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LongIslandWood
08-17-2014, 09:28 AM
I've had my pro 4896 running for a few months now and have been very happy with it so far. I've had problems here and there but was able to fix them fairly easily. I have a problem I just noticed and could use some help. I was cutting 8 identical rectangles and they didn't come out identical. They varied in width by 1/8". They should have all been 6-1/2" and some were 6-7/16 and some were 6-9/16. I need to fix this.

I have the plug n play nema 34 from cnc router parts.
Using a hitachi router with precise bits collet

Any help would be great. Thanks

vtx1029
08-17-2014, 09:35 AM
Are all the squares actually squares? Meaning are both legs the same size?

Did you actually check the move distance of each axis? Its pretty easy to do in mach 3

Did you put loctite on the jam screw for everything?

Were these cuts a single full depth profile cut or multi, if multi were the sides stair stepped.

How fast were you cutting them feed rate and DOC?

ger21
08-17-2014, 11:39 AM
When you finished, did you check to see if the machine had lost position?

nlancaster
08-17-2014, 12:32 PM
I second the loctite on the set screws. This appears to be a common oversight on the CRP machines, without locktite on the stepper belt pulley they come loose and you lose position quite easily.

graffix11
08-17-2014, 12:36 PM
Try one thing at a time.
Where did I put those steps - YouTube (http://youtu.be/4tI0rfTAb-g?list=PLSBDMgE5ym9fGZsGG6MBLR_zN6SLIGrb5)

nlancaster
08-17-2014, 04:50 PM
graffix, exactly. Only reason I backed up the suggestion on the pulleys because its a common issue with the CRP machines.

LongIslandWood
08-21-2014, 05:48 PM
Thanks for the replies...

Are all the squares actually squares? Meaning are both legs the same size?

Yes

Did you actually check the move distance of each axis? Its pretty easy to do in mach 3

No, can you tell me how to do this? Or show me a place that explains it? Thanks

Did you put loctite on the jam screw for everything?

Yes I used loctite on almost everything

Were these cuts a single full depth profile cut or multi, if multi were the sides stair stepped.

They were a single full depth cut in 1/2" plywood with an amana 1/4" compression bit

How fast were you cutting them feed rate and DOC?

35 imp conventional


Thanks again, I'm going to do some trouble shooting tonight or tomorrow

ger21
08-21-2014, 05:55 PM
When you finished, did you check to see if the machine had lost position?..

LongIslandWood
08-21-2014, 06:00 PM
No, not sure how to do that.

MobiusConcepts
08-21-2014, 06:17 PM
When you start your job, you set your X and Y (and Z) to a certain point and zero them. This point may be the center of your material, or a corner, etc. This is your job zero.

Once you have run through your cut file, send the machine back to the job zero by typing G0 X0 Y0 in the MDI (if it didn't go there at the end of the file on its own). If the machine doesn't return to the exact spot you set at the beginning, you have lost steps.

vtx1029
08-21-2014, 11:27 PM
Thanks for the replies...

Are all the squares actually squares? Meaning are both legs the same size?

Yes

Did you actually check the move distance of each axis? Its pretty easy to do in mach 3

No, can you tell me how to do this? Or show me a place that explains it? Thanks

Did you put loctite on the jam screw for everything?

Yes I used loctite on almost everything

Were these cuts a single full depth profile cut or multi, if multi were the sides stair stepped.

They were a single full depth cut in 1/2" plywood with an amana 1/4" compression bit

How fast were you cutting them feed rate and DOC?

35 imp conventional


Thanks again, I'm going to do some trouble shooting tonight or tomorrow

This video explains how to calibrate the steps per inch.

https://www.youtube.com/watch?v=XkO5tc-jSxw

ahren
08-21-2014, 11:50 PM
LongIslandWood,

Looks like you are getting some good advice here, but feel free to contact us directly tomorrow if you'd like some assistance. I doubt your issue is a steps/inch setting problem -- if it was, all of your rectangles would likely be off the same way. My guess is that something is loose mechanically. We'd be happy to walk through some things with you to try and sort out the issue more quickly.

Best regards,

Ahren
CNCRouterParts (http://www.cncrouterparts.com)