Machining method for special-shaped curved surface cover body made of quartz ceramic material

Abstract

The invention discloses a machining method for a quartz ceramic special-shaped curved surface cover body. The machining method comprises the following steps of: performing allowance uniform distribution and machining datum point determination on the cover body and a wave-transparent region molded surface milling clamp in a clamping state by adopting laser full molded surface scanning; a horizontal machining center is adopted for machining the inner and outer profiles of the wave-transparent area of the cover body, and a wave-transparent area profile milling clamp is used in a matched mode for one-time clamping to complete machining; a gantry machining center is adopted for the outer profile of a non-wave-transparent area of the cover body, an outer profile milling clamp, a four-axis rotary table and a tailstock are used in cooperation, and machining is completed through one-time clamping. The machining precision of the wall thickness of the wave-transparent area of the cover body is high, the allowance distribution and reference alignment efficiency is high, the overall machining efficiency is high, and the requirements for rapid iteration and large-batch production of novel high-precision products are met.

Description

Technical Field

[0001] The present invention belongs to the field of mechanical processing technology, and in particular relates to a mechanical processing method for a quartz ceramic material special-shaped curved surface cover. Background Art

[0002] The cover is a key component of the aerodynamic structure of the aircraft's head, and it has both the function of transmitting guidance signals and resisting ultra-high temperature ablation. As aircraft continue to develop towards high maneuverability and high-precision guidance, new covers generally adopt special-shaped curved surface structures, and the wall thickness dimensional accuracy requirements of their wave-transmitting areas are constantly increasing. However, in traditional mechanical processing solutions, the outer and inner surfaces of the wave-transmitting area of ​​the cover are processed in two clamping states. There are inevitably processing dimensional deviations due to datum alignment deviations and product deformation in different clamping states. The wall thickness processing accuracy of the wave-transmitting area is difficult to meet the high-precision requirements of new products. Traditional processing solutions often use mechanical contact datum alignment, repeated processing of rough and fine milling of internal and external surfaces, and segmented clamping and segmented milling of external surfaces. There are generally problems such as complex clamping and datum alignment, multiple processing steps, etc., which leads to low product processing efficiency and difficulty in adapting to the rapid iteration and mass production needs of new products.

[0003] Traditional machining solutions are unable to meet the high-precision and high-efficiency machining requirements of new products. Therefore, researching and implementing a high-precision and high-efficiency machining solution has become an urgent problem to be solved in the field of machining special-shaped curved covers made of quartz ceramic. Summary of the Invention

[0004] In view of the deficiencies in the prior art, the present invention provides a high-precision and efficient machining method for a quartz ceramic material special-shaped curved cover.

[0005] To achieve the above objectives, the present invention provides a method for machining a quartz ceramic special-shaped curved cover, which is as follows: When the cover and the wave-transmitting area are clamped, the milling fixture uses laser scanning of the entire surface to distribute the allowance evenly and determine the machining reference points. The inner and outer surfaces of the wave-transmitting area of ​​the cover are machined using a horizontal machining center and a wave-transmitting area surface milling fixture in one clamping operation. The outer surface of the non-wave-transmitting area of ​​the cover is processed by a gantry machining center, which is combined with an outer surface milling fixture, a four-axis turntable and a tailstock for one-time clamping to complete the processing.

[0006] Furthermore, the wave-transmitting area profile milling fixture includes a fixture body, multiple screws and three positioning screws; the fixture body includes a base plate, a left vertical plate and a right vertical plate, and the left vertical plate and the right vertical plate are arranged side by side on one side end of the base plate; a left through hole is opened in the middle part of the left vertical plate, and a right through hole is opened in the middle part of the right vertical plate, and the inner surface of the left through hole is consistent with the outer surface of the contact part of the cover body, and the inner surface of the right through hole is consistent with the outer surface of the contact part of the cover body; each screw passes through a pressure plate and is inserted into the right end face of the right vertical plate and is locked by a nut; two positioning screws are arranged at the front and rear ends of the right side of the base plate, and the third positioning screw is arranged in the middle part of the left side of the base plate; each positioning screw is assembled with a positioning nut and a reference ball in turn, and the reference ball is clamped and positioned by the positioning nut after adjusting the assembly height on the positioning screw.

[0007] Furthermore, the left edge of the inner surface of the left through hole and the right through hole is processed with a circle of left bevel, and the right edge is processed with a circle of right bevel, the outer surface of the cover body and the left and right bevels of the left through hole form glue filling grooves, and the outer surface of the cover body and the left and right bevels of the right through hole form glue filling grooves.

[0008] Furthermore, a reinforcing plate is provided between the front and rear sides of the left vertical plate and the right vertical plate; and the three positioning screws are arranged in an isosceles triangle.

[0009] Furthermore, the outer surface milling fixture includes a small-end plug and a large-end plug; the inner hole of the small-end plug is consistent with the contact surface of the small end of the cover body, the outer surface of the small-end plug is a rotating body surface, and the axis of the outer surface of the small-end plug is coaxial with the set axis of the cover body; the large-end plug is built into the inner surface of the large end of the cover body and has an inner hole of the rotating body, the axis of the inner hole of the rotating body is coaxial with the set axis of the cover body, and the outer step surface of the large-end plug built into the large end of the cover body is consistent with the contact surface of the large end of the cover body, and the other end of the large-end plug has a cylinder for supporting the chuck of the four-axis turntable, and the axis of the cylinder is coaxial with the set axis of the cover body.

[0010] Furthermore, the outer surface milling fixture also includes a small end alignment pin and a large end alignment pin, and the small end alignment pin assembled on the outer surface of the small end plug and the large end alignment pin assembled on the outer surface of the large end plug are arranged in the same direction.

[0011] Furthermore, the specific process of using the laser full-surface scanning to distribute the allowance and determine the machining reference points of the cover body and the wave-transmitting area surface milling fixture in the clamped state is as follows: 1) Place the cover and the fixture body together in an electric furnace and heat until the temperature is higher than the melting point of the hot melt adhesive; 2) Remove the cover and fixture body from the electric heating furnace and insert the cover body into the fixture body; insert each screw into the screw hole on the right end face of the right vertical plate, adjust the pressure plate until it rests on the outer surface of the large end of the cover body, and tighten the nut to lock it; fill the glue filling grooves formed by the outer surface of the cover and the left and right inclined surfaces of the left through-hole respectively with hot melt adhesive, and fill the glue filling grooves formed by the outer surface of the cover and the left and right inclined surfaces of the right through-hole respectively with hot melt adhesive; 3) Assemble the positioning screw, positioning nut, and reference ball to the bottom plate of the fixture body in sequence, and adjust the reference balls so that the distance between the top of each reference ball and the upper surface of the bottom plate is equal. Finally, use the positioning nut to tighten it in the opposite direction to achieve the positioning of the reference balls. 4) Laser scanning, the scanning area covers all inner surfaces, end surfaces, exposed parts of the outer surfaces and three reference spheres of the cover to obtain the scanning model; 5) Import the scanned model and the design model of the cover into the 3D measurement software simultaneously and perform fitting according to the design margin. After the margin distribution is determined, measure the vertical distances from the centers of the three reference spheres to the symmetrical reference plane of the design model in the 3D measurement software. 6) Adjust the reference balls according to the vertical distances from the centers of the three reference balls to the symmetric reference plane of the design model in step 5) so that the vertical distances from the centers of the three reference balls to the symmetric reference plane of the design model are equal, that is, the height difference between the centers of the three reference balls is zero, so that the plane formed by the centers of the three reference balls is parallel to the symmetric reference plane of the design model; 7) Rescan the three reference spheres and import them into the 3D measurement software to overwrite the scanned model in step 4). In the 3D measurement software, measure the vertical distances from the centers of the three reference spheres to the symmetrical reference plane of the design model to see if they are equal. If so, proceed to step 8. If not, readjust the heights of the reference sphere centers and repeat steps 6) and 7) until they are equal. 8) The intersection of the set axis of the cover design model and the large end face of the cover design model is determined as the machining coordinate origin, and the coordinate system is established with the machining coordinate origin. The positive directions of the X-axis, Y-axis, and Z-axis are the same as the positive directions of the X-axis, Y-axis, and Z-axis in the machine tool coordinate system, that is, the XY plane, YZ plane, and XZ plane are the three machining coordinate reference planes, and the theoretical coordinate values ​​of the centers of the three reference balls in the scanning model are measured.

[0012] Furthermore, in step 2), this step must be completed before the surface temperature of the cover and the clamp body drops to the melting temperature of the hot melt adhesive after the cover and the clamp body are taken out of the electric heating furnace; there are four screws, which are respectively located in four quadrants, thereby fixing the large end of the cover.

[0013] Furthermore, the inner and outer surfaces of the wave-transmitting area of ​​the cover body are machined using a horizontal machining center and a wave-transmitting area surface milling fixture in one clamping operation. The specific process is as follows: 1) Use a horizontal machining center to process the cover body, and the cover body and the wave-transmitting area surface milling fixture are clamped to the workbench of the horizontal machining center in the assembled state; 2) Use the edge finder to measure the Y value (height) of the top of the three reference balls in the machine tool coordinate system; 3) Adjust the height of the fixture body by inserting a gasket or using a reverse screw until the top heights of the three reference balls are consistent; 4) Measure the actual coordinate values ​​of the centers of the three reference balls in the X-axis and Z-axis directions in the machine tool coordinate system, compare the actual coordinate values ​​in the X-axis and Z-axis directions with the theoretical coordinate values, and adjust the turntable angle of the horizontal machining center to make the actual coordinate values ​​in the X-axis and Z-axis directions consistent with the theoretical coordinate values, that is, find the origin of the cover machining coordinate; 5) Rough milling and fine milling of the inner profile of the cover and the outer profile of the wave-transmitting area to the designed state, and rough milling and fine milling of the end face to the designed state after removing the pressure plate; and the outer profile of the cover is close to the small end, and the allowance is reserved and corresponds to the four quadrant machining reference planes of the cover. The outer profile of the cover close to the large end corresponds to the four quadrant machining reference planes of the cover, and a total of eight reference planes are tangent to the cover and parallel to the corresponding machining coordinate reference planes. At the same time, record the theoretical vertical distance between each reference plane and the corresponding machining coordinate reference plane; 6) The cover body and the wave-transmitting area surface milling fixture are placed in an electric furnace and heated until the temperature is higher than the hot melt temperature of the hot melt adhesive. After taking it out of the furnace, the cover body is removed.

