Titivating A CNC Plasma Table

[philf]

Andrew,

According to the manual for your your PC these options should be in the BIOS:

Power Management
AC Recovery Determines how the system responds when AC power is re-applied after a power loss. You can set the
AC Recovery to:
Power Off (default)
Power On
Last State

Power on would be my choice with the program you want to run in Start Up. (Or a scheduled task to run on start up.)

I am using an old Dell PC in the power house of our hydro scheme and use this facility. It has a UPS but I had to remove the UPS software which turns the PC off in the event of a Power Failure after a preset time because the PC then didn't wake up.

Phil.

[awemawson]

Phil, yes those are the settings I've experimented with.

Reverting to 'Power On' works fine if power was lost when the PC was running, but of course Windows objects to just being turned off.

Reverting to 'Power On' Does NOT work if the PC was closed down in an orderly manner.

I reckon a strategically positioned spring loaded plunger on the enclosure door pointing at the 'Power' button may end up being used 

[PK]

The power button will just go to two header pins on the motherboard. Could you not unplug it and run them to a connector on the back of the box?
That way you could plug an external power switch in. It'd be a neat and tidy solution for you. You could even keep the switch on the case in parallel (they are normally open switches.

I'm happy to put this and the external power switch assembly together for you if the electrickery stuff isn't your thing....

PK

[Pete.]

I've had several SFF optiplex's and I do recall having this problem with one of them. Only trouble is I cannot remember how I got rid of it. Probably with a clean wipe.

Do you have a Dell install disk? With those you can re-install windows without the need of a key.

[awemawson]

PK, the whole front panel electrics including two USBs etc as well as the relevant button are on one multi-way header and it's extremely cramped.. This thing is small! But thanks for the suggestion and offer.

Pete, I think it's working as they designed it, another Optiplex 780 USFF that I have does the same.

[awemawson]

So today's job - mount the electrical cabinet.

Location concept -

a/ Make the top surface below the top rail so that it doesn't get nudged when mounting plates for cutting.

b/ Position it so that the PC in its mounting sleeve will fit on the left hand side of the cabinet leaving room on the right for a shelf for the Hypertherm 45 Plasma Cutter

Now the top rail on this end of the chassis is 40 mm further 'in' on the machine than the bottom rail so somehow it needs spacing off. I was going to make some mild steel spacers from fat hex bar and paint them blue, but decided to save a day of paint drying by making them from stainless steel round bar. Only down side - needed to drill a radial hole for a tommy bar to tighten them up.

So, cut two 40 mm slices off the bar - tapped both ends M8 - Loctited some M8 BZP bolts in the end - cut the bolt heads off and bobs you uncle - spacers ready to go.

[awemawson]

So this let me hang the enclosure on the studs on those spacers, to let me mark out where to drill the cabinet to align with the lower horizontal bar.

Then it was just a case of marking and drilling the enclosure - tapping the rail M8 and fixing it on.

I have to say my hydraulic pump up table gizmo was very handy in this regard as the enclosure is blooming heavy

[awemawson]

Then to mount the PC sleeve on the left side - I could have just used nuts and bolts, but as I want to hang the door on the other side reaching round it would be a pain, so I dug out my Nutsert / Hank Bush kit. Doesn't get used very often, but one of those things that's ever so handy when needed.

Just two M8 Hank Bushes, and bolt it on - I've positioned the PC so it is slightly back from other surfaces so hopefully not the first thing to get thumped accidentally when moving it about.

[awemawson]

Then to reverse the door: cabinet obviously designed for this - just a case of pushing plastic blanking plugs out of the side that will now take the hinges, pushing out the hinge pins, unbolting the hinges and re-building it all on the other side.

.. then don't forget to put the plastic blanking plugs back where the hinges were originally - this bit took more time than the removal and re-fixing of the door - they DIDN'T want to go back 

Like most of these enclosures, this one came with a steel 'back panel' that bolts inside to take whatever you are putting in there without having to put holes in the back of the cabinet. Very heavy - made from 2.5 mm plated steel. I will probably fit a pair of handles to it to aid taking it in and out, as with all the rest of the gubbins mounted on it, it will be very unwieldy.

