Thin-Wall Milling

 

When milling thin-walled parts, it is extremely difficult to maintain both dimensional and positional accuracy. Many influencing factors exist, but some key factors are discussed below that can help improve your thin-wall milling precision.

 

 

I Using the Right Tool

 

1. Reduced-Neck Tools

In thin-wall milling, tool and cutting lengths can lead to bending, vibration, and breakage. While ensuring the machining depth meets the required specifications, it is essential to maintain tool strength as much as possible. Reduced-neck tools provide this strength and are generally capable of machining depths exceeding three times their diameter.

▲Reduced-Neck Tool

 

The reduced-neck length of an end mill refers to the length of the tool's neck when in use. This measurement is the distance from the beginning of the neck section to the bottom of the tool's cutting end. Neck thinning helps with chip evacuation and prevents shank friction when milling deep holes.

 

 

II Selecting Cutting Depth

 

1. Axial Depth of Cut (ADOC)

During thin-wall machining, a wide cross-section should be retained behind the sidewall to provide support. We recommend using a step-down approach, breaking the total height into depths that are easier to machine while processing both sides simultaneously. The axial depth of cut (ADOC) will vary depending on the material being machined and its hardness.

▲Selecting Cutting Depth

 

2. Radial Depth of Cut (RDOC)

As milling depth increases, adopting a progressive radial cutting approach is also crucial. Reducing tool pressure while cutting the material is equally important to maintain the stability of the thin wall.

 

Point A represents a five-step progressive radial cutting method. The number of cutting passes will depend on the specific machining process, material hardness, and final wall thickness.

 

This method helps reduce stress on the thin wall as the tool approaches it. Additionally, when using this RDOC strategy, alternating cuts on both sides is recommended.

 

The final RDOC cutting pass should be smaller to minimize vibration of the thin wall and ensure a smooth surface finish on the part.

 

▲Radial Depth of Cut (RDOC) 

 

 

III Thin-Wall Milling Techniques

 

1. Climb Milling

Climb milling is preferred for efficiency and extended tool life, as it minimizes heat generation and friction. The chips are ejected behind the tool, reducing the risk of chips damaging the workpiece surface quality. The chips start at their widest point and gradually decrease in size, allowing heat to be transferred into the chips rather than the tool or workpiece. This extends tool life, enabling each tool to machine more parts and reducing costs. Additionally, optimizing chip formation at the cutting edge contributes to better surface quality on the finished part.

▲Climb Milling

 

2. Supporting Materials for Stabilization

Using thermoplastic compounds or wax can provide manual vibration damping and stabilize thin walls. These materials can be removed using heat processing.

 

3. High-Efficiency Milling (HEM) Paths

Utilizing HEM paths can optimize tool performance. This advanced machining method involves combining a lower radial depth of cut (RDOC) with a higher axial depth of cut (ADOC) and an increased feed rate. This combination is designed to enhance material removal rates while reducing tool wear.

 

▲High-Efficiency Milling (HEM)