Regions not accurate

[ChrisAlb]

Got a question,
Has anyone ever tried to cut a region to an exact amount, say 5 x 5 and have it come out not exacly 5 x 5??

I've been trying to help David myers. He needs to cut and 8 x 8 and it's coming out about an 1/8 bigger.

I just ran a test on mine, 2 x 2 and it came out 2-1/16 L x 2-1/8 W ???

Just wondering if anyone else has seen the same results.

Thanks
Chris

BTW - just ran a calibration last night and this is the first carve since.

[jlitz]

Got a question,
Has anyone ever tried to cut a region to an exact amount, say 5 x 5 and have it come out not exacly 5 x 5??

I've been trying to help David myers. He needs to cut and 8 x 8 and it's coming out about an 1/8 bigger.

I just ran a test on mine, 2 x 2 and it came out 2-1/16 L x 2-1/8 W ???

Just wondering if anyone else has seen the same results.


When you create a 2 x 2 region, the data stored on the memory card is slightly larger by 10 / 128". There's always a slight feather just outside the desired region. The feather option in Designer controls the interior feather, the outside feather is not controllable from Designer.

As for the variance everyone is seeing, can't explain that beyond tolerance differences between the machines and bits due to wear and/or manufacturing.

[David Myers]

That's comes close to the over size that I'm seeing with my 8"x8"x .300" depth.

Thanks for verifying that. I plan on changing the pattern and resize the region and run another test cut this weekend.

Chris, jlitz, thanks for your help.

David

[DocWheeler]

David and Chris,

Are the sizes exact when you route? If so, carve smaller and route the outside dimension. This will give you straight side-walls also. But yoou knew all of that anyway.

I guess I mainly was curious as to the accuracy of the route compared to the carve on your machines.

[Jeff_Birt]

Chris, are you using the carving bit or cutting bit? Since you said 'cut a region' I was not sure.

[ChrisAlb]

Chris, are you using the carving bit or cutting bit? Since you said 'cut a region' I was not sure.

Hey Jeff,

Using the carving bit to do a (I'm sorry) carved region. The walls are true and straight up and down but the size is definitely off.

From what I've seen this doesn't seem to be a "new" thing. I was just wondering how to advise David. Should we just figure to "down size" the region or should this baby cut a true dimension. I've never had cause to cut a "precise" region before so this is a surprise to me as well.

[Jeff_Birt]

OK, thanks. That is what I needed to know. Were you using any bit optimization, etc?

[ChrisAlb]

OK, thanks. That is what I needed to know. Were you using any bit optimization, etc?

Oh come on now...LOL BEST always.

Actually I've tried both normal and best. Same results. An extra 1/16 on Length and an 1/8 on Width.

[David Myers]

Jeff,

I created the square that was 8" x 8" with a carve region depth of .300".
I did not use bit optimization. I uploaded the pattern to the memory card and picked best. The software/machine asked for the 1/16" carveing bit. After the carve the region measured 8-1/8" x 8-1/8" I did not check the depth.

David

[David Myers]

Doc,

I created a square pattern and clicked carve region. I don't remember or know if there is a route region?

David

[Jeff_Birt]

OK, guys have you tried the same size carve region at different depths? I'm curious if the difference in size is due to the taper of the bit. If so the deeper you go the greater the difference in width.

[David Myers]

Jeff,

No I have not tried to cut various depths. I'm still trying get the dimensions correct to finish the project for a nieghbor which I thought was going to be easy. It's his lumber and it is in limited supply. I'm going to try to add an offset the the drawing and rerun it this weekend.

Chris, sorry to drag you into this!

David

[hotpop]

Chris,

I was wondering if you cut a "drill hole" say 2" dia. if it would be cut elliptical.

If so then the problem is probably mechanical as opposed to a software glitch.

[HighTechOkie]

The dimensions for a carve region define the bit center. Thus if using a 1/16" bit, the region would be larger by the bit diameter. Least that is what Desinger seems to indicate. The extra 1/16" (for a total of 1/8") is probably a result of the taper on the carving bit.

Rob

[David Myers]

Rob,

That was my first thought when I carved the region and it was off about the thickness of the bit at the top in both the x and the y dimensions.

David

[jlitz]

The dimensions for a carve region define the bit center. Thus if using a 1/16" bit, the region would be larger by the bit diameter. Least that is what Desinger seems to indicate. The extra 1/16" (for a total of 1/8") is probably a result of the taper on the carving bit.

Rob

The bit taper and using the carving coordinates as the bit center covers most of the difference. After measuring a couple region carved samples @ 1/2" deep with a caliper, the distance at the bottom is narrower than top. This is to be expected when using a tapered bit.

The slight exterior feather which is added to all carved regions also adds a very small amount to the top measurement. Watch the carving. It'll take a few very shallow passes advancing forward and then plunge to the desired depth. The first few passes are outside the region and slightly further out then the taper of the bit on the plunge, at least on relatively shallow region carving.

Now if there's a difference in the X vs. Y distance, then there's some other unrelated issue.