So I have a few index pin locations that I use for making parts (guitar necks/bodies). They are referenced off the lower left hand corner of my spoil board. I’ve always home’d my machine, zero’d it, and then used the auto-touch plate to set my XYZ but it always basically returns the same values (give or take a few thou).
Is there really any reason to keep using the plate off the corner or can I just use the known coordinates and carry on? Am I at risk of losing enough position to make a noticeable diff?
As you state yourself, the position does not variate much with your normal workflow. If your stock has enought body to catch the deviation you do see, I don’t see why no.
I don’t use xy zero and work of my stock, move vbit to left of stock zero x, move to right of stock and devide the xvalue by 2 to get my x-zero. I do the same with y up and down. After that I put a dimple at an easy reproduceable distamce into a piece of the stock that will be waste, so I can always get my zero back for either my mill or laser,.(I like to combine them in projects) Reproducing xy0 like this is a breeze and fairly accurately repeatable.
So yeah, I think you can go without probing xy provided your stock has enough body to accomodate the seen deviations using homing.
I should mention that the index pins are used for flipping the piece (so I machine the back of the neck, then then front of the neck for example).
The original holes were drilled using the lower left as a reference using the auto touch plate… I wonder if using the touch plate each time gets me that much closer to the original (thereby making my flip more accurate) or is it always a small amount of variance no matter what.
@reidcustoms I don’t do repeatable projects where I’d use your technique.
But a while ago, I tested the repeatability for getting back to zero between power cycles of the SLB. Essentially, I power cycled the SLB, ran the homing routine, and then moved the spindle to a reference point on my table. I measured the spindle location with a dial gauge with 0.01mm accuracy. Did this several times and the zero coordinates were always spot on.
I’m fairly confident that if I note down the machine coordinates (the units in grey in gSender) of a particular reference point, it will remain the same withing 0.01mm accuracy, even between SLB power cycles (but you have to rehome)
Note that on inspection of my Altmill last month, one of the nuts holding the Y1 limit switch was loose. After tightening, it likely changed location a bit. That likely offset the machine coordinates by the same amount.
That’s cool Chucky and exactly the kind of info I was looking for.
Also I have the “check for loose parts” maintenance thing popping up at the end of every job and I keep hitting the snooze button on it haha… A good reason to go over everything.
I guess making sure to use the AZTP at the start of every job isn’t really a huge inconvenience… takes 30 seconds and would eliminate error in the event something like a sensor had come loose… considering the cost of materials I’m working with, this might be a short cut that isn’t really worth it.
Cool to know it returns to the same coordinates that accurately tho!
How are you clamping the stock?
The reason I am asking this is because I was using 3D printed dogs (my version of index pins) to do exactly that. I also had an issue with a very small discrepancy in location for the second side. As it turned out, my index pins where subject to slight deformation because of side clamping forces.
I reprinted the index pins using much more infill and the issue went away.
I do not change (by the use of the auto touch plate) the xy coordinates. Only Z gets adjusted and only if I changed tooling.
so I haven’t really even been clamping the stock down. I have 2 3/8 steel dowel pins that are snug and keep everything very secure. I’m going to start using some low profile clamps I built since I just put t-track on this weekend but really it’s not even needed with the dowel pins. I also only set my X/Y once per job. And just Z height for tool changes/flip.