[Dallas J]

I'm my mind the easiest way to get this would be to Ref all home but without machine coordinates zeroing. Then if an error accumulated It would be an easy check but I don't see a way to do this.

I thought maybe another way would be to edge find the vice and manually write the coordinates of a corner, then come back and recheck after running some Gcode for a while.

[Fastest1]

Use a dial indicator and some 1,2,3 blocks. Then in MDI enter the code to travel to a specific point and back. Repeat rapids and increase motor speed til the indicator starts to show errors in travel. Back off the speed in your tuning section by a reasonable amount 25%?, test again.

Unfortunately you will find out while making a part because the tool or part gets broken!

Why do you suspect missed steps?

[109jb]

You can go to your home position , or any other position in machine coordinates, without homing using:

G90G53G0X##Y##Z##

G53 is non-modal but send the machine to the input X,Y,Z in machine coordinates.

[dharmic]

Using Mach3? Have home position switches?

1. Home the machine (the tall skinny reference all axes button).
2. Run your part.
3. Hit the "verify" button - the machine will home again and tell you how far off machine (0,0,0) you now are.

[arizonavideo]

Zero on a location and drill a hole with a ball tip end mill in a collet or pilot drill to indicate on.

Run a program in the air.

Click the go to zero button after a hour of running and re indicate the hole.

You should be within .003" or so.

Heat will cause some change but anything over ,008" is not from heat but loosing steps or slipping couplers or end bearings. Do a backlash test while your at it.

[Dallas J]

Using Mach3? Have home position switches?

1. Home the machine (the tall skinny reference all axes button).
2. Run your part.
3. Hit the "verify" button - the machine will home again and tell you how far off machine (0,0,0) you now are.

Ahh, this is what I'm looking for. I have homing switched in X and Y but not Z. Right now Im trying to figure out how to get it to work but a little search online says this is the right function.

Right now when I try it the Z moves up to safe Z height then back down where it was and thats it. Not sure whats going on but I think I need to figure out and understand "Safe Z" setting a little more.

Previously what I had to do was:

-Home the machine
-Run a longer program usually with the feed cranked up to really stress things
-Turn off homing zero
-Ref all home.

That would give me an offset but was much more of a hassle and I knew there had to be a better way to go about it.

[Bob La Londe]

You can set a position in Z manually, and then home Z. It will just take that position as as the home position. You can set anything from that height down as safe z. I like to use zero machine coordinate as safe Z height unless the machine is really tall and really slow.

As to mounting. The mechanical practical answer is going to be dependent on your machine, but I have seen a couple machines made for resale that only have a limit in the positive direction on Z. My Syil and COTKCNC both only have limits at max height. On the other hand the quill of my Hurco has limits in both directions. Sometimes I think its a matter or practicality.

I would recommend for now that you atleast raise the Z and visually stop at just under your mechanical limits. Set that as home, and then program soft limits from there that make sense. Its not good practice, but if the machine works ok it can prevent some headaches. You will need to do the manual home setup every time you start the machine, but I think even with properly installed switches you should always home the machine as part of your startup procedure anyway.

Also, in Mach 3 if you go to the diagnostic page you can home the axis one at a time if its more convenient or safer for some reason.

And finally I get around to your actual question. LOL. The only way to know if you are losing steps is to measure to something, run the machine, and measure again.

FYI, whoever mentioned the verify button... thank you. I'll have to look for that. I'm a long time Mach 3 users, and I am not sure I even know where that is, but I'll go look as soon as I am done posting.

[dharmic]

Zero on a location and drill a hole with a ball tip end mill in a collet or pilot drill to indicate on.

Run a program in the air.

Click the go to zero button after a hour of running and re indicate the hole.

You should be within .003" or so.

Heat will cause some change but anything over ,008" is not from heat but loosing steps or slipping couplers or end bearings. Do a backlash test while your at it.

Unfortunately, chances are it won't skip steps until it's under load so this probably won't tell you anything. Need to load it up by running the job in the material you're intending to work with.

[Bob La Londe]

Sorry for the Tangent , but how does the verify function work?

[dharmic]

Bob, when you "reference all axes", the machine runs each axis until it hits the endstop and then sets the current machine coordinates to (0,0,0).

From that point on, it tracks the machine coordinates as it sends steps to the drivers.

When you hit "verify" it heads back to the endstops but, instead of resetting each axis position to 0 it tells you how far away from 0 it is, which gives you an idea of how far it's slipped since the last reset.

[rcs2022]

Checking for a small amount of missed steps is best done by the verify function as dharmic mentioned above, your switches (optical or mechanical) should have a good repeatability also.

If missed steps are meant by a stepper stalling first you would directly know as most probably the machine would have crashed and/or the part ruined.

I'm in the middle of a small project to add diy encoders to the steppers and have a small microprocessor (arduino and /or teensy) compare the actual turns of the stepper via the encoder with the pulses sent from the bob. It's not intended to be a loop back system, but just like a stall - proof diy method for avoiding huge crashes and stalls on my small sherline.

There should be some ready made equipment out there that can do similar or add a loop feedback system to monitor more precisely the lost steps. Ready made encoders can detect 1/thousands of a turn.