This little thing can cost you a lot of money!
| Alex Roberts
The #1 cause of cutter breakage.
Of the assortment of causes of cutter breakage, there is one that stand out as follows:
Many tools are now made from tungsten carbide. While this means that the cutters last much longer and can be fed a lot faster, there is a trade off that because of their increased hardness. they are totally unforgiving of any vibration.
But there is one cause which contributes to over 80% of cutter breakage.
Spring Collets, irrespective of any fancy sounding name are made from spring steel. In use, they are subject to variations of temperature, material resistance, dirt and dust.
This is why even CNC router collets, with a mass of 10-15 times that of a portable router collet have a recommended of life of 500-600 working hours.
After this number of hours of heating up and cooling down, the collet steel loses its ‘tempering’. This means it cannot grip the shank of the tool accurately, evenly or concentrically.
At 18 - 20,000 rpm can you blame the tool giving up?
To get the best out of your cutters, you need to use good, clean collets.
These will run quieter, faster and more productively than the old cutter you were trying to were trying the last ounce of life out of.
They are much easier on your $12,000 spindle nose bearings too! Just imagine if you could get another 12 or 24 months life out of these?
Discard any old ones and keep the ones you are using clinically clean by using a high quality non oily cleaning solution with a brass collet brush dedicated to the size of the collet.
When you snap a cutter, look to your collet – there’s a big chance you’ll be looking right at the culprit! When you snap a cutter, replace the collet – there’s every chance it was damaged with the snap and will not grip the tool correctly any more.
Collets are recommended to be replaced every 400 - 600 working hours.
As a rule, they generally cost far less than the cutters as its worth doing this piece of simple maintenance.