Summary of 17 key points of milling

First, let’s talk about the processing characteristics of milling. Milling is a cutting method that mainly uses the rotary motion of the milling cutter and the feed motion of the milling cutter or workpiece.

Its characteristics are:

1. Multi blade cutting tool is adopted for processing, and the cutting edge is rotated for cutting, so the tool has good cooling effect and high durability.

2. Milling has high production efficiency and wide processing range. Using different milling cutters on ordinary milling machines can complete processing tasks such as plane (parallel plane, vertical plane, inclined plane), step, groove (right angle groove, V-shaped groove, T-shaped groove, dovetail groove and other special grooves), special surface and so on. With the cooperation of indexing head and other milling machine accessories, it can also complete the milling of spline shaft, spiral shaft, tooth clutch and other workpieces.  

3. Milling has high machining accuracy, its economic machining accuracy is generally IT9-IT7, and the surface roughness Ra value is generally 12.5-1.6um. The precision of fine milling can reach IT5, and the surface roughness Ra value can reach 0.20um.  

Because milling has the above characteristics, it is particularly suitable for the processing of complex composite parts such as molds, and plays a very important role in mold manufacturing and other industries. With the rapid development of NC technology, milling plays a more and more important role in mechanical processing, especially in the processing of various special surfaces, which has advantages that other processing methods cannot match. At present, on the 5-axis CNC milling machining center, the whole artwork can even be copied and processed continuously with high efficiency.

In the actual production of milling, including machine tool settings, workpiece clamping, tool selection and other aspects of application skills, this paper briefly summarized 17 key points of milling for everyone.

1. Power capacity

Check the power capacity and machine rigidity to ensure that the machine tool can use the required milling cutter diameter.

2. Workpiece stability

Workpiece clamping conditions and considerations.

3. Overhang

Make the tool overhang on the spindle as short as possible during machining.

4. Cutting tool

When milling narrow workpieces or with gaps, ensure that there are enough blades to feed.

5. Select the correct milling cutter pitch

Use the correct milling cutter pitch for the process to ensure that no too many blades participate in the cutting, otherwise vibration will be caused.

6. Blade slot type selection

As far as possible, use an indexable insert with a front angle groove to ensure a smooth cutting effect and minimum power consumption.

7. Use correct feed

By using the recommended maximum chip thickness, ensure the correct feed of the used blade to achieve the correct cutting action.

8. Cutting direction

Use straight milling as much as possible.

9. Part Considerations

Workpiece material and configuration, and quality requirements of the surface to be machined.

10. Blade material selection

The groove type and material are selected according to the material type and application type of the workpiece.

11. Vibration reducing milling cutter

For longer overhangs that are more than 4 times the tool diameter, the vibration trend will become more obvious, and the use of damping tools can significantly improve productivity.

12. Main deflection angle

Select the most appropriate main deflection angle.

13. Milling cutter diameter

Select the correct diameter according to the width of the workpiece.

14. Milling cutter position

Position the milling cutter correctly.

15. Milling cutter cut in and cut out

It can be seen that through arc cutting, the chip thickness is always zero when the tool is retracted, so that higher feed and longer tool life can be achieved.

16. Coolant

Use coolant only when you think it is necessary. In general, milling can be performed better without coolant.

17. Maintenance

Follow tool maintenance recommendations and monitor tool wear