prs alpha help please

[jlechner]

Just got my new 48 x 96 prs alpha up and running. Wondering if anyone has any input on 3-d air cutting? to previw parts. Im nervous as to what to set the z to so I do not crash the bit into the table. Im trying to cut vacuum hold down file. Any " start up" help would be greatly appreciated!! Thanks in advance looking forward to joing the shop-bot world!

[gc3]

run the file without the bit...

[bcondon]

I air cut a lot because my materials are sometimes close in size to the design.

I design so the top of the part is Z=0. I run c2 and go to the top of the part.

I look through the file with notepad and find my most negative Z. I lift the table to the negative z plus about an inch.

SO if the most negative z is -3.25,
1. I run c2 to set z=0 on top of the part
2. I would move z past the max plus an inch so I would do a MZ 4.25
which is the absolute of -3.25 + 1 inch for good luck
3. Enter ZZ (so your Z=0 location is about an inch higher than the max depth
of the part
4. Now air cut the part and the bit should never touch the material.

I tend to air cut the outside border of the part to make sure the bit will cut the board completely and not have any gaps (and not hit those pesky screws/clamps)

Good luck!

Bob

[Brian Harnett]

For stuff that is real close in size I sometimes run a keychain laser pointer in the router collet for preview. Did it a lot when I first got the machine.

Also made a spring loaded pencil to outline parts.

[scottp55]

The very first file I ran I THOUGHT I knew what I was doing, and promptly topped the machine out before it then proceeded to cut 1/2" into my spoilboard.
SO I found my deepest cut in Vectric,added a half an inch and found a piece of wood thicker than that. Laid it on my spoilboard and zeroed to the top of that.
Flintstone technology, BUT it worked until I learned more.

[myxpykalix]

One thing you could do is to set your material on the table,
mount your bit,
Z zero to the top of your material
then remove your material and run the file
the most important tip:
HOLD THE EMERGENCY STOP IN YOUR HAND FOR THE FIRST FEW TIMES!:eek:

Or you could do this
set your material on the table,
mount your bit,
Z zero to the top of your material
The bit will usually retract to 1" above your material and wait for you to run the file
At that point i would RE Zero my Z to that 1" position above the material. That means it will run the file at a 1" height above the top of your material and you can get a better sense of whether it is going ot stay within the perimeter of your material.

Then if you're satisfied go ahead and Re Zero it to the top of your material and run the file for real....oh and say a prayer first!:eek:

[srwtlc]

Offset 2D or 3D treats the current location of the tool as 0.000" for the xy and for 3D offset, the z also.

So, for example, if your tool is zeroed on the table and is currently sitting at 1" (above the table) for the z and your total cut depth is 0.375" (you know this by the file you designed and toolpathed in PW/VCP etc.), then you're safe to run at the current location because 3D offset will consider the start location for the z as 0 and the furthest down it will go is 0.375 (0.625" above the table). You do need to take into account what your safe z moves in the file will be so that you don't top out. Say that the first line of the file is a JZ,1.00". The tool will move from the current location, 1" higher (which following the above example, will acually be 2").