Machsupport Forum

Mach Discussion => General Mach Discussion => Topic started by: Fountaine on June 09, 2012, 07:25:40 PM

Title: Inconsistent cut
Post by: Fountaine on June 09, 2012, 07:25:40 PM

I am new but learning.  I made a sign with just text "Chet's Shop".

The first time I ran it it came out perfect.  

The 2nd time I did not get a full Z plunge on Chet and on the apostrophe and the s the Z did not drop at all. I stopped it here. 

The 3rd time I ran it the Z on Chet was the same - thin, the apostrophe did not drop the Z but it did on the s and the s and shop received a full z drop. (not thin like on Chet) Also on this run, hop in shop did not pick up the Z to the zero. The router bit scraped on the X axis on the hop but not the S.

Anybody know of a reason I would get 3 different cuts on one G Code?

Title: Re: Inconsistent cut
Post by: Hood on June 10, 2012, 05:36:32 AM

Sounds like either your material is uneven or your Z axis is stalling and losing steps.
Try reducing the velocity and acceleration by half for the Z and see if its any better.
Hood

Title: Re: Inconsistent cut
Post by: Fountaine on June 10, 2012, 07:38:43 AM

Thanks. I have the Z at 4".  The material is uneven but where it cut thin was the high side with a belly in the middle.  Using plywood for my testing. The belly part was where it cut the deepest on the 2nd cut.  I will try again today and post the results.

Quick question: In the future so my Z zero does not drag again, couldn't I set my z zero at 1/4" above the material and add a 1/4" to the plunge?

Title: Re: Inconsistent cut
Post by: Hood on June 10, 2012, 07:52:41 AM

Quote from: Fountaine on June 10, 2012, 07:38:43 AM

Quick question: In the future so my Z zero does not drag again, couldn't I set my z zero at 1/4" above the material and add a 1/4" to the plunge?

You could but the normal practice would be to have a higher retract in between cuts and still have the material top as Z0.
Hood

Title: Re: Inconsistent cut
Post by: Fountaine on June 10, 2012, 10:48:16 AM

I found my problem.......I just cut the design again and it did something totally different. The 2nd time it was perfect.
My problem was the wire connectors. If I grab the wires, at the connector and wiggle it the motor will chatter.  I zip tied the wire so there is no change of stress on it as it moves and it runs perfect.  I found my A motor does the same.

I am going to hard wire all motors to eliminate the potential problem.

Now back to your suggestion.....I am not sure how to set the retract.

Title: Re: Inconsistent cut
Post by: Hood on June 10, 2012, 11:21:30 AM

Depends where you are getting the code from, if CAM then you would normally have a safe Z or clearance Z value to enter
Hood

Title: Re: Inconsistent cut
Post by: Fountaine on June 10, 2012, 12:11:52 PM

I will look.  You have been a great help.

Thanks. Bob