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My cnc mill
so...I bought a mill and cnc bits and kept it quiet and have been fiddling this week.

Setup is as follows
Proxxon MF70
TB6600HG drivers
Arduino nano running GRBL-->usb/serial on pc
toolchain: Sketchup (CAD)---> (CAM)---> (Gcode Sender)--->arduino (Gcode interpreter)--->tb6600hg (pin twiddlers)--->nema23 (vroom vroom parts)

To say I've learned a bit these last two weeks is an understatement. Tonight I had it all figured out, all set up, motors dialled in, calibrated, I was honestly ready to make my first attempt at actually doing something I drew...and pop goes one of the stepper motor controllers.

Boo. Bought another one...will arrive next week, so we wait..

Tips and advice on my toolchain, my next six months of pain and suffering or any other advice gratefully received

(I've already got a 5axis board and a older HP with parallel port and LinuxCNC installed for when I figure out the easy parts and wrap my head around it all)
Box, check...juice, battery, check.....SQUONK! Big Grin
[-] The following 1 user Likes vern's post:
  • Zelig
Best of luck with the mill. I am stuck with the dremel files and hand saw....
right now I can do more with them than with this mill.:-)
Box, check...juice, battery, check.....SQUONK! Big Grin
Possibly a wee fuse inline to stop the motors drawing too many amps from the driver until you get the bugs worked out might be a start. I was planning a setup similar but that's majorly out the window now. Very interested to hear how this unfolds for ya

Edit :-
How about setting up a multimeter between the motor that blew the driver and a power source(at the proper voltage) and measure the amp draw of the motor with a stall load and no load to see what it draws. You could check against the other motors to see if there's anything wrong with the motor(and saves blowing another driver if there is). If not then a dodgy driver mayb what's up. That's the best I can think of just now

Edit 2 :- might not hurt to check the feed to the drivers either and mayb fire a fuse in there before rigging in another driver in place of the dead one.

Do the drivers need/have heat sinks or more cooling?

Found this about them
yeah the stepper driver have a bad reputation, and I spent most of last night reading up about them. Luckily I had solved the low-torque problem in software already before even reading up about it.

Anyway, found out why it blew, which gave me confidence to order another.
One of the wires controlling the y-axis motor had come loose (bad soldering). and unplugging a motor while the driver is powered and in use is a good way to blow any driver. Even expensive ones.

So this driver died a death the same as any driver irrespective of the price. I'm running it at 3.3amps limit (out of a possible "5" *cough*cough) but may dial this down a bit once the new one comes.

Still trying to wrap my head around tool changes mid-cut and all that fun.
Box, check...juice, battery, check.....SQUONK! Big Grin
Ah, cool. Sounds a complicated business but it'll b totally worth the hassle I bet! Good luck with it.
Soldering can be a bugger sometimes, I'm having trouble getting solder to take to my terminator mods cast metal top, annoying as I liked that thing but I just don't think my skills are up to making it safe so it's an ornament for now.
new motor controller came today and I managed to set the mill up on my bench, wire it all up and do my first engraving. Still learning like a mofo though.

@ad456m re: soldering, after many years trying to not use flux (added expense, who needs it, blah blah) I used flux and it really does make all the difference. Dont think the built-in flux in your rosin-cored solder is doing any work..get some flux paste and you'll be soldering like a champ. Best way to describe it is that it acts like a mild acid, cleaning the surface and preparing it to accept solder.
Box, check...juice, battery, check.....SQUONK! Big Grin
Ooh, magic, that'll be my first buy come payday. I thought rosin was enough.
Is there a preferred one that you use yourself or are all pastes fairly standard fare?
they are all pretty much ok...there's a special one if you want to solder to stainless steel (its a more aggressive acid) (and much much more expensive)
I've got some goop in a small round tub that is red in colour and has the consistency of soft butter...I just stick some on a toothpick and smear it where I want to solder...warm the area with a soldering iron (quick touch) to liquify the flux and have it do its job, then solder as normal....about £1.20 on ebay.
Box, check...juice, battery, check.....SQUONK! Big Grin
well, yesterday was productive...
You probably knwo the door on the Kangxin Inoy 60w has a teeny overhand on the end where the squonk hole is...I sorted that out by running a very very light cut over the bottom of the door.

Well you'd never guess what....the door is actually plumb level and square out the factory and the problem is actually the box:-) I've now got the minutest underhand on the other side of the door. mwahahaha. Anyway, it doesnt feel sharp anymore.

And while I was there I tried a spot of engraving on the door. All worked out ok, and was a good learning exercise.

Made an acrylic keyring for my wife today...learned more about engraving, cutting a hole with a smaller than hole-sized mill, as well as cutting out a piece from a bigger piece. That worked fine, and then I went to flame polish the edges with a butane torch and set fire to the thing by accident.

I need to fit the limit switches so I can run an auto-homing routine at startup, as the biggest job is making sure you dont hit the end of the travel area and position your piece correctly.
I've got 60mm in Y and around 130mm in X to play with.

Another challenge is the GCODE line length in GRBL is about 70 characters max, but the makercam program can spit out lines longer than this..which means your simulation runs fine, but when you do an actual cut it misses entire parts out (line overflow error).
I've learned to "zero" my cutter way above the piece and run a real test cut in space, watch it to make sure it looks right, then rezero to true zero and go for it. There's some python stuff online to truncate the line sizes so they are suitable for GRBL use but it doesnt seem to be making my GRBL abehave any differently. Mainly happens on corner rounded edges (circles seem ot be made up of many many many straight lines with serious precision and many decimal places)
Box, check...juice, battery, check.....SQUONK! Big Grin

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