Fin punching die and processing technology thereof

Abstract

The application discloses a fin punching female die and a processing technology thereof, and belongs to the technical field of die manufacturing; wherein the processing technology of the fin punching female die comprises the following steps: grinding the large-diameter end of a punching female die blank on a centerless grinder; taking the large-diameter end of the punching female die blank as a reference to process various levels of blanking holes; clamping the large-diameter end of the punching female die blank, turning various levels of steps, and coaxially processing a blade hole; processing a blade edge at the blade hole; step grinding the small-diameter end of the blade edge; and precision flat grinding the blade edge. The application can improve the manufacturing precision of the fin punching female die, improve the coaxial precision consistency, avoid the punching female die from being easily damaged when cooperating with a punching male die, reduce the service life, and improve the processing quality of the fin.

Description

Technical Field

[0001] This invention belongs to the field of mold manufacturing technology, and specifically relates to a fin punching die and its processing technology. Background Technology

[0002] Finned heat exchangers are an important component of refrigeration equipment. The fins of a finned heat exchanger are made by punching holes in aluminum foil using a fin mold, so that they can be connected to finned tubes. However, the quality of the fins and the accuracy of their assembly are affected by the manufacturing precision of the fin mold.

[0003] The structure of a fin mold includes an upper mold assembly and a lower mold assembly. The upper mold assembly includes a punching punch and a punch fixing plate, and the lower mold assembly includes a punching die and a die fixing plate. For example, in a height-adjustable fin punching mold disclosed in utility model patent CN209109956U, if the punching die has poor processing accuracy during manufacturing, it will lead to low coaxiality of the punching punch and punching die insert, poor uniformity of the punching gap, and thus cause the stamped fin product to have problems such as large and numerous burrs and poor quality. Summary of the Invention

[0004] To address the aforementioned technical problems, the present invention aims to provide a fin punching die and its processing technology, which can improve the manufacturing precision of the fin punching die, enhance the consistency of coaxiality accuracy, and prevent the punching die from being easily damaged during operation with the punching punch, thus reducing its service life. At the same time, it is beneficial to improve the processing quality of the fins.

[0005] The technical solution adopted to solve the above-mentioned technical problems is as follows:

[0006] The first aspect of this invention discloses a processing technology for a fin punching die, which includes the following steps:

[0007] The outer diameter end of the punching die blank is ground on a centerless grinder.

[0008] Each level of blanking holes is machined using the large outer diameter end of the punching die blank as a reference.

[0009] The large outer diameter end of the punching die blank is clamped and machined to form steps of various levels, and the cutting edge hole is machined coaxially.

[0010] The cutting edge is machined at the cutting edge hole;

[0011] Perform stepped grinding on the small outer diameter end of the cutting edge;

[0012] The cutting edge is then finely ground.

[0013] The processing technology of the fin punching die provided in the first aspect of the present invention has at least the following beneficial effects: By performing centerless grinding on the large outer diameter end of the punching die blank, the large outer diameter end of the punching die blank is used as the processing reference, and various levels of blanking holes are machined; then, in the fixed state of the punching die blank, various levels of steps are manufactured by turning, and cutting edge holes are coaxially machined to create cutting edges at the cutting edge holes; next, the small outer diameter end of the cutting edge is sequentially subjected to stepped grinding and fine surface grinding, which can improve the coaxiality accuracy of the blanking holes and the cutting edge holes, thereby making the coaxiality accuracy of the punching die consistent and the manufacturing accuracy high, enabling the punching die to work better with the punching punch, improving the uniformity of the punching clearance, avoiding easy damage to the punching die when working with the punching punch, and making the processed fins of better quality.

[0014] In some embodiments of the present invention, in the step of grinding the large outer diameter end of the punching die blank on a centerless grinder, grinding is performed according to the design size of the large outer diameter end of the punching die within ±0.2mm to ensure that the consistency of the large outer diameter end is within ±0.02mm.

[0015] In some embodiments of the present invention, in the step of machining each level of steps, a 0.15mm allowance is left on each side of the outer diameter of the step to ensure coaxiality <0.05mm.

