CNC Plasma cutter, start of bits buying.

[AdrianH]

I think I may have been daft, but I have a few months to get to something useful?

I have taken the plunge and bought a Stepper motor controller off Ebay. Cnc 4 Axis Tb6560 Stepper Motor Driver Board Controller With Box + Demo Mach3. It cost £55.69 inc delivery from UK.

Can't do without steppers so have paid £81 for 3pcs Nema23 dual shaft stepper motor 425oz.in coming from Germany but was originally China.

I have sat under the bench a 24 Volt 14 amp power supply not being used so that will power the lot.

Have also bought again from the bay of E 40 bearings 606ZZ 6 x 17 x 6mm for £16.52 and so far that is the end of my spends for a while

I intend to build a frame from either inch square tube or pick up some 3 x 1 rectangular box, the plan is to use the box and bearings to form the slides and linear bearings, a bit like a wardrobe slide rail affair. I am going to try a belt driven approach rather then ballscrews, i.e similar to a printer carriage movement.

Looks like the controller will work off my old dos software called CNCpro so hope I do not have to buy any Gcode driver software. Time will tell on that!

So I basically hope over the next few weeks/months to have a simple set-up for under £200, then I seriously have to make some thing useful.

If anyone else on here has used the controller please speak up, I would be grateful of your thoughts on it.


Adrian

 

[T0rnado69]

should take a read on mycncuk forum.
i think alot of people curse those TB6560 drives.

i too am looking at making a cnc table. and converting a mill to cnc.
and was going to go the cheap way on ebay,
but thought twice about it after reading many threads and builds on mycncuk.

 

[AdrianH]

My CNC mill was done years ago and the drivers which were pic based and power fets cost me quite a bit of money and I had to build up the thing from a kit, so at the £55+ for a 4 chan low power unit does not seem bad, time will tell. I will download the spec sheet on the TB6560 and have a read.
After a quick read on that forum some issues seems to be noise from chopper circuit and step pulse time.

Adrian

 

[mike os]

Mycncuk.com is very good for this stuff.. just started work on an adopted router project myself

 

[T0rnado69]

indeed mike os, many so helpful members, and a few top notch members that build machine after machine.
and so many build and conversion threads..
so much to read and lots of build pics.
a great forum.

 

[mike os]

whats your username on there Stuart?

 

[AdrianH]

Spent a bit more time reading the manual. deciding on a few things like switching off micro-stepping why would you want 1/16 micro steps or even 1/8 steps when you loose so much torque and according top one web page on the subject accuracy, think it easier to gear if required.

Not spent to much on that forum, have enough with this, but question to Stuart one of the issues with the boards used to be motor volts before 5 volts is this correct?

I hope it is now solved on these newer boards as it only requires one PSU input, all the inputs are op-to isolated, so I am assuming one can not activate anything until 5 Volts is there?

Steppers will not arrive until next week so have to wait before connecting up.

Adrian

 

[T0rnado69]

whats your username on there Stuart?

same as on here mike

 

[T0rnado69]

Adrian, you properly know more about cnc then i do.

im looking into converting my mill to cnc, but haven't yet bought any parts yet.
im busy with lots of other stuff currently and no time to play around with the mill.
so i just read threads and take in as much info as poss.
save links to good places for parts and useful info i save to a notepad for future times.
i do plan to try get my head around the programs you need to use,
as i don't want to convert my mill only to find i cant use it as i cant use the programs lol

but i do remember one issue was blowing the chips.
as they couldn't cope with the amount of volts the steppers needed to run at a good speed.

 

[whensparksfly]

heres a few pulleys for the stepper motors http://www.ebay.co.uk/sch/i.html?_f...ulley&_nkw=stepper+motor+belt+pulley&_sacat=0

 

[AdrianH]

Thanks for the link

 

[bigbadbugga]

I was looking at doing cnc plasma a while ago, the biggest expense seems to be the type of plasma cutter you need to use, something to do with the torch and the way it starts to cut.

The common consensus is that it's difficult to make the import cutters work with the cnc, and you really need a hypertherm unit with a special torch.

Then there's torch height control. I got put off big time.

 

[AdrianH]

Well all I can do is try it and see. The pantograph I did just dragged the tip and did not cause any issues with cutting once I put back the original tip back on.

The book does suggest keeping the gap a mm above, but it is very hard to do by hand.

The bearings arrived today, still waiting for the motors, then have to get the steel to make the frame, so I am a while off yet.

Adrian

 

[T0rnado69]

a hypertherm is proberly the best one to use, as you can change the hand torch to a machine torch and the cnc can start and stop the torch.

but i did read a thread somewhere and they used an R tec plasma, ive even seen machine torches for the cut40/50 machines.

issue is the HF and how that affects computers, the steppers etc.

il see if i can find the threads..

 

[Maker]

I think you might want/need to use cy control cable and shield all the electronics to prevent HF from having an effect. Is that correct Robotstar ?

 

[T0rnado69]

yer that sounds right cy cable

 

[T0rnado69]

this is on a US forum ,but its a good read 8x4 plasma table
here one about a china HF start plasma cnc

 

[AdrianH]

One can get straight torches for the cut 40, just takes a while to arrive from China or where ever they come from. The Chinese stepper control has outputs to control a relay so switching on and off the torch will be quite simple, better then me with my switch on the pantograph. The idea of shielded cables is fairly normal for most control gear, think I still have some cable around somewhere. I like the idea of clamping the tip of the torch to ground, although I may try via a high wattage resister and decoupling cap first, say around 100 Ohm 10 Watt and a High voltage cap, save current going through the tip, but still be enough for the arc to start.

There is also a ground connection on the back of the cut 40 to help minimise RF noise, same as on my R-Tech and all meant to be connected to the welding table etc.

All still a very long way off yet, but I can say with some authority it will not be any where near an 8 x 4 ft cnc, there is no way I could get that size in the garage It would have to sit on a 1000 mm by 600 mm table, so the cutting side will be smaller then that!

Adrian

 

[AdrianH]

Just had a chance to try the motors with the controller and my 24 Volt 14 Amp supply. All seems to be OK, which is good. It will also run with CNC Pro, which is now free, but only runs under dos. Used my Mill setup to run some G-code through and all seems to be OK.

Happy bunny.

Adrian

 

[DrNik]

I've got a rake of these pulleys, don't know much about sizes etc, take a look at my items for sale a while back, I don't know how to link the advert to here so I've bumped it in the for sale thread