The standard process of CNC machining is generally 7, and each process is required to be carried out in order. If the standard process of the CNC machining center is not carried out in the order, it is easy to cause machine failure or personal safety. Staff need special attention.
1. CNC processing is ready to start up
After each power-on or machine emergency stop reset, the machine will return to the machine reference zero position (i.e., return to zero), so that the machine has a reference position for subsequent operations.
2. CNC processing workpiece clamping
Before cleaning the surface of the workpiece, clean it first, keep it away from oil, iron, and dust, and use a file (or oilstone) to remove surface burrs. The surface of the fixture must be ground and polished to make it flat and smooth. The iron and nuts must be firm and can reliably clamp the workpiece. For some small workpieces that are difficult to install, they can be directly clamped on the tiger head; the machine table should be clean and free of iron filings, dust, and oil; at the four corners of the workpiece, in the middle If the workpiece is too large, a high angle needs to be added in the middle. According to the size of the drawing, use a ruler to check whether the length and width of the workpiece are qualified.
When clamping the workpiece, follow the programming instructions for installation to avoid possible encounters with fixtures at the processing part and processing head. After the workpiece is placed on the horn, the reference plane of the workpiece needs to be pulled out according to the drawing requirements. For workpieces that have been processed on both sides, check whether the verticality is qualified. After the workpiece is drawn, the nut must be tightened to prevent the clamp from being weak and causing the workpiece to shift during processing; then pull the table once to confirm that the error is not good. It is necessary to check whether the verticality is qualified.
After the workpiece is drawn, the nut must be tightened to prevent the clamp from being weak and causing the workpiece to shift during processing; then pull the table once to confirm that the error is not good. It is necessary to check whether the verticality is qualified. After the workpiece is drawn, the nut must be tightened to prevent the clamp from being weak and causing the workpiece to shift during processing; then pull the table once to confirm that the error is not good.
cnc processing
3. Number of contacts between CNC machining workpieces
The reference zero can be processed by the number of contact heads used to clamp the workpiece, and the contact heads can be photoelectric or mechanical. There are two types of contact methods: single-sided contact and single-sided contact. The steps of split contact are as follows: photoelectric and electrostatic, and mechanical speed of 450~600rpm. Manually move the X-axis of the workbench in the middle of the touch, so that the touch head contacts one side of the workpiece. When the touch head just touches the workpiece and the red light turns on, set the relative coordinates of the point to zero; the X-axis contacts the other side of the workpiece, and the touch head The relative coordinates of the moment when the head contacts the workpiece. Subtract the head diameter (i.e. workpiece length) from its relative value,
Divide the relative coordinate number by 2, which is the middle value of the X-axis of the workpiece, then move the workbench to the middle value of the X-axis, and set the relative coordinate value of the X-axis to zero, which is the zero point of the workpiece on the X-axis. Use one of G54 to G59 to carefully record the mechanical coordinates of the zero position on the X-axis of the workpiece, and let the machine tool determine the zero position on the X-axis of the workpiece. Check the data again for correctness. The zero setting of the Y-axis of the workpiece is the same as that of the X-axis.
4. CNC machining preparation tools
According to the tool data in the programming work guide, replace the tool to be processed and let the tool hit the height meter on the datum surface. When the measurement light is on, set the relative coordinate value to zero. Move the tool to a safe position, manually move the tool down 50mm, and reset the relative coordinate value to zero. This is the zero point of the Z axis.
The mechanical Z value for this point is recorded in one of G54 to G59. This completes the zero setting of the X, Y, and Z axes of the workpiece. Check the data again for correctness. The touch method on the other side is also to touch one side of the X and Y axes of the workpiece. The points where the X and Y axes are relative to the coordinate values of the head radius are the zero points of the X and Y axes. The mechanical coordinates of the X and Y axes are recorded between G54 and G59. one. Check the data again for correctness. Check the correctness of the zero point and move the X and Y axes to one side of the workpiece. Check the correctness of the zero point according to the size of the workpiece. Copy the program files to your computer according to the file paths in the Programming Guide.