[0016] In some embodiments of the present invention, in the step of step grinding the small outer diameter end of the cutting edge, a 100# grinding wheel is used to rough grind the small outer diameter end of the cutting edge, leaving a 0.02mm allowance, and then fine grinding is performed to ensure that the surface finish of the cutting edge reaches 0.4.

[0017] In some embodiments of the present invention, in the step of fine grinding the cutting edge, an 80# grinding wheel is used to finely grind the cutting edge with a feed rate of 0.002mm each time, and the grinding is completed in place, ensuring that the surface finish of the cutting edge reaches 0.4.

[0018] In some embodiments of the present invention, after machining various steps and coaxially machining the cutting edge hole at the large outer diameter end of the clamping punch die blank, the following steps are further included:

[0019] The punching die blank is heat-treated to allow for deformation of less than 0.1 mm.

[0020] The outer diameter end of the punching die blank is rough ground with a machining allowance of 0.05-0.08mm, and then fine ground to a depth of ±0.0015mm, ensuring a coaxiality of 0.003mm.

[0021] The end face of the punching die blank is made flat with the large outer diameter end as the reference, and the perpendicularity is guaranteed to be 0.003mm.

[0022] In some embodiments of the present invention, after the flat end face with the large outer diameter end of the punching die blank is exposed to light, the following steps are also included: polishing the blanking hole to ensure a surface finish of 0.8.

[0023] In some embodiments of the present invention, after the cutting edge hole is coaxially machined, the following steps are further included: clamping the large outer diameter end of the punching die blank, aligning it, and ensuring that the runout value is <0.003mm; finely grinding the cutting edge hole to ensure that the coaxiality reaches 0.003mm and the surface finish of the cutting edge hole reaches 0.4.

[0024] In some embodiments of the present invention, the step of machining the cutting edge at the cutting edge hole includes the following steps: using a 60# grinding wheel to perform fine surface grinding on the cutting edge hole with a feed amount of 0.03mm per cycle, leaving a margin of 0.01mm; then using an 80# grinding wheel to machine the cutting edge with a feed amount of 0.002mm per cycle, and ensuring that the surface finish of the cutting edge is 0.4.

[0025] A second aspect of the present invention discloses a fin punching die, which is manufactured using the processing technology of the fin punching die of the first aspect embodiment.

[0026] The fin punching die provided in the second aspect of the present invention has at least the following beneficial effects: by using the above-mentioned processing technology to manufacture the fin punching die, the coaxiality accuracy and manufacturing accuracy of the punching die can be improved, and the punching die can be used to manufacture fins of better quality.

[0027] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0028] The present invention will be further described below with reference to the accompanying drawings and embodiments;

[0029] Figure 1 This is a schematic flowchart of the processing technology of the fin punching die provided in the embodiment of the present invention;

[0030] Figure 2 This is a detailed flowchart of step S50 in the processing technology of the fin punching die provided in the embodiment of the present invention.

[0031] Figure 3 This is a schematic flowchart of the processing technology of the fin punching die provided in another embodiment of the present invention;

[0032] Figure 4 This is a schematic flowchart of the processing technology of the fin punching die provided in another embodiment of the present invention;

[0033] Figure 5 This is a schematic flowchart of the processing technology of the fin punching die provided in another embodiment of the present invention;

[0034] Figure 6 This is a detailed flowchart of step S40 in the processing technology of the fin punching die provided in the embodiment of the present invention. Detailed Implementation

[0035] This section will describe in detail specific embodiments of the present invention. Preferred embodiments of the present invention are shown in the accompanying drawings. The purpose of the drawings is to supplement the textual description with graphics, so that people can intuitively and vividly understand each technical feature and overall technical solution of the present invention, but they should not be construed as limiting the scope of protection of the present invention.

[0036] In the description of this invention, it should be understood that the orientation descriptions, such as up, down, front, back, left, right, etc., are based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting this invention.

[0037] In the description of this invention, the use of terms such as "a number" means one or more, with "more than" meaning two or more. Terms like "greater than," "less than," and "exceeding" are understood to exclude the stated number, while terms like "above," "below," and "within" are understood to include the stated number. The use of terms like "first," "second," and "third" is merely for distinguishing technical features and should not be construed as indicating or implying relative importance, the number of indicated technical features, or the sequential relationship between indicated technical features.