So now with the cabinet mounted, I can give serious consideration to laying out the CNC modules and Power Supplies on that panel and have a proper feel for how cables will have to run.

[awemawson]

Today the duct arrived 

Quite nicely made, but I probably should have left more 'tolerance' on the size as it was a bit of a struggle to get it in place. The corners had to be peeled back (I'd had them leave them loose so I could) to get it into the plasma table. Then it was a case of locating the tapped holes for the two existing slat support rails and drilling through to them, and fixing it in place with umpteen 6 mm screws in drilled and tapped holes.

All went reasonably well - only broke one tap and sheared the heads off 5 screws 

If I was doing this again, I would have changed the shape of the funnel from symmetrical to uneven to locate the clean out door nearer the edge for ease of access.

[awemawson]

This afternoon I shortened and re-fitted the two original slat support rails, and finished welding up the new third one and fitted it. They are not yet adjusted for height - a job for tomorrow.

Another job for tomorrow is to shorten all the slats, as now the duct is installed they, like the slat support rails, are 2.4 mm too long - not that they need to be such a tight end to end fit as they were - but at the moment they won't go in 

[awemawson]

So having done the farm chores (including moving all the chicken into a sealed polytunnel due to the threat of Bird Flu H5N8 * ) I could get on with aligning the slat supports.

I set them so the top of the slat / bottom of cutting victim is 5 mm above the side rails for no reason other than it seemed sensible that they receive the sheet when being initially loaded rather than the side rails - previously they'd been a couple of mm below the rails. If it proves to be a wrong decision it is easily reversed as they mount on adjusting slots.

Having got to this stage it was time to insert a catching mesh - it will be a pain if little bits that you want fall between the slats and have to be fished out through the clearing door - at least with a mesh they can be recovered with a 'magnet on a stick' fairly easily. I'm not certain that this mesh will be entirely satisfactory as I fear that it might impede air flow too much. It just sits in so is easily replaceable - it started off as a one metre square of galvanised expanded mesh and I turned up the edges 25 mm to stiffen it a bit. (Actually it started as a full 1250 x 2500 mm sheet that was great fun manipulating single handed - amazing how often it catches on things including clothing  )

Right ho - time to trim those slats - no wait a minute, the whole idea about adding a third support rail for the slats was to curve them, which will reduce the 'chord length' - but how much. Answer - by just the right amount 

So the acceptable original slats have been returned to service along with seven new ones to replace the unacceptables.

Now I need to plot and scheme how things will be laid out in the electrical enclosure - I'm umming and arhing about whether to direct hard wire motors and sensors into the cabinet, or the use plugs and sockets. My thought at the moment is that there is no great benefit to the plugs and sockets, and its another thing to fail in the future. I intend to bring all wiring into the cabinet and first to a 'DIN rail mounted terminal strip' which will give an easy point of disconnection and also useful for test purposes.




(* http://www.edp24.co.uk/home/defra_tells_poultry_keepers_to_take_precautions_against_bird_flu_outbreak_1_4806869 )

[Spurry]

Glad you have the slats sorted. I was surprised yesterday when you said they were too long. I thought I had read of your intention to curve them, but could not find that comment, so thought perhaps I had imagined you had said it. Seems not. 
Looking good so far.
pete

[awemawson]

This afternoon I made the bits to add handles to the back panel of the enclosure that holds all the driver electronics and power supplies - It'll be too heavy to maneuver without them, and as I'm shuffling 'Blue Peter' models of the components to decide positions, they need to be able to speak for themselves in the debate 

Not exactly hi-tech - just four slices of 20 mm A/F brass drilled and tapped M8 and some flat strip I got years ago when Proops Bros were closing down - it's a bit more than mild steel (cracks if bent and is semi hard) and has rounded edges so is handy for this sort of application.

