A method for milling the large guide plate surface of a diesel engine frame

Abstract

A method for milling large guide plate surfaces on a diesel engine frame includes the following steps: Cutting heads are mounted on both sides of the lower end of the machine tool's attachment head; using one cutting head, the first large guide plate surface inside the first cavity is machined from top to bottom; the attachment head moves laterally, and using the other cutting head, the second large guide plate surface inside the first cavity is machined from bottom to top; then the attachment head moves to the next cavity on the machine frame, and the first and second large guide plate surfaces in all cavities are machined sequentially; finally, the attachment head or machine frame is adjusted 180°, and the third and fourth large guide plate surfaces in all cavities are machined sequentially. This invention avoids the shortcomings of traditional single-cut milling of large guide plate surfaces, which is time-consuming and inefficient. It shortens the milling time of the large guide plate surface, reduces the proportion of milling in the entire machining cycle, and achieves the goal of improving the machining efficiency of diesel engine frame components.

Description

Technical Field

[0001] This invention relates to the field of diesel engine processing and manufacturing technology, and in particular to a method for milling a large guide plate surface on a diesel engine frame. Background Technology

[0002] The main frame of a diesel engine is 5069mm long, 2540mm wide, and 2520mm high. It is a steel structure made of S18R steel. The machining challenges of this main frame are: the frame is a structural cavity component with insufficient rigidity; the large guide slide has a long stroke; and the rough machining efficiency of the large guide slide surface is low. Furthermore, due to the high precision of the large guide slide surface and the design requirement of R3 at the root, conventional milling methods cannot efficiently complete the machining of the large guide slide. Because traditional machining uses single-tool machining, it suffers from the drawbacks of long machining time and low efficiency for the large guide slide, with milling accounting for a significant portion of the overall machining cycle.

[0003] Chinese patent document CN 102773532 A discloses a low-speed diesel engine frame guide plate processing equipment and processing method, which adopts a gantry milling CNC machine tool. The main spindle slide of the machine tool is installed on the gantry beam, and a milling head is installed at the lower end of the main spindle slide. A left-hand cutter head and a right-hand cutter head are fixedly installed on both sides of the milling head through a connector. Its advantages are: effectively improving processing efficiency; its disadvantages are: First, the distance between the left-hand and right-hand rotary cutter heads of this processing equipment is fixed, which makes the actual application scenario poor. This is because the method can only be implemented for the same type of diesel engine, and the same type of cutter head can only be used for one type of frame part. At the same time, the size deviation of the frame blank is relatively serious in actual production. It is difficult to meet the processing requirements of the frame in practice when processing with two cutter heads at the same time. The dual-cutter head form limits the possibility of fine-tuning the actual blank shape, making it not very practical. Second, during the processing, if one side of the cutter head jams, vibrates, or the blade breaks, the other side of the cutter head will inevitably leave scratches on the corresponding guide plate surface, affecting the subsequent processing of the frame or even causing the frame to be scrapped. Summary of the Invention

[0004] To address the existing technical problems, the main objective of this invention is to provide a method for milling the large guide plate surface of a diesel engine frame. By using a double-blade, bidirectional milling process to machine the large guide plate surface inside the frame, this method avoids the shortcomings of traditional single-blade milling, which suffers from long processing time and low efficiency. It shortens the milling time of the large guide plate, reduces the proportion of milling in the overall processing cycle, and achieves the goal of improving the processing efficiency of diesel engine frame components. Furthermore, it prevents the cutter head on one side from jamming, vibrating, or breaking the blade, while the cutter head on the other side leaves scratches on the corresponding machined guide plate surface, affecting subsequent processing of the frame or even causing the frame to be scrapped.

[0005] The technical solution adopted in this invention is: a method for milling a large guide plate surface on a diesel engine frame, comprising the following steps:

[0006] S1. Tool discs are installed on both sides of the lower end of the machine tool's accessory head. The distance between the machining end faces of the two tool discs is smaller than the distance between the two large guide plate surfaces opposite each other inside the cavity.