5. CNC machining parameter settings
Spindle speed setting during processing: N=1000×V/(3.14×D)
N: spindle speed (rpm/min)
V: cutting speed (m/min)
D: Tool diameter (mm)
Processing feed speed setting: F=N×M×Fn
F: Feed rate (mm/min)
M: Number of blades
Fn: Tool cutting amount (mm/rev)
Cutting amount setting per blade: Fn=Z×Fz
Z: Number of blades
Fz: Cutting amount of each cutting edge (mm/rev)
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6. Prepare for CNC processing
At the beginning of each program, you must double-check that the tool you are using is written for the tool specified in the instruction manual. Start CNC machining feed, reduce the feed speed to the minimum, perform single-stage execution, rapid positioning, and feed. The feed must be concentrated. Your hand should be placed on the stop button. If there is a problem, stop immediately. Observe the movement direction of the tool to ensure safety. knife, and then slowly increase the feed speed to the appropriate level while using coolant or cold air on the tool and workpiece. CNC rough machining should not be too far away from the control panel. If any abnormality occurs, stop the machine immediately for inspection.
Open and pull the workbench to confirm again that the workpiece is not loose. If so, you must recalibrate and touch that number. In the process of continuously optimizing CNC machining parameters, the best CNC machining effect is obtained. Because the process is a critical process, after the CNC processing of the workpiece is completed, the main dimensions of the drawing should be measured to see if they are consistent with the drawing. If there are any problems, immediately notify the team leader or programmer for inspection. After solving the problem, it must be self-tested and sent to the inspector for special inspection.
Hole processing: In the CNC machining center, the drilling center must first be positioned with a center drill, then drilled with a drill bit that is 0.5 to 2 mm smaller than the drawing size, and finally a suitable drill bit is used for CNC finishing.
Reaming process: The reaming of the workpiece is first positioned with a center drill, then drilled with a drill bit 0.5 to 0.3mm smaller than the drawing size, and finally reamed with a reamer. The spindle speed is controlled at 70 to 180 rpm during the reaming process.
Boring processing: The workpiece is first positioned and drilled with a center drill, then drilled with a drill bit 1 to 2 mm smaller than the drawing size, and then processed with a rough boring tool (or milling cutter) until only 0.3 mm is left on one side and a suitable machining allowance , and finally use the pre-adjusted size of the fine boring tool for fine boring, and the final fine boring allowance cannot be less than 0.1mm. Direct CNC (DNC) operation: Clamp the workpiece, set zero, and set parameters before DNC machining. Open the number of processing programs on the computer to check, then let the computer enter the DNC state and enter the correct processing program file name. Press the TAPE key and program start key on the machine, and the machine controller will flash LSK.
7. Self-inspection of CNC processing workers
Before CNC processing, the processor must read the contents of the process card and understand the parts, shape and drawings of the workpiece in order to know the size of the process. Before clamping the workpiece, measure the size of the blank to see if it meets the drawing requirements. If the installation and programming instructions are consistent with the instructions, you must check the workpiece carefully. After rough machining is completed, self-inspection should be carried out in time to adjust data errors in time. The size of the self-test content is mainly the size of the processing site. For example: whether the workpiece is loose; whether the workpiece is correctly segmented; the dimensions of the CNC processed parts to the reference edge (reference point) are consistent with the requirements of the drawing; the positional dimensions between the processed parts.
After the completion of the self-test. After CNC processing is completed, workers should handle the shape and size self-inspection of the workpiece: the vertical plane at the CNC processing site detects the basic length and width dimensions and the processing site measures the basic slope dimensions marked on the drawing. After the workers complete the self-inspection of the workpiece and confirm that the workpiece conforms to the drawings and process requirements, the inspector will conduct a special inspection.