Mozaik/Sheet Issues

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I’m having an issue with cutting out sheet parts for a cabinet job using Mozaik software.

I’ve run 2 sheets on 2 separate occasions. Both times I’ve run into an issue only on the second sheet. The first sheet cuts great - shelf holes, dados, full depth part cutout, multiple tools, no issues. But both times, the second sheet I’ve cut I’ve run into issues even though I haven’t changed any parameters. I just run another job for that second sheet and go.

Today I ran the second sheet and when only heading in the Y-axis direction, it was off by about 1/4”, causing my dados to be too close to the edge, which blew out the MDF pieces when doing a final cutout. Heading in the X-axis direction stays on track.

Also, while tracking off course going in the Y-axis direction the compression bit started slipping in the collet, causing it to dig into the spoilboard pretty hard. Needless to say, I broke the bit as it hit a spoilboard fastner before I caught it. I thought I was inserting the bit far enough and tighting the collet plenty tight to hold the bit in place. But maybe because it was tracking off, it put more force on it then usual? (I’ve heard you can overtighten the collet, but I still tighten it pretty snug)

It’s just weird to me that, both times, the first sheet I cut goes great, no issues, parts are perfect. But loading up and running the job for the second sheet is where it goes haywire somewhere and causes issues.

Could it be the post processor they sent me? Could my steppers be losing steps for some reason?

I’m using a 3/8” compression bit with a full pass depth for part cutout in 3/4” MDF. Should I shorten up my pass depth so it’s not cutting all the way through in one pass?

I did an air pass with the post processor they sent me and it seemed to go well (as far as my eyeballers can tell). Although it seemed like they had to send me a custom post since the EX controller has not been listed yet on their site.

I can’t seem to upload the post processor file so someone like Eric could double check it. Let me know if it’s possible to get the post double checked by Avid.

Here’s the 2 gcode files I was running:

WORKING first sheet: S05R01.CNC (7.9 KB)

UNWORKING second sheet: S06R02.CNC (9.2 KB)

Here’s some photos of the aftermath showing only one axis tracking off (and digging into the spoilboard)

IMG_9853
IMG_98531662×1582 587 KB

IMG_9855
IMG_98551920×2560 1010 KB

IMG_9856
IMG_98561920×2560 849 KB

Ex controller, Nema 34 steppers, 8.7hp spindle.

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Before you start looking at software it’s always a good idea to verify the mechanicals of the system. There’s some good troubleshooting steps for this on our support site.

Probably, this is a big bite to take depending on the feedrate you were running.

You probably already know this, but the thing with with steppers is that if you lose steps while cutting you never know, and with servos you know instantly, that being said our Nema 34 steppers have plenty of power, and if you manage it properly you can absolutely crank out cabinetry like this on them.

I’d start with making sure the machine is mechanically sorted, lubed, etc. Then double check our toolpaths just to be sure (you can use ncviewer.com to easily look at your G code) Altough I suspect it’s fine, it’s good to look.

Then I’d back off any aggressive cuts a little bit, maybe 20% and see if you get reliable cuts. You can inch them up from there.

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Thanks for the advice Eric.

After doing some more research and investigating the “crime scene” I realized that the most likely culprit was me being a greenhorn. I was so worried that I could over-tighten the collet, that I think I was pretty far from tightening it enough to prevent bit slip.

I was applying previous advice about snugging up handheld routers so you could loosen them back up by squeezing with one hand. But after looking up ER32 collet specs, I had no idea that typically they should be torqued down to 100 ft/lbs. Correct me if I’m wrong on that. If that’s the case, I wasn’t coming anywhere near that.

When I took the bit out, it had slipped almost 1/2” down. Which means it was trying to cut 1/"2” of spoilboard + 3/4 MDF all in one shot. I would certainly imagine that could cause a few steps to be lost pushing through 1.25” of material. Whoops!

I was running a feedrate of 400ipm at 18,000rpm. And I initially was getting good results with that. But obviously that was most likely before the bit started to slip and drop 1/2”.

I’ll definitely do this.

Hopefully, after properly tightening the bit down, I can gradually increase the pass depth and still get good results.

I’ve definitely been pondering upgrading to the servos down the road for this reason. It does sound appealing not having to worry about unknowingly losing steps.

4

yeah you can really crank down collets more than you think… It always surprises me that people let these slip out.

100 ft lbs is what most car lug nuts are torqued to…

You can get something like this to help you get them cranked down: https://www.amanatool.com/atw-32-adjustable-torque-wrench-for-er32-collet-50mm-dia-x-15-1-2-inch-length.html

Or you can do what I do: Use the German spec of “GUTTENTEIGHT” that’s never failed me… :slight_smile:

1 Like
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Here’s my usual advice to clean the shipping oil off the router bit shank before using it the first time, too.

6

This solved it! I’ve adopted a prolonged tennis grunt that seems to do the trick. Smooth sailing after that!