A method for processing a narrow slot with a large aspect ratio
By combining micro-feed and side milling, the problems of tool wear and heat accumulation in the machining of narrow grooves with large depth-to-width ratios were solved, achieving efficient and low-cost narrow groove machining and improving machining accuracy and quality.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- CHONGQING HONGJIANG MACHINERY CO LTD
- Filing Date
- 2024-11-25
- Publication Date
- 2026-07-03
AI Technical Summary
Traditional milling processes for narrow slots with large aspect ratios suffer from problems such as chipping, tool breakage, low efficiency, poor surface quality, poor heat dissipation, and high tool costs, making it difficult to achieve the required precision.
The machining method employs a combination of micro-feed and unloading side milling. By feeding in the narrow groove machining direction and immediately retracting, and using circular interpolation for widening finish milling, the stress on the tool and heat accumulation are reduced. Carbide end mills are used to improve tool life and machining quality.
It improves tool life, reduces production costs, enhances machining quality and efficiency, reduces thermal damage, and enables high-precision machining of narrow slots.
Smart Images
Figure CN119703189B_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of CNC machining technology, and in particular to a method for machining narrow grooves with a large depth-to-width ratio. Background Technology
[0002] In the field of mechanical manufacturing, milling narrow slots with a large aspect ratio has always been an extremely challenging task. This type of slot is commonly found in the aerospace, shipbuilding, and precision machinery industries, such as narrow slots in large jackets (see appendix). Figure 3 The machining of components such as aircraft venturi structures and narrow slots for electric motor rotors requires small slot openings, large depths, and good surface quality. The performance of these components directly affects the stability and reliability of the entire system, thus demanding high machining precision and quality.
[0003] Traditional milling methods, such as full-cut full-groove milling, finite-time plunge milling followed by enlargement milling, high-speed, high-feed dynamic milling with light-wheel slewing, and custom-made disc milling cutters for deep and narrow groove machining, often encounter problems such as chipping, tool breakage, low efficiency, and poor surface quality when milling such narrow grooves with large depth-to-width ratios. At the same time, the heat dissipation conditions in the machining area are also poor, which easily leads to heat accumulation in the cutting area, rapid tool wear, short tool life, high tool costs, and can also easily cause thermal damage to the workpiece, affecting the machining quality and making it difficult to achieve the precision requirements of narrow groove machining. Summary of the Invention
[0004] To address the aforementioned problems, embodiments of the present invention provide a method for machining narrow grooves for large jackets.
[0005] This invention provides a method for machining narrow grooves with a large depth-to-width ratio, the method comprising the following steps:
[0006] Step S1: At the starting position of the groove to be processed, use a drill bit to process a cutting hole to the bottom of the groove.
[0007] Step S2: After changing to a milling cutter, cut down to the bottom of the machining groove at the pre-drilled cutter hole;
[0008] Step S3: The milling cutter feeds T+0.05mm along the narrow groove machining direction, where T is the groove width, calculated by the formula T = (groove width - milling cutter diameter) ÷ 2. The milling cutter immediately retracts Tmm in the opposite direction.
[0009] Step S4: Using the retracted coordinate point as the center, perform circular interpolation to side-mill a semicircle with a radius of R = T mm. Then return to the center of the circle to reach the starting position of the next machining cycle. Widen and finish mill the narrow groove to machine the entire narrow groove to the required size and connect it to the transverse feed position of the previous step.
[0010] Step S5: Repeat steps S3 and S4. When the narrow groove machining length reaches the specified machining length, stop machining to complete the machining of the narrow groove with a large depth-to-width ratio.
[0011] In some embodiments, the method further includes: selecting drill bit and milling cutter sizes that match the machining requirements, and determining the tool material and machining cutting parameters.
[0012] In some embodiments, determining the tool material includes: for steel products, selecting a carbide end mill.
[0013] In some embodiments, selecting the drill bit and milling cutter size that matches the machining requirements includes: selecting a pre-drilled hole drill bit diameter equal to the width of the groove to be machined, so that the cutter can be lowered during milling.
[0014] In some embodiments, selecting drill and milling cutter sizes that match the machining requirements further includes: selecting an end mill diameter that is 0.5 mm smaller than the machining groove size, and a milling cutter diameter that is 0.5 mm smaller than the drill diameter.
[0015] In some embodiments, step S1 further includes: if the starting position port of the groove being processed is open, then step S1 is omitted.
[0016] In some embodiments, step S2 further includes: the maximum machining depth of the milling cutter is the length of the entire cutting edge of the tool, to achieve full-edge milling and make the wear distribution of the tool edge uniform.
[0017] This invention provides a tool for machining narrow grooves with a large aspect ratio, used to perform the machining method for narrow grooves with a large aspect ratio described in any of the above embodiments.
[0018] The method for machining narrow slots with a large aspect ratio of the present invention effectively solves the problems existing in traditional machining methods by immediately retracting the milling cutter after a small transverse feed to unload and buffer the force, combined with a side milling method. Specifically, this method reduces the stress on the tool by unloading and buffering during machining, adopts side milling to reduce the wear and breakage risk of the milling cutter, and improves the tool life; at the same time, by reducing the accumulation of cutting heat, it can reduce tool vibration and thermal damage to the workpiece, and improve the machining quality of narrow slots. In addition, this method can also improve machining efficiency, shorten the production cycle, and reduce production costs. Attached Figure Description
[0019] The accompanying drawings illustrate, by way of example and not limitation, the various embodiments discussed herein.
[0020] Figure 1 This is a schematic diagram illustrating the detailed processing effect;
[0021] Figure 2 This is a schematic diagram of the processing steps;
[0022] Figure 3 This is a schematic diagram of the large jacket groove. Detailed Implementation
[0023] In order to gain a more detailed understanding of the features and technical content of the embodiments of this application, the implementation of the embodiments of this application will be described in detail below with reference to the accompanying drawings. The accompanying drawings are for reference and illustration only and are not intended to limit the embodiments of this application.
[0024] In the embodiments described in this application, it should be noted that, unless otherwise stated and limited, the term "connection" should be interpreted broadly. For example, it can be an electrical connection, or a connection between two internal components. It can be a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above term according to the specific circumstances.
[0025] It should be noted that the terms "first," "second," and "third" used in the embodiments of this application are merely used to distinguish similar objects and do not represent a specific ordering of objects. It is understood that "first," "second," and "third" can be interchanged in a specific order or sequence where permitted. It should be understood that the objects distinguished by "first," "second," and "third" can be interchanged where appropriate so that the embodiments of this application described herein can be implemented in an order other than those illustrated or described herein.
[0026] Tool selection:
[0027] Taking a typical three-axis CNC milling machine as an example, based on the part material and the length, width, and depth dimensions of the groove to be machined, select the drill and end mill sizes that match the machining requirements, and determine the tool material and machining cutting parameters. For steel products, carbide end mills are preferred. The diameter of the pre-drilled entry hole drill should be equal to the width of the groove to be machined, to facilitate the entry of the tool during milling. The diameter of the end mill is generally about 0.5mm smaller than the size of the groove, and the end mill diameter is 0.5mm smaller than the drill diameter.
[0028] This invention provides a method for machining narrow slots with a large depth-to-width ratio, such as... Figure 2 As shown, it includes the following steps S1 to S5.
[0029] Step S1: At the starting position of the groove to be processed, drill a cutting hole to the bottom of the groove. This step can be omitted if the starting position of the groove is open.
[0030] Step S2: After changing the milling cutter, lower the cutter into the pre-drilled entry hole until it reaches the bottom of the machining groove. See [link / reference]. Figure 3 The maximum machining depth of the milling cutter can reach the entire cutting edge length of the tool, truly achieving full-edge milling, so the tool edge wear is evenly distributed.
