Comprehensive CNC Machining Center Operation Experience Sharing – Be Sure to Save and Keep

In the mold factory, the CNC machining center is mainly used for processing key components of molds such as mold cores, inserts, and copper bosses, as well as other components. The quality of mold cores and inserts directly determines the quality of the mold forming part. The processing quality of copper bosses directly affects the EDM processing. To ensure the quality of CNC machining, the key lies in the preparation before processing. For this position, in addition to having rich processing experience and knowledge of molds, during work, attention should also be paid to good communication, especially with the production team and colleagues.

01 CNC processing procedure

1) Study the drawings and operation manuals

2) Transfer the corresponding program to the machine tool

3) Check the program header, cutting parameters, etc.

4) Determination of processing dimensions and allowances on the workpiece

5) Proper clamping of the workpiece

6) Precise alignment of the workpiece

7) Precise establishment of workpiece coordinates

8) Selection of appropriate cutting tools and cutting parameters

9) Proper clamping of cutting tools

10) Safe trial-cutting method

11) Observation of the processing procedure

12) Adjustment of cutting parameters

13) Problems during the processing and timely feedback from the relevant personnel

14) Inspection of the workpiece quality after processing

02 Pre-processing Precautions

1) For new molds, the processing drawings must meet the requirements and the data should be clear. The processing drawings for new molds must have the signature of the supervisor and all the columns on the drawings should be filled in.

2) The workpiece bears the quality department's approval mark.

3) After receiving the program sheet, check whether the reference position of the workpiece is consistent with the reference position specified in the drawing.

4) Carefully read through each requirement on the program sheet, and verify whether the program is consistent with the requirements of the drawings. If there are any issues, you must work with the programmer and the production team to solve them. 5) Based on the material and size of the workpiece, determine the rationality of the programmer's selection of tools for roughing or polishing programs. If you find that the tool application is unreasonable, you should immediately notify the programmer to make corresponding changes to improve processing efficiency and the machining accuracy of the workpiece.

03 Precautions for Clamping Workpieces

1) When holding the workpiece, pay attention to the position of the clamping pins and the appropriate extension length of the screws on the pressure plate. Also, when locking the angle pins, the screws must not press against the bottom.

2) The copper plates are generally processed as lock plates. Before putting them on the machine, it is necessary to check that the cutting quantity on the program sheet is consistent. At the same time, it is also necessary to ensure that the screws for receiving the plates are tightened.

3) In cases where multiple copper pieces are assembled onto a single base, it is necessary to verify whether the orientation is correct and whether there is any interference during the processing of each copper piece.

4) When clamping the workpiece according to the shape of the drawing on the program sheet and the dimensions of the workpiece, it is necessary to pay attention to the following: The notation of the workpiece dimensions is XxYxZ. Additionally, if there is a disassembled part drawing, it is necessary to verify whether the graphics on the program sheet match those of the disassembled part drawing, and pay attention to which direction the parts are output, as well as the orientation of the X and Y axes.

5) When clamping the workpiece, it is necessary to check whether the dimensions of the workpiece comply with the requirements specified in the program sheet. If there is a disassembly part drawing, it is also necessary to verify whether the dimensions in the program sheet are the same as those in the disassembly part drawing.

6) Before the workpiece is installed on the machine, the worktable and the bottom of the workpiece should be cleaned. The rough edges and damaged areas on the machine table and the workpiece surface should be removed using an oilstone.

7) When placing the blocks, make sure that the blocks do not get damaged by the knife. If necessary, communicate with the programmer. Also, if a square base is used, the blocks must be aligned with the position of the square base to achieve a balanced load distribution.

8) When using a vise for clamping, it is necessary to know the processing depth of the tool to avoid the clamping position being too long or too short.

9) The screws must be fully inserted into the T-shaped block. It is not allowed to use only part of the screw threads. When connecting screws, the upper and lower screws must each use half of the threaded section. The threaded part of the screw cap on the pressure plate must be fully utilized, and it is not allowed to only insert a few threads.

10) When determining the Z-axis depth, it is necessary to clearly identify the position of the program stop pin and the data of the highest point of Z. After entering the data into the machine tool, it is necessary to double-check it again.

04 Precautions for Clamping the Cutting Tools

1) The clamp must be securely fastened and should not be too short in the tool handle.

