Random stuff, reduction, servo motors, ideas and thoughts
thefabricator03 wrote: I would like to be able to machine linear rails flat after they have been welded.
We were actually discussing this today. I know the big guys machine the linear mounting surfaces and ART (Advanced Robotic Technology) here in Brisbane have devised a method to do the machining on the table after its built. But they are selling $150k high def plasma cutters as their entry level machine. It would be nice to have a machined slot to mount the rails into so you could register the rails to one edge as the Hiwin install instructions mandate. BUt for non high def air plasma cutting table, Is that level of accuracy required for our blunt axe plasma machines?
rodw wrote: BUt for non high def air plasma cutting table, Is that level of accuracy required for our blunt axe plasma machines?
Not really. Would be handy to be able to do that for hi def machines. But if you had a milling machine capable of doing that, it would make sense to process all welded plasma machines the same way regardless of the plasma power unit.
I would be using the machine mostly for robotic linear tracks. In robotic precision is king. Although I am working on some sensors to try and lower the high precision barrier, it would be nice to be able to skim the surface of a linear guide mounting surface to get it a bit flatter.
When I built my robot linear track, where I welded I needed to straighten the main beams a little. I then had to grind a section flat near where I welded. I just ground a little then checked with a straight edge. Its pretty flat now but not 0.01 accurate.
then you get into squareness between each axis. your not going to have precision with a pistol drill and tapping the way most go about it. with plasma you can get away with it but it's not what you need to do for more precision applications.
you could use shim stock to correct some stuff but that's a pain and a lot of work fighting with stuff to get in the ballpark.
rodw wrote: Stefan, I think for parts like that, I'd get Laser Central in Brisbane to cut the beams and the holes on their tube laser cutter.
You do know Rod that you are a bad influence on me!
Laser tube cutter sounds like it would come in handy Might have to put it on my list of projects.
I would imagine that transporting lengths of 200x100x9 around the country side would get pricey. My goal is to keep everything in house.
obviously the electrical side of things is not my strongest point i few bread crumbs of information to get me pointed in the right direction would be appreciated
would this be a basic outline of what needs to be done?
i know the DYN4 drives can be set up for the velocity mode. and since they are newer i think the drives tune themselves on that end of it. i think older drives were not as easy because this was not something that was done?
so from what i can tell the error and the rotary encoder make up the inner loop which are the P & D values and the linear encoder makes up the outer loop which is the I value of the control loop? and this is all done on the Linixcnc side and linuxcnc is the PID?
so the next question would be what kind of Mesa hardware is needed? breakout board?
and yes Linux is very new to me
I think it was Hakken who did a video of connecting a linear encoder rail.
i seen the videos of the member here that did the same thing with glass scales on a mill i just have not had time to look at them all the process was over like 3 video's. i watched them all but will have to probably watch them several times before it sink's in completely.
i'm sure there are some pitfalls to watch out for. i think the resolution of your scale is one of them. 1 micron would be nice but 5 micron or 10 even might be more realistic for what the machine is. need to look into all this stuff when i get time.
When I put scales on my manual lathe, I went with 1 micron scales that cost about $10 more each. But that gives resolution to 0.001 mm (1 micron) or 0.00004 inches. You can't work to those tolerances. Some people put a bit of tape over the last digit on their DRO. I don't know what impact the scale resolution has on the encoder frequency. But you would think that the Mesa boards would handle them.