[0014] Furthermore, the outer surface of the non-wave-transmitting area of ​​the cover body is processed by a gantry machining center, and the specific process of completing the processing by using an outer surface milling fixture, a four-axis turntable and a tailstock for one-time clamping is as follows: 1) Assemble the large-end plug and the small-end plug to the four-axis turntable and tailstock chuck of the gantry machining center respectively. Use a dial to measure and adjust the axis of the outer surface of the small-end plug and the axis of the inner hole of the rotating body of the large-end plug to be coaxial with the four-axis turntable. The small-end alignment pin assembled on the outer surface of the small-end plug and the large-end alignment pin assembled on the outer surface of the large-end plug are arranged in the same direction; 2) Assemble the cover to the large end plug and tighten it with the small end plug; measure and adjust the end face runout of the cover to meet the design index accuracy requirements, so that the difference between the measured vertical distance between the two reference surfaces at the front and rear ends of the same quadrant and the corresponding machining coordinate reference plane is no more than 0.1mm; 3) Use fixed axis processing method to complete rough milling and fine milling of the back and abdomen of the cover body 1 respectively.

[0015] The present invention's wave-transmitting area profile milling fixture is equipped with three reference spheres. Adjusting the reference spheres and combining them with scanning and comparison allows for rapid alignment of the machining datums. The wave-transmitting area profile milling fixture is attached to the non-wave-transmitting area of ​​the housing's outer surface using hot-melt adhesive, enabling single-step machining of both the inner and outer surfaces of the wave-transmitting area. This method for machining irregularly shaped curved quartz ceramic housings achieves high wall thickness accuracy and overall machining efficiency in the wave-transmitting area, meeting the demands of rapid iteration and mass production of new high-precision products.

[0016] Compared with the prior art, the present invention has the following beneficial effects: 1) High wall thickness processing precision of the wave-transmitting area of ​​the cover: The inner and outer surfaces of the wave-transmitting area of ​​the cover are processed in one clamping state. The wall thickness is directly guaranteed by the processing precision of the equipment, and the adhesive clamping method is adopted, which can completely eliminate the influence of clamping deformation on dimensional accuracy.

[0017] 2) High efficiency in stock distribution and datum alignment: The scanned model and the design model can complete the stock distribution efficiently and accurately in a virtual environment. The machining datum in each direction can be determined with the adjustable datum ball of the tooling. During product processing, rapid alignment can be achieved according to the datum in each direction.

[0018] 3) High machining efficiency of the product: the inner surface, end surface and outer surface of the wave-transparent area of ​​the cover can be processed in one clamping, and the outer surface non-wave-transparent area can also be processed in one clamping. The two processes can complete all the processing content of the product in two clamping states. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is a schematic diagram of the main view of the assembly of the cover body and the wave-transmitting area surface milling fixture of the present invention; Figure 2 for Figure 1 The enlarged schematic diagram of point B in the middle; Figure 3 It is a schematic diagram of the right side view of the assembly of the milling fixture for the cover body and the wave-transmitting area surface of the present invention; Figure 4 This is a top view of the assembly of the milling fixture for the housing and the wave-transmitting area surface of the present invention; Figure 5 for Figure 1 A in the middle is an enlarged schematic diagram; Figure 6 It is a schematic diagram of the assembly of the cover body and the outer surface milling fixture of the present invention. DETAILED DESCRIPTION

[0020] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0021] The machining method of the quartz ceramic special-shaped curved cover body of the present invention is as follows: When the cover and the wave-transmitting area are clamped, the milling fixture uses laser scanning of the entire surface to distribute the allowance evenly and determine the machining reference points. The inner and outer surfaces of the wave-transmitting area of ​​the cover are machined using a horizontal machining center and a wave-transmitting area surface milling fixture in one clamping operation. The outer surface of the non-wave-transmitting area of ​​the cover is processed by a gantry machining center, which is combined with an outer surface milling fixture, a four-axis turntable and a tailstock for one-time clamping to complete the processing.

