Help on VCarve

Hi all,

I'm having an issue with VCarve and inaccurate cuts. I think it has to do with outside and inside vectors. I'm hoping someone has an idea why.

I'm cutting plugs that will go into PVC to support the drive mechanisms of my dual yokes. I'll break it down in order, with the pic as reference:

http://i274.photobucket.com/albums/j...M/8546d34b.jpg

First I run the profile code to cut the center hole, and the curved hole for the cabling. The center hole is supposed to be 13mm in order to accommodate my 1/2 inch steel rod with a little play. The hole is too small though, barely.

Then I run the pocket code to route a pocket for the bearing that will fit in the hole. That is also just barely too small, even though I give it a few 10th's of a mm for space.

All these cuts so far are inside cuts. When I run an outside cut to cut the disk out, the size is perfect. It fits in the PVC like a glove.

I also just figured out why after about 15 minutes of running, my CNC would head off on it's own... it seems to be tied to the screen saver on the computer... that's why I use scrap to practice...

Thanks,

Warren

Not to sure about the CNC difficulties but why not cut then sand (drum sander) to make it the perfect fit. Also when using your CNC machine turn off your screen saver and screen if you are worried about your screen being damaged. If you are using a monitor built within the last 10 years anyway you should have no difficulty with burn in (never requiring a screen saver).

Also remember you are working with wood. The size of the sawdust (especially for the MDF in the photo) is about 1mm+ in size so you really can't go down to a 1/10mm the wood particles are bigger. Another way to look at this is the size of your bushing. BTW I would use a UHMW (Ultra High Molecular Weight) Poly. It can be worked like wood (high speed on your tools for clean working). It's super slippery (self lubricating) and quiet... You can find it at most woodworking tool supply stores as it's used for router surfaces and the like.

Yoke Collar (Bushing)
http://i416.photobucket.com/albums/p...YokeCollar.jpg

Plastics Retailer that sells UHMW plastic.
http://www.usplastic.com/catalog/def...arentcatid=795

Hope that helps a bit?

Warren,

This is a strange problem !

You did -not- make a mistake with a difference between inserted mill and what you told the software about it, because external milling is right.

Although very unlikely could it be a mistake with the milling direction (clockwise for internal and counter clockwise for external) ? The mill bites better in the material when they run against eache other.

Mistake in the dxf file (double lines?).

If you wish you can place the dxf here or send it private for a check.

Hessel Oosten, The Netherlands

Thanks guys,
I was going to work on it today but my trip is back on so I need to pack. I'll delve more into it this weekend. I'm fairly certain I'm doing things right.

More to follow. Thanks again,

Warren

Hi Warren, I'm happy to have a look at your VCarve file too as long as it was created in version 5.5 (update), I can't open anything created in version 5. I agree the screen saver should be turned off and don't use any other programs whilst Mach 3 or any CNC driver software is working. They are better off to work on their own without interruption.

Cheers, Gwyn

Thanks Gwyn,

I will admit, that screensaver was driving me crazy. I never thought about it, and anything I had done before was done within 15 min (ss setting). This time, just as it was finishing up..... zooommm off it goes wreaking havoc on my work.

Well, it's late, and I'm up real early in the morning,

More to follow this weekend, and I'll shoot you my VCarve file then too Gwynn, thanks again everyone.

OK,

well it has been a busy weekend but I have figured out the problem. I took some time while sitting in airports to read the VCarve manual a little closer. In doing that, I discovered offsets and ramping. I knew about them, but I was not totally up on 'em.

The issue all along was that I was using a positive number for the offset, so I was actually going the wrong way. In the manual it discusses using offsets to compensate for male-female parts (which was exactly what I was trying to do).

Anyway, figured it out, and made some perfect cuts! I also added ramping and now I don't have that initial bore-hole into the material.

I'm psyched! I took pictures, but I'll post them tomorrow or the day after when I finish up my yoke project.

Thanks again for all your help.

Warren

Hmmm,

Thanks Warren for the feedback !

I have this option too in my software, but never used it....
Good to know this usefull possibility.

Hessel