CNC machines feature high-capacity tool changers that automatically swap toolholders in and out of the spindle as needed, by means of a high speed swing arm or a rotary carousel. Periodically, toolholders should be examined for wear and if necessary replaced to maintain cutting performance.
New operators should be taught how to properly evaluate toolholders so they can recognize when toolholders need to be replaced to prevent premature cutting tool failure, or even expensive damage to the spindle.
Many operators do not know why it is necessary to replace their tooling, or have the experience to tell when it is time to do so.
Determining if toolholder components need to be replaced is not a difficult task, but does require that the operator knows what to look for. Here's a few things you should be aware of when checking your rotary toolholders.
Checking For Spindle Mouth Wear
A worn spindle can cause runout issues that affect toolholder accuracy and reduce cutting quality and productivity. This is a condition known as bell mouthing. If toolholder issues can be eliminated by bench checking T.I.R., then the source of the problem is often a worn out spindle mouth. A trained professional will be required to check and repair bell mouthing.
T.I.R. (total indicator runout) is the measurement of axial deflection of the cutting tool in the toolholder assembly. Techniks toolholders are manufactured to minimize runout and extend cutting tool life. You lose 10% of cutting tool life for every “tenth” (0.0001”) of runout. That's what the chart above depicts.
Automatic Tool Changer Alignment Issues
It’s crucial to maintain proper ATC swingarm alignment. If the ATC does not insert the toolholder perfectly, damage to the spindle and toolholder may result. Also poor cutting tool performance and reduced tool life will be evident. A trained professional will be required to check and repair ATC issues.
Evaluating Toolholders for Wear
A worn out toolholder will not provide good accuracy and will quickly wear out your cutting tools. Worn tooling can also cause poor surface finish, and may even damage your spindle. Keep and eye out for these issues and your tool life, surface finish and cycle time will all improve to help you make more money on every job in your machine shop.
Special thanks to TechniksUSA for providing this detailed information!
Technical Support Blog
At Next Generation Tool we often run into many of the same technical questions from different customers. This section should answer many of your most common questions.
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