[0022] like Figure 1 、 3 The wave-transmitting area profile milling fixture shown in 4 and 5 comprises a fixture body 2, a plurality of screws 4 and three positioning screws 8. The fixture body 2 comprises a bottom plate 24, a left vertical plate 21 and a right vertical plate 22. The left vertical plate 21 and the right vertical plate 22 are arranged side by side on one side end of the bottom plate 24. A reinforcing plate 23 is provided between the front and rear sides of the left vertical plate 21 and the right vertical plate 22. A left through hole is provided in the middle of the left vertical plate 21. Similarly, a right through hole is provided in the middle of the right vertical plate 22. The inner profile of the left through hole is consistent with the outer profile of the contact portion of the cover body, and the inner profile of the right through hole is consistent with the outer profile of the contact portion of the cover body. At the same time, the left edges of the inner profiles of the left and right through holes are processed with a circle. The left bevel and the right edge are processed with a circle of right bevel; each screw 4 passes through a pressure plate 3 and is inserted into the right end face of the right vertical plate 22 and is locked by a nut 5. The pressure plate 3 can realize the positioning of the large end face of the cover body 1; two positioning screws 8 are arranged at the front and rear ends of the right side of the base plate 24, and the third positioning screw 8 is arranged in the middle part of the left side of the base plate 24. The three positioning screws 8 are arranged in an isosceles triangle; each positioning screw 8 is assembled with a positioning nut 7 and a reference ball 6 in turn, and the reference ball 6 is clamped and positioned by the positioning nut 7 after adjusting the assembly height on the positioning screw 8.

[0023] The non-wave-transparent area of ​​the cover body 1 is fitted into the left through hole of the left vertical plate 21 of the fixture body 2 and the right through hole of the right vertical plate, and the Figure 2 The outer surface of the cover body 1 and the left and right inclined surfaces of the left through hole each form a glue filling groove 25. Similarly, the outer surface of the cover body 1 and the left and right inclined surfaces of the right through hole each form a glue filling groove 25. After being filled with hot melt adhesive, the glue filling groove 25 can realize the clamping and fixing of the cover body. In this embodiment, the depth of the glue filling groove is 6-10 mm.

[0024] like Figure 6The outer surface milling fixture shown includes a small-end plug 9, a large-end plug 10, a small-end alignment pin 11 and a large-end alignment pin 12; the inner hole 91 of the small-end plug 9 is consistent with the contact surface of the small end of the cover body 11, the outer surface of the small-end plug 9 is a rotating body surface, and the axis of the outer surface of the small-end plug 9 is coaxial with the set axis of the cover body 1, which can be used as an axis alignment reference; the inner surface of the large end plug 10 built into the large end of the cover body 11 is provided with a rotating body hole 101, and the axis of the rotating body hole 101 is coaxial with the set axis of the cover body 1 Coaxial, can be used as the axis alignment reference; and the outer step surface of the big end plug on the big end of the built-in cover body is consistent with the contact surface of the big end of the cover body, and the other end of the big end plug 10 has a cylinder 102 for the chuck support of the four-axis turntable, and the axis of the cylinder 102 is coaxial with the set axis of the cover body 1; the small end alignment pin 11 assembled to the outer surface of the small end plug 9 and the large end alignment pin 12 assembled to the outer surface of the big end plug 10 are arranged in the same direction, and the small end alignment pin 11 and the large end alignment pin 12 can be used as angular alignment references.

[0025] The specific process of using laser full-surface scanning to distribute the allowance and determine the machining reference point when the cover body and the wave-transmitting area surface milling fixture are clamped is as follows: 1) The cover 1 and the fixture body 2 are placed in an electric heating furnace and heated until the temperature is higher than the melting point of the hot melt adhesive.

[0026] 2) Take the cover 1 and the fixture body 2 out of the electric heating furnace, and Figure 1 The fixture body 2 is inserted as shown, i.e., the non-wave-transmitting area of ​​the housing 1 is inserted into the left through-hole of the left vertical plate 21 and the right through-hole of the right vertical plate 22 of the fixture body 2. Each screw 4 is inserted into the screw hole on the right end face of the right vertical plate 22. The pressure plate 3 is adjusted until it rests on the outer surface of the large end of the housing 1, and the nut 5 is tightened to lock it. Hot melt adhesive is filled into the adhesive filling grooves 25 formed by the outer surface of the housing 1 and the left and right inclined surfaces of the left through-hole, respectively. Similarly, hot melt adhesive is filled into the adhesive filling grooves 25 formed by the outer surface of the housing 1 and the left and right inclined surfaces of the right through-hole, respectively. Four screws 4 can be used, located in four quadrants, to secure the large end of the housing 1.

[0027] This step must be completed before the surface temperature of the cover body 1 and the clamp body 2 drops to the melting temperature of the hot melt adhesive after the cover body 1 and the clamp body 2 are taken out of the electric heating furnace.

[0028] 3) Assemble the positioning screw 8, positioning nut 7, and reference ball 6 to the base plate 24 of the fixture body 2 in sequence, and adjust the reference balls 6 so that the distance between the top end of each reference ball 6 and the upper surface of the base plate 24 is equal, that is, the three reference balls 6 are at the same height. Finally, use the positioning nut 7 to tighten in reverse to achieve the positioning of the reference balls 6.

[0029] 4) Laser scanning, scanning area covers the whole inner surface, end surface, exposed part of outer surface of cover 1 and three reference balls 6 to obtain a scanning model.

