Yes you are correct. Difference is the TinyG engine is more powerful. The TinyG has outputs to drive other drivers, but why pay for onboard drivers your not going to use. You could buy Gecko drive like Cliff meantioned. or any other type of drive. The TinyG is a great board for the Reprap or a small 3D printer. We need drivers that handle the current to drive the OX. Another plus is when your ready or have the dollars, buy another drive for a fourth axis.

 

You are right, the tinyG is more powerful, I almost purchased one myself but did not want to pay for drivers I would not be using. The tinyG can drive lower current versions of Nema 23's with up to 270 oz inches of torque, but these have higher inductances causing the torque to drop off quicker as feed rate increases. This may or may not be an issue.

 

Thanks Mark - most of the 3D printer platforms try to keep the build stage horizontal relative to the extruder - actually it's really fascinating to watch such Delta platforms run:

http://kiestu6.com/videopage/on/0IkqWBiyBts.html

But I am looking to build a platform with six degrees of freedom. And here is a University Project that went nowhere - flightsimulator game console. No Sir. I am too old for Video games and want to find use for such work that are beneficial to people - children who are physically less fortunate than I am. This design comes pretty close to what I need....



Everman uses linear screws - after seeing your work I am leaning towards a rack and belt six axis motion with perhaps six arduino based motor controller but all synchronized through a joy stick and/or preprogrammed (by a qualified physiotherapist and a physician and a Physiscist ) SD card.

Gopal

 

@cliff I think you could run right out of the ardunio pinouts to any driver you like using the GND/STEP/DIR.
See more here http://bildr.org/2011/06/easydriver/[/quote]
Yes Mark you can use the Ardunio pinouts to run any driver you like.

 

I have a http://www.invensense.com/mems/gyro/mpu9150.html i will be using for Tool Head and Base correction.

Top chip MPU-9150 very small can go on tool head for vibration feedback & tracking.
Flight controller below to show size. Sorry about focus, it's DARK here in Scotland.

Nice to see a gimbals working.
My Multi-Wii Se 2.5 does this with an older chip set, it is designed as a flight controller.

Yes you can use two MPU-9150s with the I2C interface!

OpenBuilds.com moderator, have we gone off track on this subject?
Will you the management re-order these posts, i am a little confused.

 

http://www.openbuilds.com/builds/openbuilds-ox-cnc-machine.341/

 

I like the tip on coils, thanks.
Great video, thanks, so far!
Still watching my evening CNC movie

27:10 in use tie wrap to stop cables pulling out.

We need to look into the software issue, not always responding!

Can you repeat the test of it failing?
Can we identify the issue exactly?

Anyone else had issues with this Arduino software?
The pre installed version that is used on this video.​

 

Thanks much - but I feel like I am hijacking this forum with my thoughts - SORRY!

Let's look at where we go with your OX design.
I have so far ordered most of the V-rails and wheels and the build plates from the store based on your two video.
Have 6xNema23 and three Nema17 steppers.
Studying different controller boards (4axis minimum - 6axis preferred)
Tossing between GT3 or GT2 - belt-pinion combination - (thanks for the B&B Mfg. as a source)
Now avaiting your finalization on the gantry plates and at least a prem- BOM.
Gopal

 

What is the effective cutting area of the smaller Ox. In the table video it was said that the MDF was 17 1/2" wide and also it was mentioned that the was a 1 1/2 area on either side the bit wouldn't reach so is the cutting width about 14 1/2". When I do build mine I may have to size it up. I want to be able to fit a guitar top in there which needs to be about a 17 1/2" cutting area.

 

I was going to order the Mk2 as it is available in the part store but then suddenly had some doubts - does the board has driver built-in also?
What about the CNC Driver - is it only 4axis?

I am looking to use >6axis USB interface BUT with external Drivers - Please advise.
Gopal

 

Hi Mark

In your video Quick and Dirty Tool Mount (about 3:20), the wheels on the left look worn. Is that a distortion ? If they are worn how many times do you need to adjust / replace them? Sorry should post in Q and A

Thanks

 

Im getting ready to order parts for 2xOx for the bigger one, the 4 foot x 2 foot. I believe the BOM is for the smaller one. Is this correct? if true, can we get a proper Big OX BOM?

Also there still "missing" parts, will they be there soon? I really want to get started.