[0038] In the description of this invention, unless otherwise explicitly defined, terms such as "set up," "install," and "connect" should be interpreted broadly, and those skilled in the art can reasonably determine the specific meaning of the above terms in this invention in conjunction with the specific content of the technical solution.

[0039] Reference Figures 1 to 6 The following are several embodiments of the fin punching die and its processing technology of the present invention.

[0040] The quality and assembly precision of fins are affected by the manufacturing precision of the fin mold. The structure of the fin mold includes an upper mold assembly and a lower mold assembly. The upper mold assembly includes a punching punch and a punch fixing plate, while the lower mold assembly includes a punching die and a die fixing plate. If the punching die has poor machining precision during manufacturing, it will result in low coaxiality between the punching punch and the punching die insert, poor uniformity of the punching clearance, and thus cause the stamped fins to have problems such as large and numerous burrs and poor quality.

[0041] Based on this, such as Figure 1 , Figure 2 and Figure 6 As shown, Embodiment 1 of the present invention provides a processing technology for a fin punching die. The processing technology for the fin punching die provided in this embodiment can improve the manufacturing precision of the fin punching die, improve the consistency of coaxiality precision, and avoid damage to the punching die when it works with the punching punch, which would lead to a reduction in service life. At the same time, it is beneficial to improve the processing quality of the fin.

[0042] The processing technology of the fin punching die in this embodiment includes the following steps:

[0043] Step S10: Grind the large outer diameter end of the punching die blank on a centerless grinder.

[0044] Understandably, before the through grinding process, workers can first go to the warehouse to collect raw materials with a diameter of Φ+0.3mm and a length of L+0.5mm. At this time, the raw materials are cylindrical. The cutting process is then completed using a wire cutting machine, specifically, cutting according to the design dimensions of the drawing +0.5mm to ensure that the two end faces of the punching die blank are flat. The cross-sectional shape of the punching die is circular. During through grinding, the punching die blank is a cylindrical part without a blanking hole, cutting edge, or step.

[0045] Specifically, in step S10, which involves grinding the outer diameter end of the punching die blank on a centerless grinder, the grinding is performed within ±0.2mm of the design dimension of the outer diameter end of the punching die, ensuring that the consistency of the outer diameter end is within ±0.02mm. After completing the blanking work, the operator uses a centerless grinder to grind the outer diameter end of the punching die blank according to the design dimension of ±0.2mm in the drawing, ensuring that the consistency of the outer diameter end of the punching die blank is within ±0.02mm, thus completing the machining work of the outer diameter end of the punching die blank. At this point, the outer circumferential surface of the outer diameter end of the punching die blank, after being treated by grinding, meets the design requirements.

[0046] Step S20: Using the large outer diameter end of the punching die blank as a reference, machine the blanking holes of each level.

[0047] After completing the machining of the outer diameter end of the punching die blank, the operator can use CNC machining equipment to machine the blanking holes of each stage of the punching die blank, using the outer diameter end of the punching die blank as the machining reference. This ensures that the blanking holes are accurately positioned relative to the outer diameter end of the punching die blank, and that the central axis of the blanking holes extends along the length of the punching die blank. The blanking holes are basically coaxial with the punching die blank, and the coaxiality accuracy of the blanking holes is high.

[0048] Step S30: Clamp the large outer diameter end of the punching die blank, machine out each step, and coaxially machine the cutting edge hole.

[0049] Specifically, workers can use CNC machining equipment to manufacture various steps and cutting edge holes on the clamped and fixed punching die blank. During the machining of each step, a 0.15mm allowance is left on each side of the outer diameter of the step to ensure coaxiality <0.05mm. Furthermore, a 0.15mm allowance is left on the inner end face of each tolerance. When machining the annular groove, a 0.2mm allowance is left on each side. Then, after completing the manufacturing of each step, the cutting edge holes are machined coaxially, with a negative 0.3mm inner diameter. The machining of each step allows the punching die to be mounted on the die fixing plate, enabling the punching die to mate with the punching punch for punching and flanging the fins.

[0050] Step S40: Machin the cutting edge at the cutting edge hole.

