CNC seems to be plunging Z axis a little bit too far?


(Louis ) #1

Im a total noob to CNC so please bear with me…

I did both tutorials great, i had an issue with my 3D model, which i fixed. But now I am trying to NOT destroy this new machine immediately.

It just seems the Z is plunging way too far and cutting rough, any ideas for how to change this / make sure im not killing this thing?

EDIT: aaaand now im getting limit switch issues…contacting support, damn.


(Mark Walker) #3

Louis, make sure you don’t just go with any software’s default depth of cut, feeds and speeds. Sanity check against the chart at http://carbide3d.com/nomad/feedandspeed/ . Tell us more about where you are seeing it go too deep too fast. How deep, how fast, with what software, what endmill and what material?


(William Adams) #4

Yeah, I realized that I was in the Nomad section, edited my reply, then decided to delete it.

Still learning my way around the Nomad, and while my post was an interesting highlight of the differences between the twain, it wasn’t helpful, hence the deletion.


(Louis ) #5

The #102 Flat end mill. Here is a screenshot of what i used, and below is a pic of the result (the spindle got caught in aluminum and stopped momentarily then started again, now i have a limit switch problem.)

I guess to a beginner the screen with all those settings is so intimidating!

Pic of settings: http://imgur.com/a/PA4Ll

Pic of result: http://imgur.com/a/FxIw8

I just wanted to make a little sign, the outline gave me trouble. The circled part is where it got stuck / skipped over the mtl. Really hope i didnt really break my machine!


(William Adams) #6

To make a sign, you may find Carbide Create a bit easier to start with (I find MeshCAM overwhelming as well).

The nice thing is, mastery of the concepts there will (should?) transfer to MeshCAM — I’m assuming the terminology is consistent between the twain — does anyone know of any discrepancies? Hmm, we had a special set of notes on the Glossary for MakerCAM — guess we need to do the same for Carbide Create/MeshCAM… http://www.shapeoko.com/wiki/index.php/Glossary

That latter in particular I want to work up as an in-depth tutorial which leaves nothing unsaid — please let me know if there’re any potential points of improvement, things left un-addressed, or any errors.


(Louis ) #7

Awesome, i will take a look shortly. I am a drafter / designer, so i mostly will be importing 3D CAD models, i was surprised at the level of difficulty in this!


(Mark Walker) #8

Yep. Too fast and too deep for aluminum. Depth per pass set to 0.01". Feed 8 in/min. Plunge 1 in/min. RPM 9200. Even that slow some of the plunges on my machine caused the spindle to slow audibly. Fusion 360 allows “ramping” to avoid plunging straight down, but MeshCAM is way easier to use and doesn’t have it, so when I’m using MeshCAM, I sometimes set the plunge even slower.


(Mark Walker) #9

Also, you can fix the endstop complaint from Grbl by turning off the machine and manually pushing it away from the endstops on all three axes and turning it back on again.

My Nomad came with a piece of paper with that little troubleshooting tip on it.


(Louis ) #10

So the other settings should be left alone? this is the result of using the “autotoolpath wizard” or whatever the option was called. Thanks for the help!


(Louis ) #11

Pushing the head away from the end? Its quite difficult to manually push, dont wanna over do it!


(Adam Albert) #12

Did you turn off your Nomad? When the power is on, the motors are engaged and try to hold their position.


(Louis ) #13

Yep was able to fix the limit switch issue, awesome thanks guys!

Just nervous to try another go at milling…I always apparently dig to far in. So basically i leave all other settings and just use the speeds and feeds chart to edit those options?


(Mark Walker) #14

Make sure the machine is off so the motors aren’t holding it and give it a good push aligned with the axis so you aren’t twisting or torquing just like you did with the bed when you unpacked it. You don’t need to move out far (a few mm). It won’t be the last time you turn it off with the endstop triggered and you’ll have to do it again. Either that or ship it back so they can. And trust me, shipping it is way harder on the machine than your little push will be.


(Louis ) #15

Fixed it haha, I think the machine was on previously or something.


(Mark Walker) #16

I’m sure you didn’t break your machine. Worst that will happen is you’ll break your endmill and that’s a consumable anyway. And that little bit of metal probably won’t even break your endmill.

Yes, I think the main problem you were having was the feed rate. So it should work if you change just the settings I said.

I’m not sure what your sign geometry looks like, so you might only have been on the first pass of the multipass rough, but you may find the material is less precisely level than you think. You can compensate by cutting a little deeper (I mean in total, not per pass).