An efficient machining method for dense hole systems in large tapered parts

Abstract

A highly efficient machining method for densely packed hole systems in large conical parts is disclosed. First, the neutral plane projection of each hole in the unfolded state of the steel plate is drawn. Using this projection dimension offset inward by X as the template size, an oxy-fuel cutting template is drawn. Then, the position lines of each hole are marked on the workpiece to be machined. The oxy-fuel cutting template is aligned with each hole position, and the bottom holes of each hole are pre-cut using oxy-fuel cutting equipment. Next, the workpiece is clamped and fixed using a fixing assembly. Rough boring is used to rough-bore each hole in the lower 1 / 3-1 / 2 area of ​​the workpiece. A fine boring tool is then used to machine each hole to the finished size. The fixing assembly is released, and the workpiece is rotated so that its unmachined area is located below the workpiece. After adjustment, the workpiece is aligned using the inner hole at the small end as a reference, and the bottom holes in the remaining 1 / 3-1 / 2 area are machined to the finished size. The workpiece is adjusted again until all holes in all areas are machined. This method is suitable for batch machining of holes on large-angle conical surfaces, providing a reliable theoretical and practical basis for machining this type of part.

Description

Technical Field

[0001] This invention relates to the field of machining technology, specifically to an efficient machining method for a dense hole system in a large conical part. Background Technology

[0002] In the field of machining, the dense hole system on the surface of large conical parts is difficult to machine. Taking the conical section used in the kiln head of a rotary kiln as an example, its structure is as follows: Figure 1-2 As shown, its outer diameter φD is generally above 6000mm, and the small end diameter φd is generally above 2000mm. Its taper is α, and hundreds of vertical holes with a size of φAmm need to be evenly distributed on its conical surface. The positional tolerance of each hole is required to be 0.3~0.5mm, the dimensional tolerance of the hole is (0, +0.1~+0.3)mm, the surface roughness is Ra6.3, and the total thickness δ of the steel plate of the machined part is above 80mm. As can be seen from the figure, there are many holes and the holes are arranged relatively densely, requiring the arrangement of related pipe fittings. The entire hole system is parallel to the axis of the conical part, not perpendicular to the conical surface. If it is necessary to machine the conical part with a dense hole system, due to the limitation of its shape, it is difficult to balance the machining accuracy and machining efficiency of the hole system on the conical surface.

[0003] Due to the large diameter of the conical section, the large angle of the conical surface, and the strict requirements for the positional relationship of each hole, conventional processing methods cannot meet the precision requirements for the manufacturing of the conical section and are very inefficient.

[0004] The conventional machining methods for this type of part are as follows: Method 1: Do not pre-cut the bottom hole when blanking. Use a large boring machine or gantry milling machine to mill a flat surface at each hole, and then use drilling or nesting to remove the excess material in the hole; Method 2: Cut the bottom hole of each hole perpendicular to the conical surface when blanking. Then use a single-edged boring tool to rough and finish bore the hole on a large boring machine, or use a circumferential cutting edge interpolation tool to perform helical interpolation on the hole.

[0005] However, the above methods are difficult to implement in the machining of dense hole systems of this type of part. The main reason is that the part has a large taper angle and there is no condition to mill out a flat surface, making method one difficult to implement. When using method two, the longest cantilever distance of the machine tool is generally more than 2500mm. At this time, the spindle rigidity is poor, and the radial force generated by the peripheral cutting will cause the tool to vibrate during the machining process. Vibration can only be alleviated by reducing the depth of cut and feed rate, which leads to a long machining time and is not suitable for batch hole machining. Summary of the Invention

[0006] The purpose of this invention is to propose an efficient machining method for dense hole systems in large conical parts. This method is suitable for batch machining of holes on large-angle conical surfaces, improving machining efficiency and providing a reliable theoretical and practical basis for machining this type of part.

[0007] The technical solution adopted in this invention is: an efficient machining method for a dense hole system of a large conical part, wherein the hole size to be machined on the conical surface is set to φAmm, and the method includes the following steps:

[0008] S1. First, draw the neutral plane projection of each hole in the unfolded state of the steel plate. Use the projection size offset inward by X as the template size, X≥30mm, and draw the gas cutting template. Then, draw the position lines of each hole on the workpiece to be processed, align the gas cutting template with each hole, and use the gas cutting equipment perpendicular to the inner conical surface of the workpiece to pre-cut the bottom hole of each hole.

