plasma table idea

[simonr]

This any good for torch holding?

https://www.youtube.com/watch?v=l9hBQafpr9M&list=UUDmxnPem-pPfJQATIkfgY2Q

Have to admit I got bored watching the 1hr video. Got the jist of how it works though.

Today I've wired most of mine up - at least connecting cables to the motors at one end and 4 XLR plugs at the other. I'm still waiting for my motion controller

http://www.ebay.co.uk/itm/251626951425?_trksid=p2059210.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT

To show up. I don't really need a USB controller for the table - but it opens up the choice of PC to drive it. I'm hoping to use an 'all-in-one' PC & Touch screen intended for EPOS (tills in shops) - but mostly they only have USB. They are low cost and very robust though.

I'd originally intended to put all the control in an Amo Tin - but I have a Peli type case about the right size. I think it came from B&Q or HomeBase and was only about £15 IIRC. I plan to have all the control in one half and the PC inside the lid so it's protected when closed and easy to store. Open it up like a BIG laptop, plug in the XLRs + mains lead and it's ready to go.

Si

[simonr]

For the controller, I bought one of these:

http://www.ebay.co.uk/itm/IEI-Technology-AFL-08A-LX-8-4-Touchscreen-PC-500MHZ-1GB-4GB-Embedded-XP-/131281696642?ssPageName=ADME:X:BOCOR:GB:1123

It runs Embedded XP which should be OK for Mach3. The embedded version is just XP with all the drivers and free apps removed. It's also write protected so the installation of Windows cannot be modified / damaged by other apps installed.

Watch out for Windows CE - it's not the same as Embedded and Mach3 will not run on it.

I'll let you know how right I turn out to be!

Si

[Cynic-al]

Some of our moulding machines have the same version of windows, the os & software is on a cf card and if you want an update or bespoke work doing the manufacturer do it and post you out a new cf. If they're the same I wonder if you could setup an image that you just dump on a CF card which is all setup ready to go so that it's an out the box machine?

[robertspark]

I was thinking about an all in one PC with a touchscreen, but I've got so many old PC's and laptops about I can't justify another one, but may weld up a wall cantilever bracket to hold one (laptop).

thought you kind of need 2 x usb ports, one for the cnc controller (if you're not using the parallel / printer port like me), and another for an pendant.

I've been collecting my bits for many years, and I have a shuttleXpress pendant..... in reality I should have held out for a proper USB pendant (+ wireless), but I'll see how I get on with the shuttleXpress given it's new and not been used yet.

been a bit distracted at present, I'll get back to it all tomorrow evening.

[CwazyWabbit]

......

thought you kind of need 2 x usb ports, one for the cnc controller (if you're not using the parallel / printer port like me), and another for an pendant.

......

Simple enough to add a USB hub, then there's as many usb ports as you like.

[simonr]

The PC has two ports - but I'm adding a 4 port hub as well. I need

1 for motion controller,

1 for keyboard,

1 for USB stick to transfer programs.

I've bought a Panel mount USB socket for the USB stick - just to make it easier.

I have a pendant (based on 'pokeys') on my mill - but I've found I've not used it much. On the first version of my Lathe controller, I had two MPG's (manual pulse generators) (a knob which generates pulses used to move the axes) for the X & Z axis, but like the pendant - I never used them!

On both, I just use the cursor keys for jog, ctrl + cursor keys for step & Shift + cursor keys for rapid. That's my plan for the Plasma too!

Si

[robertspark]

Oh dear I forgot about just adding a hub to add more USB ports..... It's official I've lost the plot!

[robertspark]

Anyone made any progress?

[CwazyWabbit]

Not yet, been collecting a few more parts and seem to have distracted myself into rebuilding a Meddings pillar drill .... I'll get back with the program soon

[simonr]

I've almost finished wiring the control box and setting up the computer. Mechanics are all but finished. My floating torch design needs a bit of work. I know what I need to do, and drawn it for laser cutting. However, I'm going to mill the components I have to make the mods rather than cut a new set.

I'm away this weekend - so there will not be much progress until next weekend. Then I want to get the XYZ driving around at the very least.

Si

[simonr]

This is the first test run of the X, Y, Z drives. I've not connected the plasma yet (obviously). If I get bored later - I might try drawing something with a felt pen though!

Si

[Lewis]

That's cool!

When can I buy one?

[simonr]

When I've got it fully working!

I'm going to change the way the Torch Lift slide works a little. The original gave too much freedom of movement in X & Y and was too stiff in Z

I'll Mill these bits for mine - but they can be laser cut for the Mk 1.1.

