New Build-12x6ft Plasma Table

[F1transportationserv]

wow guys thanks for the replies there great so far.

silyavski I was thinking of something like the image at the end of your quote build my table first use it if I need to then progress to cnc it asap. I'm new to this whole scene but I willing to try anything as long as I'm learning from it and it has something to do with my industry.

I'm thinking of a bench approx 12'6 x 6'6 so I can sit a 12x6 sheet onto it with finger or hook room. Might even place it in a room 20x8 ish with a little overhead gantry to keep it all tidy away.

The table will probably be 75x75x5 square tube and 50x50x5 square tube with a water tray similar to this.

And the left/right sides will probably be the 140x140x6mm at least. What will I make the gantry out of?

[Robin Hewitt]

The table will probably be 75x75x5 square tube and 50x50x5 square tube with a water tray similar to this.

Hang on a mo', stop drawing and start thinking...
You have to support the slats that support the work piece and you have to support them through the water bed. I don't see slat support. A water table 5' x 8' is 40 square feet so every inch depth weighs slightly over 200 lbs. You have to support that to, add some triangles perhaps.
When you weld this thing up it is going to bend. Suggest you do not weld the gantry supports because you will only end up trying to correct the misalignment with a THC. Best if you correct misalignment with screw adjustment or, let the gantry assembly rest on the table so it conforms.
More if you want it...

[F1transportationserv]

Hang on a mo', stop drawing and start thinking...
You have to support the slats that support the work piece and you have to support them through the water bed. I don't see slat support. A water table 5' x 8' is 40 square feet so every inch depth weighs slightly over 200 lbs. You have to support that to, add some triangles perhaps.
When you weld this thing up it is going to bend. Suggest you do not weld the gantry supports because you will only end up trying to correct the misalignment with a THC. Best if you correct misalignment with screw adjustment or, let the gantry assembly rest on the table so it conforms.
More if you want it...

That was an idea i came across for the table, I have this one also as an idea separate table to the gantry with maybe a 4 hole base plate for leveling up (or is this too much)??

[Davek0974]

Wow, some heavy-duty ideas there:)

I was also advised never to weld the thing 100% and i am not doing so now.

The base frame will hopefully be welded and gusseted/triangulated as one piece, right up to the support pads for the motion beams.

The beams for the Y-axis will then be bolted on so they can be adjusted, paralleled and shimmed level to each other and the bed area. Once they are set, the X-axis/gantry will be easy to fit.

That is my plan but my machine is far smaller at only 1250x1250mm cut area. I am thinking of using 50x50x5mm for the whole build including the single gantry beam.

[Robin Hewitt]

Here is another idea. You will need a torch height control. Once you accept that as a design feature it becomes obvious that the torch needs to be raised and lowered by a DC motor driven by a power op-amp. This hugely simplifies the THC and greatly reduces the weight of the torch assembly which, in turn, greatly reduces the weight of the gantry needed to accelerate it. It also reduces the wiring and without electronics at the torch head it makes you immune to interference from the arc.
If you think of torch height as an obvious job for a DC motor it is not hard to get cut and pierce heights using micro-switches rather than using a computer and vast hardware to do something absurdly simple. There are more ways to kill a cat than building an Arnold Schwartznegger, terminator look alike, cat stomping machine.

[F1transportationserv]

Yes I was thinking of an adjustable 'Z axis', the diagram of the table was only a rough idea.

I'm thinking a basic frame 75x75x5 with the braces out of 50x50x5. I'm looking to cut 6 and 10mm mostly maybe some 12mm sheets so I need to build a table braced to support a 12ftx6ft x15mm sheet if need be I will increase the sizes or just make it all outta 75x75x5???

The image of the table I attached had a .dxf file of the slat support designs I must redesign these to suit the size of table I go for and I will price them for cutting in a local engineering shop.

My biggest problem of the whole build is the motors and the rails setup. The fabrication of the table and the separate supports for the gantry is the reasonably easy part?

Do I have to buy the rails as a one piece or can they be joined?? Also how many do I need??

https://youtu.be/vETkf1sqo3M
This lad used angle irons and rollers like a roller gate set up for the liner rails will this system work?? is it a cheaper method??

Thanks again for the replies its great seeing that people are willing to talk and share there views.

[Robin Hewitt]

You can say 75x75x5 until the cows come home but it still won't mean anything. It isn't what you use it is how you use it. At the moment you are trying to build a bridge without appreciating how a bridge works. More James May, less Jeremy Clarkson please.

It might be worth mentioning that all your problems are down to the idea that it will look really neat if you lift it off the floor. If you sit it down on the floor all your problems evaporate, well, so long as the floor isn't flammable

[Davek0974]

Yes I was thinking of an adjustable 'Z axis', the diagram of the table was only a rough idea.

If by adjustable, you mean a torch height control, then I would say for a build of your size it would be essential, not just a thought ;)

My biggest problem of the whole build is the motors and the rails setup. The fabrication of the table and the separate supports for the gantry is the reasonably easy part?

One thing I have learnt so far is to take it all into consideration, but build it in parts.

Do I have to buy the rails as a one piece or can they be joined?? Also how many do I need??

Liner rail like HiWin can be butt-joined if carefully aligned, longest bit in one length I think is 3m. As to how many, if you take a look at the specs, they can take a massive load, the 15mm section am looking at can roll a 1500kg load! It must be fitted correctly though with side support etc.

This lad used angle irons and rollers like a roller gate set up for the liner rails will this system work?? is it a cheaper method??

Cheaper, yes, better, no.

I would look at proper linear rails, one per side probably 25mm size, but thats just a guess. Get the carriages fitted with wipers and scrapers.