[0009] S2. Place the large end of the workpiece processed in step S1 on the electric roller, support the small end, and then use a fixing component to clamp and fix the workpiece.

[0010] S3. Use a rough boring tool to rough bore each hole in the lower 1 / 3-1 / 2 area of ​​the workpiece, and enlarge the pre-cut bottom hole to about φA-50~60mm; then change to a fine boring tool to machine each hole in the rough boring area to the finished size.

[0011] Then loosen the fixing components, use the overhead crane and electric rollers to adjust the rotation of the workpiece so that the unprocessed area is below the workpiece. After adjustment, use the inner hole of the small end as the reference to find the alignment and open the coordinates. Use the same method to process the bottom hole in the other 1 / 3-1 / 2 area to the finished size. Continue to adjust the workpiece until the processing of all the holes in all areas is completed.

[0012] The processing method described in this invention is mainly applicable to the batch processing of holes on large-angle conical surfaces, improving processing efficiency and providing reliable theoretical and practical basis for the processing of this type of part. By optimizing the entire process steps and designing a non-circular gas-cut bottom hole template, the excess material is removed to the maximum extent, reducing the amount of subsequent processing and improving efficiency. By designing fixed fixtures and clamping methods, the workpiece can be vertically placed for processing on a large boring machine, ensuring optimal stability and rigidity of the workpiece during processing. Considering that the overall size of the workpiece is large and most machine tools cannot complete the processing in one go, the processing of subsequent holes is optimized. In conjunction with the aforementioned fixed fixtures, a segmented and step-by-step processing method is adopted to improve processing accuracy and efficiency and reduce wear and tear on the machine tool.

[0013] As a preferred embodiment, in step S1, the template size is offset inward by 30mm from the projected size.

[0014] As a preferred embodiment, step S2, the card loading process, is as follows:

[0015] S2.1. Lift the workpiece vertically, place the lower part of the outer circle of the large end of the workpiece upright on the electric roller, and support the lower part of the outer circle of the small end with a cylindrical support. After the workpiece is adjusted, place it against the bending plate on the left and right sides of the large end, and at the same time, place a pressure plate on the bending plate to press the outer circle surface of the large end of the workpiece.

[0016] S2.2 Place the square box and fixed bending plate at the middle position of the large end of the workpiece. After adjusting the height, use the tie rod and channel steel to help tighten the workpiece. When tightening, the channel steel is located near the horizontal center line of the workpiece to ensure the stability of the center of gravity. By fixing the workpiece in the above way, the stability and rigidity of the workpiece during the processing are optimized. At the same time, it is convenient to adjust the workpiece in conjunction with the subsequent process, which indirectly improves the processing quality.

[0017] As a preferred embodiment, step S3 is specifically performed as follows:

[0018] S3.1. Use a rough boring tool to rough bore each hole in the lower 1 / 3 area of ​​the workpiece, and enlarge the pre-cut bottom hole to about φA-50~60mm; replace with a fine boring tool to machine each hole in this area to the finished size;

[0019] S3.2 Loosen the fixing components, use the crane and electric rollers to adjust the rotation of the workpiece so that the unprocessed area is below the workpiece. After adjustment, use the small end inner hole as the reference to align and open the coordinates. Use the method in step S3.1 to process the bottom hole in the other 1 / 3 area to the finished size.

[0020] S3.3 After two adjustments, the machining is completed. The workpiece is then laid flat, and the actual passability of each hole is checked using an inspection template. The machining is then completed. Considering that the overall size of the workpiece is large, most machine tools cannot complete the machining in one go. Moreover, the lower 1 / 3 area of ​​the workpiece is the most stable and has the best rigidity. Therefore, the machining process of the subsequent holes is optimized by adopting a segmented and step-by-step machining method. Each hole in the lower 1 / 3 area of ​​the workpiece is machined in one go. After machining, the workpiece is rotated with the help of a crane and electric rollers so that the unmachined area is located below the workpiece. After adjustment, the small end inner hole is used as the reference for alignment and coordinate opening. The holes in the lower 1 / 3 area of ​​the workpiece are machined again until the holes in all areas are processed.

