touch plate how to

[janz]

My problem is when I cut a large relief and use the virtual to detect surface of material all is
good. Use a 1/4 end mill. Now once the rough cut is done the finish cut requires a 1/8 tapered
ball nose, so I change the bit and load the new finish g code, how the hec do I detect the surface of the
material when most of the surface has been hogged out ! Probably something simple hopefully.

[sk8nmike]

I always leave enough room on the corners for the touch plate to sit.

[janz]

What do you do for the center

[Rando]

If you're doing a manual touch-off with the plate, you do not have to do that at the origin X0Y0; you can do that anywhere you want. You don't even have to start the CNC machine from X0Y0...as long as it's properly set for your project, it will go there first....just don't hit your clamps on the way in .

Another possibility is to clamp a piece of the same thickness material somewhere else on the bed, and use THAT with the touchplate to make your Z0 touch-offs.

Regards,

Thom

[sk8nmike]

I don't do the Center once I have a crave started, just one corner

[janz]

Got it, did the corner touch it was the center that threw me. So on the finish cut you
would not use the virtual just use the one corner touch.

[Rando]

Got it, did the corner touch it was the center that threw me. So on the finish cut you
would not use the virtual just use the one corner touch.

Hmmmm....for some reason I thought you can re-touch Z0 and then tell it to use the use the previous virtual-Z settings (without re-gathering the five points).

Given how much Vectric relies on those large-area clearance toolpaths, I can't imagine how it would be possible to change bits and have it work properly if you couldn't just re-use the previous Virtual-Z settings for the next (finish) cut.

Regards,

Thom

[janz]

That was the big problem for me is after roughing with 1/4" endmill and then changing bit
to a 1/8" tapered ball nose. Thinking about it why even use virtual for roughing because if
you can't use it for finish the final z will be different although my results were ok. probably
make a difference if machining aircraft parts.

[Rando]

Yeah, we metal geeks don't use virtual-Z, we square the material

[scubanimal]

I'm sorry I don't recall exactly how, given I'm away from the shop, but I believe you can save the virtual settings, and restore them. I had always assumed that meant a touchplate zeroing would just reset the plane for that x,y position. Since the largest cut it typically the cut-out profile I would load that gcode file, do a virtual plane, and then load up the file I need and use the touch plate.

I'm guessing this would not be too hard to test, if someone had a curved board, then do a simple v-bit box/ "X" after going thru the above process, and see if it works. By zeroing to the cutout a lateral x would show pretty clearly. Though may damage the wood or worse depending on how big the curve snap the bit.

Anybody with a warped & twisted scrape should be able to do a test for us. .... just a thought.