Cut 1" square...not so square

[gamble]

So I am still having a lot of issues with cutting. As of yesterday and the torch diving almost every cut I decided to play with some setting and see how accurate my cuts are. So I drew and cut a 1" square.
X measures 1.96" which is pretty close (kerf setting was 0)
Y measures 1.7" which is pretty far off.

How would I begin to troubleshoot this? The Y and X settings (turn ratios etc) are the exact same

[Brand X]

Take a plunge type dial indicator ,and set up on the X and Y axis.. First you need to see if your machine moves the correct distance,before you cut anything. Then start looking for any slop in your table.

[Bigrhamr]

First I am assuming there is a typo and it should say .96 and .7 instead of 1.96 and 1.7 which would both be waayyy off

I would start by drawing a long line in both directions, (say 22" if you have 24" of table travel.
Then do a dry run on both lines measuring the actual distance traveled. If you have the same approx 1/4" difference between
x and y then it may be slop or backlash.
If the error increases in proportion to the distance traveled that would point more strongly to a calibration error although mechanical slippage in one axis is still possible.
Have you been over every possible point where something could slip or have slop? Setscrews, couplers, gears, belts,pulleys, gear racks not mounted securely,etc.. Belts can have a damaged cog that can't be seen without close inspection, pulleys on a shaft with a flat spot can move slightly if a key is missing or a setscrew backed out slightly. Locktite can be your friend here.

So I am still having a lot of issues with cutting. As of yesterday and the torch diving almost every cut I decided to play with some setting and see how accurate my cuts are. So I drew and cut a 1" square.
X measures 1.96" which is pretty close (kerf setting was 0)
Y measures 1.7" which is pretty far off.

How would I begin to troubleshoot this? The Y and X settings (turn ratios etc) are the exact same

[acourtjester]

One of the first thing you want to do is mount a ink pen so you can draw items to check your movement like posted here.
http://www.plasmaspider.com/viewtopic.p ... en#p116206
No need to burn metal until you have the table dialed in
Here is a video on how to do the steps per to calibrate the table's axis his screen is different but the description is the same, I do it about 3 time per axis moving a longer travel each time to get better accuracy.
https://www.youtube.com/watch?v=EVrqObwaAF4

[BTA Plasma]

If your tuning is correct then your loosing steps somewhere. The thing about an anti-backlash nut is that it will limit your upper end. With a stepper you may be getting into that RPM range where it will not maintain step and direction from the friction on the anti-backlash nut. Being 1.7" off I would be looking at actual motor tuning and also what speed are you loosing position?

[gamble]

These squares were cut around 120ipm if I recall correctly
All the lock nuts and everything is tight. Only thing that I was able to tighten 1/4 turn more is the motors.
Going to see how I can move this thing and drop it off some place to have them look at it

[gamble]

Sorry I should say cut a 2" square not a 1"

[gamble]

Cleaning some of the bearings, haven't gotten to all of them yet.
300 grit sandpaper on the side 1/2" flat rails, then some scotch brite and oil to keep it clean.
Everything on the Y axis and motors seem tight.

Still no luck at all. I cut out a 8" letter C yesterday and the bottom portion was pretty thick and the top was noticeably thinner. I have no idea what's going on with this but I'm getting very annoyed and loosing a lot of income. I probably should have gone with accumove2 setup....grrrrrr

[mazuk9999]

Any luck finding a solution ? Mine is doing the same thing and I can't figure out why

[gamble]

Yes I did! The anti back lash nuts were starting to slip and it took a long time for them to fail eventually.
Replaced them and my first cut was another square and it was perfect!

[radicalrescue]

so hows it work ing now ..

[gamble]

Not a single hiccup since changing them

[radicalrescue]

sweet buddy so that means i need to look for a new job..lol

[radicalrescue]

well i did i took a job running a wardjet 12x14...need money to buy more steel for my table my other want to keep every thing i have made to sale..well keep in touch ..

[gamble]

I need stuff cut on a water jet

[radicalrescue]

yaa they charge a lot $$$$$$ i just cut magnesium .25 x 2'' circles @ 169 ea an his bill was like 220 bucks ..well i guess they have to pay for that bad ass operator ,,,lol...

[gamble]

I need to get a job running a water jet