[0051] Specifically, step S40 includes the following steps:

[0052] Step S41: Use a 60# grinding wheel to perform fine surface grinding on the cutting edge hole with a feed rate of 0.03mm per pass, leaving a margin of 0.01mm.

[0053] It is understandable that during the fine grinding of the cutting edge hole using a 60# grinding wheel, the grinding wheel is fed multiple times to continuously process the cutting edge hole, ensuring that after processing with the 60# grinding wheel, the cutting edge hole has a margin of 0.01mm so that a grinding wheel with smaller particles can be used to process the cutting edge hole later.

[0054] Step S42: Use an 80# grinding wheel to machine the cutting edge with a feed rate of 0.002mm per pass, and ensure that the surface finish of the cutting edge is 0.4.

[0055] After machining the cutting edge hole using a 60# grinding wheel, an 80# grinding wheel is used to repeatedly grind the hole with multiple feeds to create the cutting edge, ensuring a surface finish of 0.4 (Ra value) after machining with the 80# wheel, achieving a surface finish grade of 9. The 80# wheel has smaller abrasive grains than the 60# wheel; therefore, in the fine grinding process, the cutting edge hole is first ground flat with a 60# wheel, and then further finely ground with an 80# wheel to create the cutting edge, ensuring the surface finish meets design requirements. It is understood that the cutting edge of the punching die can cooperate with the punch of the punching punch to cut off the waste material generated during the fin punching process.

[0056] Step S50: Perform step grinding on the small outer diameter end of the cutting edge.

[0057] Specifically, step S50 includes the following steps:

[0058] Step S51: Use a 100# grinding wheel to rough grind the small outer diameter end of the cutting edge, leaving a margin of 0.02mm.

[0059] Step S52: Refine grinding to ensure the surface finish of the cutting edge reaches 0.4.

[0060] Understandably, during the stepped grinding process using a 100# grinding wheel, the small outer diameter end R of the cutting edge is machined in two stages. First, the small outer diameter end of the cutting edge is rough machined, leaving a 0.02mm allowance for subsequent finish machining. During finish machining, the small outer diameter end of the cutting edge needs to be machined to the required extent to meet design requirements, ensuring a surface roughness Ra value of 0.4. Simultaneously, damage to any surface of the punching die blank must be avoided.

[0061] Step S60: Perform fine grinding on the cutting edge.

[0062] Specifically, in step S60, which is the step of fine surface grinding of the cutting edge, the cutting edge is finely ground using an 80# grinding wheel of an M7120 surface grinder with a feed rate of 0.002mm. Moreover, it is machined to the design dimensions in the drawing and the surface finish of the cutting edge is guaranteed to reach 0.4. This can reduce the wear of the cutting edge of the punching die when it works with the punch of the punching punch, and allow the waste material of the fin to be punched quickly, resulting in small and few burrs on the fin, thereby improving the processing quality of the fin.

[0063] In the processing technology of the fin punching die provided in this embodiment, the large outer diameter end of the punching die blank is centerlessly ground to use the large outer diameter end of the punching die blank as the processing reference, and various blanking holes are machined. Then, with the punching die blank in a fixed state, various steps are manufactured by turning, and cutting edge holes are coaxially machined to create cutting edges at the cutting edge holes. Next, the small outer diameter end of the cutting edge is sequentially treated by stepped grinding and fine surface grinding. This can improve the coaxiality accuracy of the blanking holes and cutting edge holes, thereby making the coaxiality accuracy of the punching die consistent and the manufacturing accuracy high. This allows the punching die to work better with the punching punch, improves the uniformity of the punching clearance, avoids easy damage to the punching die when working with the punching punch, and makes the quality of the processed fins better.

[0064] In some embodiments, such as Figure 1 and Figure 3 As shown, after step S30, which involves machining various steps and coaxially machining the cutting edge hole at the large outer diameter end of the punching die blank, the processing technology of the fin punching die also includes the following steps:

[0065] Step S31: Heat treat the punching die blank with a deformation amount of <0.1mm.

[0066] Step S32: Roughly grind the large outer diameter end of the punching die blank, leaving a machining allowance of 0.05-0.08mm, and then finely grind it to ±0.0015mm, ensuring that the coaxiality reaches 0.003mm.

