Yes Johan, Chris Laidlaw sells the plates for NEMA 23 Z-Axis.

 

Hi all,

I'm running into a little difficulty in squaring up my side rails as I complete the mechanical assembly of the OX. I'm building a 1000x15000, and the end of my 20x80 side extrusions are slightly off (as cut by me). I'm at the point of tightening down the 90-degree joining plates that link the sides to the front and back. When I tighten the plates to the ends of the side extrusions, they form an angle with the sides of 89.7 and 90.3 degrees, respectively. I roll the gantry all the way to the front and the back, squeezing the frame diagonally, and get both sides to hit the front and back at the same time. Then when I go to tighten down the bottom three screws in each plate, it pulls things way out of square, to the point where one side of the gantry hits and the other side has a gap that's maybe 7 or 8mm.

Using rise/run calculators, that seems consistent with being out by 0.4 degrees - so I'm pretty sure the un-square ends are the culprit.

I don't know that I can cut the ends any more squarely with the tools I have access to, so I'm looking for suggestions on how I might solve it otherwise.

Things I've thought of:

- use shims between the 90-degree plate and the 20x40 rail, so I can tighten them down, without pulling them out of square
- try rotating one of the 20x80 beams, s0 the out-of-square ends are mirrors of one another (thinking that would pull the frame into an isosceles trapezoid instead of a parallelogram, which I can compensate for by tightening down the other end while slightly compressing or expanding the sides)

Anyone run into the same issue and solve it somehow, besides recutting?

 

Hot glue works well

I connected the switches. Indeed no false triggers when the steppers run. However... I get often a spurious trigger when I start the router (800W Trend T4)

Frederic

 

Just ordered the parts for the larger one....

Johan

 

So here is where I am...

Finally got the Seeduino and gshield boards talking to my computer...(had to download USB driver and set the sliders to 5v and AUTO on the Seeduino)

Downloaded Arduino IDE and GRBL v0.9

Loaded GRBL v0.9 onto the Seeduino

GRBL Controller recognized my controller

Now the problem....I get no movement from any steppers. Looking at the GRBL settings, something must be amiss....I am not familiar with the settings ....When I try to move an axis (I have tried at 1mm and 10mm) Nothing moves.

Any guidance would be appreciated....and....can anyone send me their settings so that I might have a place to start please (anyone that is using the Seeduino/gshield combo)?

Thanks

 

Great forum, I took the time and read all of the posts from the beginning. A little advice to anyone new to the site do yourself a favor and read through all of the posts. A lot of the questions your asking you will find already posted by people that are actively building. The OX is a great design I looked into a mech mate about a year ago but due to time and mostly ability I never followed through. The OX is definitely something I feel confident to build and be successful. Keep up with all of the great information and I can't wait to start getting parts for my own build.

 

I switched to 0.9 a few days ago. It seems that GRBL controller (at least the one I use) does not seem to be compatible with GRBL 0.9. When moving the axes, GRBL complains that the feedrate is not set. Try entering "G01 F200" in the command box before manually moving the axes. Could this be your problem?

Do you use gShield? Do you see green flashing leds when the motors are supposed to move?

Frederic

 

What we really need is a wiki.

 

Frederic Goddeeris.... tried entering G01 F200 and I got an "Alarm Lock"...
Here are the default settings:

I hope this can be read ok....

My ox is 750x1500mm and I am using all of the standard OpenBuilds items (such as the 8mm threaded rod, 20 tooth pulleys, Seeduino/gshield boards, GT3 belt. I am also using NEMA23 steppers for all axis.

 

It means that the limiting switches where triggered and GRBL is in alarm-state. No commands will be accepted.
Do you have switches installed? If not, disable "hard limits". $21=0
When you reset GRBL, the alarm will be cleared. Also in the controller there is a button to unlock GRBL (under advanced).

Hope this helps
Frederic

 

I strongly agree

 

Thirded, a wiki would be excellent for storing information beyond build write-ups and software resources.

That said, its scope could be difficult to define. OX-only? OpenBuilds-only? DIY CNC in general? Aluminium extrusion uses? DIY hobby manufacturing? Etc...

 

Frederic, I changed to $21=0 and unlocked...then I tried to manually move the y-axis and I got a "G01 Y-10 Error: Undefined feed rate" same for the X-axis

(also, I am not running switches yet)

 

Yes, ok, try G01 F200 first, this will specify the feedrate for G01

Frederic

 

Frederic, I started a conversation with you so I don't take over this thread....

 

If it is an Ox wiki, then it should be restricted to Ox only - but really it isn't hard to have categories. Been on Wikipedia lately?

I don't see how the scope is difficult to define - machines built using OpenBuild extrusions would seem to cover it. Three main categories, just like they have here - 3D Printers, Lasers, CNC Routers - and a section for various sorts of linear motion machines.

Within the categories there would be an Ox section which would cover the build in detail, including motors, electronics, spindles, etc. Other people could create their own builds with similar levels of detail. That's how Wiki's work.

 

Hi guys signed up to comment as this OX is definitely the first CNC router I'm going to build.

I already have a couple of nema23 steppers I took out of an old copy machine years ago and I have a Planet CNC Mk 2/4 interface plus a 36v with 12v secondary output cnc power supply.