2) Before each knife pull operation, it is necessary to check whether the knife meets the requirements. The length of the knife pull should be determined according to the processing depth indicated in the program sheet. Generally, it should be slightly longer than the processing depth value by 2mm, and the possibility of the knife handle colliding should also be considered.

3) In cases where the processing depth is very deep, it is advisable to communicate with the programmer and adopt the method of using two cutting tools. That is, first cut to half or two-thirds of the length, and then when processing to a deeper position, cut a longer distance. This can improve the processing efficiency.

4) When using the extended rope cutter, it is particularly important to understand the data such as the cutting depth and the required length of the blade.

5) Before installing the cutter head onto the machine, the conical fitting position should be wiped clean with a clean cloth. The corresponding position of the machine tool's cutter sleeve should also be cleaned to avoid any iron filings on the mating surface, which could affect the accuracy and damage the machine.

6) Generally, the length of the tool is measured using the tool tip alignment method (in special cases, the tool middle alignment method is used). During alignment, it is necessary to carefully check the instructions on the program sheet.

7) When the program is interrupted or reprogramming is necessary for re-tooling, it is important to ensure that the depth aligns with the previous one. Generally, a 0.1mm increase can be made first, and then adjustments can be made based on the situation.

8) For the rotating and retractable tool head, if water-soluble cutting fluid is used, it should be lubricated with oil for several hours every half month for maintenance. This can ensure that the internal components of the tool head are lubricated and thus prevent wear.

05 Precautions for Correcting and Aligning Workpieces

When moving the workpiece, one must pay attention to the verticality. First, level one side, then move the vertical edge.

2) When aligning the workpiece, verification must be conducted twice.

3) After dividing the dimensions, they should be checked against the external dimensions provided in the program sheet and the dimensions shown on the disassembly drawings.

4) All workpieces must be centered using the centering method. The zero position must also be centered using the centering method and then moved to the edge. It is necessary to ensure that the remaining thickness on both sides is consistent. In case of special circumstances where the measurement is taken on only one side, it must be reconfirmed by the production team before it can be approved. After the measurement on one side is completed, remember to compensate for the radius of the centering rod.

5) The zero position input for the workpiece center must be the same as the center of the third axis on the workstation computer diagram.

06 Precautions During Processing

1) If the remaining material on the top surface of the workpiece is too thick, when using a large knife to manually remove the excess material, be sure not to cut too deeply.

2) The most crucial step in processing is the first cut. By operating carefully and conducting checks, one can determine whether there are errors in the tool length compensation, tool diameter compensation, program, speed, etc., thus avoiding damage to the workpiece, the tool, and the machine.

3) Follow the procedure below for trial cutting:

a) The first point: The height is increased by a maximum of 100mm. Use your eyes to check if it is correct.

b) Set the "fast move" control to 25% and the feed rate to 0%.

c) When the cutting tool is approximately 10mm away from the processing surface, stop the machine.

(d) Check whether the remaining journey and procedures are correct;

(e) After restarting the machine, place one hand on the stop button to be ready to stop it at any time, and use the other hand to control the feed speed.

f) When the cutting tool is very close to the workpiece surface, it can be stopped again. It is necessary to check the remaining travel of the Z-axis.

(g) After the cutting line is properly aligned and stabilized, then restore all controls to their normal settings.

4) After entering the program name, copy it back onto the screen and then compare it with the program sheet. When opening the program, pay attention to checking whether the tool diameter size in the program is consistent with that on the program sheet. Immediately fill in the file name and tool diameter size in the "Operator's Signature" column on the program sheet. It is strictly prohibited to fill in it after or before the operation.

5) In principle, during the rough machining of the workpiece, the NC operator must not leave the machine. In case of tool change or assistance in adjusting other machines, if it is necessary for the operator to leave the machine, other NC team members should be invited or he/she should return for inspection at regular intervals.

6) When performing medium-intensity machining, NC technicians should pay special attention to the areas that were not machined during the roughing process, to prevent the tool from colliding with these regions.

7) Program Trimming. If the program is interrupted during processing and has to be restarted from the beginning, which would waste too much time, it is necessary to inform the team leader and the programmer to modify the program and remove the parts that have already been executed.

8) Program anomaly. In case the program encounters abnormal conditions and you are unsure about the situation, you can suspend it to observe the process and then decide on the next action.

9) During the processing, the feed rate and rotational speed provided by the programmer can be adjusted by the NC technician as needed. However, it is particularly important to note that when machining small copper parts for roughing, the feed rate should not be set too high to prevent the workpiece from loosening due to vibration.