[0067] Step S33: Using the large outer diameter end of the punching die blank as a reference, flatten the end face to expose it to light, and ensure that the perpendicularity reaches 0.003mm.

[0068] By heat-treating the punching die blank, the hardness and strength of the punching die are increased to meet the design requirements of the drawings. A centerless grinder is used to perform rough grinding and finish grinding on the large outer diameter end of the punching die blank, machining it to ±0.0015mm while ensuring a coaxiality of 0.003mm, facilitating subsequent end-face grinding. After rough and finish grinding of the large outer diameter end of the punching die blank, an M7120 surface grinder is used, with the large outer diameter end as the machining reference, to grind the end face of the punching die blank until it is smooth, while ensuring a perpendicularity of 0.003mm. This improves the assembly accuracy between the punching die and the die fixing plate, allowing the punching die to work better with the punching punch to produce higher-quality fins.

[0069] In some embodiments, such as Figure 1 and Figure 4 As shown, after step S33, which involves ensuring the flat end face of the punching die blank is exposed to light and the perpendicularity reaches 0.003mm, the processing technology of the fin punching die also includes the following steps:

[0070] Step S34: Polish the blanking hole to ensure a surface finish of 0.8.

[0071] After machining the blanking holes and grinding the outer diameter end of the punching die blank, the polishing wheel of the internal grinding machine is used to polish the blanking holes of each level on the punching die blank, so as to improve the surface finish of the blanking holes and make the finish reach 0.8.

[0072] In some embodiments, between steps S33 and S34, the following step is also included: using an 80# grinding wheel of an external grinding machine, with the large outer diameter end of the punching die blank as a reference, the end of the punching die blank is machined to produce an inverted conical surface with a length of 3mm.

[0073] Then, using a Harding lathe, while clamping and fixing the large outer diameter end of the punching die blank, various steps are machined in place according to the design requirements of the drawings; next, a retaining ring groove is machined at the other end of the punching die blank, in place according to the design requirements of the drawings, and chamfering is performed.

[0074] After the inverted conical surface is machined, the inverted conical surface is ground smooth using a 100# grinding wheel in the stepped grinding step.

[0075] In some embodiments, such as Figure 1 , Figures 3 to 5 As shown, after step S30, which involves machining various steps and coaxially machining the cutting edge hole at the large outer diameter end of the punching die blank, the processing technology of the fin punching die also includes the following steps:

[0076] Step S35: Clamp the large outer diameter end of the punching die blank, align it, and ensure that the runout value is <0.003mm.

[0077] Step S36: Grind the cutting edge hole to the required level, ensuring a coaxiality of 0.003mm and a surface finish of 0.4.

[0078] After creating various steps and cutting edge holes on the punching die blank, the outer diameter end of the punching die blank is clamped and fixed, and alignment is performed to ensure that the runout value is less than 0.003mm. Then, the inner hole of the cutting edge is finely ground and polished using an internal grinding machine. After the inner hole of the cutting edge is machined in place, the coaxiality is ensured to be within 0.003mm. At the same time, the surface finish of the inner hole of the cutting edge is improved to a finish of 0.4, so that the cutting edge can be machined at the cutting edge hole in the future.

[0079] In some embodiments, between steps S50 and S60, the following step is further included: covering the large outer diameter end of the punching die blank with a copper sheet and clamping and fixing the large outer diameter end of the punching die blank; this can prevent damage to the large outer diameter end of the punching die blank, thus avoiding damage to the workpiece. Then, using polishing paste such as W20 polishing paste, the surface of the cork is applied to polish the outer diameter of the punch cutting edge until the surface finish reaches 0.2.

[0080] After completing step S60, the following steps are also included: using a copper rod to remove burrs from the cutting edge hole to produce a finished punching die. Then, a fixture is used to place the finished punching die into an ultrasonic cleaner for cleaning, and the cutting edge hole is checked again for any residue. Next, a magnifying glass and a coaxiality meter are used to inspect the finished punching die.

[0081] In addition, embodiments of the present invention also provide a fin punching die, which is manufactured using the processing technology of a fin punching die.

