Reducing Vibration Problems in Deep Grooving Operations

November 1, 2018 2:23 pm

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Part grooves are typically required to allow for multiple parts to be assembled.  Parts are cut-off to separate a completed part from the raw material.  Although part-off and grooving operations are quite common, they can sometimes create some complications due to tool vibrations.

Vibration in deep grooves

Deep grooves are inherently difficult operations.  Tool rigidity is compromised as tool extension increases. The result is instability of the tool in cut.  While in cut, the tool deflects which causes vibration, resulting in poor part finish and reduced tool life.

Vibration can occur due to several factors: machine and clamping system rigidity, part shape, tool and insert design, and cutting parameters. In many cases, however, especially in deep grooving applications, it is not possible to design cutting tools that will avoid vibration in a conventional way. The general recommendation to avoid vibration issues is to work with toolholders with high rigidity and clamping force and to choose the best inserts for this type of operation.

Here are some tips to resolve vibration issues:

 

1. Analyze your machine’s capabilities

 The characteristics of the machine play a fundamental role in deep grooving operations. Analyzing key features – like machine horsepower, rigidity and coolant pressure – is a necessary step to determine the success of the operation. Additionally, proper machine alignment is critical to keeping grooves properly shaped and sized.

 

2. Understand the properties of the cutting material

 Understanding the material properties, such as tensile strength, work hardening characteristics and ductility is critical to knowing how the workpiece will respond to the cutting tool. The quantity of material that needs to be removed is also important in determining what cutting tools should be used.

 

3. Select the proper inserts for the application

 Deep grooving and parting operations usually require advanced insert geometries. Grooving inserts have either a square or round shape on the end.  Square grooving inserts reduce cutting forces and cut more efficiently.  For the tool holder, the tool overhang should be minimized to improve the stability of the tool during plunge moves.

The Anti-Vibration blades are designed to be tunable. Depending upon how far the blade is extended from the holder, you can tune the blade to cancel out the different vibrations.

4. Utilize vibration-dampening technology

Advanced anti-vibration technology is a good solution to resolve problems in deep grooving operations.

ISCAR recently introduced a new technology designed to eliminate vibration problems. The new WHISPERLINE blade features a damping unit that absorbs vibration, which enables a stable machining process even at elevated cutting conditions.

 

5. Maintain accurate feeds and speeds

The Anti-Vibrations are designed with ports directly to flank out the inserts to extend tool life and help with chip evacuation.

Feeds and speeds play a critical role in groove creation. Incorrect feeds and speeds can result in chatter, reduced tool life, and poor cycle times. The RPM varies based on the cut diameter and SFM. As some materials will work better at a specific SFM, understanding the material characteristic is critical to identify the correct RPM.   The concept is that to use this tool correctly, you must not use the constant SFM feature in the cut-off or groove program.  Constant SFM will vary the RPM and change the vibration from beginning to end of cut (as RPM is varying).  Using constant RPM allows for the vibration to be a constant frequency and the grooving tool vibration damper can then be tuned to cancel or minimize the vibration.

 

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