Restarting a carve after moving project off cnc

[rlanpheare]

I have searched everything I possibly can and I am sure there is content on this but I must not be searching the correct things. If I were to start a vcarve project, stop the project and then remove the product off of the cnc, how would I ensure I can restart the project with precise zeroing/positioning on the cnc?

[garylmast]

I had to do that once. I was using center of material for 0,0,0 point, so what I did was drill 4 reference points (2 for x and 2 for y) at each side of the material then wrote down the distance to center. If your model is not covering the center point, you can drill one there instead.

Gary

[TReischl]

It pays to actually locate material on a cnc by using things like references edges, or pins, etc.

If a person gets in the habit of doing that (as many do) it makes it much easier to put a piece back in a precise position.

I use a vise for a lot of the stuff I do, so the back jaw of the vise is one reference edge. I either use a swivel stop which is fastened to the back jaw of the vise or a stop located out on the table. Pretty standard stuff for machinists and tool makers.

[jfederer]

There are 2 parts to the answer. First, you need to reference the part. For that, I use dowel pins, just as if I was doing a 2-sided project. Second, you need to reset the X0Y0. For that, I insert a 15 degree v-bit and make a small mark on the X0Y0 location before removing the work piece and shutting off the machine. Then at the next session I put the piece back on, using the dowels for reference. Then I manually jog the spindle, with that same V-bit mounted, until it is as close to the mark as I can get it using a fine jog. Reset the X0Y0, and you're back where you were before taking your break. It may not be accurate to within the resolution of your machine, but it'll probably be with 0.1 mm or a few thousandths of an inch.

[martin54]

There are 2 parts to the answer. First, you need to reference the part. For that, I use dowel pins, just as if I was doing a 2-sided project. Second, you need to reset the X0Y0. For that, I insert a 15 degree v-bit and make a small mark on the X0Y0 location before removing the work piece and shutting off the machine. Then at the next session I put the piece back on, using the dowels for reference. Then I manually jog the spindle, with that same V-bit mounted, until it is as close to the mark as I can get it using a fine jog. Reset the X0Y0, and you're back where you were before taking your break. It may not be accurate to within the resolution of your machine, but it'll probably be with 0.1 mm or a few thousandths of an inch.

You can actually forget about the resetting your X0 Y0 position if you cut the dowel holes in the spoilboard when you come back from your break & it should be closer than 0.1mm , I often do this with 2 sided jobs as I don't always have time to cut both sides on the same day

Pick a spot where you think X0 Y0 should be & set them as X0Y0, from that point run the dowel toolpath for the spoilboard, pop your dowels in & locate your workpiece on the dowels, secure workpiece & your good to go

[Real Mercier]

Just another suggestion. If I know I will move the part, besides pins and/or edges, I will zero the X and Y to the table (Lower left). Then move the spindle to my desired start point. Write the X and Y position on a masking tape and stick that to the side of the machine and set the zero position. Then If something happens, I'll reset the X and Y to the table and then move to my original start point and reset the original zero. No more guessing.
Hope that helps.

Real Mercier

[jfederer]

Martin, that's even better. Thanks for pointing that out. Of course you only need relative references, and the dowel holes provide that. KISS!

[Jan.vanderlinden]

I bought a carpenters square and mounted to the bed of my machine.
Used a dial indicator to align the X and Y.
Perfect repeatability every time.

[TReischl]

Or. . . .

I also use a cheap chinese microscrope mounted alongside the spindle. I run Mach3, not sure if other control software allows the use of something like this or not? Anyway, it was simple to set up. Moved out onto a scrap piece, set X0Y0, milled a hole. Then jogged the machine over until the microscope view was centered over the hole. Noted the coordinate in X and Y and used those for the offsets.

In operation I just jog over to where I want the X0Y0 visible in the microscope view, hit the icon to set zero, and I am all done. Note that I also use Ger21's most excellent ScreenSet which is set up to do this sort of thing. That was another $20, but it is way more useful than the standard Mach screens.

It is also useful for tramming a piece.

The whole thing cost about $18 US.

[wb9tpg]

You can actually forget about the resetting your X0 Y0 position if you cut the dowel holes in the spoilboard when you come back from your break & it should be closer than 0.1mm , I often do this with 2 sided jobs as I don't always have time to cut both sides on the same day

Pick a spot where you think X0 Y0 should be & set them as X0Y0, from that point run the dowel toolpath for the spoilboard, pop your dowels in & locate your workpiece on the dowels, secure workpiece & your good to go

I use this exact method as well. It works great