In the mold factory, CNC machining centers are mainly used to process mold cores, inserts, and other key mold parts and copper males. The mold core and insert quality directly determine the mold-forming part’s quality. The quality of copper processing directly constrains the influence of EDM processing. For the assurance of CNC machining quality, the key lies in the preparation before machining. For this position, in addition to rich machining experience and mold knowledge, good communication should also be paid attention to during work, especially with the production team and colleagues.
CNC machining process
1) Read drawings and program sheets
2) Transfer the corresponding program to the machine tool
3) Check the program header, cutting parameters, etc.
4) Determination of the machining size and allowance of the workpiece on the workpiece
5) Reasonable clamping of the workpiece
6) Precise alignment of the workpiece
7) Accurate establishment of workpiece coordinates
8) Selection of reasonable tools and cutting parameters
9) Reasonable clamping of tools
10) Safe trial cutting method
11) Observation of the machining process
12) Adjustment of cutting parameters
13) Problems during processing and timely feedback from corresponding personnel
14) Inspection of workpiece quality after processing
Precautions before processing
1) For the new mold, the processing drawing must meet the requirements, and the data must be clear; the supervisor must sign the processing drawing of the new mold, and each column of the processing drawing must be filled in.
2) The workpiece has the qualified mark of the quality department.
3) After receiving the program sheet, check whether the reference position of the workpiece is consistent with the reference position of the drawing.
4) Look at each requirement on the program sheet, and confirm whether the program and the requirements of the drawing are consistent. If there is a problem, you must work with the programmer and the production team to solve the problem.
5) According to the material and size of the workpiece, judge the rationality of the programmer’s V core: UG5209 Lingling free CNC course roughing or smooth knife program selection of tools
If it is found that the tool application is unreasonable, the programmer should be notified immediately to make corresponding changes to improve the processing efficiency and workpiece processing accuracy.
Precautions for clamping workpieces
1) When clamping the workpiece, pay attention to the position of the code and the extension length of the nut and bolt on the pressure plate. In addition, the screw should not be on the top and bottom when locking the corner.
2) Copper males are generally processed for locking plates. Before starting the machine, the number of openings on the program sheet should be checked to ensure that they are consistent, and at the same time, check whether the closing screws are tightened.
3) For the case of receiving multiple copper materials on one board, check whether the direction is correct and whether each copper material interferes during processing.
4) The workpiece is clamped according to the shape of the diagram in the program sheet and the data of the workpiece size. It must be noted that the writing method of the workpiece size data is XxYxZ. At the same time, if there is a part diagram, the program sheet’s graphics and the part diagram must be checked. Whether it matches, pay attention to which direction goes out and the pendulum method of the X and Y axes.
5) When clamping the workpiece, it must be checked whether the size of the workpiece meets the size requirements of the program sheet, and if there is a part drawing, it must be checked whether the size of the program sheet is the same as the size of the part drawing.
6) Before the workpiece is put on the machine, the worktable and the bottom of the workpiece should be cleaned. The machine tool table and workpiece surface should be pushed out with whetstone to remove the burrs and damaged positions.
7) When coding the code boy, ensure that the code boy will not be hurt by the knife, and communicate with the programmer if necessary. At the same time, if the bottom pad is square, the yard must be aligned with the square position of the pad to achieve the purpose of balanced force.
8) When using a vise for clamping, you must know the machining depth of the tool to prevent the clamped position from being too long or too short.
9) The screw must be placed in the T-block, and only a part of the thread must be used. If the screw needs to be connected, the upper and lower screws must each use half the thread of the joint. The public number of the nut on the pressure plate: UG programming base camp thread must be used completely, not only a few threads.
10) When setting the Z depth number, check the position of the single touch number in the program and the data of the highest point of Z. After entering the data into the machine tool, it must be checked again.
Precautions for clamping tools
1) The tool should be clamped firmly and not too short in the handle.
2) Before each cable, check whether the tool meets the requirements. The cable length should be determined according to the machining depth indicated by the program sheet. Generally, it should be slightly longer than the machining depth value by 2mm and consider whether the tool holder collides.
3) In the case of deep processing depth, you can communicate with the programmer and use the method of two cable cables as appropriate; that is, first obtain half to 2/3 of the length and then ask for a longer length when processing to a deeper position. This improves processing efficiency.
4) The data, such as the depth of the lower knife and the required length, should be known when using the extension cable nozzle.
5) Before the cutter head is installed on the machine, the taper matching position should be wiped clean with a cleaning cloth, and the corresponding position of the machine tool sleeve should be cleaned as well to avoid iron filings on the matching surface affecting the accuracy and damaging the machine tool.
6) Usually, the tool nose setting method is used for the length of the tool (the case where the tool is used in the special case), and the instructions in the program sheet should be carefully checked when setting the tool.
7) When the program is interrupted, or the tool must be re-calibrated again, attention should be paid to whether the depth can be connected to the front. Generally, it can be increased by 0.1mm and adjusted according to the situation.
8) For the rotary retractable cutter head, if water-soluble cutting fluid is used, it should be immersed in lubricating oil for several hours every half month for maintenance so that the internal parts of the cutter head can be lubricated and not worn.
Precautions for correcting and aligning workpieces
1) When dragging the workpiece, you must pay attention to the verticality. One side is leveled, and then the vertical side is dragged.
2) When the workpiece is divided, it must be divided twice for verification.
