Looking for different ideas as to what all should be calibrated on my point-to-points and what are some good verification tests to run on my machines, as far as test patterns and so on. Do most people use laser calibration, good old fashion dial indicators, or even a Renishaw QC10 Ballbar system? I currently have three Weeke BP-145's, one Weeke BP-120, and two Busellatos.
We have done a few things here. Just looking to see what others have done or tried that seems to work good for you.
I'd appreciate any and all info I can get.
On wood working machinery, I regularly calibrate both routers and point to points using digital calipers. In the event of a catostrophic crash I will align the router spindle or boring block with dial indicators and a rectified flat plane ( I usually keep a ground piece of steel plate for this purpose). I also use a graduated jewelers loupe.
Rarely will you find people using laser inferometer or ball bar testing units on wood working based machinery. The reason is the accuracy is normally not required, and often the machines are not "spec'd" for such accuracy. + or - .1 mm (.0039 in) is common and reasonable accuracy when working with wood.
A normal calibration procedure for a point to point;
Align the head and boring unit perpindicular to the table. If the table and bed need releveling, then this should happen first. Then mount the indicator in each respective spindle. Place the flat steel plate on the table and "tram" it with the indicator (move it linear in each axis) to insure it is flat. Once this is done, swing the indicator by rotating it in the spindle ( note the indicator mount should provide that you can swing the indicator on an arc). This will show you how far out of perpindicular the router and boring unit are to the table, you would then loosen the bolts afixxing the relative unit to the machine head and either realign by moving, shimming or both until the indicator can be swung on an arc and read "0" at all locations on the flat steel plate.
Once this is done, I align the router to the boring unit by drilling a hole with each in the same location and using the jewelers loupe to align each unit that they are placed in the same location.
Finally I check all and adjust to the origins with dial calipers. At this time I would also recalibrate all fixed style tool holders if applicable.
An additional test to check accuracy through out the length of travel is to drill a "grid" of holes throughout the machine in both axes. If there is variance in different locations throughout, there are normally tables within the control to account for lagg, thermal growth, backlash etc. This information will be specific to your machine, mfg and control.
I hope this helps, if anymore questions visit my website www.cnccustomservices.com and email me there or at firstname.lastname@example.org