[0030] 5) The scanning model and the design model of cover 1 are imported into the three-dimensional measurement software synchronously, and fitting is performed according to the design allowance; after the allowance distribution is determined, the vertical distance from the center of the three reference balls 6 to the symmetric reference plane of the design model is measured in the three-dimensional measurement software.

[0031] 6) The vertical distance from the center of the three reference balls 6 to the symmetric reference plane of the design model is adjusted according to the vertical distance in step 5), so that the vertical distance from the center of the three reference balls 6 to the symmetric reference plane of the design model is equal, i.e. the height difference of the center of the three reference balls is zero, so that the plane formed by the center of the three reference balls is parallel to the symmetric reference plane of the design model.

[0032] 7) The three reference balls 6 are scanned again and imported into the three-dimensional measurement software to cover the scanning model in step 4), and in the three-dimensional measurement software, it is measured whether the vertical distance from the center of the three reference balls 6 to the symmetric reference plane of the design model is equal; if equal, proceed to step 8); if not equal, adjust the height of the center of the reference ball 6 again, repeat steps 6) and 7) until equal.

[0033] 8) The intersection of the design axis of the cover 1 design model and the large end face of the cover 1 design model is determined as the machining coordinate origin, which is the machining reference point, and a coordinate system is established with the machining coordinate origin, the positive directions of X, Y and Z axes are the same as the positive directions of X, Y and Z axes in the machine tool coordinate system, i.e. XY, YZ and XZ are three machining coordinate reference planes, and the theoretical coordinate values of the centers of the three reference balls in the scanning model are measured.

[0034] The inner and outer surfaces of the cover wave-transparent zone are machined by using a horizontal machining center, and the wave-transparent zone profile milling fixture is used to complete the machining of the cover in one clamping as follows: 1) The horizontal machining center is used for cover machining, and the cover 1 and the wave-transparent zone profile milling fixture are clamped to the workbench of the horizontal machining center in the assembled state.

[0035] 2) The height of the top of the three reference balls 6 in the machine tool coordinate system is measured by using a boundary finder.

[0036] 3) The height of the fixture body 2 is adjusted by using a spacer or a reverse top screw until the heights of the tops of the three reference balls 6 are consistent, i.e. coplanar.

[0037] 4) Measure the actual coordinate values ​​of the centers of the three reference balls 6 in the X-axis and Z-axis directions in the machine tool coordinate system, compare the actual coordinate values ​​in the X-axis and Z-axis directions with the theoretical coordinate values, and adjust the turntable angle of the horizontal machining center to make the actual coordinate values ​​in the X-axis and Z-axis directions consistent with the theoretical coordinate values, that is, find the origin of the cover body machining coordinate.

[0038] 5) Rough milling and fine milling of the inner surface of the cover body 1 and the outer surface of the wave-transmitting area to the designed state, and after removing the pressure plate 3, rough milling and fine milling of the end face to the designed state; and the outer surface of the cover body 1 close to the small end has a reserved allowance and corresponds to the four quadrant machining reference planes of the cover body 1, and the outer surface of the cover body 1 close to the large end face corresponds to the four quadrant machining reference planes of the cover body 1, and a total of eight reference planes are tangent to the cover body 1 and parallel to the corresponding machining coordinate reference planes. At the same time, record the theoretical vertical distance between each reference plane and the corresponding machining coordinate reference plane.

[0039] 6) The cover body 1 and the wave-transmitting area surface milling fixture are placed in an electric furnace and heated until the temperature is higher than the hot melt temperature of the hot melt adhesive. After taking it out of the furnace, the cover body is removed.

[0040] The outer surface of the non-wave-transmitting area of ​​the cover body is processed by a gantry machining center and a surface milling fixture in one clamping to complete the processing. The details are as follows: 1) Assemble the large-end plug 10 and the small-end plug 9 to the four-axis turntable and the chuck of the tailstock of the gantry machining center respectively, measure and adjust the axis of the outer surface of the small-end plug 9 and the axis of the inner hole 101 of the rotating body of the large-end plug 10 to be coaxial with the four-axis turntable, and arrange the small-end alignment pin 11 assembled to the outer surface of the small-end plug 9 and the large-end alignment pin 12 assembled to the outer surface of the large-end plug 10 in the same direction.

[0041] 2) Assemble the housing 1 to the large end plug 10 and tighten with the small end plug 9 to achieve clamping. Measure and adjust the housing end face runout to meet the design accuracy requirements, ensuring that the difference between the measured vertical distances between the two reference surfaces at the front and rear ends of the same quadrant and the corresponding machining coordinate reference planes is no more than 0.1 mm from the difference between the theoretical vertical distances between the two reference surfaces.

[0042] 3) Use fixed axis processing method to complete rough milling and fine milling of the back and abdomen of the cover body 1 respectively.

[0043] Example A new type of mask Figure 1 The material is quartz ceramic composite material, with a total height of 1540±0.5, a wall thickness of 21.8±0.15mm in the wave-transmitting area, a verticality requirement of 0.24mm at the end face, and both the inner and outer surfaces are special-shaped surfaces. The product is processed using a DBC130SL CNC boring and milling machine and a PM1230HA gantry machining center. The specific implementation plan is as follows: 1. Place the cover and the wave-transmitting area surface milling fixture into an electric heating furnace, heat to 70°C, and keep warm for 80 minutes.

