I love this design! I tried to order the parts from your part store, but not all of it can be ordered. The V-Slots and OX Plates will be the most difficult to get here in South Africa. I am really excited, and want one for myself for Christmas. 'The selected product combination is currently unavailable.' ? Do I just wait?

 

I´m a novice openbuilding engineer and i have a basic question. This question was already made in this forum but with no answer. There are two types of eccentric spacers, 6mm and 1/4" inch, witch are very similar. Witch one may i use in this project? what are the differences between them? height?

 

@Williams they only differ in length. It probably doesn't really matter which ones you use as long as you are consistent.

However, since the wheels come with 1/4" Aluminium tube spacers that can be used for the fixed wheels it makes sense (to me) to use 1/4" eccentrics instead of buying new 6mm Aluminum spacers.

 

Ok, so I'm building a variant of the OX and I have it all assembled and just discovered that I failed to drop in my t-nuts to secure my X axis belt. Any bright ideas to fix my stupid mistake without taking apart the gantry? Drop in t-nuts appear to be too thick to allow the belt to get under the t-nut.

 

slide them from the side

 

Yeah, I just noticed that some brilliant designer had anticipated this failure and put a nice little cutout in the plate. Saved me a ton of time

On another note, has anyone felt the need to lubricate the leadscrew/delrin nut? If so, what did you use?

 

No, it will loosen itself enough in a couple of uses

 

Need help something strange with z axis
I made a simple square with 2 circles inside. When I start to cut the first circle cut fine but when moves up and go to cut the second circle the z axis goes all way down and had to stop it to prevent damage. I'm using cut 2d with the shapeoko post processor in Grbl. The gcode looks right on note pad but keep doing the same thing. Any ideas what's wrong with this.

Regards,

Alberto

 

Just a guess, but it could be that your acceleration and velocity settings for the Z axis are too high resulting in a loss of steps when the axis is raised thus cutting too deep when the Z axis returns down.

Tweakie.

 

Quick question: If you intend to use a Nema 23 for the Z axis, do you need 2 of the new Nema 23 threaded rod plates (new item from the OpenBuilds parts store), or 1 normal (Nema 17) threaded rod plate and 1 Nema 23 threaded rod plate?

Thanks.

 

Would someone be so kind as to post their GRBL settings on here? (0.9)
I've used everything listed in the Openbuilds store.
Using the settings KRAM gave as a starting point seem to be giving me problems.
I'm just curious to see what everyone else is getting for STEP/MM travel etc...

thank you so much!

PS.... changing feedrate (G01 FXXX) does not seems to change anything at all on my X and Y axis....
help!

Brayden

 

One would be enough

 

Being a newbie to this CNC thing, I too can't wait to get started on this build. My experience is in the computer and printer world so most of this will not be too hard. The applications though, will be something to study to see what file types can be converted to other types and then to the g-code needed to feed to the CNC. Discovered Sketchup so that is a start. Converting PDF to a cad file is not working so well. Thought , at first, that a kit would be nice but I found the parts list so that will do nicely. I wonder if this can be scaled out to cut on 4' X 8' sheets for cutting out parts to build a dresser or any such larger project?

 

You only need one to mount the Nema 23 to the Z-axis. You can use the Nema 17 plate on the bottom, or if you prefer for aesthetic reasons, you can use a Nema 23 plate there also.
-Nugz

 

ok read thru most of the posts and can't find the answer.
I need a power supply
I'm looking at 24v but how many amps? is 10 enough?
thanks Bob

 

24v is fine, amps depend on the motors you want to use and how many, Nema 23's usually draw about 3.5A each, and according to the parts store looks like 17's take about 1.68 A/Phase. Figure out what motors you want to use and how many then multiply the amps rating to get an idea of what size PW supply. Some people run the on less than what the total amps required is and they work just fine... For me I err on the side of more can't hurt.

 

Ok thank you looks like 15 - 20 should do it.
Bob

 

Hi Guys,

So after about 10 hours work I have got my Ox mostly together and wanted to test out the electronics.

I am relatively familiar with the mechanical side of things but am a novice with electronics.

Is anyone here using the xPro board from Spark Concepts?? I have the new V2 model and it came with absolutely no documentation. Does anyone know where I can find some setup guidelines?

After a long while I managed to find some drivers from a random website and got it connected to my computer via Universal G-Code Sender. It seems to be moving the Z axis nicely but I would be interested in seeing how others are configuring/setting up this controller with the Ox.

Cheers
J

 

Hi,
it would be nice if there was a PDF file with the measures (metric) of the OX plates, to get ideas for creating new designs for new types of machines ( laser, foam cutter, ecc... )

 

@Jeremy Young
This should get you going Jeremy:
https://github.com/Spark-Concepts/xPRO/wiki
https://github.com/Spark-Concepts/xPRO/blob/master/CNC xPRO QUICK START GUIDE V2.pdf?raw=true
http://www.openbuilds.com/builds/cnc-xpro-driver.643/
http://openbuildspartstore.com/blog/tag/xPRO
-Nugz

 

Two questions:

Self tapping screws:
I am just about to begin my Ox build - UPS came today! Have a question about the self tapping screws. Any caveats? Once threads are cut, can the screws be removed and reinserted?

Limit switches:
Are snap action switches preferred? Not sure of any issues with hysteresis with open/close.

Thanks!

JohnM

 

Hi John,

Yes, self tappers can be removed and re-inserted. When re-inserting, with a bit of care (turn anticlock until you feel the indent then turn clockwise) they can be fitted back into the same thread they made first time.

Switches have 'contact bounce' more so when closing so it is considered preferable to use 'normally closed' contacts which open when the limit is reached. Perhaps take a bit of time to read Electronics101 - it may be helpful to you. http://openbuilds.com/threads/electronics-101.693/

Tweakie.

 

Also some CAM software have an anti bounce built in, might want to check into your software settings. I use Mach 3 and there is a setting to compensate for bounce, I use proximity sensors so it's not much of a problem but from what I gather micro switches are more prone to suffer from bounce.

 

Thanks for the helpful link! I didn't know if there was any difference between "snap action" and non. Seems like snap action switches would be less prone to contact bounce.

John

 

Hi @Nugz thanks for your reply. I have previously been through most of those links and saw nothing about having to load drivers. I thought it was odd that I had to search for them myself and was just wondering whether other users had similar troubles.

By the way I am using Universal G-Code sender on Mac OSX.

Thanks @GrayUK , I have tried emailing him but have had no reply, I have also posted in the xPro controller discussion, hopefully i'll get some info there.

 

Getting close to completing my OX build. One more UPS delivery away...

Shout out to Serge E for putting together the OX Calculator BOM spreadsheet! I couldn't have come this far without it. A huge time saver in keeping track of everything required as my design changed in size a few times, and I didn't wind up with too many extra parts.

 

My OX is complete! Basic testing done with motors and controller. Any ideas for wire management? I'm using xPRO CNC controller, but with an ATX power supply, so I don't think mounting to the x-axis crossbeam will work. Thinking maybe putting wire blocks on the x-axis to terminate everything, and then a single bundle of wire running from wire blocks to xPRO. Other option is of course to buy a 24v supply and mount everything to the x-axis.

 

I've been reading about power supply ratings, and just want to point out that most off the stepper chips peak at about 2.5 amps max, so there's not much point in running above 12 amps, reguardless of voltage.
My build is almost done, hoping to have it running over christmas break.