In the mold factory, the CNC machining center is mainly used for mold key parts such as mold cores and inserts, and copper and other processing. The quality of the mold and the insert directly determines the quality of the molded part of the mold. The quality of copper processing directly limits the impact of EDM processing. For the guarantee of CNC processing quality, the key lies in the preparation before processing. In addition to having rich processing experience and mold knowledge, we must pay attention to good communication, especially communication with the production team and colleagues.
CNC machining process
1) Reading drawings and procedures
2) Transfer the corresponding program to the machine
3) Check the program head, cutting parameters, etc.
4) Determination of process size and margin on the workpiece
5) Reasonable clamping of the workpiece
6) Accurate alignment of the workpiece
7) Accurate establishment of workpiece coordinates
8) Selection of reasonable tools and cutting parameters
9) Reasonable clamping of the tool
10) Safe trial cutting method
11) Observation of the processing process
12) Adjustment of cutting parameters
13) Problems in the process and timely feedback from the corresponding personnel
14) Detection of workpiece quality after machining
Precautions before processing
1) For the new model, the processing map should meet the requirements, and the data is clear; the processing map of the new model must have the signature of the supervisor, and the columns of the processing map are filled out.
2) The workpiece has a qualified mark for the quality department.
3) After receiving the program list, check whether the workpiece reference position is consistent with the drawing reference position.
4) Look at each requirement on the program sheet to confirm that the program and drawing requirements are consistent. If there is a problem, you must solve the problem together with the programmer and the production team.
5) According to the material of the workpiece and its size, judge the rationality of the tool used by the programmer to open the rough or light knife program.
If the tool is found to be unreasonable, the programmer should be notified immediately to make changes to improve machining efficiency and workpiece machining accuracy.
Precautions for clamping workpieces
1) When clamping the workpiece, pay attention to the position of the pallet and the extension length of the nut-bolt on the pressure plate. In addition, the screw cannot be bottomed when the angle is locked.
2) Tonggong is generally used for lock plate processing. Before the machine is installed, it should be checked against the number of materials on the program sheet. At the same time, check whether the closing screw is tightened.
3) For the case where a board receives multiple pieces of copper material, check whether the direction is correct and whether the copper materials interfere during processing.
4) According to the shape of the program sheet and the data of the workpiece size, it is necessary to note that the workpiece size data is written as XxYxZ. At the same time, if there is a piece map, the graphics of the program sheet and the figure of the parts drawing must be checked. Whether it is consistent, pay attention to which direction to go out, and the X, Y axis of the pendulum.
5) When clamping the workpiece, it is necessary to check whether the workpiece size meets the size requirements of the program sheet. If there is a part drawing, it is necessary to check whether the size of the program sheet is the same as the size of the parts drawing.
6) The workbench and the bottom of the workpiece should be cleaned before the workpiece is placed on the machine. Apply the oil stone on the machine table and the workpiece surface to push off the burrs and the damaged position.
7) When the code is coded, make sure the chip is not damaged by the knife and communicate with the programmer if necessary. At the same time, if the bottom pad is square, the code must be aligned with the square of the pad to achieve the purpose of force balance.
8) When using a vise clamp, you must know the depth of the tool to prevent it from being too long or too short.
9) Screws must be included in the T-shaped block. Do not use only a part of the thread. If the screw is to be connected, the upper and lower screws must use the thread of the half joint. The thread of the nut on the pressure plate must be completely used. Thread.
10) When determining the Z depth number, you should see the position of the program single touch number and the data of the highest point of Z. After inputting the data into the machine tool, you must check it again.
Precautions for clamping tools
1) It must be firmly clamped and not too short in the handle.
2) Before each shovel, check whether the tool meets the requirements. The length of the knives should be determined according to the machining depth indicated by the program. Generally, it should be slightly longer than the machining depth value of 2mm and the shank should be considered.
3) If you encounter a deep processing depth, you can communicate with the programmer. If you want to use the knife twice, you should first obtain half the length of 2/3, and then wait longer when you process to a deeper position. This can improve processing efficiency.
4) When using the extension cord, you should especially know the depth of the lower knife and the required length of the knife.
5) Before the cutter head is installed on the machine, its taper fit position is cleaned with a cleaning cloth, and the corresponding position of the machine tool sleeve is also cleaned to avoid the iron filings on the mating surface affecting the accuracy and damage the machine tool.
6) Generally, the tool length is used for the tool length (in the case of the knife in the special case), the program order should be checked carefully.
7) When the program is interrupted or repaired, it is necessary to pay attention to whether the depth can be connected with the front. Under normal circumstances, the line can be adjusted upward by 0.1mm, and then adjusted according to the situation.
8) Rotating and removing the 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 without wear.
Precautions for correcting the alignment of the workpiece
1) When the workpiece is towed, you must pay attention to the verticality, while dragging, and then dragging the vertical edge.
2) When the workpiece is divided, it must be verified twice.