[0021] As a preferred embodiment, in step S3, the rough boring tool consists of 3 to 4 layers of inserts, with 5 inserts evenly distributed per revolution. Its outer diameter is φA-50~60mm, and its minimum machining dimension is φA-140~150mm. The finish boring tool consists of 2 layers of inserts, with 6 inserts evenly distributed per revolution. Its outer diameter is φA, with the first layer having a dimension of φA-30~40mm. Both layers participate in the cutting. This solution uses a complete set of boring tools to machine each hole. Using this set of tools, holes can be directly rough and finish bored, resulting in high efficiency. The efficiency of machining a single hole using this set of tools is more than 5 times that of traditional interpolation milling methods. During use, multi-directional, multi-edge, and multi-layer cutting occurs simultaneously, resulting in uniform radial force and reduced tool vibration. Attached Figure Description

[0022] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0023] Figure 1 This is a three-dimensional schematic diagram of the conical section used in rotary kilns in the prior art;

[0024] Figure 2 This is a schematic cross-sectional view of the cone section used in a rotary kiln.

[0025] Figure 3 This is a schematic diagram of the mounting of the workpiece to be processed in this invention;

[0026] Figure 4 This is a front view of the roughing boring tool used in this invention;

[0027] Figure 5 This is a side view of the rough boring tool used in this invention;

[0028] Figure 6 This is a front view of the precision boring tool used in this invention;

[0029] Figure 7 This is a side view of the precision boring tool used in this invention.

[0030] Reference numerals: 1. Workpiece to be processed; 2. Fixed bending plate; 3. Electric roller; 4. Cylindrical support; 5. Tie rod. Detailed Implementation

[0031] The present invention will now be described in detail through exemplary embodiments. However, it should be understood that, without further description, elements, structures, and features in one embodiment may be advantageously incorporated into other embodiments.

[0032] It should be noted that, unless otherwise defined, the technical or scientific terms used herein should have the ordinary meaning understood by one of ordinary skill in the art to which this invention pertains; the words "a," "an," or "the" and similar terms used in the patent application specification and claims of this invention do not express a quantity limitation, but rather indicate the presence of at least one; the words "comprising" or "including" and similar terms indicate that the elements or objects preceding "comprising" or "including" cover the elements or objects listed following "comprising" or "including" and their equivalents, but do not exclude other elements or objects having the same function;

[0033] Example 1

[0034] An efficient machining method for a dense hole system in a large tapered part, comprising the following steps:

[0035] Step 1: Pre-cut the bottom hole at each hole before processing:

[0036] (1) First, draw the neutral plane projection of each hole in the unfolded state of the steel plate, and use the projection size offset inward by 30mm as the template size to draw the gas cutting template.

[0037] (2) After cutting and welding, first mark the position lines of each hole on the blank, then place the gas cutting template with each hole position, and finally use the gas cutting equipment perpendicular to the inner conical surface of the workpiece to pre-cut the bottom hole of each hole; in order to ensure the size of the pre-cut hole, each hole needs to be cut perpendicular to the conical surface angle during pre-cutting. After cutting the hole, use the template to control the minimum size of the cut bottom hole to ensure that the subsequent processing amount is as small as possible.

[0038] Step 2: Install and secure the cone section vertically.

[0039] (1) Prepare electric rollers, square boxes and bending plates in advance, and place each tooling fixture in the approximate position according to the form that the outer conical surface of the workpiece faces the machine tool spindle;

[0040] (2) Combination Figure 3 In detail, the workpiece 1 to be processed is vertically lifted, and the lower part of the outer circle of the large end of the workpiece is placed on the electric roller 3. A cylindrical support 4 is supported on the lower part of the outer circle of the small end. After the workpiece is adjusted, it is placed against the bending plate 2 on the left and right sides of the large end. At the same time, a pressure plate is placed on the bending plate 2 to press the outer circle surface of the large end of the workpiece.

[0041] (3) Place the square box and the bent plate in the middle of the large end of the workpiece. After adjusting the height, use the tie rod 5 and the channel steel to help tighten the workpiece. One end of the tie rod 5 is fixed on the bent plate 2. When tightening, the channel steel is located near the horizontal center line of the workpiece to ensure the stability of the center of gravity.

