in-situ laser preheating and water-guided laser beam and drill bit to process thick plate holes simultaneously, which can realize uniform processing of high depth-to-diameter ratio holes in difficult-to-machine materials (processing depth-to-diameter ratio > 10:1), while reducing the heat-affected zone (heat-affected zone thickness ≤ 50 μm) and the drilling force during the drilling process (drilling force is reduced by 40% compared with traditional drilling), improving the integrity of the inlet and outlet holes, the perpendicularity of the hole wall and the surface roughness (hole wall roughness Ra ≤ 0.8 μm) after processing, and improving the processing quality of parts;

[0021] 2. The water-guided laser composite drilling method of the present invention can remove burrs and chips in the hole in real time by forming a high-pressure jet on the chip removal spiral groove of the drill bit (the removal efficiency is improved by 60%), improve the surface finish and machining accuracy, reduce tool wear, increase tool life (compared to traditional drilling, tool life is increased by 3-5 times), shorten the process changeover time, and save processing costs.

[0022] 3. The water-guided laser composite drilling device of the present invention can dynamically adjust the laser power, water pressure and drilling parameters to adapt to the processing of various materials (silicon carbide, titanium alloy, etc.).

[0023] 4. The water-guided laser composite drilling and machining device of the present invention has a simple design and is easy to operate. It can dynamically adjust the water flow parameters and laser parameters according to the machining depth, and does not require frequent switching of processes. It is easy to disassemble and avoids readjusting the tool spacing during tool changing, thereby improving machining efficiency. Attached Figure Description

[0024] The present invention will be further described below with reference to the accompanying drawings and specific embodiments:

[0025] Figure 1 This is a schematic diagram of the structure of the water-guided laser composite drilling device of the present invention.

[0026] Figure 2 This is a schematic diagram of the water-guided laser electric spindle structure of the water-guided laser composite drilling device of the present invention.

[0027] Figure 3 This is a schematic diagram of the water-guided laser rotary joint structure of the water-guided laser composite drilling device of the present invention.

[0028] Figure 4 This is a schematic diagram of the structure of the water-guided laser composite drilling device with micro-hole drill bit of the present invention.

[0029] Figure 5 This is a schematic diagram of the channel connector structure of the water-guided laser composite drilling device of the present invention.

[0030] In the diagram, 1-pressure tank, 2-hydraulic tank, 3-water-guided laser rotary joint, 4-reflector, 5-laser, 6-water-guided laser electric spindle, 7-drill bit with micro-hole, 8-stage with pressure sensor, 9-Z-axis slide, 10-X-axis slide, 11-Y-axis slide, 12-water-guided laser rotary joint end cap, 13-focusing lens, 14-sapphire optical window, 15-water-guided laser channel, 16-hollow spindle, 17-channel connector, 18-ER tool holder, 19-ER chuck. Detailed Implementation

[0031] A water-guided laser composite drilling device is suitable for efficient and precise machining of high-hardness, difficult-to-machine materials (such as ceramics, silicon carbide, metal-based and ceramic-based composite materials) and thick plate holes. Through the coaxial coupling of the water jet and the laser, it achieves low thermal damage, high-precision drilling, and real-time chip removal. Figures 1-5 As shown, the entire device is installed on a marble platform and includes a control system, a water-guided laser electric spindle, a water jet device, a laser module, and a three-axis motion platform.

[0032] The control system integrates pressure sensors, infrared temperature measurement modules, and adaptive control algorithms to dynamically adjust laser power (5%-10% increase per 1mm depth), water pressure (0.5-1MPa increase per 1mm), and spindle speed according to the processing depth.

[0033] The water-guided laser electric spindle 6 is coaxially integrated with the drill bit 7 with micro-holes. The chip removal groove of the drill bit is provided with a micro-hole array with a diameter of 50-200μm. The array of micro-holes is centrally symmetrical when connected on the chip removal groove. The included angle between the axes of the micro-holes is 15°-30°. The included angle between the axis of the micro-holes and the axis of the drill bit is 15°-30°. The coaxiality error is ≤5μm.

[0034] This structure can form a vortex jet field through micropores in a high-pressure jet system, and remove chips by utilizing the Bernoulli effect.