Been cogitating on the best way of getting all the existing (*) cables into the cabinet - went through a/ 50 mm galvanised conduit b/ weld up a duct from 70 mm box section c/ a length of 50 mm Adaptaflex flexible conduit - all designed to keep the cables away from the sparks. Then reason prevailed when I realised that the cable drag chain / flexible duct is plastic anyway, and the new extraction duct nicely shields things from sparks. So I've decided to use a bundle of perfectly ordinary corrugated 20 mm pvc cable duct, slightly influenced by the fact that I already have it on the shelf 

(* I'm actually going to replace the cabling as it's rather tatty - two drums of 4 way screened on order in 0.5 csa and 0.75 csa )

[Will_D]

Watching "How its Made" tonight on Discovery, they were building Big road rollers in Scandinavia (?).

They were plasma cutting 25 mm steel.

Question is how do you stop cutting the support matrix (i.e. your slats)?

Same goes for laser cutters and water jets

[awemawson]

You don't - they are expendable. The reason for curving them is that you are less likely to cut all the way along a slat as most cuts are straight lines.

[awemawson]

More layout cogitation this morning, aided by making 'Blue Peter' models of the items needed mounting just to make sure everything fits and can be 'got at' for wiring and later servicing.

Can't go much further until an order for more DIN terminals arrives - hopefully tomorrow.

[awemawson]

Then I made and fitted a 'Plasma Perch' - just a shelf to put the Hypertherm 45 on so that it is out of all the muck and bullets on the floor.

Simple job bent up from 1.2 mm Zintec and re-inforced by a pair of brackets left over from making the pig-sty's 

Trouble was that there are very limited places it could go, and no easy way of stiffening it up without those heavy duty galvanised brackets, which actually double up as stops for the Hypertherm, preventing it walking backwards or forwards - happen stance - not planned 

I will need to put a 90 degree fitting on the air inlet, or the pipe will go though an unacceptable bend radius.

[mattinker]

What is Zintec ?[


Knit one, pearl one............

All the best, Matthew.

[awemawson]

Zintec is electro-zinc plated steel Mathew. So essentially rust proof, but the zinc is nothing like as thick as on hot dipped galvanised.

[awemawson]

Trying to knock off all the mechanical jobs before I start re-wiring. Yesterday afternoon, and today's task was to sort out the mounting for the 'Gallows Bracket' - this is the davit affair that supports the cable going to the plasma torch, allowing it to reach the full gambit of the table.

When I bought it, the 25mm square tube it's made from was tack welded to a bracket that was tack welded to the main frame tube. I'd had to cut it off with an angle grinder to clear the door when I brought the table home, and had crudely bolted it back on as a temporary measure to use the table.

I decided to remove the tack welds and get the original bracket off the frame, and re-work it into a trunion allowing the gallows bracket to swing, and also be lifted out for transport. First I cut and bored a length of 30 mm bar with a 19 mm hole axially, then trimmed the original bracket and welded them together to form the trunion.

Then from the same 30 mm bar I turned one end down to 19 mm and made the other end 22.5 mm square using the 4th axis on the CNC mill. This allows the square to enter the tube and rest on a collar that I formed.

Then bolting the trunion back where it was removed from it was time for a trial fit - yes works fine.

Just needs a nice coat of blue paint - I'm slowly accumulating enough little bits to paint to make it worth while using a spray gun.

[DICKEYBIRD]

Following along with you projects is always a learning experience Andrew.  Where else can us Americans get such a worldly education for free?  Along with the many tips & tricks contained in your threads, I learned a new word (titivate) in this one.  I also learned the term "Blue Peter".  Had to look that one up on Wikipedia.

I hope you enjoy creating these threads as much as I enjoy reading them!

[awemawson]

Dickybird, thanks for the kind words. Glad someone is following   

Motivation for the threads is largely to keep a record of what I've done, and also sort my thoughts out as I'm updating things - surprising how often I'll go back over an old thread to look something up, and if people are enjoying them then that's another fillip 

[DICKEYBIRD]

....if people are enjoying them then that's another fillip

There's another one!

[Pete W.]

Dickybird, thanks for the kind words. Glad someone is following   

Motivation for the threads is largely to keep a record of what I've done, and also sort my thoughts out as I'm updating things - surprising how often I'll go back over an old thread to look something up, and if people are enjoying them then that's another fillip 

I've been following!  And enjoying!!