No problem. I also have a very heavy interest and career aspiration for precision machine tool building/rebuilding.
Originally Posted by AustinT  After thinking it over you are probably right it might not be worth the effort to make a system that automatically compensates for one machine . Would it be worth it however if it was standard input on a control such as Mach? It just seems like after it was built and working, Users could put down a couple of magnetic mounts with a wire stretched between the mounts . Then the machine in Mach could be slowly jogged from one end to the other. Mach would know the linear distance to the error and then would remember to compenstate for the error later on. |
The problem I see with this is that error correction and compensation are only truly effective on a small (but relative) scale. A lot of machines I've seen on various forums built as a DIY project have larger, fundamental misalignment problems that make it hard to apply either correction or compensation.
A set of machine ways that are "fundamentally" misaligned will cause apparently unpredictable (nondeterministic, in the technical vocabulary) motions in the table that can't be properly compensated for. Poor ways on a linear axis will cause apparent unpredictability in not only the axis that has the error, but will cause linear and
angular errors in the other axes that will change with load and other machine parameters.
When you get a set of guides, angular or linear, that true to a fine tolerance, error correction becomes more deterministic rather than apparently random. The errors in the axes are more repeatable due to the effects that take hold at higher tolerances (reliable elastic averaging) and become far more repeatable.
This is all under the dual assumption that there is a way to precisely align the string in the first place, and that there is a way to separate the vertical and horizontal components of the error motion.