CNC Plasma cutter, start of bits buying.

[AdrianH]

Cheers DrNik, not sure of what I need yet, still need to build frame. No plans here as I do it as I go.
Video of testing motors and controller less then 2 mins .

Adrian

 

[DrNik]

I purchased some of that bolt together aluminum channel, serious heavy duty stuff, bolts together with D shaped nuts that slide into the groove in the channel, I've been collecting stuff for a while but never got round to building it, got linear rails and ball screws gathering dust under the bed

 

[skotl]

Cheers DrNik, not sure of what I need yet, still need to build frame. No plans here as I do it as I go.
Video of testing motors and controller less then 2 mins .

Adrian

Looks like a good start! I'll follow this thread with interest

 

[whensparksfly]

here s alink to aluminium rails http://www.ebay.co.uk/itm/V-Slot-Al...055?pt=LH_DefaultDomain_3&hash=item339c22987f

 

[DrNik]

Do you think that rail would be a smooth enough runner/track and not skip or jump

 

[whensparksfly]

I don't know what dose your rail look like he sells bearing kit to fit the rails.

 

[DrNik]

I've some of these, but my frame is more rougher as it's been used and a lot bigger profile

 

[T0rnado69]

that looks like supported round rails. ?
from what ive read on cnc sites the best is hiwin linear rails but they do come at a price like most things.

 

[skotl]

Just starting to look into this and a set of round rails and screw rails (are they still rails if they are screwed threads?) are £300 and beyond, even shipped from China.
Seems like these rails will be the single most expensive set of components.

 

[T0rnado69]

ballscrews.... ?

skotl what length rails you needing.

 

[Wedg1e]

I've used a couple of different types of linear slide rails, each has their pros and cons.
The 'square' type are good, I prefer the carriages to have the wider mounting surface unless space is at a premium... just makes for a larger contact area and wider bolt spacings.
For vertical rails, the supported round 25mm type are the dog's danglers: I used them to carry 150Kg sliding doors.
The unsupported round type deflect under load so you have to be careful how you use them.

I used 15mm square rails and HiWin carriages, 5mm pitch ballscrews and 20:1 reduction gearing on NEMA 23s (I think) on a 7m long inspection tank last year... one tip, drive your X-axis carriage at both ends otherwise, regardless of how stiff you (we!) think it is, it'll deflect due to stiction in the undriven side rail. I used rack and pinion on one side but am currently looking into fitting rack to the opposite side and running a driveshaft through the hollow extruded alloy beam (160mm x 80mm x 1.5m) rather than trying to persuade two steppers to stay in synch.

These are the motor/gearboxes...

http://www.cnc4you.co.uk/Planetary-...x-20:1-Ratio-fitted-Stepper-Motor-45Nm-Output

Used this power supply as we only really need to move one axis at a time; inspection is a bit slower than machining

http://www.cnc4you.co.uk/Breakout-Board-and-PSU's/400W-PSU-36Volt-11Amp

Three of these stepper drivers...

http://www.cnc4you.co.uk/Microstepp...tor-Driver-4.5A,-50V-CNC-Microstepping-CW5045

The steppers all have double-ended spindles so you can fit rotary encoders to the non-drive end; I'm still waiting for our software guy to work out how to read the encoders to fine-tune position... the control system is a Siemens PLC.

 

[AdrianH]

My frame is slowly being built and I am collecting the bits as I go, only thing to say it will be cheap. As to how accurate and reliable is anyone’s guess at the moment. Only a small frame of 1 metre by 600 mm as I am not trying to get industrial.

As usual figure it out as I go.

Adrian

 

[skotl]

ballscrews.... ?

skotl what length rails you needing.

Nowhere near that right now - just gathering my thoughts for a future project

 

[skotl]

These are the motor/gearboxes...

http://www.cnc4you.co.uk/Planetary-...x-20:1-Ratio-fitted-Stepper-Motor-45Nm-Output

£213 per motor?

only thing to say it will be cheap

Ahem - yes.