10) During the processing of the workpiece, the NC technician should compare it with the component drawings to check for any abnormalities. If there is a discrepancy between the two, the machine must be stopped immediately and the team leader informed. The error should be verified.

11) When using cutting tools longer than 200mm for processing, one must pay attention to issues such as the amount of material removal, the depth of cut, the rotational speed, and the line speed. This is to prevent chipping. Moreover, the line speed at the corner positions should be strictly controlled.

12) For those cases where the program form requires the measurement of the tool diameter, the operator must be meticulous and responsible. At the same time, the measured diameter should be recorded. If it exceeds the tolerance range, it should be immediately reported to the team leader or the tool should be replaced.

13) When the machine is operating automatically or is idle, the operator should go to the workstation to understand the remaining processing programming situation, prepare and sharpen the appropriate tools for the next processing, so as to avoid downtime.

14) Process errors are the main cause of wasted time: improper use of inappropriate tools, incorrect sequence of processing steps, wasting time at positions that do not require processing or cannot be processed by computer, and using improper processing conditions (too slow rotational speed, empty cutting, too dense cutting path, too slow feed rate, etc.). When such incidents occur, they can be related to programming, etc.

15) During the processing, it is necessary to pay attention to the wear condition of the cutting tools. Appropriate replacement of the cutting inserts or the tools should be carried out. After replacing the cutting inserts, pay attention to whether the junction boundaries of the processing are consistent.

07 Post-processing Precautions

Confirm that all the procedures and instructions specified in the program list 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, based on the disassembly diagram or process diagram, conduct self-inspection of the workpiece dimensions to promptly identify any errors.

3) Check whether there are any abnormalities at each position of the workpiece. If any doubts arise, notify the NC supervisor immediately.

4) When a larger workpiece is taken off the machine, it is necessary to notify the team leader, the programmer and the production supervisor.

5) When unloading the workpiece, pay attention to safety. Especially when unloading larger workpieces, ensure the protection of both the workpiece and the NC machine.

08 Differentiation of requirements for processing accuracy: Surface quality with extremely high precision:

1) Mold cores, inserts

2) Copper King

3) Avoid positions near the clamping head holes of the clamping plate

4) Eliminate the vibration knife pattern phenomenon

The size of the mirror:

The measured dimensions must be strictly inspected after processing.

2) When processing for a long time, it is necessary to consider the wear of the cutting tools, especially at the sealing position and other areas where the cutting edges are exposed.

3) For the best results, new hard alloy cutting tools should be used as much as possible.

4) The visual processing requires the determination of the reduced modulus after polishing.

5) Confirmation of quality such as processing results and product quality

6) The visual processing requires controlling the tool wear during the sealing adhesive application process.

09 Handover of Shifts

Confirm the operation status of the current shift, including the processing situation and the mold condition, etc.

2) Verify whether the equipment for the current shift is operating normally.

3) Other handover and confirmation matters, including drawings, operation manuals, tools, measuring instruments, fixtures, etc.

10 Workplace Organization

Carry out in accordance with the 5S standards.

2) Tools, measuring tools, fixtures, workpieces, and tools are placed in separate categories and arranged neatly.

3) Cleaning of the machine tools.

4) Cleaning of the workplace floor.

5) Storage of processed tools, idle tools and measuring tools.

6) The processed workpieces are sent for inspection to the quality control department or the corresponding department.

Hefei Jinjiao CNC Equipment Co., Ltd. is located in Hefei, Anhui Province, a city renowned for its education and innovation. It covers an area of approximately 20,000 square meters. This company is a national-level high-tech enterprise specializing in the research, development, manufacturing, sales and service of high-precision equipment, including CNC equipment and complete automated production lines. The company's main products include composite material processing center equipment, automated equipment for board furniture, automated drilling equipment, various automatic edge-fitting machines, wood door automated production lines, wood door automated equipment, five-axis machining centers, various custom processing centers, wood and stone engraving machines, etc. The company is a high-tech enterprise, has passed CE certification, ISO9001 certification, AAA product certification, and is a trustworthy enterprise that honors contracts. Its sales and service network covers provincial capitals and municipalities across the country, and is also exported to many countries and regions such as Europe, Southeast Asia, and the Middle East. It has won wide acclaim from the industry. We welcome all business owners to come and purchase equipment!