Guidelines for the Machining Process of Vertical Machining Centers with Optics and Fine Mechanics

The operator must be familiar with the operation manual of the machining center and the performance of the machine tool, and have undergone relevant training and practical training on vertical machining centers. Only by passing the exam and obtaining a job certificate can they have the qualification to operate a vertical machining center.

1、 Preparation before startup:

1. After each start-up or emergency stop reset of the machine tool, it first returns to the machine tool reference zero position (i.e. return to zero), so that the machine tool has a reference position for its subsequent operations.

2. Clamping the workpiece:

3. Before clamping the workpiece, all surfaces should be cleaned to prevent oil stains, iron filings, and dust, and burrs on the workpiece surface should be removed with a file (or oilstone).

4. The high-speed rail used for clamping must be ground flat on all surfaces by a grinder to make it smooth and even. The code iron and nut must be sturdy and able to reliably clamp the workpiece. For some difficult to clamp small workpieces, they can be directly clamped on the vise.

5. The machine tool worktable should be clean and free of iron filings, dust, and oil stains.

6. The shim is usually placed at the four corners of the workpiece, and for workpieces with excessive span, a height shim should be added in the middle.

7. Use a ruler to check whether the length, width, and height of the workpiece are qualified according to the dimensions on the drawing.

When clamping workpieces, according to the programming operation manual, the clamping placement should be considered to avoid the machining parts and the possibility of the cutting head touching the fixture during machining.

After the workpiece is placed on the shim, the workpiece reference surface should be pulled according to the drawing requirements. The length direction error of the workpiece should be less than 0.02mm, and the horizontal error of the top surface in the X and Y directions should be less than 0.05mm. For workpieces that have already been ground on all six sides, their verticality should be checked to ensure it is qualified.

10. After the workpiece is pulled, be sure to tighten the nut to prevent the workpiece from shifting during processing due to unstable clamping.

11. Pull the meter again to ensure that the error does not exceed the tolerance after clamping.

12. Workpiece collision number: For clamped workpieces, a collision head can be used to determine the machining reference zero position. There are two types of collision heads: photoelectric and mechanical. There are two methods for selecting collision numbers: middle collision number and single-sided collision number. The steps for middle collision number are as follows:

13. Collision method: photoelectric static, mechanical speed 450-600rpm.

14. Move the X-axis of the worktable manually to make the counting head touch one side of the workpiece. When the counting head just touches the workpiece and the red light is on, set the relative coordinate value of this point to zero; Manually move the X-axis of the workbench again so that the counting head touches the other side of the workpiece. When the counting head first touches the workpiece, record the relative coordinates at this time.

15. Based on its relative value minus the diameter of the collision head (i.e. the length of the workpiece), check whether the length of the workpiece meets the requirements of the drawing.

16. Divide this relative coordinate number by 2 to obtain the middle value of the workpiece's X-axis. Then move the worktable to the middle value on the X-axis and set the relative coordinate value of this point on the X-axis to zero, which is the zero position on the workpiece's X-axis.

17. 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. Carefully check the accuracy of the data again.

The steps for setting the Y-axis zero position of the workpiece are the same as the operation for the X-axis.

Prepare all cutting tools according to the programming assignment manual.

20. According to the tool data in the programming assignment manual, change the tool to be machined and let it touch the height measuring device placed on the reference surface. When the red light of the measuring device lights up, set the relative coordinate value of this point to zero.

21. Move the tool to a safe location, manually move the tool down 50mm, and reset the relative coordinate value of this point to zero, which is the zero position of the Z-axis.

22. 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. Carefully check the accuracy of the data again.

23. For single-sided counting, also follow the above method to touch one side of the X and Y axes of the workpiece. Offset the relative coordinate values of this point's X and Y axes by the radius of the counting head, which is the zero position of the X and Y axes. Finally, record the mechanical coordinates of a point's X and Y axes in one of G54~G59. Carefully check the accuracy of the data again.

24. Check the correctness of the zero point, move the X and Y axes to the edge of the workpiece, and visually inspect the correctness of the zero point based on the size of the workpiece.

25. Copy the program files to the computer according to the file path in the programming assignment manual.

2、 Start up processing:

At the beginning of executing each program, it is necessary to carefully check whether the tool used is the one specified in the programming manual. When starting the machining process, the feed rate should be adjusted to the minimum and executed in a single section. When quickly positioning, cutting, and feeding, one must concentrate and place their hand on the stop button. If there is a problem, stop immediately. Pay attention to the direction of tool movement to ensure safe feeding, and then slowly increase the feed rate to the appropriate level. At the same time, coolant or cold air should be added to the tool and workpiece.

2. When starting rough machining, do not be too far away from the control panel. If there are any abnormal phenomena, stop the machine for inspection in a timely manner.

3. After roughing, pull the gauge again to confirm that the workpiece is not loose. If there is any side, it must be recalibrated and counted again.

4. Continuously optimize processing parameters during the manufacturing process to achieve optimal processing results.

5. As this process is a critical process, after the workpiece is processed, its main dimensional values should be measured to ensure consistency with the drawing requirements. If there are any problems, the team leader or programmer should be notified immediately for inspection and resolution. After self inspection and passing the inspection, it can be removed and must be sent to the inspector for special inspection.

6. Clean the machine tool worktable promptly after disassembling the workpiece.

7. Processing type:

8. Hole processing:

9. Drilling: Before drilling on the machining center, it is necessary to first use a center drill for positioning, then use a drill bit that is 0.5-2mm smaller than the drawing size to drill, and finally use a suitable drill bit for precision machining.

10. Reaming hole processing: When reaming the workpiece, it is also necessary to first use a center drill for positioning, then use a drill bit that is 0.5~0.3mm smaller than the drawing size to drill the hole, and finally use a reamer to ream the hole. During reaming, pay attention to controlling the spindle speed within 70~180rpm/min.

11. Boring: When boring the workpiece, first use a center drill to locate it, then use a drill bit 1-2mm smaller than the drawing size to drill the hole, and then use a rough boring tool (or milling cutter) to machine until only about 0.3mm of machining allowance is left on one side. Finally, use a pre adjusted precision boring tool for precision boring, and the final precision boring allowance should not be less than 0.1mm.

12. 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.

14. Open the processing program to be transmitted in the computer for inspection, then put the computer into DNC state and enter the correct file name of the processing program.

15. Press the TAPE key and program start key on the machining machine, and the machine controller will display the flashing LSK message.

16. Press Enter on the computer keyboard to perform DNC data processing.

3、 Worker self inspection content and scope:

1. Before processing, the processor must carefully read the content of the process card, clearly understand the part, shape, dimensions on the drawing, and know the processing content of the next process.

Before clamping the workpiece, the size of the billet should be measured to ensure it meets the requirements of the drawing. When clamping the workpiece, it must be carefully checked whether its placement is consistent with the programming operation manual.

3. After rough machining is completed, self inspection should be carried out in a timely manner to adjust data with errors in a timely manner. The main content of self inspection is the position and size of the processing parts. For example: (1) Whether the workpiece is loose; (2) Is the workpiece correctly centered; (3) Whether the dimensions from the processing area to the reference edge (reference point) meet the requirements of the drawing; (4) The position and size of the processing parts relative to each other. After checking the position dimensions, the rough machined shape ruler should be measured (excluding arcs).

4. Perform precision machining only after rough machining self inspection. After precision machining, workers should perform self inspection on the shape and dimensions of the machining parts: check the basic length and width dimensions of the machining parts on the vertical plane; Measure the base point size marked on the drawing for the machining part of the inclined surface.

5. Workers must complete self inspection of the workpiece and confirm that it meets the requirements of the drawings and processes before they can remove the workpiece and send it to the inspector for special inspection.

4、 List of reasons for errors, special attention, and corrective measures:

Reason for the error

Particular attention

Corrective measures

1. The length, width, and height dimensions of the workpiece were not checked

Before starting the machine, it is necessary to carefully check whether the length, width, and height dimensions of the workpiece comply with the drawings

Use methods such as measuring tape and counting to check its correctness

2. Placement direction of workpieces

According to the requirements of the programming assignment manual, determine the placement direction of the workpiece by comparing it with the drawing

Carefully check the orientation of the workpiece, and then operate according to the placement instructions in the manual

3. Collision offset

Method of counting, checking after counting, and checking input data

After counting, move the spindle to the edge of the workpiece according to its length and width dimensions, and check the correctness of the counting; After inputting the data, check its correctness again

4. Using the wrong tool

Carefully check whether the installed cutting tools are consistent with the instructions in the manual

When executing the first sentence of the program, it is necessary to confirm the tool used

5. The tool shatters during rough cutting, resulting in overcutting of the workpiece and tool scrap

Do not be too far away from the control panel when opening

Stop the machine promptly for inspection if there are any abnormal phenomena

6. Workpiece displacement after roughing

When clamping, it is necessary to ensure that it is securely fastened

After opening the gauge, pull it again and touch the numbers

7. The size of the workpiece is less than a certain number

Check the tools used; Notify programming check program

For important positions, ensure the use of new cutting tools for machining; Modify or add programs

8. Wrong file name entered

Before processing, it is necessary to carefully check the file names corresponding to the tools used in the program

Carefully check the correctness of the input file name