Looking good.. it is of similar construction to mine Have you thought about strapping the two x profiles together? like mine its probably cutting great, but its been an idea of mine to bolt some lengths of channel vertically on the back of profiles. got myself some 3"x 3" x 4mm thick channel to do it only not got round to it yet.

My Thinking is, having the channel just strapping the profiles in 3 places over the span of 1500mm is going to be less likely to twist over say strapping them the entire length with a plate. Okay not aesthetically very pleasing but the more rigidity the better.

 

I have considered doing that, but with my x axis only being 36" wide the 90mmx90mm series 15 extrusions are VERY rigid. Here's a view on the two stacked together, that was a idea I scrapped along the way;



The webs of those extrusions are almost a 1/4" thick! The sideplates are 1/2" thick with several angle brackets linking them in addition to the 4 5/16x2 1/2" bolts in each end.

I've considered filling the major voids in the extrusions with concrete or epoxy/stone matrix to add more mass, but the only flexing or movement I've detected has been in the spindle/z axis. That seems to just be the linear bearings moving slightly, just enough to feel as the cutter is cutting aluminum. I think the only cure for that would be to change over to the flat linear rail and carts. I'll have to save some more pennies before doing that.

While I'm waiting to become independently wealthy, I've just started building a new Ox for those projects that it can doing while my Oxillia is cutting other things. I'm planning to run GRBL on it with Chilipepper. I've been wanting to tinker with that.

 

So, if I understand you correctly, the fact that your machine takes just under 3 hours to cut that job minus the drilling makes you come to the conclusion that the same job at 3mm DOC would take 7 hours? But before you stated that a modestly detailed sheet would take 10+ hours per sheet. This confuses me a bit. I was under the impression that CNC is all about numeric control (by a computer) and that would imply that somehow things should add up mathematically. Surely there must be some mathematical, scientific system to work things out in CNC. Maybe something you and I (and of course others too) might not be aware off?

Anyway, you threw in a term completely new to me. "federates at internal corners". What does that mean?

 

Aha….federates is a spelling checker hick-up! Feed rates it is…..

 

7hours at 4m/min praux

Don't think that you will get that from an ox. In fact I know you won't. But you are thinking correctly yes? 3mm doc = six passes plus finishing passes

yes you could hog it out faster for a rough finish but that's not the point is it?

Sorry praux I missed out a space, slowing feed Rates in internal corners? otherwise called feed optimisation possibly something a little more advanced that you haven't learnt yet. its a way of combating run out, something that is essential in an ox especially. if your cutting your internal 90 degrees at 3m/min you likely to get inaccurate cuts and its advisable to slow your feed-rate before the turn, and return to normal just after.

maybe i didnt explain it very well. really its simple math, if a job that has 3 passes takes 2 hours plus an hour drilling, a job that takes 9 passes (that's 6 rough 3 finish as an ox cant finish 18mm in a single pass) is going to take 7 hours (2hours x 3 = 9 passes plus 1 hour drilling) @ 4m/min add 1/4 to get 3m/min is 8.75 hours. okay not quite ten but you can see a sheet with smaller parts will easily run into 10 hours.

 

is this set good for my OX BUILD http://www.ebay.com/itm/Top-Selling...838?pt=LH_DefaultDomain_0&hash=item2c8e2c216e

 

If you are building the standard size Ox, with belts no problem. However, if you are changing the design much, you might tell us how you are changing it. The key thing I look at first is the "inductance" of the steppers. These are 3.5mh/phase which is a tad higher than I like, but are useable. The higher the inductance, the less low end torque you will have available. In extreme cases you might need to put reduction gears on the steppers and run them at a higher RPM to get the slow speed torque you need.

As for the controller board, it's one reason they are choosing these lower torque steppers - they pull less current and stay within the amperage rating of the board. We do seem to hear a lot of failures of this design, and some users go to extraordinary efforts to make them work. Others have no problem at all. I have one gathering dust that arrived with 2 drives operational and two that were dead.

I switched to separate drivers for each stepper and the ever reliable C10 board. This proved to be a good idea when one driver died and all that I needed to do was to unplug a $32 brick and plug a new one in it's place. Modular construction makes sense to me, even if it may cost a tad more up front.

I purchased almost all of my steppers from this company and a few other things. I have found them reliable and reasonably priced. YMMV

 

THANK YOU FOR THE REPLY AND YES THIS IS THE STANDERED ONE MY FIRST CNC MACHINE I AM BUILDING

 

Great! If you can swing it, I might suggest http://www.ebay.com/itm/US-Ship-dis...069?pt=LH_DefaultDomain_0&hash=item2c9b50dd6d Only because I'm using this very one on a much bigger CNC and it works great. I know the inductance is high, but at 36v you have a much different power curve. Put your Y axis on seperate drives and you'll never go over current. (but I'm running both on one drive and it's doing fine. The DQ542MA driver seems very stable compared to some I've seen. It really provides more power than a Ox might need, but you'll never wish you had just a bit MORE power for a deep cut.

Good luck and keep posting!

 

Avoid all tb**** drivers, they are for 3d printing not CNC.

 

My TB6560 work great for over a year now...

 

i will go with your advices thanks

 

My TB6600's work great for almost a year! But now they're going to go for heavy testing, micro stepping to 1/4 and 2 extra power supplies on it to get 48V. Hope the Buffalo will cope with it…..