3) After hitting the number of points, check the median according to the external dimensions provided in the program sheet and the dimensions on the part drawing.
4) All workpieces must be centered by the centering method, and the zero position on the side of the workpiece must also be centered by the centering method and then moved to the side. It must be ensured that the margins on both sides are the same. In special cases, V-core must be added: when UG5209 takes the free numerical control course unilaterally, it must be confirmed by the production team again before passing. After taking the number on one side, remember to compensate for the radius of the rod in the back score.
5) The zero input of the workpiece center must be the same as the three-axis center of the workstation computer diagram.
1) When the allowance on the top surface of the workpiece is too large when using a large knife to manually remove the allowance, remember not to go too deep.
2) The most important part of processing is the first tool because if you operate and check carefully, you can know whether the tool length compensation, tool radius compensation, program, speed, etc., are wrong, to avoid damage to the workpiece, tool, and machine tool.
3) Trial cutting procedure as follows:
a) The height of the first point is up to 100mm, and it is correct to feel it with the eyes;
b) Control “rapid traverse” to 25% and feed to 0%;
c) Pause the machine when the tool approaches (about 10mm) the machining surface;
d) Check whether the remaining stroke and the program are correct;
e) After starting the machine again, put one hand on the pause switch, ready to stop at any time, and control the feed speed with the other hand;
f) When the tool is very close to the workpiece surface, it can be stopped again, and the remaining travel of the Z axis must be checked.
g) After the smooth and stable machining and cutting line, adjust each control to its normal state.
4) After entering the program name, use a pen to copy the program name on the screen and then check with the program sheet. When opening the program, pay attention to checking whether the size of the tool diameter in the program is consistent with the program sheet, and sign the processor on the program sheet. Fill in the file name and tool diameter immediately in the column; it is forbidden to fill in afterward or in advance.
5) The NC mechanic cannot leave when the workpiece is roughed. If it is necessary to change the tool or assist in adjusting other machine tools, etc., when it is necessary to leave, other NC team members must be invited or come back regularly to check.
5) When doing medium light, the NC mechanic should pay special attention to the places not opened when roughing to prevent the tool from hitting this area.
6) Program cut. If the program is interrupted during processing and wastes too much time to run from the beginning, the team leader and the programmer should be notified to modify the program and cut off the part that has been run.
6) The program is abnormal. If there is an abnormal situation in the program and you are not sure, you can hang it up to observe the process and then decide on the next action.
9) The travel and rotational speed provided by the programmer during the machining process can be adjusted by the NC mechanic as appropriate. However, special attention should be paid to the fact that the traveling speed of small pieces of copper is not fast when the copper is open and thick to avoid loosening the workpiece due to vibration.
10) During the processing of the workpiece, the NC mechanic should check with the parts drawing to see if there is any abnormality. Once it is found that the two do not match, it must immediately stop and notify the team leader to check whether there is any error.
11) When machining with a tool longer than 200mm, you must pay attention to adding V-core: UG5209 free CNC course allowance, feed depth, speed, travel speed, and other issues to avoid knife swinging, and the travel speed at the corner should be controlled.
11) The operator must be conscientious and responsible for the diameter of the tool that is required to be tested on the program sheet and, at the same time, record the diameter of the test. If it exceeds the tolerance range, it should be immediately reported to the team leader or tool change.
13) When the machine tool is in automatic operation or has time, the operator should go to the workstation to learn about the remaining processing programming and prepare and grind appropriate tools for the subsequent processing to avoid downtime.
14) Process errors are the main reasons for wasting time: incorrect use of inappropriate tools, wrong processing arrangements, wasting time in locations that do not require processing or non-computer processing, using improper processing conditions (too slow speed, empty tool, the tool path is too dense, the feed is too slow, etc.), when the above events occur, you can contact the programming.
15) During the processing, attention must be paid to the tool’s wear, and the blade or tool should be replaced appropriately. After replacing the blade, pay attention to whether the processing boundary is consistent.
Precautions after processing
1) Confirm that each procedure and each instruction required by the procedure sheet have been completed.
2) After the processing is completed, it is necessary to check whether the shape of the workpiece meets the requirements. At the same time, carry out self-inspection of the workpiece size according to the parts drawing or process drawing, and find mistakes in time.
3) Check any abnormality in each position of the workpiece. If in doubt, notify the NC team leader.
4) When the larger workpiece is dismounted, the team leader, programmer, and production team leader should be notified.
5) Pay attention to safety when the workpiece is unloaded, especially when the larger workpiece is unloaded; the workpiece and the NC machine should be protected. Differential treatment of machining accuracy requirements
The size of the light:
1) The measurable size should strictly implement the post-processing self-inspection
2) When processing for a long time, the loss of the tool should be considered, especially the sealing position and other parts of the batch.
3) For finishing, new carbide tools should be used as much as possible
4) Determine the saving modulus after finishing according to the processing requirements
5) Confirmation of quality, such as production and quality after processing
6) Depending on the processing requirements, control the tool loss during the sealing position processing
FINISHED SURFACE QUALITY:
1) Mold kernels and inserts
2) Copper male
3) Avoid the space in the support head hole of the thimble plate, etc.
4) Eliminate the phenomenon of vibration knife pattern
1) Confirm the working conditions of the work, including processing conditions, mold conditions, etc.
2) Confirm whether the equipment is working normally during work hours.
3) Other handover and confirmation, including drawings, program sheets, measuring tools, fixtures, etc.
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