Cut speeds for 50 amp Chinese plasma cutter

[wiltshire_chris]

Hi folks, I'm nearing the end of my table build. The metal work side of the build is fairly straightforward but the electric/software side has been a interesting learning curve, the bit I need a bit of guidance on is what cut speeds shall I start with as a ball park figure? The cutter I'm using is a cheap Chinese 50 amp machine, if I can't get that to work properly then its going to have a Jasic cut 45. but the hope is to have to up and running for less than £600.

[Plasma-art]

Cut speed is dependent on material thickness.
For my build looked up some cut charts, lowered it by half and started cutting and sped it up each cut to find the limit.

Don't run that 50 amp machine at full 50 amp otherwise it's going to overheat pretty fast.
Find a nice speed at around 40 amps max to get a good balance between cut speed and duty cycle.
It is doable with the Chinese machines but just a bit harder.

Got pictures of the table? Interested to see what you built .

[wiltshire_chris]

So its a copy of a copy, the cut area is 120cmx80cm. We have a standard size sheet off 100x200, the idea is I can over hang the sheet, the idler wheel is height ajustable to allow for sheet thickness. It's a theory.

[Plasma-art]

Got the plans for a similar table lying around, it's easy to build with minimal tools and a 3d printer.
Looks like a decent starter design.
I doubt you are going to be able to run it as fast as the hypertherm cut chart would state considering the 3dprinted part is the weakest link in this setup.

Start out with maybe 1000mm/m and go from there.
You might need to lower the amperage a bit to get clean cuts at those speeds.

[wiltshire_chris]

the initial idea behind it was to assist with the bbq's I make.I'll see how it goes, if I can get it to work and it pays for itself then ill look at upgrade options. I don't have recent pictures of it but the slats are made, ill order the steel for the water pan this week, I'm waiting on a 20 tooth drive gear and need to wire the relay to the Arduino, I hope to have it cutting by the end of the week. The thickest metal will be circa 6mm

[acourtjester]

Welcome aboard Chris, Good to see other DIY types join the site. Your table looks like a first gen Langmuir table, that will get you feet wet and see if you want to go farther in the future. I have built 10 table myself as a DIY guy, learned a lot and am having fun. Any questions about the electronics just ask, many here to help. One problem with the cheap Chinese plasma is the nozzle sizes, they sell them mainly to chop metal apart not some much for clean cutting. You can use the search function here to look at past posts about cutting speeds and what to look for.
have fun
Tom

[Plasma-art]

and need to wire the relay to the Arduino, I hope to have it cutting by the end of the week.

Be aware that arduino's and especially arduino clone boards hate EMI.
Ground everything to a star ground and get a ground rod put into the ground and tested by an electrician to combat that.

[weldguy]

Interesting build, I like it! I would suggest starting with the Powermax 45 cut charts which can be found here viewforum.php?f=163 but reduce the cut speed by 10-20% as a starting point and once you find the ideal speed for each material that you cut just edit the chart for future reference. Curious to hear how this setup works out for you. Best of luck