Building a chain driven Plasma table.

With todays engineering capability even cheap sprockets should be pretty close to having their bores concentric with the teeth. 1mm is hugely out of tolerance.

I made my table with chain (on the cheap) but wouldn't do it again. Next time I'll be going with heavy duty non-stretch synchronous belt. My chains are horizontally suspended and with a table size of 2500 x 1500, even with tight chains, you get lots of chain bouncing and that transfers to the cut. It would be better if the chains can be laid along a flat surface and they wrap around a drive sprocket on the gantry. That would eliminate chain bounce.
One other issue though may be chain wear (stretch as many call it). If you cut more in one section of the table than others the chain wear will be more in that area and you won't get linear travel any more. It's a bit like a toothed rack "stretching" in length at a certain section. I'm a mechanical fitter and it's quite surprising how much length change you get when a chain starts wearing. Not a massive issue for transmission purposes but may be for accuracy on a long CNC table.
Another issue is keeping the chains lubricated. You oil chains and oil helps plasma dust stick to it. Belts are dry and if you install a belt with the teeth facing down, resting on a flat surface, and wrapping around a sprocket on the gantry, I think you've got the best of all worlds. The main thing will be to get a belt/pulley type that has zero or very little backlash, as the drive pulley reverses direction.

Keith

I agree with you with today’s technology. It Needs a lot of stupidity for making pulleys and sprockets 1 mm out of center.
But still half of my sprockets were out by 1mm.

Maybe for some people the definition of a cam pulleys is A pulley where the pilot hole is not in the center.

As far as chain goes I m planning to do exactly what you suggested. Will post some pictures when I get there.

Just wonder about chain wear if it is the same as on a dirt bike. Worst case I got driving in dirt roads with lots of dust.

I got 3000km day with plasma you want to change it earlier so say 1000km

That is 10000000 meters how long does it take for the Gantry to travel this far?

I am no thinking of adding a fifth axle since I already have a chuck available so I am wondering what is the most convenient place. Within the Table next to the water tray or on the side of the table?

The sprockets came from a reputable company. I would not mention the name.

But I guess it is made in China. But at least they should check the quality.

It is time Europe and America gets weaned from outsourcing from China. Western companies have become so dependent on China that they can do whatever they want.

The cam pulleys are from China.
Shipping from China is cheap. And why should I buy locally if it comes from China anyway.

Hi to all
Just want to share, found a cheap plug for the CPC Port of my Hyperterm Powermax 45.

www.aliexpress.com/item/1005002589682498...1.0.0.42094c4djpcp0q

Just wander what cable would be good to connect to it.
I am thinking of a Cat7 Network cable. Would this work?

I only need 6 cores.
Just concerned they may be a bit thin. Do they break easily if flexing a lot?

CAT cable is only for Cpc port.
Thinking of using Mike cables for sensors.
And automotive cables for Stepper Motors. Do I need to shield the cables for the Stepper Motors?