[0082] Using the above processing technology to manufacture fin punching dies can improve the coaxiality and manufacturing accuracy of the punching dies, allowing the punching dies to be better mounted on the die fixing plate, minimizing assembly error problems between the punching dies and the die fixing plate, and improving the working fit between the punching dies and the punching punches, reducing the amount of burrs on the processed fins, and enabling the manufacture of higher quality fins.

[0083] The preferred embodiments of the present invention have been described in detail above, but the present invention is not limited to the embodiments described. Those skilled in the art can make various equivalent modifications or substitutions without departing from the spirit of the present invention, and these equivalent modifications or substitutions are all included within the scope defined by the claims of this application.

Claims

1. A processing technology for a fin punching die, characterized in that, The steps include the following: The outer diameter end of the punching die blank is ground on a centerless grinder. Each level of blanking holes is machined using the large outer diameter end of the punching die blank as a reference. The large outer diameter end of the punching die blank is clamped and machined to form steps of various levels, and the cutting edge hole is machined coaxially. The cutting edge is machined at the cutting edge hole; Perform stepped grinding on the small outer diameter end of the cutting edge; The cutting edge is finely ground; In the step of step grinding the small outer diameter end of the cutting edge, a 100# grinding wheel is used to rough grind the small outer diameter end of the cutting edge, leaving a 0.02mm allowance, and then fine grinding is performed to ensure that the surface finish of the cutting edge reaches 0.

4. In the step of fine grinding the cutting edge, an 80# grinding wheel is used to finely grind the cutting edge with a feed rate of 0.002mm each time, and the grinding is completed to the required depth, ensuring that the surface finish of the cutting edge reaches 0.

4. Between the step of performing stepped grinding on the small outer diameter end of the cutting edge and the step of performing fine surface grinding on the cutting edge, the following step is also included: The outer diameter end of the punching die blank is covered with a copper sheet and clamped and fixed. Apply polishing compound to the surface of the cork to polish the outer diameter of the punch cutting edge until the surface finish reaches 0.

2.

2. The processing technology of the fin punching die according to claim 1, characterized in that, In the step of grinding the outer diameter end of the punching die blank on a centerless grinder, the grinding is performed according to the design size of the outer diameter end of the punching die within ±0.2mm to ensure that the consistency of the outer diameter end is within ±0.02mm.

3. The processing technology of the fin punching die according to claim 1, characterized in that, In the step of machining each level of steps, a 0.15mm allowance is left on each side of the outer diameter of the step to ensure coaxiality <0.05mm.

4. The processing technology of the fin punching die according to claim 1, characterized in that, After machining various steps and coaxially machining the cutting edge hole at the large outer diameter end of the clamping punch die blank, the following steps are also included: Heat-treat the punching die blank with a deformation of <0.1mm; The outer diameter end of the punching die blank is rough ground with a machining allowance of 0.05-0.08mm, and then fine ground to a depth of ±0.0015mm, ensuring a coaxiality of 0.003mm. The end face of the punching die blank is made flat with the large outer diameter end as the reference, and the perpendicularity is guaranteed to be 0.003mm.

5. The processing technology of the fin punching die according to claim 4, characterized in that, After the flat end face of the punching die blank, which is based on the large outer diameter end, is exposed to light, the following steps are also included: polishing the blanking hole to ensure a surface finish of 0.

8.

6. The processing technology of the fin punching die according to claim 1, characterized in that, After the cutting edge hole is coaxially machined, the following steps are also included: clamping the large outer diameter end of the punching die blank, aligning it, and ensuring that the runout value is <0.003mm; fine grinding the cutting edge hole to ensure that the coaxiality reaches 0.003mm and the surface finish of the cutting edge hole reaches 0.

4.

7. The processing technology of the fin punching die according to claim 1, characterized in that, The process of machining the cutting edge at the cutting edge hole includes the following steps: using a 60# grinding wheel to perform fine surface grinding on the cutting edge hole with a feed rate of 0.03mm per cycle, leaving a margin of 0.01mm; then using an 80# grinding wheel to machine the cutting edge with a feed rate of 0.002mm per cycle, ensuring that the surface finish of the cutting edge is 0.

4.

8. A fin punching die, characterized in that, It is manufactured using the processing technology of the fin punching die as described in any one of claims 1 to 7.

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