Common misunderstandings and coping strategies in high speed milling

As high-end manufacturing industries continue to increase their requirements for processing efficiency and precision, high speed milling (HSM), as an advanced cutting process, is increasingly being used in industries such as aviation, molds, automobiles, and precision instruments. With its high speed, high feed, and low cutting depth, it has shown significant advantages in both processing efficiency and surface quality.

However, in the actual promotion process, due to insufficient understanding of high speed milling technology, unreasonable parameter settings, or improper process matching, the processing results are often unsatisfactory, and even lead to serious problems such as tool damage and scrapped parts. This article will sort out the five common misunderstandings in high speed milling, deeply analyze the causes, and provide targeted coping strategies to help technicians apply this advanced process efficiently and stably.

1. Misunderstanding 1: The higher the speed, the better the processing effect

(1) Problem manifestation:

Many users use "high speed" as a one-sided measure when understanding "high speed milling", believing that the faster the spindle rotates, the higher the processing efficiency and quality. However, in actual applications, excessive spindle speed may cause early tool wear, increased machining vibration, and even workpiece ablation.

(2) Cause analysis:

The essence of high speed milling is not to simply increase the speed, but to reduce the unit cutting force, reduce cutting heat, and improve machining quality through the combination of "high speed + high feed + small cutting depth". When the speed far exceeds the allowable limit of the tool, and the feed and cutting depth are not optimized synchronously, the cutting edge will cause repeated friction in the local area for a long time, the temperature rises too fast, and the wear is aggravated.

(3) Countermeasures:

● According to the characteristics of the tool material (such as cemented carbide, coating material) and the material being processed, the spindle speed should be reasonably set.

● Combined with the characteristics of the machining surface, the cutting path and feed rate are adjusted to avoid "idle" high-speed machining.

● Use machine tools with spindle status monitoring function to control temperature rise and vibration level in real time.

2. Myth 2: High speed milling is not suitable for rough machining

(1) Problem manifestation:

Many factories still limit high speed milling to the field of finishing, believing that it has a shallow cutting depth and light feed, does not have a high metal removal rate, and is not competent for rough machining tasks.

(2) Cause analysis:

In traditional cognition, rough machining emphasizes "deep cutting and slow speed", while high speed milling is mainly based on "shallow cutting, high speed, and high feed". However, by reasonably selecting machining paths (such as circular cutting, dynamic trajectory), multi-tool collaboration strategies and optimizing parameter settings, high speed milling can fully play its high-efficiency advantages in rough machining, especially in thin-walled, easily deformed or difficult-to-cut materials, showing good rigidity control and heat dissipation performance.

(3) Countermeasures:

● Use dynamic tool path technology (such as Trochoidal Milling) to achieve high-efficiency material stripping.

● Use small-diameter tools and multi-channel parallel processing strategies for layered cutting.

● Use a high-rigidity fixture system to prevent workpiece deformation.

3. Myth 3: As long as the equipment is high-speed, the processing quality is guaranteed

(1) Problem manifestation:

Some companies have invested in high-speed machining centers, but found that the processing effect has not been significantly improved. Instead, they have encountered more stability problems, such as vibration, overcutting, and dimensional drift.

(2) Cause analysis:

High-speed machining not only relies on the speed capability of the equipment, but also emphasizes system coordination: machine tool rigidity, tool accuracy, fixture structure, cooling system, CNC interpolation capability and other links are indispensable. If the supporting capacity of high-speed equipment is insufficient, it will not only be difficult to achieve the ideal processing effect, but may also accelerate tool wear and reduce the service life of the whole machine.

(3) Countermeasures:

● Prefer HSM equipment with high-rigidity spindle, linear motor drive and thermal compensation function.

● Equipped with high-precision dynamic balancing tools and tool holders to ensure rotation stability.

● Configure high-pressure cooling and air mist lubrication system to control thermal deformation.

● Use CNC system with Look Ahead function to improve surface processing accuracy.

4. Myth 4: One set of parameters applies to all materials

(1) Problem manifestation:

In multi-variety and small-batch processing scenarios, some operators tend to use "universal parameters" without distinguishing material properties, resulting in unstable processing and reduced surface quality.

(2) Cause analysis:

Different materials have large differences in thermal conductivity, viscosity, strength, hardening tendency, etc. during cutting. Tool load sensitivity is high in high speed milling, and chipping, built-up edge or thermal cracking will occur if there is any inappropriateness.

(3) Countermeasures:

● Develop a dedicated high-speed cutting database for materials such as aluminum alloy, stainless steel, titanium alloy, and graphite;

● Use tool-specific coatings (such as AlTiN for high-temperature alloys and DLC for aluminum);

● Configure the material property module in the tool path generation software to intelligently recommend cutting parameters.

5. Myth 5: Ignoring tool wear and life management

(1) Problem manifestation:

While pursuing processing efficiency, some factories have failed to establish an effective tool life management system, resulting in abnormal tool wear, part tolerance, and frequent rework.

(2) Cause analysis:

During high-speed cutting, the tool is subjected to higher heat load and wear rate. If no warning or replacement cycle is set, "hidden failure" is very likely to occur, and the processing error will gradually expand.

(3) Countermeasures:

● Establish a corresponding table between processing batches and tool life, and update the usage records regularly;

● Use an intelligent tool monitoring system to identify spindle load and vibration changes;

● Regularly observe the tool microscopically to determine the status of tool edge damage, edge wear, coating shedding, etc.

6. Conclusion

High speed milling is an advanced process with strong integration. It has great potential for improving processing efficiency and surface quality, but the premise is to have a comprehensive understanding and reasonable application of its process logic, equipment matching and parameter control. The five major misunderstandings analyzed in this article are precisely the problems that many companies are most likely to ignore in high speed milling practice. Only by establishing a scientific processing cognition system, formulating a detailed process parameter table, and flexibly adjusting it in combination with actual scenarios can the value of high speed milling be truly brought into play and the goal of efficient, stable and low-cost modern manufacturing can be achieved.