Adding a Z-Axis Brake

[@MakeTechPtyLtd]

Nice one. Thanks for sharing this mod. -Ken

[@calebbridges]

I realize i'm very late to the party here but I'm in the process of upgrading my spindle on my avid 48x96 pro with nema 34's. I found your video because I've been a little nervous about adding a 46 pound spindle to my z-axis. Sounds like i will need to add a brake to the Z axis. Now that you have been operating your cnc for a couple years, any tips or things I should consider in my spindle transplant? Have you had any issues with regidity or other problems related to your spindle weight? Thanks for any advice you can provide!

[@QuestionableEngineering]

The brake is definitely recommended; without it, the spindle will crash into the bed when e-stopped or powered down. Not shown in this video (but maybe on the z-axis teardown) is a little one-way bearing that tries to take some of the load off the z-axis servo. I took that out, and my servo has to work pretty hard to keep the z-axis from falling when operating. It was overheating and shutting down until I added a fan to it. It is probably undersized for the mass of my spindle. If you’re using simple steppers, you’ll want to oversize it for sure. I do experience ringing, generally seen as ripples in the cut just after 90° turns. 80/20 is not the most rigid structure, but I’m sure I’m pushing reasonable limits with this spindle (and I still want to add a retractable dust shoe!). I could probably stand to lower the acceleration (my table is scary fast), and I’d love to someday put an accelerometer on it and see if it can be finely tuned. The ripples have so far not been a problem, as they’re minor enough to sand out. Off the top of my head I can’t remember which axis shows the ringing. I would expect them to be in Y, as that would be the least rigid one, but I just can’t remember (it has sadly been a while since I’ve used it). I will recommend Teknic SDSK servos over steppers. They are amazing!

[@calebbridges]

@@QuestionableEngineering Thanks for the quick response! I'm going to certainly follow your advice and oversize the stepper/ add the brake. Thanks again!

[@ekbiker]

I'm glad I found your video! I'm building a CNC router with LinuxCNC and ClearPath servos with a Z brake. I'm trying to figure out how to configure the files. How did you find which lines you needed to capture the HLFB servo ready signal and then activate the 24v to release the brake. I see you're using a 7i76e board, and also have ATC. I'm using an ATC spindle as well. It would be great to see your hal files. Can you share those? Would much appreciated, thanks!

[@QuestionableEngineering]

Yeah, my repo is a mess, but I'm using the stuff down in `router3`. I need to clean this up: github.com/jetforme/router-table

[@rufustoad1]

Well its a good video but i wish you would have detailed more on wiring it and configuring it.

[@QuestionableEngineering]

Thank you. That’s a fair request, and I did intend to write a companion article with more details. I’m swamped at work for the next couple of weeks but I’ll try to get one posted after things cool down.

[@AstroStrongBox]

What is URL for “Linux CNC”?

[@QuestionableEngineering]

Added a link to the description.

[@AstroStrongBox]

Could use some low key music during time lapse parts. Cool content tho!!!

[@roosanon9985]

I, for one, appreciate that it's just you telling us what's going on. Finding the right music can be tough.