[0042] Step 3: Machining using roughing and finishing boring tools:

[0043] (1) Use a rough boring tool to rough bore each hole in the lower 1 / 3 area of ​​the workpiece, and enlarge the pre-cut bottom hole to about φA-50~60mm to eliminate the hardened layer formed by gas cutting;

[0044] (2) Replace the fine boring tool and machine each hole in the rough boring area to the finished size.

[0045] (3) Adjustment: After the lower 1 / 3 is processed, loosen the pressure plates, channel steel and tie rods, and use the crane and electric rollers to adjust the rotation of the workpiece so that the unprocessed area is below the workpiece. After adjustment, use the inner hole of the small end as the reference to find the coordinate and open the coordinate. Process the hole in the other 1 / 3 area to the finished size.

[0046] (4) After adjusting twice, complete the machining of all holes in the area. After unloading, lay the workpiece flat and use the inspection sample column to check the actual passability of each hole to complete the machining.

[0047] Example 2

[0048] An efficient machining method for a dense hole system in a large tapered part, comprising the following steps:

[0049] Step 1: Pre-cut the bottom hole at each hole before processing:

[0050] (1) First, draw the neutral plane projection of each hole in the unfolded state of the steel plate, and use the projection size offset inward by 40mm as the template size to draw the gas cutting template.

[0051] (2) After cutting and welding, first mark the position lines of each hole on the blank, then place the gas cutting template with each hole position, and finally use the gas cutting equipment perpendicular to the inner conical surface of the workpiece to pre-cut the bottom hole of each hole; in order to ensure the size of the pre-cut hole, each hole needs to be cut perpendicular to the conical surface angle during pre-cutting. After cutting the hole, use the template to control the minimum size of the cut bottom hole to ensure that the subsequent processing amount is as small as possible.

[0052] Step 2: Install and secure the cone section vertically.

[0053] (1) Prepare electric rollers, square boxes and bending plates in advance, and place each tooling fixture in the approximate position according to the form that the outer conical surface of the workpiece faces the machine tool spindle;

[0054] (2) The workpiece 1 to be processed is lifted vertically, and the lower part of the outer circle of the large end of the workpiece is placed on the electric roller 3. A cylindrical support 4 is placed on the lower part of the outer circle of the small end. After the workpiece is adjusted, it is placed against the bending plate 2 on the left and right sides of the large end. At the same time, a pressure plate is placed on the bending plate 2 to press the outer circle surface of the large end of the workpiece.

[0055] (3) Place the square box and the bent plate in the middle of the large end of the workpiece. After adjusting the height, use the tie rod 5 and the channel steel to help tighten the workpiece. One end of the tie rod 5 is fixed on the bent plate 2. When tightening, the channel steel is located near the horizontal center line of the workpiece to ensure the stability of the center of gravity.

[0056] Step 3: Machining using roughing and finishing boring tools:

[0057] (1) Use a rough boring tool to rough bore each hole in the lower 1 / 2 area of ​​the workpiece, and enlarge the pre-cut bottom hole to about φA-50~60mm to eliminate the hardened layer formed by gas cutting;

[0058] (2) Replace the fine boring tool and machine each hole in the rough boring area to the finished size.

[0059] (3) Adjustment: Loosen all pressure plates, channel steel and tie rods, use the crane and electric roller to adjust the rotation of the workpiece so that the unprocessed area is below the workpiece. After adjustment, use the small end inner hole as the reference to find the coordinate and open the coordinate. Process the holes in the remaining 1 / 2 area to the finished size. Then lay the workpiece flat and use the inspection sample column to check the actual passability of each hole to complete the processing.

[0060] The high-efficiency machining technology for dense hole systems in large conical parts proposed in this invention has been applied to the mass production process of our company's products, improving production efficiency, reducing production costs, and shortening the production cycle; thus, this process method is a relatively novel and practical machining method.

[0061] In the above embodiments, such as Figure 4-5 As shown, the rough boring tool used consists of 3 to 4 layers of inserts, with 5 inserts evenly distributed in each revolution. To fully eliminate the hardened layer from the gas cutting, its outer diameter is φA-50~60mm; to prevent pre-cutting dimensional errors, its minimum machining dimension is φA-140~150mm, and it generally does not participate in cutting; as Figure 6-7 As shown, the precision boring tool consists of two layers of inserts, with six inserts evenly distributed in each ring. The outer diameter of the insert is φA, and the first layer has a size of φA-30~40mm. The two layers work together to participate in the cutting, optimizing the force on the tool and thus improving the surface quality of the machined part.

