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Author Topic: "Ugly, Bumpy" Cuts  (Read 3275 times)

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Offline DanZ

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"Ugly, Bumpy" Cuts
« on: June 09, 2012, 07:26:28 AM »
I have (2) troubles...
1) When I cut an "X"...or a "W"...the diagonal cut that begins at the "Near" end of my table and travels "Away" from me..."Up and to the Left"...is "Bumpy"..."wiggly"..."rough". BUT...when the diagonals that are being cut...anywhere else...such as; down to the right...moving toward...etc...are beautiful....all of them. SO...I know the machine can perform.
SO...over the last two months...I've been told two conflicting things...or I just don't get it...
A) "When you set the machine up for the first time...the dimension you entered for that particular direction of travel...is wrong.
SIMPLY...go back in and change it to take a "shorter" path...and it'll be straight. That means it's a Mach Program thing. I can't help you...( the Seller ) Just change that setting. It's not the machine." The trouble there is this...it was the SELLER that "Set it up".
B) "If all the other diagonal cuts are nice looking then I do not think it is something that can be fixed in the software, or you would see the “bumpy” lines on the other sections as well. Have you physically inspected the axis for the section of that move?"
This sounds right. I even called the seller to just tell me..."Hey...your certain motor is going out. I'll ship another".
That would've been great.

Bottom line...I'm actually hoping it was the answer given in "B". That way, I could simply buy a new...something: ...motor...drive...whatever. BUT...if it's just adjusting a dimension in the Program...can you walk me through that?

Here's my second trouble...
I don't know what..."Have you physically inspected the axis for the section of that move?"...means.
I use this machine everyday to make my living. I cut the same things for 100 people.
But...I don't know what that means.
SO...do you think there's something I need to replace on the machine...if so...what are your thoughts?
...or a data entry / change that I need to make in the Mach Program?..if so...can you walk me through it?
Thanks.
Dan

Offline Sam

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Re: "Ugly, Bumpy" Cuts
« Reply #1 on: June 09, 2012, 01:19:20 PM »
Hello Dan,
I am totally lost on the "A" description. I just do not understand what is being explained.

Quote
"If all the other diagonal cuts are nice looking.....you would see the “bumpy” lines on the other sections as well.
I agree. UNLESS....
1. your G-code does not command a straight line, which happens sometimes with segmented code, and the machine is actually moving just as it is told to move.
2. your machine is binding at that particular spot on the axis, which explains your next question-
Quote
I don't know what..."Have you physically inspected the axis for the section of that move?"...means.

Binding can be caused by many things. A worn part(s), a misaligned part(s), a badly designed machine, or many other things.
"Racking" or "twisting" of an axis can cause the axis to "jump" or "stutter" when the binding forces are overcome and the axis tries to "catch up", causing what you describe. This usually happens at the point farthest away from whatever is driving the axis (ball-screw, pulley, etc..). In my opinion, this would indicate a poorly designed machine, or the user is pushing the machine beyond its intended limits.

Because the wiggly cuts are only on part of the table, I doubt the error is in the code, but post it here anyways, just to rule it out.
Do you have a link to the machine you purchased?
First, I would go through the machine and make sure everything is aligned and fitted as is it should be, and inspect components for damage or wear.
« Last Edit: June 09, 2012, 01:25:25 PM by Sam »
"CONFIDENCE: it's the feeling you experience before you fully understand the situation."

Offline DanZ

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Re: "Ugly, Bumpy" Cuts
« Reply #2 on: June 09, 2012, 04:56:03 PM »
Hello Sam
First...it really seems you know what you're talking about.
Next...it's all foreign to me. You may have just explained how to revitalize the dash board electronics to a Porsche. I can't.
That said...I need a mechanic...at my shop.
Next...I think you're on to something with thew "A" description. THAT was told to me buy the Seller.
Accordingly...by "Link" do you mean to the store that I bought it from? If so...here it is...
http://www.vortechcnc.com/
He's not much help...and he thinks I'm a dumb a**. ( I still have that email. )
Sam...I desperately need a real mechanic...like you...and a place to buy parts...or you just bring them and install them...just like when I take my truck to the shop.
I'm still optimistic about my machine. It cuts well everywhere else. BUT...if it goes down...I have no one and no way to fill daily orders.
I hope to find someone. If you can find someone like you...close to me...Central OH...I'm all ears.
Sam, thanks.
Dan