3) After the number of hits, the median size should be provided according to the program and the size on the parts map should be checked.
4) All workpieces must be divided into sub-centers. The zero position must be divided into the sub-centers and then moved to the side. It must be ensured that the balances on both sides are consistent. If a special case must be taken unilaterally, it must be confirmed by the production team before it can pass. After the unilateral number is taken, remember the radius of the rod in the compensation back.
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 amount of the top surface of the workpiece is too large, use a large knife to manually remove the remaining amount, and remember not to be deep.
2) The most important processing is the first knife. If you carefully operate and check, 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 the procedure as follows:
a) The height of the first point is up to 100mm, and it is correct to use the eye to feel it;
b) control “quick shift” to 25% and feed to 0%;
c) When the tool approaches (about 10mm) the working surface, the machine is suspended;
d) check the remaining stroke and the program is correct;
e) After turning on the power again, put one hand on the pause,, ready to stop at any time, and the other hand controls the feed speed;
f) When the tool is very close to the workpiece surface, it can be stopped again. The remaining stroke of the Z-axis must be checked.
g) After the machining is smooth and stable, return the control to the normal state.
4) After entering the program name, use the pen to copy the name of the program on the screen, and then check with the program. When opening the program, check whether the size of the tool in the program matches the program list, and sign the processor on the program. Fill in the file name and the size of the tool in the column, and do not fill it in afterward or beforehand.
5) In principle, the NC mechanic must not leave when the workpiece is roughed. If you need to change the knife or assist in adjusting other machine tools, you must ask other NC team members or check back regularly.
6) When doing medium light, the NC mechanic should pay special attention to the place where the opening is not open when the thickening is made to prevent the tool from hitting this area.
7) Program cutting. If the program breaks during processing and wastes too much time from the beginning, the team leader and the programmer should be notified to modify the program and cut off the part that has been done.
8) The program is abnormal. If the program has a different situation and is not sure, you can hang up to observe the process and then decide the next action.
9) The speed and 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 small pieces of copper cannot be opened at a high speed to avoid loosening of the workpiece due to shock.
10) During the machining of the workpiece, the NC mechanic should check with the parts drawing to see if there is any abnormal condition. Once the two are found to be inconsistent, the team leader must be immediately shut down to check whether there is any error.
11) When using a tool with a length of more than 200mm, it is necessary to pay attention to the margin and the depth of the feed, the speed of the feed, etc., in order to avoid the knives, and the speed of the corner should be controlled.
12) The operator must be responsible for detecting the diameter of the tool on the program sheet. At the same time, the diameter of the test shall be recorded. If the tolerance is exceeded, it shall be immediately reported to the team leader or the tool change.
13) When the machine tool is in automatic operation or available, the operator should go to the workstation to learn about the remaining machining programming, prepare and grind the appropriate tool for the next machining standby to avoid downtime.
14) Process errors are the main reasons for wasting time: incorrect use of improper tools, processing errors, waste of time in locations where no machining or non-computer processing is required, improper use of machining conditions (slow speed, empty knife), the knife path is too dense, the feed is too slow, etc.), the above events can be contacted during programming.
15) During the machining process, attention must be paid to the wear of the tool. The blade or tool should be replaced appropriately. After replacing the blade, pay attention to whether the boundary of the machining is consistent.
1) Confirm that each procedure and each instruction required by the procedure has been completed.
2) After the processing is completed, it is necessary to check whether the shape of the workpiece meets the requirements, and at the same time, the workpiece size self-test is performed according to the part drawing or the process drawing, and the error is found in time.
3) Check the position of the workpiece for any abnormality. If in doubt, notify the NC team leader.
4) The large group of workpieces must be notified to the team leader, programmer and production team leader.
5) Pay attention to safety when the workpiece is off the machine, especially when the workpiece is off the machine, the workpiece and the NC machine should be protected.
Different treatments of processing accuracy requirements
The surface quality of polished light:
1) mold core, insert
3) thimble plate support hole and other places to avoid vacancies
4) Eliminate the vibration of the knife
The size of the fine light:
1) Measurable size must be strictly performed after processing self-test
2) Consider the loss of the tool during long-term processing, especially the sealing position.
3) The fine light should use new cemented carbide tools as much as possible
4) Determine the modulus of the lens after finishing the light according to the processing requirements
5) Confirmation of quality after processing and quality
6) Control the tool loss during the processing of the sealant depending on the processing requirements
1) Confirm the operation of the work, including the processing situation, mold conditions, etc.
2) Confirm that the working equipment of the shift is normal.
3) Other handovers and confirmations, including drawings, program sheets, tools, gauges, fixtures, etc.
1) Execute according to 5S requirements.
2) The tools, measuring tools, fixtures, workpieces, tools, etc. are placed neatly.
3) Cleaning of the machine tool.
4) Cleaning the workplace floor.
5) Returning the processed tool, idle tool and measuring tool.
6) The processed parts are sent to the product inspection or the corresponding department.