[0044] 2. Assemble the cover to the milling fixture for the wave-transmitting area and fill the glue groove with hot melt adhesive. The assembly and hot melt adhesive filling must be completed within 15 minutes after the cover and fixture are removed from the electric heating furnace.

[0045] 3. Perform laser scanning, and the scanning area covers all measurable surfaces of the cover body 1 and three reference spheres 6 to obtain a scanned model.

[0046] 4. The scanned model and the design model of the cover are simultaneously imported into the 3D measurement software, and fitted according to the design margin. After the margin distribution is determined, the vertical distances from the centers of the three reference spheres 6 to the symmetric reference plane of the design model are measured in the 3D measurement software, and the reference sphere 6 is adjusted so that the vertical distances from the centers of the three reference spheres 6 to the symmetric reference plane of the design model are equal, that is, the height difference between the centers of the three reference spheres is zero, so that the plane formed by the centers of the three reference spheres is parallel to the symmetric reference plane of the design model; then rescan until the heights are the same.

[0047] 5. The intersection of the set axis of the cover body and the end surface of the large head of the cover body is determined as the processing coordinate origin. The processing coordinate origin is the processing reference point, and the coordinate system is established with the processing coordinate origin. The positive directions of the X-axis, Y-axis, and Z-axis are the same as the positive directions of the X-axis, Y-axis, and Z-axis in the machine tool coordinate system. The theoretical coordinate values ​​of the centers of the three reference balls in the scanning model are measured.

[0048] 6. Assemble the hood and the wave-transmitting area profile milling fixture to the worktable of the CNC boring and milling machine. Use the edge finder to measure the Y value, i.e., the height, of the tops of the three reference balls in the machine coordinate system. Adjust the base height by inserting gaskets or using anti-top screws until the top heights of the three reference balls 6 are consistent, with a deviation of no more than 0.1 mm, i.e., they are coplanar.

[0049] 7. Measure the actual coordinate values ​​of the centers of the three reference balls in the X-axis and Z-axis directions in the machine tool coordinate system, compare the actual coordinate values ​​in the X-axis and Z-axis directions with the theoretical coordinate values, and adjust the turntable angle of the horizontal machining center to make the actual coordinate values ​​in the X-axis and Z-axis directions consistent with the theoretical coordinate values, that is, find the origin of the cover body machining coordinate.

[0050] 8. Rough and fine mill the inner and outer surfaces of the shield 1 and the wave-transmitting area to the designed state. After removing the pressure plate 3, rough and fine mill the end surface to the designed state. The outer surface of the shield 1 near the small end should be left with an allowance corresponding to the four quadrant machining datum surfaces of the shield 1. The outer surface of the shield 1 near the large end should correspond to the four quadrant machining datum surfaces of the shield 1. All eight datum surfaces should be tangent to the shield 1 and parallel to the corresponding machining coordinate datum planes. The theoretical vertical distance between each datum surface and the corresponding machining coordinate datum plane should be recorded.

[0051] 9. Place the cover body and the wave-transmitting area surface milling fixture into an electric furnace and heat to 120°C. Keep warm for 90 minutes. Remove the cover body after taking it out of the furnace.

[0052] 10. Assemble the large-end plug and small-end plug of the contour surface milling fixture to the four-axis turntable and tailstock chuck of the gantry machining center respectively. Use a dial to measure and adjust the axis of the outer surface of the small-end plug 9 and the axis of the inner hole of the large-end plug 10 to be coaxial with the four-axis turntable, with a deviation of no more than 0.1mm. Assemble the cover body to the large-end plug and tighten it with the small-end plug to achieve clamping. Align the end face runout of the cover body to no more than 0.20mm, measure and adjust the coordinate deviation of the reference plane at both ends of the cover body to no more than 0.1mm from the value recorded in the previous process. Monitor the axis of the tooling at both ends, and the center deviation is no more than 0.3mm. Monitor the angle of the alignment pin, and the angle deviation is no more than 10'.

[0053] 11. Use fixed axis processing method to complete rough milling and fine milling of the back and abdomen of the cover body respectively.

[0054] The contents not described in detail in the present invention belong to the prior art known to professionals in this field.

Claims

1. A method for machining a quartz ceramic special-shaped curved cover, characterized by: The machining method is as follows: When the cover and the wave-transmitting area are clamped, the milling fixture uses laser scanning of the entire surface to distribute the allowance evenly and determine the machining reference points. The inner and outer surfaces of the wave-transmitting area of ​​the cover are machined using a horizontal machining center and a wave-transmitting area surface milling fixture in one clamping operation. The outer surface of the non-wave-transmitting area of ​​the cover is processed by a gantry machining center, which is combined with an outer surface milling fixture, a four-axis turntable and a tailstock for one-time clamping to complete the processing.

