View Full Version : BUILD LOG: From Chinese to Taffynese

19-04-2013, 12:28 AM
As most would know through my initial postings on joining the site you would have seen that I'd bought a Chinese machine that has proven to be A) fairly adequate and B) bloody rubbish - so while I wait on the nice postman to deliver my couplings (today I hope) I've decided to tear the machine down and rebuild it except making it 300mm longer and wider and made out of 45mm square steel, which will give me approximately a 700x600 workable area - the height however is fine as it's only a hobby after all and I only want it for working with wood and plastic. I do have plans on making it a vacuum table and upping the motors.

First things first though, the controller.
The el cheapo controller has made way (sorta not quite finished wiring *shudder*) for 3x542's and a bob utilising the existing controller PSU, all encased in a mac G4 tower with internal/external cooling and exhaust - built this way because of the heat in my shed during the summer 40degs plus on some days. I realise it's all overkill but protecting the electrics sounds like a plan to me :eagerness: Why use a mac case? Cheap for a start I bought two of the buggers as running computers and gutted this one for spares for $20 or 12 quid there-abouts and secondly they're build quality is amazing, you don't realise it until you have to gut the buggers, thirdly no undoing screws to gain access to the inside - just pull a lever.

So far parts re-used are the two fans (one sucks one blows) and the zip drive mount once turned upside down and a couple of reversed edge bends made an ideal bob holder once pop-rivetted to the drop down door.

Attached are a couple of photos of the controller box build process as a start. I'm off to the shop to buy a shed loada different coloured wire to get it all wired up

The large hole is where the original speaker was - now going to hold my E-Stop, above that is where the the spindle motor speed knob is going, with the main power switch and spindle power switch
The larger section of the stock PSU will be mounted in the base at the front of the case.

Now to find plans for a vacuum setup for the table before I go ballistic with the welder.

19-04-2013, 12:35 AM
It's actually quite a clean space in there, ideally suited for this

19-04-2013, 05:59 AM
It's actually quite a clean space in there, ideally suited for this

Miles of space for sure - all that really needs to come out of it frame wise is the CD/DVD/Zip support that runs the full depth of the case, only pop rivetted in so that was easy.

My problem now is the actual wiring, I'm a tad confused - I can see where X, Y, Z, the E-Stop, switches, mains power goes etc but the original PSU is not connected apart from a 24v plug and one that says PWM to the yoocnc board. I'm guessing I'll need the one board (the lower one) but I'd really like a knowledgeable comment here as I'm not in the mood to blow the new stuff up.

The attached image shows the following things as marked OK - I've sussed them out, what's confused me is there are two power connections, 18v and 36v plus the 24v going from the one board to the other.

If I do need to use the lower board, do I make the 24v power cable a three way split for each stepper?


Pity they had to make the X,Y,Z wires all yellow and white - cheap swines!!!

08-07-2013, 12:51 AM
After being flat out making stuff with the cheezoid yoocnc setup I finally decided to get stuck in to building the 542 with bob box - the main reason being the yoocnc went tit's up (spindle won't stop spinning) so with that said I got the 542's wired to the bob, I can see where the e-stop, limit switches etc go, where the X,Y,Z wires go but what about the spindle and or spindle power? The only other free connection says 'relay' - or is the spindle powered by the 5v???

These are the bits I bought, gunna make use of my existing PSU which looks like the round jobby - 3X M542 CNC Stepper Driver FOR NEMA17 NEMA23 NEMA34 Motor 5 Axis Breakout Board | eBay (http://www.ebay.com.au/itm/3x-M542-CNC-Stepper-Driver-For-Nema17-Nema23-Nema34-Motor-5-Axis-Breakout-Board-/390611888710?pt=LH_DefaultDomain_0&hash=item5af2486a46)

Looking at all that has me none the wiser so any help wiring it up would be much appreciated.

08-07-2013, 05:03 AM
Ok, hard to tell from the pics but I suspect you're a little confused. What you're calling the PSU (the round jobby) is just the transformer - it is only one component of the PSU. It has, I'd guess from the picture, two 18volt AC secondary windings. The primary is the 240v winding (suggest you read up on transformers on wikipedia). The lower board rectifies the 18volt AC to give approx 24v DC. You will need to connect this to the 3 new drivers. The easiest way would be to use a bit of 10amp 'chocolate block' connector strip to act as a splitter. I'd do you a drawing but can't on my phone.

Its not clear from the pic what the spindle connections are so I'm not going to comment right now, but PWM (pulse width modulation) suggests that lower board also has the spindle speed controller on it. Can you post a close up of the lower board only.

08-07-2013, 01:10 PM
OK had a chance to do a little more research. There are various versions of this board but its possible that it takes the 240v AC and rectifies this to provide the DC for the spindle so be careful how you relocate this into the new box as there could be 340v DC on that board.

Personally I'd get a new 36v power supply for the steppers as the new drivers can handle it and you'd get speed/torque benefits.

09-07-2013, 12:03 AM
My thoughts exactly (replacement that is) to be honest.

As I said, I've worked out where the X,Y,Z etc go and the power but still don't quite understand how to wire up the spindle, does that require a seperate PSU as the ebay sellers are as useless as tits on a bull when it comes to answering questions, and how does one work out which wire from let's say X goes in to where on the steppers. I've tried I think every combination in to A+ A- B+ B- but can't get movement so frustration is creepin' in now :dispirited: