Hi I just build the open build Ox cnc the small version. I've been trying set it up in grbl panel. I don't even know what to import in the configuration in setting. Can someone help me setup grbl panel. Thank

 

Home · grbl/grbl Wiki · GitHub
Good overview here

Compiling Grbl · grbl/grbl Wiki · GitHub
Use this if you need to load GRBL onto the arduino

Configuring Grbl v0.9 · grbl/grbl Wiki · GitHub
How to config the latest GRBL if its already loaded on the arduino/board.

If you are running a CNCsheild (protoneer or clone) Watch out for the Z limit and Spin En pins as they have been swapped in this newer version so some older boards silk screen can be misleading. Do other boards have issues in the change of pinout in the new version?

I have attached a screen grab of my settings but use with caution as they are only mildly tested on my machine as I run Mach3 99% of the time. I also run NC homing switches so you may need to check that setting if you are running NO switches

 

I've been planning out my build of a mid sized 1000mm X and Y axis length OX for about a month now; I was wondering if anyone had any input on using a standard nut block on the z axis vs the anti backlash nut block... This is for general purpose materials up to maybe 1/2" mdf/wood, 1/4" aluminum, so not sure if it makes a difference. Anyone have any input on that?

Just got my order placed for about 95% of my parts yesterday, but was unsure on the above.

Cheers!

Edit: I'd also like to thank Mark the OP of this build for his contributions. This build has inspired me to build an OX based machine as well as given me ideas for many other projects including upgrading my 3D printer with more stable parts. Great instructional videos as well.

 

The less backlash the machine has the better, with anti back lash nut you do sacrifice some speed in the z but it will be faster than you will likely run it.

Backlash can be a real b***h if you have so I'd personally get the the anti type.

 

Thanks Jonny. I'll add one to my next order.

 

Here's my initial mock-up. Based on Mark C's design, but all black and 1000mm x 1000mm with a few tweaks. Just the right size for what I'm after. Please excuse my Sketchup skills, I'm still learning (some of my y-axis v-slot faces have disappeared).

 

OX mods..

Im putting together a 4x4 OX as a CNC plasma.

Mods include using standard Bosch style profile, gantry is 2 pieces 30x60 and gt5 belt 10mm wide.

I am using 20x40 profile with a plate to join together instead of the 20x80 profile also.

Import taxes are very high so I need to use as much local manufacture as possible.

Electronics are USB Mach3 CNC

4 Axis CNC Mach3 USB Motion Controller Card Interface Breakout Board

and 4 Sainsmart 3 amp drivers all running at 24v

Software is Mach3

Porma Elektronika Torch Height Control.

I would have preferred to use GRBL but getting the torch height control to work with GRBL will take a lot longer to set up and this machine is needed to run ASAP.

 

@Jonny Norris
I take your point - for some ODD reason I probably hadn't fully internalized the fact that if I am designer, drafts-person and fabricator then there is little/no NEED for dimension-ed drawings.
Truly a senior moment (-:
The model's detains are held internally in the model and passed from CAD to CAM (or 3Dprint, which is also CAM).

I did the tech-drawing/drafting classes with Tee square, set squares, scale rule, templates, curve square (or whatever we called that thing that we joined 3 points with) etc. SO LONG AGO.

Now there is no need to pass paper drawings to a tool and die maker, or prototype builder , THOSE were the folk that "needed" the drawings.
I suppose "Approval Authorities" still demand paper with dimensions on EVERYTHING, but maybe they will take model files ONE DAY.

 

For who wants to know; 2 out of the 2 Wantai 36V power supplies are failures. 1 DOA the other one has some loose part causing the DC circuit GND to get connected to the AC Earth in the PS. Caused a lot of trouble in tripping limit switches at random, mostly in the middle of the cutting....GRRR. So, be warned for that crap.

 

Hey guy. I'm starting to making my ox move (after a long time waiting for parts and having some problems but that's just blahblahblah). What I wanted to ask is if any of you guys think my machine is making too much noise. It sounds like there is something wrong, probably with the configuration but I'm still a bit worried. Not really sure if this is the normal noise but it doesn't sound like it.