[0007] S2. Place and fix the frame to be processed onto the worktable of the machine tool;

[0008] S3. Using the cutter head on one side, process the large guide plate surface on one side of the first cavity from top to bottom;

[0009] S4. The attachment head moves laterally, and the large guide plate surface inside the first cavity is machined from bottom to top through the cutter head on the other side;

[0010] S5. Then the attachment head moves to the next cavity of the frame and processes the large guide plate surface one on one side of the cavity from top to bottom through the cutter head on one side. Then it moves horizontally and processes the large guide plate surface two on the other side from bottom to top through the cutter head on the other side. Repeat the above actions to process the large guide plate surface one and large guide plate surface two in all cavities in sequence.

[0011] S6. Then adjust the attachment head or frame by 180°, move the attachment head above the last cavity of the frame, and process the large guide plate surface on one side of the first cavity from top to bottom through the cutter head on one side.

[0012] S7. The attachment head moves laterally a certain distance and processes the large guide plate surface inside the cavity from bottom to top through the cutter head on the other side;

[0013] S8. Then the attachment head moves to the next cavity of the machine frame and processes the large guide plate surface three on one side of the next cavity from top to bottom through the cutter head on one side. After moving laterally for a distance, it processes the large guide plate surface four on the other side. Through the above steps, the large guide plate surface three and large guide plate surface four in all cavities are processed in sequence.

[0014] The machine tool is a gantry milling machine. The machine tool's attachment head has two spindle end faces, and cutter heads are mounted on the two spindle end faces respectively, with the two cutter heads facing away from each other.

[0015] Before S1, there is also a step of selecting the cutter head based on the size of the machine frame cavity and the accessory head.

[0016] The parameters of the cutter head are: diameter 250mm, number of teeth 10, principal cutting edge angle 90°, axial positive rake angle, radial positive rake angle, cutter tip radius 0.1mm, maximum depth of cut 20mm, cutting speed 150~300mm / min, and cutting depth 0.2~0.8mm.

[0017] Before S3, there is also a step of selecting the cutting depth and feed rate of the cutter head based on the power of the accessory head.

[0018] Based on the power of the attachment head, the depth of cut and feed rate of the cutter head are selected using the following formula:

[0019] ;

[0020] In the formula: For cutting power, To compare cutting resistance, For depth of cut, For cutting width, This is the cutting feed rate.

[0021] The specific cutting resistance value is determined based on the material of the frame, the rigidity of the frame, and the stability of the machine tool ram during its large stroke extension.

[0022] The present invention has the following beneficial effects:

[0023] 1. The improved method decomposes the unified, overall processing steps. Although it slightly increases the number of paths or steps, it is more applicable to the processing of multiple series of diesel engines. This processing method can be applied to all models of low-speed diesel engines. By determining the required machining amount for each surface based on the actual dimensions of the frame blank, the machining accuracy is better. At the same time, the differentiated overall processing steps ensure the adjustability of the CNC machining program, improve the accuracy of dimensional machining, and reduce the significant time and effort required for rework, repairs, and program adjustments, resulting in higher overall production efficiency. Therefore, this method is more suitable for actual production needs. Furthermore, it prevents issues such as jamming, vibration, or blade breakage on one side of the cutter head, while the cutter head on the other side leaves scratches on the corresponding guide plate surface, affecting subsequent processing of the frame or even causing the frame to be scrapped.

[0024] 2. This method avoids the traditional single-blade milling of large guide slides by using double-blade bidirectional milling to machine the large guide slide surface inside the machine frame. The optimized double-blade bidirectional milling method reduces the total machining time by 26.6% and the machine tool idle time by 95%. The effective machining time ratio of the machine tool increases from 72% to 98.2%, effectively improving machining efficiency and machine tool utilization. This avoids the shortcomings of traditional single-blade milling of large guide slides, which is characterized by long machining time and low efficiency. It shortens the milling time of the large guide slides, reduces the proportion of milling in the entire machining cycle, and achieves the goal of improving the machining efficiency of diesel engine frame components. Attached Figure Description

[0025] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0026] Figure 1 This is a three-dimensional structural diagram of the diesel engine frame to be processed.

[0027] Figure 2 This is a top view of the diesel engine frame to be processed.

[0028] Figure 3 This is a schematic diagram of the movement trajectory of the cutter head inside the cavity of the machine frame.

[0029] Figure 4 This is a schematic diagram of the movement trajectory of the cutter head at the top of the frame.

[0030] Figure 5 This is a schematic diagram of the path of the cutter head when machining large guide plate surface one and large guide plate surface two.

[0031] Figure 6 This is a schematic diagram of the path of the cutter head when machining large guide plate surface three and large guide plate surface four.

[0032] Figure label:

[0033] T1 path 1, T2 path 2, T3 path 3, T4 path 4;

[0034] Frame 10, cavity 11, large guide plate surface one 12, large guide plate surface two 13, large guide plate surface three 14, large guide plate surface four 15;

[0035] Attachment head 20, cutter head 21. Detailed Implementation

[0036] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0037] Example 1:

[0038] See Figure 1-6 This invention provides a method for milling a large guide plate surface on a diesel engine frame, comprising the following steps:

[0039] S1. Tool heads 21 are installed on both sides of the lower end of the machine tool accessory head 20; the distance between the machining end faces of the tool heads 21 on both sides is smaller than the distance between the two large guide plates opposite each other in the cavity 11.

[0040] S2. Place and fix the frame 10 to be processed onto the worktable of the machine tool;

[0041] S3. Move the cutter head 21 above the frame 10 and align it with the first cavity 11. Then, using the cutter head 21 on one side, machine the large guide plate surface 12 on one side of the first cavity 11 from top to bottom. Figure 3 T1 path 1;

[0042] S4, Attachment head 20 horizontally shifted, that is Figure 3 In path T2 2; the large guide plate surface 13 inside the first cavity 11 is machined from bottom to top through the cutter head 21 on the other side, i.e. Figure 3 T3 path 3;

[0043] S5, then the attachment head 20 moves above the next cavity 11 of the frame 10, that is Figure 4 In the T4 path 4; through the cutter head 21 on one side, the large guide plate surface 12 on one side of the cavity 11 is processed from top to bottom, and then moved laterally, through the cutter head 21 on the other side, the large guide plate surface 13 on the other side is processed from bottom to top. The above actions are repeated to process the large guide plate surface 12 and the large guide plate surface 13 in all cavities 11 in sequence.

[0044] S6. Then adjust the attachment head 20 or the frame 10 by 180°. Move the attachment head 20 above the last cavity 11 of the frame 10 and process the large guide plate surface 3 14 on one side of the first cavity 11 from top to bottom through the cutter head 21 on one side.

[0045] S7. The attachment head 20 moves laterally a certain distance and processes the large guide plate surface 15 inside the cavity 11 from bottom to top through the cutter head 21 on the other side;

[0046] S8. Then the attachment head 20 moves to the next cavity 11 of the frame 10 and processes the large guide plate surface 3 14 on one side of the next cavity 11 from top to bottom through the cutter head 21 on one side. After moving laterally for a distance, it processes the large guide plate surface 4 15 on the other side. Through the above steps, the large guide plate surface 3 14 and the large guide plate surface 4 15 in all cavities 11 are processed in sequence.

[0047] By following the above steps, the shortcomings of traditional single-blade milling of large guide slides, such as long processing time and low efficiency, are avoided. The milling time of large guide slides is shortened, the proportion of milling in the entire processing cycle is reduced, and the goal of improving the processing efficiency of diesel engine frame components is achieved.

[0048] use Figure 4 The T4 path 4 in the code makes the entire machining program simpler to program. Once a machining program for one cavity is programmed, it can be copied to other cavities for continuous machining.

[0049] In this embodiment, see Figure 2 The diesel engine frame 10 has six cavities 11, numbered 1#-6#. Figure 2 In the image, the solid arrows indicate the machining directions from S2 to S5. Figure 5 In the text, it still indicates the processing direction of S2-S5. Figure 2 In the diagram, the dashed arrows indicate the machining directions from S6 to S8. Figure 6 In the middle, it still indicates the processing direction of S6-S8.

[0050] Specifically, in S1, the machine tool is a gantry milling machine. The machine tool's accessory head 20 has two spindle end faces, and cutter heads 21 are mounted on the two spindle end faces respectively. The two cutter heads 21 are opposite to each other. See [reference needed]. Figure 3 , 5 6.