2. The machining method for a quartz ceramic special-shaped curved cover according to claim 1, characterized in that: The wave-transmitting area profile milling fixture comprises a fixture body (2), a plurality of screws (4) and three positioning screws (8); the fixture body (2) comprises a bottom plate (24), a left vertical plate (21) and a right vertical plate (22), the left vertical plate (21) and the right vertical plate (22) being arranged side by side on one side of the bottom plate (24); a left through hole is opened in the middle of the left vertical plate (21), and a right through hole is opened in the middle of the right vertical plate (22), and the inner profile of the left through hole is consistent with the outer profile of the contact portion of the cover body, and the inner profile of the right through hole is consistent with the outer profile of the contact portion of the cover body. The outer profiles of the contact parts of the cover body are consistent; each screw (4) passes through a pressure plate (3) and is inserted into the right end face of the right vertical plate (22) and is locked by a nut (5); two positioning screws (8) are arranged at the front and rear ends of the right side of the bottom plate (24), and the third positioning screw (8) is arranged in the middle part of the left side of the bottom plate (24); each positioning screw (8) is assembled with a positioning nut (7) and a reference ball (6) in sequence, and the reference ball (6) is clamped and positioned by the positioning nut (7) after adjusting the assembly height on the positioning screw (8).

3. The machining method for a quartz ceramic special-shaped curved cover according to claim 2, characterized in that: The left edges of the inner surfaces of the left through hole and the right through hole are processed with a circle of left bevel, and the right edges are processed with a circle of right bevel. The outer surface of the cover body (1) and the left and right bevels of the left through hole form a glue filling groove (25), and the outer surface of the cover body (1) and the left and right bevels of the right through hole form a glue filling groove (25).

4. The machining method for a quartz ceramic special-shaped curved cover according to claim 2 or 3, characterized in that: A reinforcing plate (23) is provided between the front and rear sides of the left vertical plate (21) and the right vertical plate (22); and the three positioning screws (8) are arranged in an isosceles triangle.

5. The machining method for a quartz ceramic special-shaped curved cover according to claim 1, characterized in that: The outer profile milling fixture comprises a small end plug (9) and a large end plug (10); the inner hole (91) of the small end plug (9) is consistent with the contact surface of the small end of the cover body (11), the outer profile of the small end plug (9) is a revolving body profile, and the axis of the outer profile of the small end plug (9) is coaxial with the set axis of the cover body (1); the large end plug (10) is built into the inner surface of the large end of the cover body (11) and is provided with a revolving body inner hole (101), the axis of the revolving body inner hole (101) is coaxial with the set axis of the cover body (1), and the outer step surface of the large end plug built into the large end of the cover body is consistent with the contact surface of the large end of the cover body, and the other end of the large end plug (10) is provided with a cylinder (102) for supporting the chuck of the four-axis turntable, and the axis of the cylinder (102) is coaxial with the set axis of the cover body (1).

6. The method for machining a quartz ceramic special-shaped curved cover according to claim 5, characterized in that: The outer surface milling fixture further comprises a small end alignment pin (11) and a large end alignment pin (12), wherein the small end alignment pin (11) assembled on the outer surface of the small end plug (9) and the large end alignment pin (12) assembled on the outer surface of the large end plug (10) are arranged in the same direction.

7. The method for machining a quartz ceramic special-shaped curved cover according to claim 2, characterized in that: The specific process of using the laser full-surface scanning to distribute the allowance and determine the machining reference point for the housing and the wave-transmitting area profile milling fixture in the clamped state is as follows: 1) The cover (1) and the fixture body (2) are placed together in an electric heating furnace and heated until the temperature is higher than the melting point of the hot melt adhesive; 2) The cover body (1) and the fixture body (2) are taken out of the electric heating furnace, and the cover body (1) is inserted into the fixture body (2); each screw (4) is inserted into the screw hole on the right end face of the right vertical plate (22), and the pressure plate (3) is adjusted until the pressure plate (3) is against the outer surface of the large end of the cover body (1), and the nut (5) is tightened to lock it; hot melt adhesive is filled into the glue filling groove (25) formed by the outer surface of the cover body (1) and the left inclined surface and the right inclined surface of the left through hole respectively, and hot melt adhesive is filled into the glue filling groove (25) formed by the outer surface of the cover body (1) and the left inclined surface and the right inclined surface of the right through hole respectively; 3) Assemble the positioning screw (8), positioning nut (7), and reference ball (6) to the bottom plate (24) of the fixture body (2) in sequence, and adjust the reference ball (6) so that the distance between the top end of each reference ball (6) and the upper surface of the bottom plate (24) is equal. Finally, use the positioning nut (7) to tighten it in the opposite direction to achieve the positioning of the reference ball (6); 4) Laser scanning, where the scanning area covers all inner surfaces, end surfaces, exposed parts of the outer surfaces and three reference spheres (6) of the cover body (1) to obtain a scanned model; 5) Import the scanned model and the design model of the cover (1) into the 3D measurement software simultaneously and fit them according to the design margin; after the margin distribution is determined, measure the vertical distances from the centers of the three reference spheres (6) to the symmetrical reference plane of the design model in the 3D measurement software; 6) According to the vertical distances from the centers of the three reference spheres (6) to the symmetric reference plane of the design model in step 5), the reference sphere (6) is adjusted so that the vertical distances from the centers of the three reference spheres (6) to the symmetric reference plane of the design model are equal, that is, the height difference between the centers of the three reference spheres is zero, so that the plane formed by the centers of the three reference spheres is parallel to the symmetric reference plane of the design model; 7) Rescan the three reference spheres (6) and import them into the 3D measurement software to cover the scanned model in step 4). In the 3D measurement software, measure whether the vertical distances from the centers of the three reference spheres (6) to the symmetrical reference plane of the design model are equal; if they are equal, proceed to step 8); if not, readjust the height of the center of the reference sphere (6) and repeat steps 6) and 7) until they are equal; 8) The intersection of the set axis of the cover body (1) design model and the large end face of the cover body (1) design model is determined as the machining coordinate origin, and the machining coordinate origin is the machining reference point. A coordinate system is established with the machining coordinate origin. The positive directions of the X axis, Y axis, and Z axis are the same as the positive directions of the X axis, Y axis, and Z axis in the machine tool coordinate system, that is, the XY plane, YZ plane, and XZ plane are three machining coordinate reference planes, and the theoretical coordinate values ​​of the centers of the three reference balls in the scanning model are measured.

