[ASB79]

I will be building an Openbuilds OX CNC in the coming weeks. Looks like a neat machine for cutting plastic, wood and maybe soft metal.

My build will consist of 1m Gantry beams and 1.5m longitudinal Beams. Hoping for an approx cutting area of 900x1200. I will be using a 700W Makita Router Trimmer but may change to the DIY ER11 Collet and Brushless Motor Spindle detailed on the openbuilds site. I've estimated the total build cost will be between $1200-$1300 AUD

I will be using a gshield (v5) and will try and run the TinyG firmware with the Arudino Due. Any advice on this would be appreciated.

All hardware is ordered and on the way. The rails are on Backorder right now and not available until early April. I have also opted to use Gates Powergrip GT3 belts (supposedly 30% better power transmission than their GT2 series). I'll also be using Aluminium Gantry plates which I've had cut locally from 6mm plate.

The OpenBuilds Videos looked very comprehensive but if there is anything you'd like me to look out for please let me know.

Cheers
Anthony

[blitz355]

Hi ASB,

I'm in the same boat as you, only from the US. I plan on doing the same setup as you (1m gantry, 1.5m y axis..). I knew the v slot was on backorder/out of stock, but had no idea they were a month out! Where did you find out about this? I'm also curious as to how much you got those plates cut for? I have a small desktop cnc that could cut the parts, but I'm not extremely confident in how precise I could achieve it.

[ASB79]

Hi blitz,

The timing on the rail is when it will be available from the distributor here is Aus, hopefully you will see it sooner in the US. I should have clarified that initially before scaring all the US folk.

The plates cost me $115AUD for the 8 piece set. I am still waiting for the hardware to verify the eccentrics fit properly but the holes measure ok on the vernier.

Cheers
Anthony

[Multiprops]

Hey guys I have an ox built I'm running the 310mmx480mm version. It's a great machine still working on getting it tuned in to where I'm happy with it.

Sent from my SPH-L900 using Tapatalk

[ASB79]

Hi Multiprops,

Good to hear someones positive feedback on the machine. I haven't actually seen one in action (cutting), would be great to see a clip of your machine running if that's possible.

I can't proceed with my build until the the extrusion is back in stock, I have all the hardware except for the steppers, pulleys, and z-axis threaded rod. Hopefully they will be in the store stortly.

What controller are you using? I have a gShield and am trying to run TinyG2 for the 3rd order motion but I'm having a lot of trouble flashing it onto my Arduino Due.

Cheers
Anthony

[Multiprops]

I will try to share a video tomorrow so you can see it in action. I'm using a hobbycnc board and 3 305oz nema 23 and one 94oz nema 17.

Sent from my SPH-L900 using Tapatalk

[diro]

Any news on these guys? Thinking of going down the OX path but still deciding between the OX and the Routy CNC.

[ASB79]

I've got all the gear to build my OX except for the extrusion. Can't report anything other than that at the moment.

I had a batch of aluminium Gantry plates waterjet cut to help other builders considering the OX machine, they wouldn't cost much more than the gantry plates used on the Routy.

[jrqc14]

Hi Asb79. I bought my parts from you. Thanks for the cuts, but still waiting for them... Australia is quite far !

As for the controller, I got a smoothieboard Smoothie Project to control 175oz step motors. A new Z motor plate for nema23 will be one of the first upgrade, since the spindle is heavy ! Will consider upgrading to 425oz Y axis with external driver if needed. I will build it to be 1500x1500 and will decide if I cut the X axis to 1000cm.

I got a Makita RT0700c Compact Router, it is exactly 65mm so it will fit in this 65mm Diameter Spindle Motor Mount Bracket Clamp $21.61 Free Shipping @GoodLuckBuy.com holder. The only note is that there is no precision collet available and I ordered a Astro Pneumatic Tool Co 200-283 Slot 1/4-1/8-Inch Collet Reducer to try to use 1/8 bits.

Ideas I got for my CNC :
Control pannel : use an arduino to control 3x 8 digits for coordinates and to read buttons and joystick input and feed commands to the control board. LED displays : 8 Bits Digital Tube Serial Module 595 Drive Module $3.21 Free Shipping @GoodLuckBuy.com There is a control panel and it looks like it has a atmega onboard CNC Router Digital Display Panel For TB6560 A3977 3 Axis Stepper Motor Board $24.75 Free Shipping @GoodLuckBuy.com, but it seems easier to make one than reverse engineer a chinese board.

Touch probe : Dennis made a realy cool touch probe A DIY Touch Probe » fadedbits.com . I will stick to a quicker hack. I didn't see any one else do it, but I've come up with the idea to use a digital dial and read the values. The iGagein http://www.incrementaltools.com/iGag...iga-35-128.htm dial has a usb connector, NOT USB COMPATIBLE, but it can be interfaced with arduino to read values : https://gist.github.com/nitsky/6788941 . I will use it to adjust my machine square and might try to probe with it. The drawback is that it doesn't support lateral collision. But hey, for 50$, that's a good start !

Tool height : I've come across Force Sensing Resistors http://reprap.org/wiki/FSR and think that using it with a plexy glass on top could enable easy and relatively precise tool height. Digi-Key Part Number 1027-1001-ND

On the software side :
I'm still having trouble making g-code files. The inkscape->makercam->openscam seems the best free route. But it's still not what I expected. makercam is not a full featured application ...
I am looking to engrave with V bits for the most part, and I am having trouble getting good gradients. Workflow I am trying is :
Take .jpg in GIMP, color->levels to turn black/white and remove artifices.
Select black and gradiant fill angular. Save to .png. Convert .png to .stl. Generate G-code from the stl.
The stl file is not realy good looking, the gradiant doesn't provide smooth transition so the G-code will not provide a good result.
Any ideas about this ? I'm trying using inkscape to convert to .svg, shrink the lines and import it to F-Engrave as a .dxf. But I get errors in F-Engrave and colors don't work...
Still lot's of work to do...

