If I Want To Do An Air Pass?

[shilala]

A lot of times I'd like to do an air pass, just to feel safe. It'd save me lots of wrecked projects.
My question is this...
Can I zero my z with my plate, then just add an inch to the z, run the air pass a bit just to see if everything is okay, then stop the file, subtract the inch from the z, reload the file and start my project?
I can see where adding an inch might be trouble on thick material, but I usually work with 3/4" lumber. Sometimes 1". I don't think I'd ever run out my z by adding an inch. On top of that, I just want to see a little bit of the file run, just to make sure it's doing what it should.

I hope this makes sense.
Thanks!!!

[bleeth]

Zero your bit to material.
When done you should be 1" above material if this is what you have as safe z.
Type zz. This will set your current height as Z zero.

You can then run your file and look it over as it cuts as long as you have no cuts at or below 1" down or too high for your z movement.

When done, run your Z zeroing routine again and then run your file.

[bearcat]

I've used 3D Offset option in the Part file load fill in sheet to do air cuts.

Ed

[myxpykalix]

I do like Dave suggests mostly and especially if i'm working on someone else's material i'd rather be safe then sorry.

Just keep in mind that you want to compensate for the depth of cut on your first pass because if you set your Z at 1" above material and you have a .25" depth of cut on your first pass, the bit will be .75" above the material on your aircut.

[bobmoore]

I just put an appropriate thickness shim under the plate for the z zero. Run the air cut and then rezero to the material top.
Bob

[jerry_stanek]

On some jobs that are going to be close like when I have to cut out pre printed material I will roll out some news print and use my plotter pens to cut on the line it draws the cut out and I can see where I have to make adjustments.

[srwtlc]

Easiest way to do an air cut is like Ed stated. Raise your z axis up to account for the depth of cut, load part file, choose 3D offset and run.

[dlcw]

I've got a 1" thick piece of wood (for 3/4" project material). I place the 1" piece of wood on top of the project material and Z-zero to that. Then I can do an air cut. When done, Z-zero to the top of project material and go.

[shilala]

I've used 3D Offset option in the Part file load fill in sheet to do air cuts.

Ed


Easiest way to do an air cut is like Ed stated. Raise your z axis up to account for the depth of cut, load part file, choose 3D offset and run.
I've tried this a few times now.
I'm not sure if I'm not understanding what to do on the fill in sheet or what. I've stared at these two posts for a long time and still can't seem to pick up what you guys are laying down.
Could you possibly break it down step-by-step for me? It'd be greatly appreciated.

[srwtlc]

Scott,

It goes like this.... Say you have your material/blank secured on the table and the Z axis set to either the material or table surface (according to your file), the XY set to 0,0 at the intended location (generally at lower left or center of the material/blank, but could be any corner as preferred and set in your file/drawing). At this point, your ready to cut your part if desired or run an air cut. To do an air cut, raise the Z axis with the keypad to be higher than what your depth of cut will be (if the total depth of cut is 0.75", raise the Z axis more than that). Load your file and in the fill-in sheet, drop down and select 3D offset and run the file from there. When it's done, if all is what you wanted, you can load the file again and run with no offset to cut the part. Doing it this way, there is no need to zero the Z axis off a thicker block first to run an air cut or raise it and then change the value etc., just set up as normal and then raise to allow for clearance and then run it in 3D offset. When you're done, you're ready to cut normally.

The other way using the same 3D offset option would be if you don't have any material on the table and just want to run a test, just raise the Z axis enough to clear anything on the table and do a ZZ to zero the Z axis there and then run the file in 3D offset. You could also just raise the Z some and ZZ to set Z axis there and run with no offset if your cut depth in the file doesn't exceed the distance between the Z axis and the table and the path is clear.

One thing that you need to be sure of when running a file in 3D offset is that you have enough Z axis height travel left to allow the Z to raise to the Safe Z and any rapids that are in your file, otherwise the Z axis may 'top out'.

The offset option in the fill-in sheet....

[curtiss]

Z-Zero to the top of a piece of scrap on top of the work surface, say 3/4 inch thick.

Run the air pass. This will show you what will happen as long as your max depth of cut is .... less than.... 3/4 inch.

[khaos]

I just put an appropriate thickness shim under the plate for the z zero. Run the air cut and then rezero to the material top.
Bob

These simple but effective answers often serve to remind me of how hard I make some ****!!!

[srwtlc]

Not that any of the various ways mentioned are wrong, but why bother with a shim of the right thickness and re-z zeroing when a simple selection of the 3D offset (after raising up the Z) will work. Once done and satisfied with the air cut, just run as normal with no offset.

No need to over think it. ;) In the fill-in sheet, 'No Offset', cut as normal XYZ. '2D Offset', cut from the current XY location as 0,0. 'Offset 3D' cut from current location XYZ as 0,0,0.

[scottp55]

"Offset from current location" that explains why after doing c2 and then running table surfacer without doing a c3 my desktop tried to push off my backwall and put itself on the floor. No damage but the desktop is a strong little sucker and it was a few seconds between "What is it DOING!" to hitting the spacebar. Thanks. My first of many stupid moves but I couldn't figure it out.

[shilala]

Thank You, Scott. That works , and it's super simple. No extra steps. That's what I was looking for. :)