Going from 3d printing to first cuts

Mostly Printed CNC - MPCNC Troubleshooting
#1

I have been 3d printing fine for almost a year but wanted to try out the CNC part.

I bought my entire kit on this site.

I’m using this firmware. Was RC8, now RC7 https://www.v1engineering.com/wp-content/uploads/2015/12/RC7_MPCNC_LCD_9916.zip

I’m using this fusion post processor. https://github.com/martindb/mpcnc_posts_processor

I’ve uploaded my g-code… nvm it wont allow that file.

This is my fusion file (cam and model and my setting) http://a360.co/2jlZnm4

When I did the post processing in fusion I did not select options because I didn’t know if I needed to.

I send the gcode using repteier host and laptop. I don’t see any type of preview in my repteier host.

So what happens is it starts, and it starts to helix rapid in, and then the print time drops from 14 mins to 9 seconds and it just stops moving but it’s making a weird humming noise.

I can take a video if you would like.

#2

RC8 has issues for us right now, even the bugfix.

the same gcode will probably work with RC7

#3

ahh… this the one then? https://www.v1engineering.com/wp-content/uploads/2015/12/RC7_MPCNC_LCD_9916.zip

#4

yup

#5

I have flashed https://www.v1engineering.com/wp-content/uploads/2015/12/RC7_MPCNC_LCD_9916.zip

My LCD is still going from x0 y0 z0 to ?0 ?0 ?0 and back again.

My set home offsets via the prepare menu is still not working.

Edit: and the machine is still freezing.

#6

What happens when you hit start?

You can insert a line of gcode that zeros all your axis before it cuts. We use it in the fusion post processor.

#7

It was a speeds and feeds issue that was cauing the machine to freeze. I have fixed that.

I don’t recall my LCD doing the ? mark thing… is that normal?

Why is my set home offsets not cauing the xyz to zero?

When I hit start it behaves like normal, but thats because once I get the head into position Im turning the power off and on to set the xyz to 0.

#8

question marks are normal.

RC8 does have issues, please don’t use if for anything other than a laser. It will randomly crash on z moves, very randomly.

#9

If you look at the bottom of my album https://goo.gl/photos/NoN3S24TkqsHsSki8 you will see a video I posted where I’m not able to use my LCD to set the xyz back to 0? I used to be able to that.

I also added my first test cut to that video. Direct link here https://goo.gl/photos/vZb6sxoYD2wqjLEC9

#10

That is officially the largest bit I’ve seen used with this cnc router so far!!! I have one that size, just haven’t used it yet.

#11

Sorry I have not tried that I move the machine by hand. I will look into it on the next firmware update. I did not change anything is RC7 or 8 to cuase that so it must be some sort of auto home feature. I am assuming I need to turn them off now instead of just normally open and it will enable that feature again.

That is a giant bit and it seemed to do very well. Maybe we are all doing it wrong with these tiny bits.

#12

@Barry I was scared lol. I wasn’t worried about the size of the bit, but burning up the bit due to heat. If you notice I cut 3 identical pockets? That was because I was going to try 3 different spindle speeds. The first pocket was 15kish and it was too slow, chatter in the beginning so I turned it up to 20kish. The third one was 25kish, but no matter what speed it seemed to have trouble ramping into that white coating. So I halved the ramp speed to 240mm/min. The third clean up pass around the edges was only to see how the bit did ploughing into the full .1mm of material but it was fine. The depth of cut was .05mm for the first pass and then passes at .025. I’m not sure how deep I can cut but I plan on finding out. Speed was 30mm/sec. I also ended up with very faint lines in the finish X direction but I felt like I might end up worse if I tried to shim the tool.

@Vicious It’s not that important. I was just used to using that since I have been for a year lol.

I need to cut a 19inch by 19inch pocket with square corners, 1/8 inch deep to fit my mirror for 3d printing. I’m in the house so no more milling after this lol. Any suggestions would be great. I also noticed Fusion defaulted to a lot of step over %, any thoughts?

#13

Good news, the bit can easily handle that super fine MDF. I cut at 1.1mm DOC at 30k RPM’s with ease. Might be able to do a little more. Bad news is my table top was so off, that cutting the spoilboard flat created so much dust I decided not to cut a pocket for my mirror and just set it on top of the spoilboard and find a way to attach it. The good news I should be up and printing this weekend.