Keep us informed how it works on your site. I'm waiting for lots of parts... I can't seem to find 1/8 shims.

[ASB79]

Hi jrqc14,

I have the exact same router, thanks for the link to the mounting clamp, it looks Ideal. I am still considering the Brushless motor spindle as a lightweight option, I already have the 8mm collet.

Initially I will use a gShield like what was shown on the Openbuilds video, depending how that works out I may change to the PlanetCNC USB controller.

Unfortunately I haven't been able to progress too much with my machine as the V-Slot is still unavailable here, I've been told its due any time now. I have everything else ready to go. Sounds like you have progressed the electronic software side of things much more than I have.

Please let me know if your plates don't show up in the next few days and I'll try and track them down through the post office.

Cheers
Anthony

[Joe Lighty]

Hi, I'm looking embark on this project too. How's your progress going?

[ASB79]

V-slot extrusion arrived on Friday, am planning to get busy building this weekend. Will post progress reports as it happens.
Cheers
Anthony

[ASB79]

This project has taken a bit longer than I anticipated but I can now say this build is finally underway.

The extrusion arrived last week and was cut to size this Monday. I used a drop saw with a 60 tooth Aluminium blade. I spent some time cutting scrap timber ensuring the saw angles were set square as possible, don't rely on the markings! I bolted the saw to my workbench then secured an appropriately spaced block to the bench to serve as a length gauge, I cut the 20x60 and 20x40 rails in the same setup to ensure they are the same length.

A tip for anyone embarking on this project is to check the squareness of the extrusion as it is received, the 20x80 lengths I got were square on one end but a bit off at the other, probably not a big deal for the long rails but is somewhat more important for the Gantry pieces.

A drilling tap was used to tap the ends, very easy to do this way, just make sure you use a lubricant. A small spray of WD40 in the holes was enough.

Attachment 239572
BTW, I will use the desk to mount the finished machine.

I have now built most of the Gantry, following the Openbuilds video. I did need to visit the hardware store to pick up some M5x20 Panhead screws to secure the z-nut, the 15mm were too short and the 25mm too long. I also deviated a little and used eccentric spacers on the fixed side of the z-axis, not for adjustment but for added support.

Also, the two bits of 20x60 extrusion I have are ever so slightly different, there is enough warp in the rails where it is nearly impossible to achieve a condition where all the rollers are making contact over the entire span. I'm going to live with it for now, there are enough wheels making contact at any one time so the gantry doesn't "rock" and it is running smooth.

I did have to use a file to hand dress a few of the slots in the side plates so the screws fit through. Otherwise the waterjet cut plates work fine and all the holes are in the right spots.

Attachment 239576

That's all for now.

Shout out if you want me to pay particular attention to any part of the build.

Cheers
Anthony

[PaulRowntree]

Hi Anthony
I used an office desk as my base. It was tightly integrated into the machine design, probably more than what you are planning. I must say it was my first and biggest mistake, because the desk wasn't nearly stiff enough, nor square enough for what I needed. Most are built out of glue-board, and are not made for lateral forces or even dimensional stability (mine is in a garage). Under high acceleration mine will try to walk out the garage door too.

[ASB79]

Thanks for the heads up Paul, what did you end up using to support your machine?

[PaulRowntree]

Thanks for the heads up Paul, what did you end up using to support your machine?

It is so tightly integrated that I am using it as-is, and working towards a separate steel frame / machine approach. Mostly in my head at this point though.

[ASB79]

Have not been able to progress too far since last time, waiting for a few bit of hardware to arrive to finish constructing the z-axis.

The frame structure has largely been completed, y and x axis move smoothly across the whole range of motion. I made a small modification to the corner frame joiner to get an extra screw onto the table support, probably doesn't need it but it can't hurt.

Attachment 241014

[K_G_B]

ASB79
I've been interested in building the same machine. based in Adelaide. Can you share any specific stores for us Aussies where we can find some of the components?
You mentioned that the extrusions were not exactly straight. That worries me a little. Are we talking 0.00xx mm deviation or significant to be seen by eye?

Any tips are welsome.

[ASB79]

Hi K_G_B,

Openlab.com.au is the distributor for much of the Openbuild hardware. Anything you can't get from Openlab you'd probably have to order from the States.

I had a batch of Gantry plates manufactured by a local Waterjet cutter and can help you out there. Also, in most places you don't need to use the low profile screws, button heads fit fine in all places except where the z-axis spacers are mounted to the x gantry.

I purchased on of the router clamps mentioned further up the thread, it will work with the Makita router trimmer I got from Bunnings.

In terms of extrusion straightness, I haven't measured it but it is certainly isn't visual by eye. It was only obvious to me when I sandwiched the two 20x60 lengths together for the Gantry and rolled the carriage from one end to the other and the tension on the wheel changed slightly, It isn't significant enough for me to worry about though.

I've just cut the threaded rod, so hopefully will be able to get the z-axis built soon. So far the assembly has been a piece of cake, am hoping the electronics side isn't too complicated.

Cheers
Anthony

[ASB79]

Also, for the Aussies looking for Stepper motors I used Stepperonline, they have a large range to select from and is significantly cheaper than any local sources I could find.