High-precision efficient numerical control machining method for edge strip group holes

Abstract

The invention discloses a high-precision efficient numerical control machining method for edge strip group holes, and relates to the technical field of numerical control machining. The method comprises the steps that a universal heightening tool is used for lifting an edge strip to be machined to the height of the free swing angle of a machine tool spindle head, and then clamping is conducted; rough machining is conducted on the edge strip to be machined, and the finish machining allowance ranging from 2 mm to 4 mm is reserved; the edge strip to be machined is subjected to finish machining to the theoretical size; and all assembly fine holes are manufactured by using a machine tool main shaft A shaft swing angle of 90 degrees. According to the method, an angle head is not needed, tool clamping time is shortened, tool purchase cost is reduced, and machining efficiency is improved; compared with an angle head machining edge strip hole, the hole forming precision is improved by 30%; compared with a traditional mode that a hole is formed after a boss is downwards broken after part machining is completed, the precision is improved by 68.5%; meanwhile, no external connecting boss exists, the material cost is reduced, the bench worker polishing amount is reduced, and the manufacturing period is shortened.

Description

Technical Field

[0001] This application relates to the field of numerical control machining technology, and particularly to a high-precision and efficient numerical control machining method for a group of holes on the flange edge. Background Art

[0002] Machining manufacturing has always been committed to shortening the manufacturing and assembly cycle. In the field of aviation manufacturing, making the precision holes for flange assembly before the numerical control machining stage will greatly improve the manufacturing precision and efficiency.

[0003] Currently, when setting external bosses to machine the precision holes for flange assembly, the following two methods are usually used for hole making: (1) Milling an avoidance groove on the external boss and using an angle head to make holes. This method can only meet the holes with a hole position tolerance of more than ±0.2 mm, and the angle head is expensive, with an average price of 100,000 yuan per piece. It takes about 35 minutes for workers to install the tool per piece, increasing the manufacturing cost and time; (2) Since the external boss interferes and the flange holes cannot be machined, the parts are all machined and then the bosses are manually removed and polished, and then the numerical control machine tool is used to make holes again. The qualified rate of the hole position of this method is only 32%, and the re-clamping and alignment time is about 120 minutes per piece, seriously affecting the delivery quality and cycle. Therefore, a high-precision and efficient numerical control machining method for a group of holes on the flange edge is of great significance. Summary of the Invention

[0004] The main purpose of this application is to provide a high-precision and efficient numerical control machining method for a group of holes on the flange edge, aiming to solve the technical problems of low precision, slow efficiency, and high cost in the machining of flange assembly holes of aluminum alloy parts.

[0005] The technical solution adopted by this application is as follows:

[0006] A high-precision and efficient numerical control machining method for a group of holes on the flange edge, including:

[0007] Using a general heightening tooling to raise the flange edge to be machined to the height at which the spindle head of the machine tool can freely swing the angle and then clamping it;

[0008] Rough machining the flange edge to be machined and leaving a finishing allowance of 2 mm - 4 mm;

[0009] Finishing machining the flange edge to be machined to the theoretical size;

[0010] Using the A-axis of the machine tool spindle to swing the angle by 90° to make all the assembly precision holes.

[0011] Optionally, the bottom of the flange edge to be machined has a groove cavity, and the general heightening tooling has a boss adapted to the groove cavity.

[0012] Optionally, the flange edge to be machined is clamped to the general heightening tooling by bolt pressing or stud reverse pulling.

[0013] Optionally, the height of the general heightening tooling is determined according to the swing angle stroke of the machine tool.

[0014] Optionally, before machining the assembly precision holes, trial drilling and inspection should be carried out first, and then hole-making machining can be carried out after it is correct.

[0015] Compared with the prior art, the beneficial effects of this application are as follows:

[0016] First: A high-precision rib group hole efficient numerical control machining method proposed in the embodiment of this application has high hole-making precision. By using the swing angle of the machine tool, high-precision assembly holes can be machined for parts in the same clamping state. Compared with hole-making by an angle head through trial cutting and measurement, the hole-making precision is improved by more than 30%, and the hole position tolerance can reach 0.07 mm, which has a good impact on the subsequent overall machine assembly.

[0017] Second: A high-precision rib group hole efficient numerical control machining method proposed in the embodiment of this application has high machining efficiency. Since there is no need to use an angle head, the machine tool downtime during machining caused by clamping the angle head is reduced, the tool installation time and manual intervention time are reduced, and the machining efficiency is significantly improved.

[0018] Third: A high-precision rib group hole efficient numerical control machining method proposed in the embodiment of this application reduces the machining cost. Since this method does not use an angle head for hole-making, the interference hidden danger of the angle head is avoided, the purchase and maintenance costs of the angle head are eliminated, and the time cost of clamping the angle head is saved. After the convex platform is built-in, the blank size is reduced, the material utilization rate is increased, and the blank cost is significantly reduced. At the same time, without the external convex platform, the fitter workload can be greatly reduced, the cycle can be shortened, the delivery rate can be improved, and the labor cost is significantly reduced. Description of the Drawings

[0019] Figure 1 is a process flow block diagram of a high-precision rib group hole efficient numerical control machining method provided by an embodiment of this application;

[0020] Figure 2 is a schematic diagram of the clamping state of the rib to be machined Figure 1 ;

[0021] Figure 3 is a schematic diagram of the clamping state of the rib to be machined Figure 2 。

[0022] Explanation of the reference numerals in the drawings:

[0023] 1 - part to be machined, 2 - general heightening tooling, 3 - threaded hole, 4 - bolt. Detailed Embodiment

[0024] Next, in combination with the accompanying drawings in the embodiments of the present application, the technical solutions in the embodiments of the present application will be clearly and completely described. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present application.

[0025] It should be noted that all directional indications (such as up, down, left, right, front, back...) in the embodiments of the present application are only used to explain the relative position relationship and movement conditions between components in a specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indications will also change accordingly.

[0026] In the present application, unless otherwise clearly defined and limited, terms such as "connection" and "fixation" should be understood in a broad sense. For example, "fixation" can be a fixed connection, a detachable connection, or integrated; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two components or the interaction relationship between two components, unless otherwise clearly limited. For those of ordinary skill in the art, the specific meanings of the above terms in the present application can be understood according to specific circumstances.

[0027] In addition, if there are descriptions involving "first", "second", etc. in the embodiments of the present application, the descriptions of "first", "second", etc. are only for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include at least one of such features. In addition, the meaning of "and / or" appearing throughout the text includes three parallel solutions. Taking "A and / or B" as an example, it includes solution A, solution B, or the solution where A and B are satisfied simultaneously. In addition, the technical solutions between the various embodiments can be combined with each other, but it must be based on the fact that those of ordinary skill in the art can implement it. When the combination of technical solutions conflicts with each other or cannot be implemented, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection required by the present application.

[0028] Referring to the attached Figure 1 , the embodiments of the present application provide a high-precision rib group hole high-efficiency numerical control processing method, including:

[0029] S1: Use a general heightening tooling to raise the rib to be processed to the height at which the machine tool spindle head can freely swing the angle and then clamp it;

[0030] S2: Rough process the rib to be processed and leave a finishing allowance of 2 mm - 4 mm;

[0031] S3: Finish machining the to-be-machined flange to the theoretical size;

[0032] S4: Use the A-axis swing angle of the machine tool spindle to be 90° to machine all assembly precision holes.

[0033] When designing the general heightening tooling, an internal convex platform design is adopted. The bottom of the to-be-machined flange has a groove cavity, and the general heightening tooling has a convex platform embedded in the groove cavity. The internal convex platform structure avoids hindering the machining of the flange. In step S1, the clamping method of the to-be-machined flange needs to be determined according to the specific structure of the to-be-machined flange. If there are through holes in the groove cavity that can be used to arrange the convex platform, pressing holes are set. If not, reverse pull threaded studs are arranged for reverse pull clamping.