 

[Wedg1e]

£213 per motor?

yep! One each for X and Y (sorry, I think I said 3, however the Z-axis (mast) has a NEMA 23 direct to its ballscrew). I like overkill, especially when someone else is paying

 

[skotl]

yep! One each for X and Y (sorry, I think I said 3, however the Z-axis (mast) has a NEMA 23 direct to its ballscrew). I like overkill, especially when someone else is paying

Ah! Phew... thought I was being a cheapskate

 

[mike os]

I hear hiwin 15 can be a bit of a pita to get something to fit grease nipples... how did you find it?

 

[Wedg1e]

I hear hiwin 15 can be a bit of a pita to get something to fit grease nipples... how did you find it?

They are a bit; if you screw the nips up tight (ooer missus) they tend to end up pointing in whichever direction gives you no access - my air-powered grease gun fits them OK but they have to be either left slack or undone a bit to get the gun on. You also can't turn them a full rotation once the carriage is on the rail.

I've used the Hiwin 15s a few times over the years; probably my best effort was a top-loading lead cabinet used for irradiating mice to kill their immune systems (anyone see the cancer prog a couple of nights back, those hairless mice are called 'nudes', they're bred with no hair and each one costs hundreds).
Anyway the doors are cast from lead up to 75mm thick, weigh about 40Kg each and are shaped to overlap each other and the walls of the chamber to prevent radiation leakage; they have to open and close with less than a millimetre gap all round and meet perfectly in the middle. They also have to move using an electric motor about as powerful as that from a slot racer (to avoid crush injuries). Piece of cake with linear rails

Anyway, a quick couple of pics of my latest creation; this is the Y-axis carriage seen from one end of the X-axis beam (motor and 20:1 reduction box at left):

The Z-axis is hidden behind that blue cover, another of which hides all the untidy bits you can see here. You can see how close the carriage grease nipple is to the rail!

The belt-driven encoder is due to my forgetting to allow enough headroom above the Y-axis motor (the encoder would normally be mounted directly onto it); it was easier and cheaper to do it this way than to have a new alloy cover fabricated and powder-coated.
The rubber rollers in the background support and rotate the solid steel bars under test.
Note proxy sensors used to determine axis travel limits; the triggers are alloy cylinders with a screw through into a captive nut in the channel (seen to left of the Hiwin carriage in the first pic), makes for rapid re-positioning. Grey cables exiting hole at right in pic above are from the Z-axis proxies.

Bit blurred but this is the Manual control page of the HMI, allows each axis and the rollers to be run for setup etc.

 

[Wedg1e]

Some pics of one of my lead shielding cabinets...

One of the doors with its support frame:

Doors mounted to linear rails:

Fully open, the doors retract to leave full access to the irradiation chamber, which has a fabricated nylon liner installed to catch any animal 'spillages'. The lower chamber houses a powerful x-ray tube that provides the radiation necessary to nuke the immune system of the subjects. As the primary radiation beam is firing directly upwards, the doors have to be a close fit to avoid everyone in the vicinity getting dosed:

Not very clear, but you can see how the doors 'interlock' with the chamber walls (and each other) with minimal clearance:

The whole thing is installed in a stainless steel fabricated cabinet so all the operator sees is a hole into which to drop his rats and mice
Digressing a bit from CNC I know, sorry, but I just found the pics and remembered I'd mentioned the thing...

 

[skotl]

...Anyway, a quick couple of pics of my latest creation; this is the Y-axis carriage seen from one end of the X-axis beam (motor and 20:1 reduction box at left):

View attachment 59722

The Z-axis is hidden behind that blue cover, another of which hides all the untidy bits you can see here. You can see how close the carriage grease nipple is to the rail!

View attachment 59721

The belt-driven encoder is due to my forgetting to allow enough headroom above the Y-axis motor (the encoder would normally be mounted directly onto it); it was easier and cheaper to do it this way than to have a new alloy cover fabricated and powder-coated.
The rubber rollers in the background support and rotate the solid steel bars under test.
Note proxy sensors used to determine axis travel limits; the triggers are alloy cylinders with a screw through into a captive nut in the channel (seen to left of the Hiwin carriage in the first pic), makes for rapid re-positioning. Grey cables exiting hole at right in pic above are from the Z-axis proxies.

View attachment 59720

Bit blurred but this is the Manual control page of the HMI, allows each axis and the rollers to be run for setup etc.

That's an incredibly impressive looking bit of kit.