[0062] In this embodiment, a set of boring tools is designed to machine each hole. Using this set of tools, each hole can be directly rough and fine bored, which is highly efficient. The efficiency of machining a single hole using this set of tools is more than 5 times that of the traditional interpolation milling method. At the same time, when using it, multi-directional multi-edge cutting is performed in layers, and the radial force is uniform during machining, making it less prone to vibration.

[0063] The parts not described in detail in the above embodiments are existing technologies.

[0064] It should be noted that although the various steps of the present invention have been described through the above embodiments, the present invention may have many other embodiments. Without departing from the spirit and scope of the present invention, those skilled in the art can obviously make various corresponding changes and modifications to the present invention, but these changes and modifications should all fall within the scope of protection of the appended claims and their equivalents.

Claims

1. A high-efficiency processing method for a large conical part with a dense hole system, the size of the hole processed on the conical surface is φA mm, characterized in that: Includes the following steps: S1. First, draw the neutral plane projection of each hole in the unfolded state of the steel plate. Use the projection size offset inward by X as the template size, X≥30mm, and draw the gas cutting template. Then, mark the position lines of each hole on the workpiece to be processed, align the gas cutting template with each hole, and use the gas cutting equipment perpendicular to the inner conical surface of the workpiece to pre-cut the bottom hole of each hole. S2. Place the large end of the workpiece processed in step S1 onto the electric idler roller, support the small end, and then use a fixing assembly to clamp and fix the workpiece; the clamping process is as follows: S2.

1. Lift the workpiece vertically, place the lower part of the outer circle of the large end of the workpiece upright on the electric roller, and support the lower part of the outer circle of the small end with a cylindrical support. After the workpiece is adjusted, place it against the bending plate on the left and right sides of the large end, and at the same time, place a pressure plate on the bending plate to press the outer circle surface of the large end of the workpiece. S2.2 Place the square box and fixed bending plate at the middle position of the large end of the workpiece. After adjusting the height, use the tie rod and channel steel to help tighten the workpiece. When tightening, the channel steel should be located near the horizontal center line of the workpiece to ensure the stability of the center of gravity. S3. Use a rough boring tool to rough bore each hole in the lower 1 / 3-1 / 2 area of ​​the workpiece, and enlarge the pre-cut bottom hole to about φA-50~60mm; then change to a fine boring tool to machine each hole in the rough boring area to the finished size. Then loosen the fixing components, and use the overhead crane and electric rollers to adjust the rotation of the workpiece so that the unprocessed area is below the workpiece. After adjustment, use the inner hole of the small end as a reference to align and open the coordinates. Use the same method to process the bottom holes in the other 1 / 3-1 / 2 area to the finished size; continue to adjust the workpiece until the processing of all holes in all areas is completed; step S3, the specific process is as follows: S3.1 Use a rough boring tool to rough bore each hole in the lower 1 / 3 area of ​​the workpiece, and enlarge the pre-cut bottom hole to about φA-50~60mm; replace with a fine boring tool to machine each hole in this area to the finished size; S3.2 Loosen the fixing components, use the crane and electric rollers to adjust the rotation of the workpiece so that the unprocessed area is below the workpiece. After adjustment, use the small end inner hole as the reference to align and open the coordinates. Use the method in step S3.1 to process the bottom hole in the other 1 / 3 area to the finished size. S3.3 After two adjustments, the machining is completed. Then, the workpiece is laid flat, and the actual passability of each hole is checked using an inspection sample column to complete the machining.

2. The method according to claim 1, wherein: In step S1, the template size is offset inward by 30mm from the projected size.

3. The method according to claim 1, wherein: In step S3, the rough boring tool used consists of 3 to 4 layers of inserts, with 5 inserts evenly distributed in each circle. Its outer diameter is φA-50~60mm, and its minimum machining size is φA-140~150mm.

4. The method according to claim 1, wherein: In step S3, the precision boring tool used consists of two layers of inserts, with six inserts evenly distributed in each circle. The outer diameter of the insert is φA, and the first layer has a size of φA-30~40mm. Both layers participate in the cutting.

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