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Re: accuracy is off
« on: June 06, 2018, 01:09:17 PM »
HELP, I have a wood CNC 48X48 from CNC routerparts, had it for about 5 years. All of a sudden I am getting errors of 1/16" too large on inside of a 2" pocket cut and minus 1/8" on outside diameter of 12 1/2" cut.

went through the whole machine and am very certain its not mechanical. Is it in Mach3? or could it be Vcarve pro?

Thanks for any help you can offer
Re: Re: accuracy is off
« Reply #1 on: June 06, 2018, 01:58:02 PM »
Did you measure your tooling?  I had this once, was using sharpened 1/4" two flute bits.  So the bit was no longer 1/4" wide.  However I think your problems are opposite that.

Does this machine have timing belts?  I know I get stretchy ones before they break and that messes things up.  Slop in the rack and pinion?

Could be VCarve pro if you picked the wrong tool in the program.
Re: accuracy is off
« Reply #2 on: June 06, 2018, 03:31:47 PM »
Hi; Thanks for the reply, double checked the machine, and everything is tight. Just tried axis calibration and its spot on. Has to be either Vcarve Pro or Mach3

my tool is exactly 1/4 end mill, tool offset is set to 0
Re: accuracy is off
« Reply #3 on: June 09, 2018, 02:23:11 PM »
Well I am about ready to commit harry carry, there is nothing more frustrating than having aCNC machine and not being able to use it.

I am 99.9%  sure the problem is Mach3 but dont know how to fix it, I am still getting 2 1/16" ID on a pocket cut when I clearly asked for 2"

my out side dia. is supposed to be 12  1/2" well in Y axis its 12  1/2 but in X its 12  3/8" I know its not my machine I spent close to three

days going over the whole thing, I damn near tore the whole thing apart and put it back together again, its as tight as a frogs ass.

 I have my steps per in. set right, what else could it be?? HELP please!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

Offline Tweakie.CNC

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Re: accuracy is off
« Reply #4 on: June 10, 2018, 02:27:45 AM »
Hi Mike,

If you post (or send me) a copy of your problem Gcode I will run it here and see if I can find the problem.

Tweakie.
Success consists of going from failure to failure without loss of enthusiasm.  Winston Churchill.

Offline ger21

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Re: Re: accuracy is off
« Reply #5 on: June 10, 2018, 09:35:10 AM »
Quote
I am 99.9%  sure the problem is Mach3

I'm 99.9% sure the problem is NOT Mach3.
These questions come up all the time. The issue is almost always deflection, most often in the machine. Tool size can also be an issue, but would be much more minor.
Gerry

2010 Screenset
http://www.thecncwoodworker.com/2010.html

JointCAM Dovetail and Box Joint software
http://www.g-forcecnc.com/jointcam.html
Re: accuracy is off
« Reply #6 on: June 10, 2018, 12:20:48 PM »
Hi Tweakie, Here is the xml file
Re: accuracy is off
« Reply #7 on: June 10, 2018, 04:06:32 PM »
to ger21, if my machine was deflecting 1/8 " would it not show up in this test?
Re: accuracy is off
« Reply #8 on: June 10, 2018, 04:10:41 PM »
neednto explain the pictures , the 1/4 steel pin fits perfectly into the kerf, the roundness of the cutouts is within .0025. the hole on the left is supposed to be 3" the plug on the right is supposed to be 3"

Offline ger21

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Re: Re: accuracy is off
« Reply #9 on: June 10, 2018, 06:31:14 PM »
Can you post the g-code?
Gerry

2010 Screenset
http://www.thecncwoodworker.com/2010.html

JointCAM Dovetail and Box Joint software
http://www.g-forcecnc.com/jointcam.html