The processing process rules of vertical CNC machining center are reflected in three aspects: preparation before startup, startup processing, contents and scope of self inspection by workers. In addition, the article summarizes the causes of errors, special attention and corrective measures for reference······
1、 Preparation before startup:
1. After the machine tool is started or reset according to the emergency stop, first return to the reference zero position of the machine tool (i.e. return to zero), so that the machine tool has a reference position for its subsequent operation.
2. Clamping workpiece:
3. Before clamping the workpiece, clean all surfaces without oil stain, iron filings and dust, and remove the burrs on the workpiece surface with a file (or oilstone).
4. All surfaces of high-speed iron used for clamping must be ground by grinding machine to make them smooth and flat. The code iron and nut must be firm and can reliably clamp the workpiece. Some small workpieces that are difficult to clamp can be directly clamped on the vice.
5. The workbench of the machine tool shall be clean and free of iron filings, dust and oil stain.
6. The sizing block is generally placed at the four corners of the workpiece. For the workpiece with large span, the equal height sizing block shall be placed in the middle.
7. Check whether the length, width and height of the workpiece are qualified with a ruler according to the size of the drawing.
8. When clamping the workpiece, according to the clamping and placement mode of the programming operation instructions, the parts to be processed and the situation that the cutter head may touch the fixture during processing shall be considered.
9. After the workpiece is placed on the sizing block, the workpiece reference surface shall be drawn 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. Check whether the perpendicularity of workpieces that have been ground on six sides is qualified.
10. The nut must be tightened after the workpiece is pulled to prevent the workpiece from being displaced during processing due to the unstable clamping.
11. Pull the meter again to ensure that the error is not out of tolerance after clamping.
12. Workpiece touch number: for the clamped workpiece, the touch number head can be used to set the reference zero position for processing. The touch number head can be of photoelectric type and mechanical type. The touch selection method can be divided into middle touch number and single side touch 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. Once again, carefully check the correctness of the data.
14. Prepare all tools according to the programming operation instructions.
15. According to the tool data in the programming operation instruction, change the tool to be processed, let the tool touch the height measuring instrument placed on the reference plane, and set the relative coordinate value of this point to zero when the red light of the measuring instrument is on.
16. Move the tool to a safe place, manually move the tool down by 50mm, and set the relative coordinate value of this point to zero, 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 position setting of the X, y and Z axes of the workpiece. Once again, carefully check the correctness of the data.
18. Check the correctness of the zero point, move the X and Y axes to the side suspension of the workpiece, and visually check the correctness of the zero point according to the size of the workpiece.
2、 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 machining, the feed speed shall be adjusted to the minimum, and it shall be executed in a single section. During rapid positioning, tool dropping and tool feeding, attention shall be paid to put the hand on the stop key. If there is any problem, stop immediately. Pay attention to the direction of tool movement to ensure safe feeding, and then slowly increase the feed speed to the appropriate level. At the same time, coolant or cold air shall be added to the tool and workpiece.
2. During rough machining, it shall not be too far away from the control panel. In case of any abnormality, stop the machine for inspection.
3. Pull the gauge again after roughening to ensure that the workpiece is not loose. If there is any side, it must be corrected and touched again.
4. Continuously optimize the processing parameters in the processing process to achieve the best processing effect.
5. Since this process is a key process, after the workpiece is processed, measure whether the main dimension value is consistent with the drawing requirements. If there is any problem, immediately notify the shift leader or programmer to check and solve it. It can be removed after passing the self inspection 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 transmitted in the computer for inspection, then let the computer enter the DNC state, and input the file name of the correct processing program.
10. Press the tape key and the program start key on the processing machine tool. At this time, the machine tool controller will display the flashing words LSK.
11. Press enter on the computer to carry out DNC data transmission processing.
3、 Contents and scope of self inspection by workers:
1. Before processing, the processor must clearly see the contents of the process card, clearly know the parts to be processed, the shape and the dimensions of the drawing, and know the processing contents of the next process.
2. Before workpiece clamping, measure whether the blank size meets the drawing requirements. During workpiece clamping, carefully check whether the placement is consistent with the programming operation instructions.
3. Self inspection shall be carried out in time after rough machining, so as to adjust the data with errors in time. The self inspection contents mainly include the position and size of the processing 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 reference edge (reference point) meets the drawing requirements; （4）. The position dimension between the processing parts. After checking the position and size, measure the rough machined shape ruler (except 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 parts: the basic length and width of the processing parts on the vertical surface shall be detected; Measure the base point size marked on the drawing for the processing part of the inclined surface.
5. The worker can remove the workpiece and send it to the inspector for special inspection after completing the self inspection of the workpiece and confirming that it conforms to the drawing and process requirements.
4、 List of error causes, special attention and corrective measures:
