Accuracy vs Speed
Heating of a recirculating ball screw during multipass milling at 10m/min. This thermographic snapshot shows temperatures of 25°C to 40°C.
I recommend that your new machine have Glass Scales (linear scales) to maintain its accuracy.
You may wonder why I say that when I’m selling you a new machine that has been built to an accurate standard. Well, the picture above shows what happens when you start moving your machine around a lot, and at a fast speed. Today’s rapid speeds and high cutting rates cause temperature changes in different parts of the machine, which causes thermal growth. If you only use a rotary encoder to measure table position, then there will be differences in positional accuracy. Linear scales can compensate for this heat problem.
In some cases the temperature change won’t affect the job you are machining, but what happens after five years and the ball screws have developed some wear? Then you need linear scales.
We in NZ are struggling to compete against Asian manufacturing, so we must fight this by investing in good quality machinery that will maintain long-term accuracy.
I have an excellent article on this subject that I can share with you. Give me a call on 0800 85 87 84, or send me an email here.