The processing process rules of vertical CNC machining centers are respectively reflected in three aspects: preparation before startup, startup processing, content and scope of workers' self inspection. In addition, the article summarizes the causes of errors, special attention, and corrective measures in a list for reference······
Preparation before startup:
1. Each time the machine tool is started or reset by pressing the emergency stop, first return to the reference zero position of the machine tool (that is, return to zero), so that the machine tool has a reference position for its subsequent operations.
2. Clamping workpiece:
3. Before clamping the workpiece, all surfaces shall be cleaned without oil stain, scrap iron and dust, and burrs on the workpiece surface shall be removed with a file (or oilstone).
4. The equal speed rail used for clamping must be ground smooth and flat by the grinder. The sizing iron and nut must be firm and can reliably clamp the workpiece. For some small workpieces that are difficult to be clamped, they can be directly clamped on the vise.
5. The machine tool workbench shall be clean and free of iron filings, dust and oil stains.
6. The sizing block is generally placed at the four corners of the workpiece. For workpieces with excessive span, an equal height sizing block must be placed in the middle.
7. Use a ruler to check whether the length, width and height of the workpiece are qualified according to the size of the drawing.
8. When clamping the workpiece, according to the clamping and placement method in the programming operation instructions, it is necessary to consider avoiding the processing parts and the situation that the cutter head may encounter the fixture during processing.
9. After the workpiece is placed on the sizing block, the datum plane of the workpiece shall be pulled according to the drawing requirements. The error in the length direction of the workpiece is less than 0.02mm, and the horizontal error in the X and Y directions of the top surface is less than 0.05mm. For workpieces that have been ground on six sides, check whether their verticality is qualified.
10. After the workpiece is pulled, the nut must be tightened to prevent the workpiece from shifting during processing due to insecure clamping.
11. Pull the meter again to ensure that the error does not exceed the tolerance after clamping.
12. Number of workpiece collisions: for the clamped workpiece, the number of collision heads can be used to determine the reference zero position for processing. The number of collision heads can be photoelectric or mechanical. The method of collision selection can be divided into two types: middle collision number and single collision number,
The mechanical speed is 450-600rpm.
13. Carefully record the mechanical coordinate value of the zero position on the X axis of the workpiece in one of G54~G59, and let the machine tool determine the zero position on the X axis of the workpiece. Check the correctness of the data again.
14. Prepare all tools according to the programming instructions.
15. According to the tool data in the programming operation instruction, replace the tool to be processed and let the tool touch the height measuring device on the reference plane. When the red light of the measuring device is on, set the relative coordinate value of this point to zero.
16. Move the tool to a safe place, manually move the tool down 50mm, and set the relative coordinate value of this point to zero again, which is the zero position of Z-axis.
17. Record the mechanical coordinate Z value of this point in one of G54~G59. This completes the zero setting of X, Y, Z axes of the workpiece. Check the correctness of the data again.
18. Check the correctness of the zero point, move the X and Y axes to the edge of the workpiece, and visually check the correctness of the zero point according to the size of the workpiece.
Start up processing:
1. At the beginning of each program, carefully check whether the tool used is the tool specified in the programming instruction. At the beginning of processing, the feed speed shall be adjusted to the minimum, and the single section operation shall be performed. The quick positioning, tool dropping and tool feeding shall be carried out with concentration. If there is a problem with the hand on the stop key, stop immediately. Pay attention to the direction of the tool movement to ensure safe tool feeding, and then slowly increase the feed speed to the appropriate level. At the same time, add coolant or cold air to the tool and workpiece.
2. The rough machining shall not be too far away from the control panel, and the machine shall be shut down for inspection in case of any abnormality.
3. Pull the meter again after roughening to ensure that the workpiece is not loose. If there is a side, it must be corrected and touched again.
4. Continuously optimize the processing parameters during the processing to achieve the best processing effect.
5. Since this process is a key process, after the workpiece is processed, measure whether its main dimension values are consistent with the drawing requirements. If there are problems, immediately notify the shift leader or programmer to check and solve them. After the self inspection is qualified, it can be removed, and must be sent to the inspector for special inspection.
6. Clean the machine tool workbench in time after the workpiece is removed.
7. Direct numerical control (DNC) operation:
8. Before DNC numerical control processing, the workpiece shall be clamped, the zero position shall be set, and the parameters shall be set.
9. Open the processing program to be transferred in the computer to check, then let the computer enter the DNC state, and input the file name of the correct processing program.
10. Press TAPE key and program start key on the processing machine tool, and the machine controller will flash LSK.
11. Press the Enter key on the computer to conduct DNC data transmission processing.
3、 Self inspection content and scope of workers:
1. Before processing, the processor must see the contents of the process card clearly, know the part, shape, drawing dimensions of the workpiece to be processed, and know the processing content of the next process.
2. Before clamping the workpiece, measure whether the blank size meets the drawing requirements. When clamping the workpiece, carefully check whether its placement is consistent with the programming operation instructions.
3. After the rough machining is completed, self inspection shall be carried out in time to adjust the data with errors in time. The self inspection mainly covers the position and size of the machining parts. For example: (1) Whether the workpiece is loose; (2) . Whether the workpiece is correctly centered; (3) Whether the dimension from the processing part to the datum edge (datum point) meets the drawing requirements; （4）. The position and size of processing parts. After checking the position and size, measure the rough machined shape ruler (except the arc).
4. Finish machining can only be carried out after rough machining and self inspection. After finishing, the workers shall conduct self inspection on the shape and size of the processing part: detect the basic length and width of the processing part of the vertical surface; Measure the base point size marked on the drawing for the processing part of the inclined plane.
5. After the workers finish the self inspection of the workpiece, they can remove the workpiece and send it to the inspector for special inspection after confirming that it conforms to the drawing and process requirements.