Trouble with a rectangle

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howeclan
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Trouble with a rectangle

Post by howeclan »

Did a search but could not locate anything that explains what I may be missing while programing a rectangle and have it cut correct in a squared off fashion

When I draw a rectangle like for a camper window it looks correct.
I then build the tool path and preview it. it looks correct in aspire.

When I send the code to Mach 3 to cut, it will make the windows with large curves in the corners and will not completely close the rectangle. It is like the V-bit comes out early. This also happens when the doors are done also

I am using a profile tool path and have also tried a v-carve, but the v-carve tries to clean out the complete inside of the window.
Small windows have come out correct, but when I have to make them larger they mess up.

I also have straight lines wrong also V-bit looks like it ramps out early.

I just know it is something simple, but I am at a loss

can anyone help??

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FixitMike
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Re: Trouble with a rectangle

Post by FixitMike »

Check that you have selected the correct post processor. The wrong one can have weird effects.
Good judgement comes from experience.
Experience comes from bad judgement.

howeclan
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Re: Trouble with a rectangle

Post by howeclan »

I am using the same one I always use.

Mach 2/3 Arcs (inch) (*.txt)

howeclan
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Re: Trouble with a rectangle

Post by howeclan »

This is the issue.
One good rectangle and the rest are bad.
They are all programed the same. Just different sizes.
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Rcnewcomb
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Re: Trouble with a rectangle

Post by Rcnewcomb »

Increase your acceleration or lower your feedrate.

See this thread on CNCzone.com: HELP Mach3 strange corner radius issue happening
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howeclan
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Re: Trouble with a rectangle

Post by howeclan »

I will give that a shot. The Thread did make sense.

4DThinker
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Re: Trouble with a rectangle

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ger21
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Re: Trouble with a rectangle

Post by ger21 »

In General Config, check "Exact Stop on Angles >" and set it to 89.
Gerry - http://www.thecncwoodworker.com

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martin54
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Re: Trouble with a rectangle

Post by martin54 »

ger21 wrote:In General Config, check "Exact Stop on Angles >" and set it to 89.
Gerry I know you are an expert with mach3 so is that recommendation something that has changed over the years? Can't remember what figure it is set at but pretty sure my machine is set a lot lower than angles less than 89 degrees which was something I read on the mach support forum a few years ago :lol: :lol:

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Re: Trouble with a rectangle

Post by ger21 »

It really depends on what you are doing. There is no "one size fits all" setting.

But if you're cutting mostly 90° corners, than the 89° settings works well.
Gerry - http://www.thecncwoodworker.com

howeclan
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Re: Trouble with a rectangle

Post by howeclan »

Thanks for all the Help.

I will try all suggestions tonight after work.

howeclan
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Re: Trouble with a rectangle

Post by howeclan »

Slowing down the feed rate corrected it all.
Never thought that would make that big of a difference.

Thanks everyone for the help

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Re: Trouble with a rectangle

Post by ger21 »

Slowing down is probably the least desirable fix.
Increasing acceleration is the better option, if your machine is capable of it.
Second best option is adjusting the CV controls.

Slowing down results in shorter tool life, and longer cut times.
Gerry - http://www.thecncwoodworker.com

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