[0051] Before S1, there is also a step of selecting the cutter head 21 according to the size of the cavity of the frame and the accessory head.

[0052] Due to the size limitations of the cavity 11 of the frame 10 and the accessory head 20, the range of milling cutter head models is small, with only the Φ250 cutter head meeting the requirements. Two types of Φ250 cutter heads are provided, as shown in the table below:

[0053]

[0054] The data in the table above shows that the geometric parameters of the two cutter heads are roughly similar, with the only difference being the type of blade and the material of the frame 10. A comparison of the two types of blades reveals the following:

[0055] The inserts of cutter head one have positive rake angles in both the axial and radial directions, resulting in low cutting resistance and smooth machining. The inserts of cutter head two have negative rake angles in both the axial and radial directions, resulting in high cutting resistance and a tendency to cause vibration.

[0056] The blade tip of cutter head one is R1.0, which has good stability, wear resistance, long service life, and good economy; the blade tip of cutter head two is R0.1, which has poor stability, easy wear, short service life, and poor economy.

[0057] Based on the comparison results and the feedback from actual use, the first cutter head is superior to the second cutter head in terms of both machining performance and economy. Therefore, the first cutter head is selected as the machining cutter head for the large guide plate surface.

[0058] Specifically, the parameters of the cutter head 21 are: diameter 250mm, number of teeth 10, principal cutting edge angle 90°, axial positive rake angle, radial positive rake angle, cutter tip radius 0.1mm, maximum depth of cut 20mm, cutting speed 150~300mm / min, and cutting depth 0.2~0.8mm.

[0059] Before S3, there is also a step of selecting the cutting depth and feed rate of the cutter head 21 based on the power of the accessory head 20.

[0060] Specifically, based on the power of the attachment head 20, the depth of cut and feed rate of the cutter head 21 are selected using the following formula:

[0061] ;

[0062] In the formula: For cutting power, To compare cutting resistance, For depth of cut, For cutting width, This is the cutting feed rate.

[0063] In this embodiment, the maximum power of the machine tool accessory head is 30KW, and the maximum speed is 600r / min.

[0064] The specific cutting resistance value is determined based on the material of the machine frame 10, the rigidity of the machine frame 10, and the stability of the machine tool ram during its large stroke extension. Therefore, four specific cutting resistance values ​​kC that are more consistent with actual working conditions are selected, as shown in the table below:

[0065]

[0066] The machining parameters can be calculated using the cutting power formula, as shown in the table below:

[0067]

[0068] When using transmission machining technology: the total running time of the machine tool for machining the large guide plate surface of the 10-frame machine is:

[0069]

[0070] In the above formula, 5.6 is the time required for one processing step, in minutes, and 6×3×4 is the total number of processing steps for the large guide plate.

[0071] The total idle running time of the machine tool is:

[0072]

[0073] In the above formula, 2520+500 / 2000 and 700 / 10000 are the time spent by the tool moving in the air along different paths.

[0074] The idle time of machine tools accounts for 28% of the total operating time. This processing method results in serious waste of machine tool resources, low processing efficiency, and cannot meet the current production situation.

[0075] exist Figure 3 The diagram shows path 1 (T1), path 2 (T2), path 3 (T3), and path 4 (T4).

[0076] In the above formula The time required for path 2 in T2. This is the time required for path 3 (T3).

[0077] After using the method of the present invention, see [link to relevant documentation]. Figure 3 , 4 The machining trajectory of the double-blade bidirectional milling of the large guide plate surface has obvious advantages. The machine tool's idle run is only T2 path 2, and the time required for one up-and-down movement on the two large guide plate surfaces is only 2.