Here is a video of a movement test i was doing. It is short but you can defo hear the noises:


My configurations so far are these:

$0=30 (step pulse, usec)
$1=25 (step idle delay, msec)
$2=0 (step port invert mask:00000000)
$3=0 (dir port invert mask:00000000)
$4=0 (step enable invert, bool)
$5=0 (limit pins invert, bool)
$6=0 (probe pin invert, bool)
$10=3 (status report mask:00000011)
$11=0.020 (junction deviation, mm)
$12=0.100 (arc tolerance, mm)
$13=0 (report inches, bool)
$20=0 (soft limits, bool)
$21=0 (hard limits, bool)
$22=0 (homing cycle, bool)
$23=0 (homing dir invert mask:00000000)
$24=25.000 (homing feed, mm/min)
$25=500.000 (homing seek, mm/min)
$26=250 (homing debounce, msec)
$27=1.000 (homing pull-off, mm)
$100=26.667 (x, step/mm)
$101=26.667 (y, step/mm)
$102=200.000 (z, step/mm)
$110=1000.000 (x max rate, mm/min)
$111=1000.000 (y max rate, mm/min)
$112=1000.000 (z max rate, mm/min)
$120=50.000 (x accel, mm/sec^2)
$121=50.000 (y accel, mm/sec^2)
$122=50.000 (z accel, mm/sec^2)
$130=505.000 (x max travel, mm)
$131=302.000 (y max travel, mm)
$132=70.000 (z max travel, mm)

My OX is 750X500. X/Y use a nema 23 (200 steps/rev) with belt pitch 0.12in (3mm) and a pulley with 20 teeth. Z is a nema 17 (200 steps/rev) with a 8mm threaded rod (2mm pitch). The stepper are set up to 8usteps. I'm using the CNC xPro.

Any ideas???? Any help is more than welcome.

Btw, the motors make that noise even when they are not connected to the machine

 

I had some problems with my power supply as well. It was shorting. I open it up and the inductor was loose which caused it to spark. Got the thing soldered and it is now working. Might help you. Just be careful.

 

@RomCorrea
To ME that sounds like the motors are skipping.
I would look for binding , or insufficient current to the motors.

Can you issue it a command to do a long straight X move, i.e. X motor ONLY driving.
Then do a long straight Y move.
If they both sound the same I would guess low current from power supply.
If different troubleshoot the one that sounds worst.

 

They both sound equally bad tbh. The Y is louder cos it is moving more weight and it is 2 moving and not just one.
I gave that a try with the amps and it didn't really help. If I increase the max rate ans acceleration it solves the problem with it chattering but then the motor seems to run too fast. I had to up it to about 50000 to get it to stop making noise so I imagine there is some sort of configuration that might hit the sweet spot. It would still make noise while at slow speeds

 

I would also change the step pulse - yours is quite high - and leave the idle delay set at 255, which keep the motors always energized. I think that's going to be the default moving forward in grbl anyway.
Here are my settings, that work pretty smoothly. I also tweaked the driver pots a bit (make sure you are powered off first!) and they are set at between 50 and 75% or so.

$0=3 (step pulse, usec)
$1=255 (step idle delay, msec)
$2=0 (step port invert mask:00000000)
$3=6 (dir port invert mask:00000110)
$4=0 (step enable invert, bool)
$5=0 (limit pins invert, bool)
$6=0 (probe pin invert, bool)
$10=3 (status report mask:00000011)
$11=0.020 (junction deviation, mm)
$12=0.002 (arc tolerance, mm)
$13=0 (report inches, bool)
$20=1 (soft limits, bool)
$21=0 (hard limits, bool)
$22=1 (homing cycle, bool)
$23=3 (homing dir invert mask:00000011)
$24=50.000 (homing feed, mm/min)
$25=1200.000 (homing seek, mm/min)
$26=25 (homing debounce, msec)
$27=5.000 (homing pull-off, mm)
$100=26.670 (x, step/mm)
$101=26.670 (y, step/mm)
$102=200.000 (z, step/mm)
$110=7500.000 (x max rate, mm/min)
$111=7500.000 (y max rate, mm/min)
$112=1500.000 (z max rate, mm/min)
$120=150.000 (x accel, mm/sec^2)
$121=150.000 (y accel, mm/sec^2)
$122=150.000 (z accel, mm/sec^2)
$130=510.000 (x max travel, mm)
$131=770.000 (y max travel, mm)
$132=170.000 (z max travel, mm)

 

That sounds a lot better. Still a little noise but I think I'm almost there. maybe just some fine tuning. Just wish I knew what to look for. Gonna get a dial indicator and see how it is doing regarding precision. But thank you very much, it was really a massive help.