[0034] This machining method does not require the use of an angle head, reduces the tool clamping time, lowers the tool purchase cost, and improves the machining efficiency; and compared with machining the flange holes with an angle head, the hole-making accuracy is increased by 30%; compared with the traditional method of machining the part to complete the lower break convex platform and then making holes, the accuracy is increased by 68.5%; at the same time, there is no external connecting convex platform, reducing the material cost, reducing the fitter grinding amount, and shortening the manufacturing cycle.

[0035] It should be noted that this machining method is applicable to aluminum alloy parts with high-precision flange assembly group holes, especially applicable to parts where the machining of the flange holes will interfere with the external connecting convex platform. The machining equipment must be a bridge-type machine tool.

[0036] As Figures 2 to 3 shown, to better illustrate this machining method, taking the machining of a certain part as an example, the specific features of this part are as follows:

[0037] Aluminum alloy double-sided integral frame, with dimensions of 1200mm×1100mm, assembly precision holes (5-Φ3.3, 55-Φ3.9, 15-Φ4.9) are drilled around the flange, and the hole diameter and hole position tolerance are: ±0.1mm. There are small relief holes inside the groove cavity, and it is impossible to set a pressing convex platform, and the reverse pull method is used for machining.

[0038] For the above-mentioned part, the entire detailed machining process can be specifically as follows:

[0039] S1: Drill the pressing holes: Set threaded holes 3 in the web of the to-be-machined part 1 that match the general heightening tooling 2;

[0040] S2: Clamp the part: Turn the part over and fix the to-be-machined part 1 to the heightening tooling 2 by reverse pulling with bolts 4;

[0041] S3: Rough mill the part: Ensure that the allowances for the outer shape, inner shape, and web are 3mm, and machine the internal reverse pull threaded studs at the web, without retaining the convex platform outside;

[0042] S4: Finish machining the outer shape: Finish machining the outer shape of the part to the theoretical size;

[0043] S5: Machining the flange holes: The A-axis of the machine tool spindle swings at an angle of 90° to machine high-precision holes for flange assembly.

[0044] S6: Machining the remaining features: Finish machining the internal profile, web and other features to the theoretical dimensions, and retain the internal threaded studs.

[0045] S7: Precision milling the second side: Turn the part over and use the threaded studs machined by S3 for reverse pulling and clamping. After machining the internal profile features in place first, when machining the suspended thin web, machine from the weakest rigidity part to the stronger part. Select a tool with a diameter of Φ12 or Φ25, and the length-diameter ratio should be ≤3:1 as much as possible. Machine all features to the theoretical dimensions, and do not retain the internal threaded studs.

[0046] S8: Removing the threaded studs: Turn the part over and magnetically clamp it, and remove the threaded studs retained by S3.

[0047] The above are only the preferred embodiments of the present application, and are not intended to limit the present application. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present application shall be included within the protection scope of the present application.

Claims

1. A high-precision edge group hole efficient CNC machining method, characterized in that: include: Use a universal raising tool to raise the edge strip to be processed to a height where the machine tool spindle head can freely swing and then clamp it; Rough machining the edge strip to be machined and leaving a finishing allowance of 2mm-4mm; Finishing the edge strip to be processed to a theoretical size; Use the machine tool spindle A-axis swing angle of 90° to make all assembly precision holes.

2. A high-precision edge strip group hole efficient CNC machining method according to claim 1, characterized in that: The bottom of the edge strip to be processed has a groove cavity, and the universal raising tool has a boss adapted to fit in the groove cavity.

3. The high-precision edge strip group hole efficient CNC machining method according to claim 1, characterized in that: The edge strip to be processed is clamped on the universal raising tool by bolt compression or stud reverse pulling.

4. The high-precision edge strip group hole efficient CNC machining method according to claim 1, characterized in that: The height of the universal raising tool is determined by the swing angle stroke of the random bed.

5. The high-precision edge strip group hole efficient CNC machining method according to claim 1, characterized in that: Before machining the assembly precision hole, a trial drilling and inspection should be carried out, and the hole making process can be carried out only after it is correct.

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