Si

[Bowie69]

Very cool, I guess now you can manufacture parts for the next one, using that, and iterate further from there, in fact it has a whole lot of feeling like Arnie is about to walk through that wall over there, carrying a shotgun....

*edit I like this, apart from the sound

[robertspark]

Very nice Si.

Impressed with the motion and use of the cable chain. Tell me does the cable chain only bend one way and that's why it rolls up over its self

Take it the point of sale PC works fine?

rob

[simonr]

The cable chain, as you suggested, only bends one way. It's a bit Chinese - and not very strong so the segments pop apart way to easily. I may replace it with proper IGUS cable chain at some point - or make better supports for the ends!

The PC I ended up using was a Dell Optiplex 160, which was made as a Media PC to Velcro to the back of your telly. It's about 200mm square and 45mm tall - but not at all bad in PC terms. Mine came with Win7, but I changed to XP as it works better with Mach 3. I used an Elo USB touch screen which is intended for point of sale use.

The original all-in-one PC was useless! It ran a version of XP Embedded edition which didn't like Mach 3 at all (blue screen of death) so I swapped it with the vendor for the PC and Screen. He gave me a brilliant service!

After a couple of hours milling, I've changed my torch lift assembly to the thing pictured above - and it works nicely! The torch lift is so that you can lower the torch until it touches the plate (to detect the height). As the Z axis drives down, the plate the torch is attached to lifts a few mm, closing a switch. Mach 3 uses this to reset the Z zero position. This is the poor mans version of the auto torch height control Robert has bought. I figured I don't need to cut corrugated plate and if it works, I've got better things to do with £150! Time will tell!

A little more tinkering tomorrow then hopefully I'll try cutting on Sunday!

Si

[Blanco]

Watching with interest..... agree about the sound,.... but wonder too about the expat dragon??

[simonr]

Bit of an update today. I didn't quite have time over the weekend to actually cut metal - but it's a lot closer!

It took a few hours to figure out how to use SheetCAM. It would have been quicker if I'd figured out it does most of it for you - just accept the defaults.

I also learned that in your source drawing, you have to remove all the construction lines - otherwise it will try to cut these too. While it seems to understand layers - it wants to cut all the layers regardless of what you select. Maybe this is a difference between the free and paid for version?

Today, I attached a sharpie pen - and it drew this:

Not too bad - dimensionally, it's perfect! You can see where SheetCAM has added little loops on the sharp corners so you get a point on the cut item (rather than a rounded end).

I also realised today that my original plan of cutting on top of a pallet is a dumb idea! Why? Because the top of the pallet is never level with the machine. With the fully auto torch height control, it might work - but I aint got that!

I've modified the original drawings to add a tray for cutting. Like the other bits, this is a no-weld fitment (though I did weld mine in place). It's just made of two bits of 25mm angle, one at each end then a load of lengths of angle spanning the ends. It seems to work pretty well!

Hopefully I'll cut something for real next weekend!

Si

[discomikey]

oh now that is smart, and much more compact than i had envisaged, i seemed to think it was going to be cube shaped not slab shaped for some reason.

if only i could afford a plasma cutter!!!

[robertspark]

Nice work Si!

That was a similar arrangement to what I was thinking using a bit of angle iron for a grate.

My control box is finished, just wiring up the THC, and soldering my leads with plugs on both ends, if I pull my finder out this evening I could be there.

I'm not so sure about my floating head arrangement on mine, the microswitch seems to require a little too much movement for my liking. Been thinking about using inductive or capacitive proximity sensors for the zeroing of the z-axis before pierce height and beginning to cut.

Inductive seems fine.... until you put aluminium under it to be cut and I'd not sure how an inductive sensor would react. Also thinking about torch tip collision and how to deal with that in the long term.

Rob

[CwazyWabbit]

..... Also thinking about torch tip collision and how to deal with that in the long term.

Rob

Don't plasmacam just have a metal contact clipped to the side of the ceramic and when it touches the metal being cut it shuts the machine off?

EDIT the fancy term seems to be ohmic contact .... used for both setting initial height and for torch collision

[simonr]

Rob - don't worry about the amount of movement in the switch, there is a setting in the post processor in SheetCAM to compensate for the switch movement. Mine takes about 2mm - and it seems to work.

The 'ohmic' contacts only work if the sheet you are cutting is shiny & clean. Forget it with rusty old sheet! A straightforward switch (or inductive) on the other hand works fine either way.

Si

[simonr]

Guess what?

I'm not going to tell you! You'll have to watch & see!!!

http://www.youtube.com/watch?v=N7ui46wcZ6I

Si

[Blanco]

It is a rare pleasure when it all goes to plan.... great effort :i-m_so_happy:

[Cynic-al]

Nice