[0035] Bernoulli's equation describes the relationship between velocity and pressure in a steady flow process of an ideal fluid:

[0036]

[0037] Where P is the static pressure, ρ is the fluid density, v is the flow velocity, g is the acceleration due to gravity, and h is the height. In horizontal flow and ignoring the effect of gravity, the static pressure decreases in regions where the flow velocity increases, and vice versa.

[0038] In water-guided laser composite drilling, high-pressure jets are ejected at high speed through micro-holes in the drill bit's chip removal grooves, forming a specific flow pattern (such as a vortex jet), with the following specific effects:

[0039] (1) Formation of local low-pressure areas

[0040] When high-pressure water is ejected at high speed through micro-holes, the flow velocity is highest at the center of the jet. According to the Bernoulli effect, the static pressure is lowest at this point, forming a local low-pressure zone. The adhesion between the chips and the machined surface is weakened by the low-pressure zone, and the chips are "adsorbed" into the low-pressure area.

[0041] (2) Sucking and removing chips

[0042] The pressure difference generated in the low-pressure zone drives the chips towards the center of the jet, where they are then entrained by the high-speed water flow and discharged from the hole along the drill bit's chip removal grooves. Vortex jet designs (such as micro-orifice axes at an angle of 15°–30° to the drill bit axis) can enhance the rotational motion of the fluid, improving the mixing and flushing efficiency of the chips.

[0043] (3) Synergistic cooling and lubrication

[0044] While removing chips, the water flow also reduces the temperature of the cutting tool and workpiece through convection heat transfer, minimizing thermal damage. The water flow also lubricates the contact surface between the cutting tool and the workpiece, further reducing drilling resistance.

[0045] Specifically, the water jet device consists of a pressure tank 1 and a hydraulic tank 2, which are connected to the water-guided laser spindle 6 via a water-guided laser rotary joint 3.

[0046] The laser module mainly includes a reflector 4, a laser 5, a focusing lens 13, a water-cooled box, and a laser controller. The laser enters the water-guided laser channel of the water-guided laser electric spindle 6 through the reflector 4 and hits the workpiece.

[0047] The water-guided laser spindle 6 is fixed on a marble gantry and consists of a water-guided laser rotary joint 3, a hollow spindle 16, a channel connector 17, an ER tool holder 18, and an ER chuck 19. A micro-drill bit 7 is fixed to the ER tool holder 18 via the ER chuck and connected to the channel connector 17 and the water-guided laser rotary joint 3 via the ER tool holder 18, forming a water-guided laser channel. The workpiece can be fixed on a stage 8 with a pressure sensor via a fixture, and its movement in the X, Y, and Z directions is controlled by the Z-axis slide 9, X-axis slide 10, and Y-axis slide 11 connected to the stage 8 with the pressure sensor. The water-guided laser rotary joint 3 includes a water-guided laser rotary joint end cap 12, a focusing lens 13, a sapphire optical window 14, and a water-guided laser channel 15.

[0048] Implementation process of this invention:

[0049] A water-guided laser composite drilling method, using the aforementioned water-guided laser composite drilling device, includes the following steps, which are performed sequentially.

[0050] Step 1: Use ANSYS Workbench finite element simulation software to perform laser heating simulation and water-guided laser composite cutting simulation. This provides guidance for setting water jet parameters, laser parameters, and drilling parameters in the control system program.

[0051] Step 2, Preparation Stage: Install and fix the workpiece onto the stage 8 with pressure sensor, and then select the corresponding micro-hole drill bit 7 according to the size of the hole to be processed, and fix it on the water-conducting laser electric spindle through the ER chuck.

[0052] Step 3: Turn on the control system to control the X, Y and Z axes, return the machine tool to zero, turn on the laser's infrared positioning, and confirm the machining position.

[0053] Step 4: Open the machining program in the control system, set the parameters based on the parameters in Step 1, and perform water-guided laser composite drilling.

[0054] 1) First, perform continuous laser irradiation (power 200-500W) for 10-30s to heat the surface of the material to the softening point (e.g., 800-1000℃ for ceramics) to form a 0.1-0.3mm guide hole;

[0055] 2) Then turn on the water jet coupled laser and drill bit for synchronous processing. Drilling (500-3000 rpm) and water-guided laser beam (pulse frequency 1-10 kHz) work together. The water pressure is increased in a gradient (initially 10 MPa, increasing by 2 MPa every 1 mm), and the laser power is linearly reduced (initially 80%, decreasing by 5% every 1 mm).