 

Thanks, mate. Without exactly knowing (or understanding) what an inductor is I found the problem was exactly that! It was loose and touching the housing of the PS, causing the DC GND to be connected to Earth. Some isolation tape on the inside of the PS housing solved it. Running smooth again!

(Just googled inductor and found it to be the **** thing!).

 

What am I missing? Trying to line up the nut plate on the Z axis and it is not aligned, looks like the wheel need an extra spacer, but I cannot find anything other than the normal spacers in the sketchup drawing?!?

 

Yes, using the spacer blocks...in a breif spat of "know-it-all-ness", I did not slot the z axis plate mounting holes (that attach to the ends of the rails) I put a slightly oversize (for a small amount of adjustment) hole righ in the center (at 10mm from the edge. Will measure when I take it back apart to see what is what, but I ended up sloting the holes now everything is wirking. Just have to go back and see where I went wrong...trying to follow/combine/redraw the OX 8.1 plates and the OOZnest plates in AutoCad was a journey in itself!

 

Do the rail sizes spec'd in the current parts list for this machine build the 2'x4' CNC version? Is it possible to bump the size up to 3'x5' or will it sacrifice the rigidity of the unit?

 

The parts list calls for 500mm x 750mm which is ~19.7" x 29.5" which is smaller than 2' x 4'. I'm no structural engineer, but I would think the larger you go the probability to flex more also goes up. I guess it depends on what exactly you are looking to cut/engrave. I am currently building a version which is ~ 39.4" x 39.4" (actual work area is smaller 30" x 32"), which is just a tad smaller then 4' x 4' and seems very stout for the general purpose stuff I'll be throwing at it. I actually wish now that I had started with a smaller one, because this thing is HUGE at the size I decided on.

 

Thanks for the reply @azarock. Yeah, makes sense. Have you made any structural changes to your system to accommodate the increase in bed size? I do want to make sure that I can work with the full 2' width of material and 4' to 5' of length would be ideal. I'm looking at swapping out the side 20x80 V-Slots for C-Beams and going the full 1500 in length. Could anyone tell me if that would be adequate to solve any flex problems?

 

@Ken Marold

No modifications to mine other than making it bigger. It feels strong enough as is so I'll test it the way it sits before making any modifications to it.

 

You will not regret getting the anti-backlash nut for the z-axis. I wished I had known about it during the original build of my OX. I had to break down the z-axis and rebuild mine, but I do not regret it; since it has eliminated some major issues with the heavy PC router that I have installed on mine.

Hope your build is going well.
Paul

 

I've had some trouble with belt slippage lately and thinking of going to a dual belt system.
Does saw dust and chips cause a problem if it gets in between the two belts and how does one control the problem?

 

I've heard quite a few are using double belts, but you might also try my mount/dust collector combo...
at stores.ebay.com/chrisclub1

 

Hi Everyone! Well, I'm back, and no, I haven't built my Ox yet.

Way back in May I was having troubles with my x-axis being so tight is took two hands to move the head back and forth.

I have two questions that I hope you guys (gals?) can help with.

1) What should the outer distance be on the x-axis plates for the wheel holes?

I measured mine with a decent quality caliper and the front plate has 85mm on both holes, but my rear plate is 84.9 and 84.95.

2) I bought a new pair of rails from the OpenBuilds store since I had dented the old rails trying to get the z-axis to roll freely. However, the ends are not cut "perfectly" square.
What are you guys using to get a perfect square end? I don't know if disc sander would be better than trying to re-cut the ends with a chop saw.

Thanks and in advance for any help or suggestions you have!