I noticed in the thread someone mentioned about the steppers not fitting tight to the gantry plates and needing spacers due to the eccentric shaft hole to allow movement, I've attached a dxf where I've had a play and looks like there is just about enough space to allow a full sized hole?

I'm going to get the gantry plates waterjet cut from 6mm ali and if there's interest in the UK could get more done at the same time?

Have fun guys.

Ben

 

Thanks for the comments Gray the 2 steppers I have are a pair and are both 140oz, I'll probably have a nema 17 left over from a 3d printer build.

I've emailed the dxf to a local waterjet place today but have 3 or 4 more to email it to as well to get prices.

Ben

 

That's what I was thinking

Ben

 

I've realised that the OX X/Z gantry is exactly what I'm looking for on my build, but for the Y axis the platform itself will be the moving part to eliminate racking and make custom plate manufacture unnecessary (since the build is actually itself to create custom parts for a laser cutter). I'm basing my build on the Roland MDX-540; hopefully- but probably not immediately- with its 4th axis and automated tool changing too. Just not for $20-35k! I may need to beef it up a little for a 1.5kW spindle, though.

Seems fairly pointless to do that when we already have build logs with various information sections that theoretically fulfill that need- they just haven't yet been filled in with all the OX information yet. To roll an entire wiki, it seems like there should be more to it to make it truly worthwhile over what is already available, but to expand it beyond OpenBuilds hardware seems a little presumptuous of authority within a disparate set of communities. So yes, scope is tricky.

 

I am beginning to get a little frustrated with this Seeduino/gshield board combo......Apparently, there's not another single person on the entire face of this planet that has one working. So, I think I may switch over to a TinyG board. Any recommendations/thoughts/suggestions on this? and....is there anybody out there that might be able to help out with that one? Or should I look at even other alternatives....???

EDIT---- I have been doing some reading thru forums....It doesn't look like the TinyG will support 3 NEMA23's (the ones that OpenBuilds sell. Sooo, can someone suggest a board/board combo that will push the 3 NEMA23's? I have a mid-tower windows 7 x64bit high-powered gaming computer attached to my cnc for control (I just had it lying around, so I figured I would use it). I would like to save the bank and stay AROUND the $100 mark. But, I will pay what I must to get operational. I am not a programmer, so anything that requires me to write code may be difficult.

 

I was having the same issue with my gt2's, that and stretching. upgraded to gt3 has fixed the stretching. as for slipping i would suggest adding extra tee nuts, or colin of robocutters.co.uk has supplied me with some clamps he has design himself which are like extra long tee nuts with slots in that you can thread the belt through like a buckle.. these seem to work nicely

 

ruling out the ones that you cant use with mach 3 will probably better answer your question.

First rule out arduino based boards.. only compatible with mach 3 through modbus for which nobody seems to have compiled working firmware for. and seems to be a programming nightmare.
Make sure it has the correct number of axis outputs,
Does it have the correct input, parallel or usb that you prefer?
does it have enough pins for the number of limit and home switches you need?
would be a good time to choose your motor drivers if you havent already in which case: they will tell you the input voltage required, in other words the logic, these in most cases need to match. i was initially under the impression that opto-couplers would translate any difference between bob and driver logic, however have been recently corrected by pi-bot, this is not the case (even tho i am running a 3.3v bob and pi-bot 5v drivers with optos absolutely fine, the manufacturer of pi-bot says otherwise, so i shall go with what they say) however level translators could be use in this scenario but not preferable as requires more electronics to be housed. (pretty obvious but make sure the driver output the current required for your motors)
and do they have opto-couplers? if not you need opto-couplers between the drivers and bob, so does the bob have opto-couplers? if it does and your drivers have them then im not sure but it may not work. just one bank would be my preference.

finally and i feel is very important.. does the bob supplier have a mack 3 plugin file to suit? it helps remove any confusion when trying to get them to interface.. failing that a mach 3 setup guide.

there is probably many more factors, but these are the ones that come to mind
hope this helps and sorry if i have listed the obvious.

 

It uses 4 x TI DRV8818 driver chips - more than capable of pushing a NEMA 23. Why do you think it won't?

If it can push one on the X and Y Axes, it can push one on the Z.

THe TI DRV8818 is capable of 2.5A per winding. The steppers that OpenBuilds sells are 175 oz units rated at 2.8A - they will work fine.

The worst case, you can run an external driver for whatever axis you want - bypassing the DRV8818.

 

Thanks for the responses....and I have found the setup that I will go with...

I am going with the TOAD4 board and EasyCNC controller software. All of the info can be found at http://www.sparetimelabs.com/eazycnc/welcome/welcome.php

I talked with Kustii at EasyCNC today and I was able to purchase 5 Toad4 pcb's. I spent the rest of the day ordering all of the components I would need from about twenty different suppliers (lol). I will have a lot of components leftover for sure (Most all bulk items like packs of 100 resistors, 25 capacitors, etc). Except for the stepper chips, I will have enough to complete all 5 of the boards. I figured since this is a DIY cnc, why not make it all DIY

Anywho, the firmware is opensource and the Easy CNC software is free from the website above. The Toad4 will run 4-axis, up to 3A ea stepper, is probe, coolant, and motor control capable, is Win7 / USB compatible, and doggoneit, it just looks nice (it's in color) hehehe.

So, that's my story, build will be on hold kinda until all my parts come in. Might do some fiddling on the table with anything that I can improve on.