[0031] Step S3: Then, the milling cutter feeds T+0.05mm along the narrow groove machining direction. At this moment, the tool path center point is at point 1. See Appendix. Figure 2 In step "1", the milling cutter immediately retracts in the opposite direction by Tmm to point 2. See attached document. Figure 2 In step "2", after the milling cutter completes these two steps, the actual machining amount is only a tiny 0.05mm, as shown in the appendix. Figure 2 The dimensions marked in step "1" mean that the milling cutter is retracted and unloaded every 0.05mm of transverse feed. This can effectively prevent the tool from continuously increasing radial force, which could lead to problems such as tool chipping or breakage.
[0032] T = (groove width - cutter diameter) ÷ 2 — also known as the groove width
[0033] Step S4: Then, perform circular interpolation using the retracted coordinate points as the center. See Appendix. Figure 2 In step "3", a semicircle with radius R = T mm is side-milled, and then the process returns to the center of the circle. See Appendix. Figure 2 Step "4" marks the beginning of the next machining cycle. This step primarily involves widening and finish milling the narrow groove. The machined area is a circular interpolation region; see appendix for details. Figure 2 In step "3", the entire narrow groove is machined to the required size and leveled with the lateral feed position of the previous step.
[0034] Step S5: Repeat steps S3-S4. When the narrow groove machining length reaches the specified machining length, stop machining to complete the machining of the narrow groove with a large depth-to-width ratio. This milling method can be figuratively called "pecking milling".
[0035] In this embodiment of the invention, for instantaneous unloading after a small amount of feed:
[0036] During the cross-cutting process, a micro-feed strategy is employed. This means that once the tool has completed a given micro-feed, the feed is immediately stopped and the tool retracts to unload the load, thus preventing a continuous increase in radial force on the milling cutter. (See [link to relevant documentation]). Figure 1 and Figure 2 This effectively avoids chipping, tool breakage, and heat accumulation during machining. Practice has proven that this milling method is very practical and effective.
[0037] In this embodiment of the invention, for side milling operations:
[0038] After unloading, side milling is used to enlarge and finish the narrow groove. Side milling effectively reduces the contact area between the tool and the workpiece surface, thereby reducing friction, lowering the generation of cutting heat, and promoting the diffusion of cutting heat.
[0039] Compared to traditional cold machining methods for narrow slots: In traditional slot milling, the contact arc length of the cutter's entire normal arc surface reaches its maximum, approximately half the tool's circumference. This results in maximum friction and radial cutting force, with the tool continuously under stress. Consequently, the axial machining depth is severely limited. Slightly deeper slots cannot be machined in a single pass, requiring more longitudinal passes, leading to longer machining times and lower efficiency. Furthermore, increased tool vibration and poorer heat dissipation contribute to poorer slot machining quality.
[0040] After a small transverse feed, the milling cutter is immediately retracted to unload the load before performing circular interpolation side milling. This utilizes the characteristic of instantaneous force application and unloading of the tool, minimizing tool damage. Simultaneously, side milling reduces the radial depth of cut, minimizing the contact arc length between the tool and workpiece, resulting in low friction on the tool. With low overall tool stress and effective unloading buffering, a large axial depth of cut can be used, achieving full-edge cutting and consistently keeping cutting forces at a low level, preventing tool damage. It also ensures even tool wear distribution, effectively improving heat dissipation, accelerating heat dissipation, and extending tool life.
[0041] An application example of the above embodiments of this application is as follows. Suppose we want to machine a sleeve with a narrow groove having a large aspect ratio, the groove dimensions being a depth of 40mm and a width of 6.5mm. Tool selection:
[0042] Taking a typical three-axis CNC milling machine as an example, based on the material of the part and the length, width and depth dimensions of the groove to be machined, a Φ6.5mm ordinary high-speed steel drill bit that matches the machining requirements is selected for pre-drilling the entry hole, a Φ6mm extended end mill is selected, and a solid carbide end mill is preferred for better rigidity and higher surface quality.
