The machine tool of the CNC machining center must first return to the machine reference zero position (ie return to zero) every time the machine is turned on or the CNC machine is reset by emergency stop, so that the CNC machine tool has a reference position for its subsequent operations.
Clamping the workpiece
Before CNC machining, the workpiece should be clamped. The surface of the workpiece should be cleaned before it is clamped. There should be no oil, iron filings and dust, and the surface of the workpiece should be removed with a file (or oil stone).
The high-speed rail used for clamping must be smoothed by a grinder to make it smooth and flat. The code iron and nut must be sturdy and able to clamp the work piece reliably. The hard-to-clamp school co-construction should be clamped directly on the tiger. The worktable of the CNC machine tool must be clean and free of iron filings, dust and oil; the shim iron is usually placed on the work piece. At the four corners of the steel, contour horns must be placed in the middle of the workpiece with too large span.
Check the length, width and height of the workpiece according to the size of the drawing. When clamping the workpiece, according to the clamping and placing method of the programming operation guide, consider avoiding the processed parts and the situation where the tool head may touch the fixture during processing.
After the workpiece is placed on the horn, pull the reference surface of the workpiece according to the requirements of the drawing, and check whether the verticality of the workpiece that has been ground on all six sides is qualified. The nut must be tightened after the workpiece drawing table of the CNC machining center is completed to avoid the phenomenon that the workpiece is displaced during processing due to the unstable clamping; the table is pulled again to ensure that the error is not excessive after the clamping is completed.
Number of workpiece touches
The CNC machining center uses the digital touch head to set the reference zero position of the clamped workpiece. The digital touch head can be photoelectric or mechanical. There are two methods: mid-point bumping and unilateral bumping. The steps for splitting bumping are as follows:
Photoelectric static mechanical rotation 450~600rpm. Manually move the X-axis of the worktable with the middle touch, let the touch head touch one side of the workpiece, when the touch head just touches the workpiece and the red light is on, set the relative coordinate value of this point to zero; then move the work manually The X-axis of the stage makes the digital head touch the other side of the workpiece. When the digital head just touches the workpiece, write down the relative coordinates at this time.
Workpiece CAM software programming
The CNC programmers of the CNC machining center select the workpiece to be processed through the CAM software WorkNC to program it, generate the tool path, use the WorkNC simulation module to interfere and check the tool path, and then perform post-processing to generate safe and stable NC code, which is transmitted to the workshop machine.
Prepare all tools according to programming instructions
The CNC machining center replaces the machining CNC tool with the machining CNC tool according to the tool data in the programming operation guide, and makes the CNC tool touch the height measuring device. When the red light of the measuring device is on, the relative coordinate value of this point is set to zero. Move the CNC tool to a safe place, manually move the tool down 50mm, and set the relative coordinate value of this point to zero again. This point is the zero position of the Z axis. Record the machine coordinate Z value of this point in one of G54~G59. This completes the zero setting of the X, Y, and Z axes of the workpiece.
Check the accuracy of the numerical control again. The one-side touch count also touches one side of the X and Y axis of the workpiece according to the above method. The relative coordinate value of the X and Y axis of the point is offset. The radius of the touch count head is the X and Y axis. Finally, mark the mechanical coordinates of the X and Y axes in one of G54~G59. Once again, carefully check the correctness of the data.
Setting of processing parameters
Setting of spindle speed during processing: N=1000×V/(3.14×D)
N: Spindle speed (rpm/min)
V: Cutting speed (m/min)
D: Tool diameter (mm)
Processing feedrate setting: F=N×M×Fn
F: Feeding speed (mm/min)
M: Number of cutting edges
Fn: Cutting amount of the tool (mm/revolution)
Setting of cutting amount per blade: Fn=Z×Fz
Z: The number of blades of the tool
Fz: Cutting amount of each edge of the tool (mm/revolution)
When the CNC machining center executes each program, it must carefully check whether the tool used is the CNC tool specified in the programming guide. When starting processing, the feed speed should be adjusted to the minimum, single block execution, fast positioning, falling, and feeding must be concentrated. Put your hand on the stop button and stop immediately when there is a problem. Pay attention to the movement of the CNC tool. Direction to ensure safe feed, then slowly increase the feed speed to the right, and at the same time add coolant or cold air to the CNC tool and workpiece.
The CNC machining center should not be too far away from the control panel when roughing. If there is any abnormality, it should be stopped in time for inspection. Pull the meter again after roughing, to make sure that the workpiece is not loose. If so, re-calibrate and count. Continuously optimize the processing parameters in the CNC machining process to achieve the best processing effect.
Content and scope of workers' self-inspection
The processor of the CNC machining center must read the content of the process card before processing, clearly understand the part, shape, and size of the workpiece to be processed, and know the processing content of the next process.
Before the workpiece is clamped, the size of the blank must be measured whether it meets the requirements of the drawing. When the workpiece is clamped, it must be carefully checked whether the placement is consistent with the programming operation guide.
The CNC machining center should conduct self-check in time after rough machining is completed, and adjust the data with errors in time. The content of the self-check is mainly the position and size of the processing part. The CNC machining center only performs finishing after roughing self-inspection. After finishing processing, workers should conduct self-inspection on the shape and size of the processed parts: test the basic length and width dimensions of the processed parts of the vertical surface; measure the basic point size marked on the drawing for the processed parts of the inclined surface. After the worker completes the self-inspection of the workpiece and confirms that it is in compliance with the drawings and process requirements, the workpiece can be removed and sent to the inspector for special inspection.