[0078]

[0079] To reduce the idle time of the machine tool between cylinder spacing on the machine frame, the two large guide slide surfaces symmetrical to each other in the same cavity are rough-machined before machining the next cylinder. Therefore, the total machining time is:

[0080]

[0081] The total idle running time of the machine tool:

[0082]

[0083] Specifically, the milling methods are compared as follows:

[0084] Milling method Total processing time (min) Idle run time (min) Idle running time percentage (%) Traditional processing methods 403.2 113.76 28% The method of the present invention 296 5.5 1.8%

[0085] Comparing the machining data of the two methods, the dual-blade bidirectional milling method of this invention reduces the total machining time by 26.6% and the machine tool idle time by 95%. The effective machining time of the machine tool increases from 72% to 98.2%, curbing the waste of machine tool resources and improving the effective utilization rate of the machine tool. Therefore, the dual-blade bidirectional milling method of this invention is currently the optimal solution for machining large guide slides.

[0086] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for milling a large guide plate surface on a diesel engine frame, characterized in that, Includes the following steps: S1. Tool heads (21) are installed on both sides of the lower end of the machine tool accessory head (20). The distance between the processing end faces of the tool heads (21) on both sides is smaller than the distance between the two large guide plate surfaces opposite each other in the cavity (11). S2. Place and fix the frame (10) to be processed onto the worktable of the machine tool; S3. Using the cutter head (21) on one side, process the large guide plate surface (12) on one side of the first cavity (11) from top to bottom. S4. The attachment head (20) moves laterally and processes the large guide plate surface (13) inside the first cavity (11) from bottom to top through the cutter head (21) on the other side. S5. Then the attachment head (20) moves to the next cavity (11) of the frame (10) and processes the large guide plate surface one (12) on one side of the cavity (11) from top to bottom through the cutter head (21) on one side. Then it moves horizontally and processes the large guide plate surface two (13) on the other side from bottom to top through the cutter head (21) on the other side. Repeat the above actions to process the large guide plate surface one (12) and large guide plate surface two (13) in all cavities (11) in sequence. S6. Then adjust the attachment head (20) or the frame (10) by 180°, move the attachment head (20) above the last cavity (11) of the frame (10), and process the large guide plate surface three (14) on one side of the first cavity (11) from top to bottom through the cutter head (21) on one side. S7. The attachment head (20) moves laterally a certain distance and processes the large guide plate surface (15) inside the cavity (11) from bottom to top through the cutter head (21) on the other side. S8. Then the attachment head (20) moves to the next cavity (11) of the frame (10) and processes the large guide plate surface three (14) on one side of the next cavity (11) from top to bottom through the cutter head (21) on one side. Then it moves laterally for a distance and processes the large guide plate surface four (15) on the other side. Through the above steps, the large guide plate surface three (14) and large guide plate surface four (15) in all cavities (11) are processed in sequence.

2. The method for milling a large guide plate surface on a diesel engine frame according to claim 1, characterized in that, In S1, the machine tool is a gantry milling machine tool. The attachment head (20) of the machine tool has two spindle end faces, and cutter heads (21) are respectively installed on the two spindle end faces. The two cutter heads (21) are opposite to each other.

3. The method for milling a large guide plate surface on a diesel engine frame according to claim 1, characterized in that, Before S1, there is also a step of selecting the cutter head (21) according to the size of the cavity of the frame and the accessory head.

4. The method for milling a large guide plate surface on a diesel engine frame according to claim 3, characterized in that, The parameters of the cutter head (21) are: diameter 250mm, number of teeth 10, principal cutting edge angle 90°, axial positive rake angle, radial positive rake angle, cutter tip R0.1mm, maximum cutting depth 20mm, cutting speed 150~300mm / min, and cutting depth 0.2~0.8mm.

5. The method for milling a large guide plate surface on a diesel engine frame according to claim 1, characterized in that, Before S3, there is also a step of selecting the cutting depth and feed rate of the cutter head (21) based on the power of the accessory head (20).

6. The method for milling a large guide plate surface on a diesel engine frame according to claim 5, characterized in that, Based on the power of the attachment head (20), the depth of cut and feed rate of the cutter head (21) are selected using the following formula: ； In the formula: For cutting power, To compare cutting resistance, For depth of cut, For cutting width, This is the cutting feed rate.

7. The method for milling a large guide plate surface on a diesel engine frame according to claim 6, characterized in that, The specific cutting resistance value is determined based on the material of the frame (10), the rigidity of the frame (10), and the stability of the machine tool slide during its large stroke extension.

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