[0056] Step 5: After the hole is machined, the control system first shuts down the laser, then retracts the tool. During the retraction process, the high-pressure jet (10-30MPa) forms a spiral scouring effect through the microhole (the temperature rise of the drill bit and hole wall is ≤50℃). Finally, the water jet is turned off.

[0057] Specific implementation method: Machining holes in a thick silicon carbide ceramic plate (10mm thickness, 0.5mm hole diameter).

[0058] Traditional drilling method: tool wear 0.2 mm / hole, surface roughness Ra 3.2 μm, heat-affected zone 200 μm;

[0059] The water-guided laser composite drilling process of this invention achieves the following results: tool wear of 0.05 mm / hole, surface roughness Ra of 0.8 μm, heat-affected zone ≤ 50 μm, and efficiency improvement of 40%.

Claims

1. A water-guided laser composite drilling processing device, wherein the device is integrally mounted on a marble platform, characterized in that: The system includes a control system, a water-guided laser electric spindle, a water jet device, a laser module, and a three-axis motion platform. The water-guided laser electric spindle (6) includes a water-guided laser rotary joint (3), a hollow spindle (16), a channel connector (17), an ER tool holder (18), and an ER chuck (19). The chuck (19) fixes the drill bit (7) with micro-holes on the ER tool holder (18). The drill bit (7) with micro-holes is provided with a micro-hole array structure with a diameter of 50-200μm. The micro-hole array structure is centrally symmetrical when connected on the chip removal groove. The included angle between the micro-hole axes is 15°-30°, and the included angle between the micro-hole axis and the drill axis is 15°-30°. The coaxiality error is ≤5μm. Under high-pressure jet conditions, the micro-hole array structure forms a vortex jet field through the micro-holes and uses the Bernoulli effect to remove chips.

2. The water-guided laser composite drilling device according to claim 1, characterized in that: The water-guided laser rotary connector (3) includes a water-guided laser rotary connector end cap (12), a focusing lens (13), a sapphire optical window (14), and a water-guided laser channel (15).

3. The water-guided laser composite drilling device according to claim 1, characterized in that: The water jet device includes a pressure tank (1) and a hydraulic tank (2), which are connected to the water-guided laser spindle (6) via a water-guided laser rotary connector (3).

4. The water-guided laser composite drilling device according to claim 1, characterized in that: The laser module includes a reflector (4), a laser (5), a focusing lens (13), and a water-cooled box volume laser controller. The laser emitted by the laser (5) enters the water-guided laser spindle (6) through the reflector (4) and hits the workpiece through the water-guided laser channel (15).

5. The water-guided laser composite drilling device according to claim 1, characterized in that: The three-axis motion platform includes a Z-axis slide (9), an X-axis slide (10), and a Y-axis slide (11). The Z-axis slide (9) is equipped with a stage (8) with a pressure sensor.

6. The water-guided laser composite drilling device according to claim 1, characterized in that: The control system integrates a pressure sensor, an infrared temperature measurement module, and an adaptive control algorithm unit to dynamically adjust laser power, water pressure, and spindle speed according to the processing depth.

7. A water-guided laser composite drilling method, characterized in that: The water-guided laser composite drilling apparatus as described in claim 1 includes the following steps, which are performed sequentially: Step 1: Use ANSYS Workbench finite element simulation software to perform laser heating simulation and water-guided laser composite cutting simulation; Step 2: Install and fix the workpiece onto the stage (8) with pressure sensor, select the corresponding micro-hole drill bit (7) according to the size of the hole to be processed, and fix it on the water-guided laser electric spindle (6) through the ER chuck (19); Step 3: Control the X-axis, Y-axis and Z-axis through the control system to return the machine tool to zero, turn on the infrared positioning of the laser (5) and confirm the processing position; Step 4: Open the machining program in the control system, set the parameters based on the parameters in Step 1, and perform water-guided laser composite drilling. 1) First, perform continuous laser irradiation for 10-30 seconds to heat the material surface to the softening point and form a 0.1-0.3mm guide hole; 2) Then, the water jet coupled laser and the drill bit are turned on for synchronous processing. The drilling and the water-guided laser beam work together, the water pressure is increased according to the gradient, and the laser power is linearly reduced. Step 5: After the hole is processed, the control system first turns off the laser (5) and then retracts the tool. During the retraction process, the high-pressure jet forms a spiral scouring through the microhole. Finally, the water jet is turned off.

Images