Double Sided Milling and Ver 10 VCP

[johntech]

I have VCarve Pro 10.012 and working on a 2 sided project. I created the front side design with text. To keep things in alignment, I copied the design to the back and made corrections
so the text would appear correct when looking at the back side. Then I flipped the material front to back using the flip icon so I could change the text on the back.
With the Front and Back layers turned on, both appear to be lined up correctly.
The problem, and maybe this is where the error occurs, when I machine the front text then flip it over to the back, same direction as in the software, then mill the text on the back.
When I do the profile cut to cut the part out, the text on the front and on the back do not line up even though it shows aligned in the software. All the measurements for the material are correct.
When I set the home on both sides, it is in the lower left of the material.

I just saw there was a new update for the software today and there was a fix for the 2 sided milling.

Has anyone else ran into this since ver 10 has been released??

John Frankforther

[highpockets]

How are you registering your material ! If you're just resetting XY zero to lower left then you're building in an error.

[johntech]

I have a jig on the spoil board the material fits into so the material registration never changes except front to back.
So I mill the front, flip the board top to bottom and mill the bottom using the same zero as the top. I guess I assumed the software would know the offset when flipping the material.
Also in the preview display, everything is correctly aligned when you rotate the piece.

Any suggestions?

John Frankforther

[highpockets]

It's not in the software, it's in your material setup. With out seeing the jig setup it's hard to say what the problem is....

[johntech]

Well I just updated the software to 10.014, went in and deleted the files for the part I'm making, went back and recreated the files again and now it is cutting properly!!

So it looks like it could have been a software issue since nothing has changed on my setup jig.

John

[highpockets]

Glad it's working.

[johntech]

I have setup a 2 sided design where there is text on the front and the back. The board is 24" x 7 1/2" x 3/4". Yes I have measured the board width and it is exactly 7 1/2" and the settings in VCP 10 are set for 7 1/2". I will be cutting 5 pieces out of this board. The text and the cutout match via the preview screen. I had been using an up cut bit to cut through Baltic Birch plywood. All was well until the wood was splintering when cutting all the way through for the cutout. Yes I should have used a compression bit but I didn't have one. I did have a down cut bit but it was only good for 1/2" depth. So I thought I'd cut the front side profile along with the text on the front then flip it over and cut the text on the back then finish the profile cut on the back. When I pulled the board off, the profile cut from front to back was off by about 1/16"

The jig I am using holds the board firmly at the same location for front and back cuts with the same 0,0 starting point. The preview screen shows that the parts are properly aligned as I copied the front cutout to the back. I have checked and double the settings, the drawings, measured the distance from the edge of the material to the edge of the cutout in the software, front and back, and they are both the same distance. In theory my jig should be no different than using locating pins. If I had a compression bit there would be no problem. Since I don't and have to use this 1/2" down cut bit for now, I need help figuring out why this is happening.

Your Ideas a welcome and appreciated.

John Frankforther

[highpockets]

" In theory my jig should be no different"

Use pins....

[johntech]

" In theory my jig should be no different"

Use pins....

If my jig holds the board in the same orientation as pins would, how would using pins make a difference? I mean if I flip the board in my jig, wouldn't it be the same as flipping it on the pins?
From what I have been reading, the software is supposed to take care of the offset.

My jig is pinned to the spoil board parallel with the X axis. If I set the software to 7.5" and my board wasn't 7.5" I could see that happening. If I move the back profile 1/16" offset from the front things are fine.
I just can't figure out where the 1/16" offset is coming from.

[gkas]

I just can't figure out where the 1/16" offset is coming from.

If I remember correctly, it's actually 1/32" error. The error gets doubled when you flip it. Save yourself some grief and follow John's advise and use pins. If you want a jig... make the jig with pins. A very good example is the folks trying to make the Next Wave chess pieces with a jig, and no pins. Everyone has terrible alignment problems.

[ezurick]

" In theory my jig should be no different"

Use pins....

I agree with Highpockets. I stay away from jigs when doing double sided mainly because of the placement of the pins (I use 1/4" dowels). Once you finish the front side, you remove the material and zero the 1/4" end mill to the spoilboard and drill the holes for the pins on the spoilboard from the bottom side of the vcarve. Then you place the pins in the holes on the material, flip it and secure it to the spoilboard. Once again, you zero ONLY the Z. Then run the jobs for the bottom side. If there was any kind of jig setup, it would have to be removed for the bottom side.

[SteveNelson46]

I use the method in the Vectric two sided Marlin tutorial. It demonstrates the 3 asymmetrical pins method and it has worked perfect for me every time.

https://www.vectric.com/support/tutoria ... _Machining

[ger21]

If my jig holds the board in the same orientation as pins would, how would using pins make a difference?

Pins eliminate a few sources of errors.
Mainly, board width deviation, and dust or chips against the jig.
It's very difficult to cut a piece of wood EXACTLY the with you want it, and it a lot of cases, the width can change from humidity, sometimes rather quickly.

[johntech]

I just can't figure out where the 1/16" offset is coming from.

If I remember correctly, it's actually 1/32" error. The error gets doubled when you flip it. Save yourself some grief and follow John's advise and use pins. If you want a jig... make the jig with pins. A very good example is the folks trying to make the Next Wave chess pieces with a jig, and no pins. Everyone has terrible alignment problems.

I under stand the pinning process as I have watched many videos on it. My jig is pined to the spoilboard so it doesn't move. The board fits in the jig at the same place front and back every time.
I don't have to set X & Y zero since the boards are cut to the same measurement. Yes, I measure every board and use jigs on my table saw to make sure of that. Again from what I have been
reading, the software should make adjustments to compensate for flipping the material. I have contacted Vectric about this and see what they say.

Thank you all for your input.

John Frankforther

[gkas]

Again from what I have been reading, the software should make adjustments to compensate for flipping the material.

They do correct for flip. The error is in your setup.