Beginner Question > Wrench Project > Z-Depth


(Burt Abreu) #1

Hi. Finally got my Nomad up, went through the tutorials and started the wrench project.

Two verry basic questions.

1- is there a way to move the spindle up in the z direction when I am not running a project (ie with Motion)? I wanted to change the collet, nut and cutter to follow the tutorial (I purchased 1/4 and 1/8) and the spindle was far enough down that it wasn’t easy to put the cutter in without raising i a little.

2- what is the best way to set the z-depth. I put down the aluminum composite, then set the z-depth by eye using a piece of paper then set it to zero.

When I ran it the the first time I cut air for a couple loops so the wrench didn’t cut free. I tried again, this time ‘bumping’ the material when I lowered the cutter, and backing off .01mm, but this time it cut too deep, right through the material and into the waste board on the first loop so I stopped it - not sure how much it is supposed to shave off on each pass - or how many passes it makes.

Thanks for answering my baby questions.


(William Adams) #2

1 - you want a tool change operation to happen — this will happen automatically when setting things up for a tool change in Carbide Create or MeshCAM — the wrench project is a bit odd in that it’s provided as a single G-Code file, and one is expected to have the correct endmill loaded.

2 - that’s the standard way to do it if one doesn’t have a Probe. Some folks use feeler gauges. A traditional machinist’s technique for this is to take a rod of known dimension, place it on the reference surface, then lower the endmill (or raise the endmill) until the rod just barely clears it.


(Phil Gorsuch) #3

Hey Burt - good to meet another Nomad user.

I find the paper method works best when I use a lighter grade of paper (thin) and I slide it back and back and forth as I lower down the end mill. I stop when I start having real trouble sliding the paper back and forth (like just about to tear). That usually gets me pretty close.

Rather sounds like your second attempt had some sort of Z zero problem - probably related to exactly what Will mentioned (No explicit tool change at the start of the program). If you had adjusted the end mill in the collet between your two runs that might have done it.


#4

I used to use brass feeler stock (doesn’t damage tooling), but have gone to plastic feeler/shim stock, as I use it for other things and it is inexpensive. Set the tool for light drag and compensate position. 0.50mm plastic is a bit more forgiving than 0.05mm paper.


(mikep) #5

Direct answer to #1: Yes. In CM you want the “Jog” screen. You can move the spindle someplace convenient to do your tool change, etc.


(Burt Abreu) #6

Thanks for all the great ideas and answers. It dawned on me after the fact that I should also break out the rulers and calipers and start getting use to measuring stuff - a little more exactness required than the way I usually do things. :slight_smile:


(Steve) #7

I had the same problem when I got my Nomad about 2 weeks ago. Out of the box, the spindle was so low that it was almost impossible to put an endmill in it…and since absolutely no documentation or instructions come with the machine, it was a pretty frustrating experience.


(Burt Abreu) #8

Not sure of correct etiquette but I will tag a similar beginner question here rather than clogging the forum with all my questions.

I notice the wrench was cut out with a series of passes from top to bottom. When I created my own test project I used your suggestions above and used a brass strip of known thickness and was able to to get the end mill to cut the 1/4" aluminum without touching the wasteboard. The problem is it ‘plunged’ straight through the material to the base and so the torque popped it off the wasteboard as it started to move.

Do I make multiple toolpaths with different depths, or is there a setting somewhere that tells it to cut down in smaller increments?


(William Adams) #9

Cutting in multiple smaller increments is brought about by the depth per pass in the CAM tool being less than the desired feature depth.

Please see: http://docs.carbide3d.com/assembly/carbidecreate/video-tutorials/#toolpaths

and https://wiki.shapeoko.com/index.php/Glossary may be of assistance.


(Phil Gorsuch) #10

Think Will has got it but if your Nomad spindle is pulling the part off the wasteboard and spinning around instead of stalling the spindle I would take a look at a little stronger workholding as I suspect you might run into trouble with parts moving/shifting even with normal operation.