 

The board is designed for external drivers. There are no drivers on board.
Planet CMC has has.more information and videos.
http://www.planet-cnc.com/index.php?page=features
A software license comes with the board and the software is very flexible. I have not used the board before but the reviews are good. A short double shielded USB cable is highly recommended to avoid noise causing communication drop-outs. Of course I would recommend that with all USB CNC environments. Longer cables can be used if they're buffered. I have the board on order, should have it early next week and will be able to answer more questions then. In the meantime Mark maybe a better source of info.

 

Thank you so much! I had already made one purchase (TinyG) which I am told will not be able to drive four axis providing adequate force (torque) with the built-in H-bridges (DRV88xx) and Synthetos even advised me to return the board for a full refund. In any case, I would have had to add two more drivers.

I don't want to make the same mistake of ordering Mk-2 from Planet CNC and then find that I still have to use external drivers and disable the on-board ones. If the mk2 has no drivers and output STEP-DIRECTION-ENABLE signals, my construction would be so much better.

Since you are buying one (I have put one on my wishlist) I will wait for you to do the review if that is ok with you.

 

WANTED - I realize the part drawings aren't released but I want to order some material for the G10 plates. Do you have the overall dimensions that the individual parts could be cut from? Such as side plates for gantry 10" x 6".

Thanks
-david

 

I checked their website and they show a Mk3 board which is specified as supporting 9 axes and "uses dual core ARM processor". Mk2 on the other hand seems to have only 4axes. Are these true. I looked at the schematic which also shows 4 sets of step/dir outout from a PIC chip. PLEASE HELP!

 

Thanks, Mark. I was, not surprisingly, confused by the block sketch (didn't read the description below that, duh!)

But it looks like MK2 has only 4 axes support but claim that the new MK3 has 9axes!

 

I will post a bench test review in the controllers forum once I get the drivers built. I will be using THB6064AH's from MassMind driving 270 oz in steppers, 4 to start with. Drivers should arrive in a few days. Should be able to post late next week, if all goes well. Router setup will come later, l like many others will have to decide how to machine the plates.

 

I have no way to make the plates at this point. Is there someone (Kram242)? That would be willing to make me a set that I can buy?

 

At mentioned in my last post, I am looking for suggestions on how to machine the plates. From previous trial and error using a drill press, I have found that the most critical difficult part of machining the plates is getting the holes for the wheels positioned right. This is especially more difficult when installing three or more wheels on the top and bottom of a plate. Less than 0.5 mm out on the eccentric hole renders it useless. Even tighter tolerances on the fixed wheels otherwise they become useless. Elongating the holes to allow for some adjustment is a bad idea since it requires the screws to be over tightened on the bearings which leads to all sorts of problems.

Don't get me wrong, this in not a grip secession, just a heads up for those who have limited tools and machining experience like myself that are planning on machining the plates themselves. I have had some success in drilling the holes, but have generated a lot of scrap plates also. What I have done is use a digital caliper to scribe mark the hold location, punch the scribed mark (Punching the hole works on aluminum but not on garolite), pilot drill a starter hold, then a 5mm drill to open it up. On the eccentric I have done the same but used a 7mm drill to open it up. Seems to work it the drill does not walk to much. I also drill the eccentric holes a 0.25 mm closer to the fixed wheel in comparison to the online plates to give them a better chance of working, rather have them slightly tight then not tight enough. I also machine these first so that not much time is wasted if I have to scrap the plate.

I have found that purchasing the plates is always cheaper if there is a plate that will meet your needs. But for the OX we may have to wait a while. What I am thinking is fabricating temporary aluminum plates and then using the OX to machine the lighter more accurate garolite plates.

What do you think? Does anyone have suggestions on how to drill the wheel holes with better accuracy?
Thanks.

 

Sorry for the confusion, what I was trying to say is that the garolite cut would be more accurate, being cut on a CNC machine, where as the aluminum cut would be done by hand using a drill press. I though that making the plate out of aluminum would be easier since you can punch aluminum and then machining a garolite plate because it is lighter. However, since I posted, dawned on me that I can make a jig and slide the plate along the jig to get aligned holes. If that works I may not need to make a temporary aluminum plate, just drill the garolite plate on a drill press.
I have not worked with garolite before, and am not sure how easy it is to drill and cut with a drill press and miter saw. I do have a harbor freight micro mill and it may work but is probably to small for these plates, besides I was looking for a solution others may be able to use as well.

Any thoughts? Would it be wiser to wait until plates are available?