[0043] At least the following steps are included:
[0044] Step S110: At the starting position of the groove to be processed, select a drill bit speed of S800 r / min and a feed rate of F60 mm / min, and use the drill bit to process a cutting hole with a depth ≥40 mm. In this example, the starting position of the groove is open, so this step can be omitted.
[0045] Step S120: Select the milling cutter cutting parameters as follows: rotation speed S1200r / min, feed rate F100mm / min. After changing the milling cutter, cut the cutter at the pre-drilled cutter hole to a depth of 40mm, which is slightly larger than the bottom of the groove.
[0046] In step S130, the milling cutter feeds T+0.05=0.3mm along the narrow groove machining direction, and then immediately retracts 0.25mm in the opposite direction of feed. The actual machining amount of the milling cutter in this step is only 0.05mm each time.
[0047] T = (6.5 - 6) ÷ 2 = 0.25 — This can also be called the width of the groove.
[0048] In step S140, following the previous step, the coordinate point after the milling cutter retracts is used as the center for circular interpolation. A semicircle with a radius of R = 0.25mm is traversed, and then the milling cutter returns to the center. In this way, the machining groove is widened and refined by side milling, and the entire narrow groove is machined to the required size and leveled with the transverse feed position of the previous step.
[0049] Step S150: Repeat steps S130-S140. When the narrow groove machining length reaches the specified machining length, stop machining to complete the machining of the narrow groove with a large depth-to-width ratio. This milling method can be figuratively called "pecking milling".
[0050] The technical solutions described in the embodiments of this application can be combined arbitrarily without conflict.
[0051] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.
Claims
1. A method of processing a large aspect ratio narrow slot, characterized by, The method includes the following steps: Step S1: At the starting position of the groove to be processed, use a drill bit to process a cutting hole to the bottom of the groove. Step S2: After changing to a milling cutter, cut down to the bottom of the machining groove at the pre-drilled cutter hole; Step S3: The milling cutter feeds (T+0.05) mm along the narrow groove machining direction, where T is the groove width, calculated by the formula T=(groove width-milling cutter diameter)÷2. The milling cutter immediately retracts T mm in the opposite direction. The maximum machining depth of the milling cutter is the length of the entire cutting edge of the tool, achieving full-edge milling and making the tool edge wear distribution uniform. Step S4: Using the retracted coordinate point as the center, perform circular interpolation to side-mill a semicircle with a radius of R=Tmm. Then return to the center of the circle to reach the starting position of the next machining cycle. Widen and finish mill the narrow groove to machine the entire narrow groove to the required size and connect it to the transverse feed position of the previous step. Step S5: Repeat steps S3 and S4. When the narrow groove machining length reaches the specified machining length, stop machining to complete the machining of the narrow groove with a large depth-to-width ratio.
2. The method for machining narrow grooves with a large depth-to-width ratio according to claim 1, characterized in that, The method also includes: selecting drill bit and milling cutter sizes that match the machining requirements, and determining the tool material and machining cutting parameters.
3. The method for machining narrow grooves with a large depth-to-width ratio according to claim 2, characterized in that, The determination of the tool material includes: for steel products, selecting carbide end mills.
4. The method for machining narrow grooves with a large depth-to-width ratio according to claim 2, characterized in that, The selection of drill bit and milling cutter sizes that match the processing requirements includes: selecting a drill bit diameter for the pre-drilled entry hole that is equal to the width of the groove to be processed, so that the cutter can be lowered during milling.
5. The method for machining narrow grooves with a large depth-to-width ratio according to claim 2, characterized in that, The selection of drill and milling cutter sizes that match the processing requirements also includes: the end mill diameter being 0.5 mm smaller than the machining groove size, and the milling cutter diameter being 0.5 mm smaller than the drill diameter.
6. The method for machining narrow grooves with a large depth-to-width ratio according to claim 1, characterized in that, Step S1 further includes: if the starting position port of the groove being processed is open, then step S1 is omitted.
7. A tool for machining narrow grooves with a large depth-to-width ratio, characterized in that, Used to perform the narrow groove machining method with a large aspect ratio as described in any one of claims 1 to 6.