After each start-up or emergency stop reset of the machine tool, the machine tool first returns to the reference mark of the machine tool (i.e., back to zero), so that the machine tool has a reference position for its future operation.
Before clamping the workpiece, clean the surface first, do not stick to oil, iron filings and dust, and use a file (or oil stone) to remove the burrs on the surface of the workpiece.
The high-speed iron used for clamping must be smoothed by the grinder to make it smooth and flat. The yard iron and nut must be strong, can reliably clamp the workpiece, and can be directly clamped on the tiger for some small workpieces that are difficult to clamp; The workbench of the machine tool should be clean and free of iron filings, dust and oil; The horn is generally placed at the four corners of the workpiece, and the contour horn should be added in the middle of the workpiece with too large span.
According to the size of the drawing, use the pull ruler to check whether the length, width and height of the workpiece are qualified.
When clamping the workpiece, according to the clamping and placement method of the programming work instructions, it is necessary to avoid the machining part and the situation that the cutter head may touch the fixture during processing.
After the workpiece is placed on the horn, it is necessary to pull the table on the workpiece datum according to the requirements of the drawing, and check whether its verticality is qualified for the workpiece that has been ground on all six sides.
After the workpiece is pulled, the nut must be tightened to prevent the workpiece from being displaced during processing due to the unstable clamping; Pull the table again to make sure that the error is not out of tolerance after clamping.
The clamped workpiece can be used to determine the reference mark of the number of contacts, and the number of contacts can be used in two types: photoelectric and mechanical. There are two methods: the number of collisions in the division and the number of unilateral collisions, and the steps are as follows:
Photoelectric stationary, mechanical speed 450~600rpm. Manually move the X-axis of the workbench in the middle of the number of contacts, so that the number of heads touches one side of the workpiece, and when the number of heads just touches the workpiece and the red light is on, the relative coordinate value of this point is set to zero; Then manually move the X-axis of the workbench so that the number of heads touches the other side of the workpiece, and when the number of heads just touches the workpiece, write down the relative coordinates at this time.
According to its relative value, minus the diameter of the bumper head (i.e. the length of the workpiece), check whether the length of the workpiece meets the requirements of the drawing.
Divide this relative coordinate number by 2, and the obtained value is the middle value of the X-axis of the workpiece, and then move the table to the middle value of the X-axis, and set the relative coordinate value of the X-axis of this point to zero, which is the zero position on the X-axis of the workpiece.
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. Again, carefully check the correctness of the data. The procedure for setting the zero position of the workpiece on the Y-axis is the same as that for the X-axis.
According to the tool data of the programming work instruction, replace the tool to be processed, let the tool touch the height measuring device placed on the datum plane, and set the relative coordinate value of this point to zero when the measuring machine is red light. Mold people magazine WeChat is good, worth paying attention to! Move the tool to a safe place, manually move the tool down 50mm, and set the relative coordinate value of this point to zero, which is the zero position of the Z axis.
Record the Z value of the mechanical coordinates of this point in one of G54~G59. This completes the zero setting of the X, Y, and Z axes of the workpiece. Again, carefully check the correctness of the data.
The unilateral number of collisions is also according to the above method to touch one side of the X, Y axis of the workpiece, the relative coordinate value of the X and Y axis of this point is offset by the radius of the number of X, Y axis zero, and finally a point of X, Y axis mechanical sitting mark in one of G54~G59. Again, carefully check the correctness of the data.
Check the correctness of the zero point, move the X and Y axes to the side overhang of the workpiece, and visually check the correctness of the zero point according to the size of the workpiece.
Copy the program files to the computer according to the file path of the programming work instructions.
Spindle speed setting during machining: N=1000×V/(3.14×D)
N：主轴转速（rpm/min）
V：切削速度（m/min）
D: Tool diameter (mm)
The feed rate of machining is set: F=N×M×Fn
F：进给速度（mm/min）
M: Number of cutting edges
Fn: Cutting amount of the tool (mm/revolution)
Stock removal per edge setting: Fn=Z×Fz
Z: The number of blades of the tool
Fz: Cutting amount per edge of the tool (mm/revolution)
At the beginning of each procedure, it is necessary to carefully check that the tool used is the tool specified in the programming instruction. When starting to process, the feed speed should be adjusted to the minimum, a single section of execution, rapid positioning, dropping, and feeding must be concentrated, the hand should be placed on the stop button to stop immediately, pay attention to observe the direction of movement of the tool to ensure safe feeding, and then slowly increase the feed speed to the appropriate, and at the same time add coolant or cold air to the tool and the workpiece.
Do not be too far away from the control panel when roughing, and stop the machine for inspection in time if there is an abnormal phenomenon.
Pull the table again after opening the roughness to make sure that the workpiece is not loose. If so, it must be re-calibrated and touched.
Continuously optimize the machining parameters during the machining process to achieve the best machining results.
Because this process is a key process, so after the workpiece is processed, the main size value should be measured to be consistent with the requirements of the drawing, if there is a problem, immediately notify the team leader or programmer to check, solve, after passing the self-inspection can be removed, and must be sent to the inspector for special inspection.
Processing type: Hole processing: Before drilling on the machining center, you must first use the center drill to position, then use a drill bit 0.5~2mm smaller than the drawing size to drill the hole, and finally use a suitable drill bit for finishing.
Reaming processing: The workpiece is also reamed with the center drill to position, and then with a drill bit 0.5~0.3mm smaller than the size of the drawing, and finally with a reamer reaming, pay attention to control the spindle speed within 70~180rpm/min during reaming processing.
Boring processing: the workpiece should be bored with a center drill to position, and then drilled with a drill bit smaller than the size of the drawing 1~2mm, and then processed with a rough boring cutter (or milling cutter) until there is only about 0.3mm machining allowance on one side, and finally fine boring with a fine boring cutter with a pre-adjusted size, and the last fine boring allowance can not be less than 0.1mm.
Direct numerical control (DNC) operation: Before DNC CNC machining, the workpiece should be clamped, the zero position should be set, and the parameters should be set. Open the processing program to be transferred to the computer to check it, then let the computer enter the DNC state, and enter the file name of the correct processing program. Daren WeChat ID: mujuren Press the TAPE key and the program start button on the processing machine, and then the machine controller will flash the LSK word. Press the enter keyboard on the computer to perform DNC data transfer processing.
The processor must read the content of the process card clearly before processing, clearly know the parts, shapes, and dimensions of the drawings to be processed of the workpiece, and know the processing content of the next process.
Before clamping the workpiece, the size of the blank should be measured to see if it meets the requirements of the drawing, and the workpiece must be carefully checked to see if it is consistent with the programming work instruction when clamping.
After the roughing is completed, the self-test should be carried out in time so that the data with errors can be adjusted in time. The self-test content is mainly the position and size of the processing part. Such as: whether the workpiece is loose; whether the workpiece is correctly aligned; Whether the size of the processing part to the datum edge (datum point) meets the requirements of the drawing; The size of the position of the machined parts against each other. After checking the position dimensions, the roughing shape ruler is measured (except for arcs).
Finishing is carried out after roughing self-inspection. After finishing, the worker should self-check the shape and size of the processing part: check the basic length and width of the processing part of the vertical plane; Measure the size of the base point marked on the drawing for the machining part of the inclined plane.
Workers can remove the workpiece and send it to the inspector for special inspection after completing the workpiece self-inspection and confirming that it is consistent with the drawings and process requirements.