 

sorry for all the ? but iam new at this .MY ? IS THE ONES YOU POINTED OUT HAVE A DOUBLE SHAFT ON THEM DOSE IT MADER BECUASE I AM PLACEING MY ORDER

 

Will Do!! I went with stargeezer advice got best offer in hopeing they will take it lol

 

If you don't mind doing some soldering, might I suggest an even better affordable stepper motor driver? The THB6064AH

I'm sure it's been posted before, but these drivers are great. I am using them on all kinds of machines. If you buy the 3 Axis kit you can be up in running in no time, mind you the break out board is a parallel port based setup. At any rate, you can use these drivers on any number of other controllers. Don't be intimidated by the soldering, it is REALLY easy even if you have no experience.

http://techref.massmind.org/Techref/io/stepper/THB6064/index.htm#

 

Hmm.. datasheet shows a drop between the input and output voltages, which means the chip steals voltage from the power supply and that wasted voltage goes into heating up the chip so sorry to say it similar to the rest of the tb chips these will go into thermal shut down before they even get close to 4a. Infact the input and output voltages are exactly the same as the tb6600.

Which means only consider these if you have less or equal to 2.5A motors.

 

think this thread must have exceeded its max page limit, posts keep disapearing lol

 

Do a search on those chips and read on some other forums about peoples reviews/experiences. These drivers are practically bullet proof. There's only been one case I know of where a guy fried a chip, he was pulling close to 4.5-5 amps and the machine was outside in the sun in the desert and even then, they lasted awhile overheating. He got a new chip, soldered it on and provided better cooling due to the environment and I believe had no other problems. One of the main things this design fixes were the overheating/failure flaws of the other drivers design. Not only that, you can buy their heatsink and fan and cool the chip. I have yet to find one negative review from anyone who has purchased and used these drivers.

There is always going to be a voltage drop unless you're rectifying the output voltage.

 

The datasheet for the chip says 4.5a Max input operating current is 4a. That's not stating a drop and should not be assumed. Further down in the spec sheet, it is listed that the max output current is rated at 4.5a. When I get my new oscilloscope, I will do some tests. But from my experience and the many people who have found and use these drivers, they a leagues better than any of the other TB designs. It's not so much the chip that is the issue with most of the TB drivers but the actual design.

 

The drop is in the voltage not the current. Look at input voltage and output voltage.


This effect is pretty well documented I'm afraid to say.

Ploss = V drop I Motor so that chip with a 4a motor the power loss is 1.3v x 4 = 5.2w the same as a tb6600. Regardless of the control circuits this is the power the chip is going to loose to reach 4a.

It too like the tb6600 has the same max operating temperature of 85 Celsius, it has a standard heat sink so i cant see where the difference is to be honest.

 

I was addressing current specs because current is what produces heat, not voltage. Maybe I don't know what I'm talking about? This isn't my expertise. But I'm having a hard time understanding how a minor voltage drop is heating up the chip like you describe. The chip is only going to pull what it needs to run. If anything a voltage drop would usually equate to less current being pulled thus less heat? Most stepper motors will operate at a wide range of voltages but you still need a power supply appropriate to the specs of the stepper motor. I can see if you're trying to run a stepper motor at too low of a voltage, the stepper motor would pull more current then? Thus generating more heat which would heat up the chip. In which case, you need to get a different power supply and up the input voltage. This isn't a fault of the TB chip or it's minor voltage drop.

 

pretty straight forward tho it can be explained with ohms law and P=IE. Energy is conserved. Any electrical energy that is lost by the circuit is transformed into some other kind of energy. In the case of the tb chips its heat, if it wasn't there would be no requirement for heat sinks.

 

I've looked at those drivers before and while they look good, most of the steppers I use are in the 5amp + range. That said, the design and electronics look solid and so, I'm ordering a set to play around with soon. I'll be certain to post a evaluation here in the forum.

 

And now they're backordered. Figures.

 

hello stargeezer i have got the set you said? got her down to $280 waiting on her to except .but it looks like they have shaft in front and in rear is that oky i have asked her for the single shaft hope she gives it to me .

 

The double shaft is handy on the z axis. Inventables sells a crank handle for the rear shaft. When the system is powered down you can crank the spindle up out of the way without starting the computer, software, router, etc, just to move the spindle. Glad you saved a few dollars. That company cuts things pretty close to the bone, so I wasn't sure what kind of deal they might make.

 

I'm building a new Ox. I've not posted the build yet but will soon. This is going to be a test bed that I can try different pieces of hardware on and post some reviews. Here's a sneek peek. Please overlook my messy bench.





It's a plain-jane Ox, with a cut area of 24"x42". Yes the plates were cut from diamond plate on my Oxilla. The plates are 1/4" thick plus the raised cross hatching which adds just shy of 1/8" and has sharp edges on them. I bought the plate surplus and have no idea where I could get more, but I'd sure like to.

Oh, I forgot the name - what else except my "Diamond Ox".

Larry

 

I made the mistake of asking the following question in the Routy discussion, I should have asked it here.

The Routy formed much of the basis for the OX.
One of the really nice and NEAT things about the Routy (IMO, etc.) is the motors mounted UNDERNEATH.
Not only the motors, but more importantly the belts and the GROOVES that they run in.

OX certainly LOOKS good, but I can't help thinking that the belts lay in troughs that WILL collect milling debris, i.e. chips will fly into them.

Question: WHY didn't OX retain the underslung motors and drive belt system ?

 

From experience, the site will occassionally say back ordered until they update the inventory. It is likely it's not really backordered, I'd contact them. If you look at the inventory count, everything says in stock, so the kit shouldn't be showing back ordered as far as I can tell. Alternatively, you can order the parts separately instead of the kit, might cost a bit more.