8. The method for machining a quartz ceramic special-shaped curved cover according to claim 7, characterized in that: In the step 2), this step must be completed after the cover body (1) and the clamp body (2) are taken out of the electric heating furnace and before the surface temperature of the cover body (1) and the clamp body (2) drops to the hot melt temperature of the hot melt adhesive; there are four screws (4), which are respectively located in four quadrants, thereby fixing the large end of the cover body (1).

9. The method for machining a quartz ceramic special-shaped curved cover according to claim 7, characterized in that: The inner and outer surfaces of the wave-transmitting area of ​​the cover are machined using a horizontal machining center and a wave-transmitting area surface milling fixture in one clamping operation. The specific process is as follows: 1) The cover body is processed using a horizontal machining center, and the cover body (1) and the wave-transmitting area profile milling fixture are clamped to the workbench of the horizontal machining center in an assembled state; 2) Use the edge finder to measure the Y value, i.e., the height, of the top of the three reference balls (6) in the machine tool coordinate system; 3) Adjust the height of the fixture body (2) by inserting a gasket or using a reverse screw until the top heights of the three reference balls (6) are consistent; 4) Measure the actual coordinate values ​​of the centers of the three reference balls (6) in the X-axis and Z-axis directions in the machine tool coordinate system, compare the actual coordinate values ​​in the X-axis and Z-axis directions with the theoretical coordinate values, and adjust the turntable angle of the horizontal machining center to make the actual coordinate values ​​in the X-axis and Z-axis directions consistent with the theoretical coordinate values, that is, find the origin of the cover body machining coordinates; 5) Rough milling and fine milling of the inner surface of the cover body (1) and the outer surface of the wave-transmitting area to the design state, and after removing the pressure plate (3), rough milling and fine milling of the end face to the design state; and the outer surface of the cover body (1) near the small end is reserved and corresponds to the four quadrant processing reference planes of the cover body (1), and the outer surface of the cover body (1) near the large end face corresponds to the four quadrant processing reference planes of the cover body (1), and a total of eight reference planes are tangent to the cover body (1) and parallel to the corresponding processing coordinate reference planes, and at the same time record the theoretical vertical distance between each reference plane and the corresponding processing coordinate reference plane; 6) The cover (1) and the wave-transmitting area surface milling fixture are placed in an electric furnace and heated until the temperature is higher than the melting temperature of the hot melt adhesive. After taking it out of the furnace, the cover is removed.

10. The method for machining a quartz ceramic special-shaped curved cover according to claim 5, characterized in that: The outer surface of the non-wave-transmitting area of ​​the cover body is processed by a gantry machining center, with the use of an outer surface milling fixture, a four-axis turntable and a tailstock for one-time clamping. The specific process is as follows: 1) Assemble the large-end plug (10) and the small-end plug (9) to the chuck of the four-axis turntable and the tailstock of the gantry machining center respectively, measure and adjust the axis of the outer surface of the small-end plug (9) and the axis of the inner hole (101) of the rotating body of the large-end plug (10) to be coaxial with the four-axis turntable, and arrange the small-end alignment pin (11) assembled to the outer surface of the small-end plug (9) and the large-end alignment pin (12) assembled to the outer surface of the large-end plug (10) in the same direction; 2) Assemble the cover (1) to the large end plug (10) and tighten it with the small end plug (9); measure and adjust the end face runout of the cover to meet the design index accuracy requirements, so that the difference between the measured vertical distance between the two reference planes at the front and rear ends of the same quadrant and the corresponding machining coordinate reference plane is not greater than 0.1mm; 3) Use fixed axis processing to complete the rough milling and fine milling of the back and abdomen of the cover body (1).

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