[DZstar]

Hi all,

I have been looking at owing a cnc plasma cutting table as a hobby since early this year, but being living in Algeria was not that easy to get good qoutes for shipping and after that paying customs (50%) for the parts imported, besides I didn't have that much money to spent (same old story), so I decided on building one if possible.

As most of you out there, I searched the internet for months and downloaded lots of documents and images, finally I went through and made a simple design out of the images i downloaded from the internet.

to make the story short I will post the pictures here, the table table is finally ready , what I miss is the THC and the plasma cutter which I have not decided to which one I should buy yet and need your help guys on this one, there is not much of choices locally but I will list them and you can help me.

I bought the controller from Damen CNC in the netherlands from Kevin, price was good and shipping was by DHL fast and easy.

here is some pictures and if intretsed I can post more,

Regards,
Dzstar

[xjdubber]

Looks good, i would go for hypertherm for the plasma cutter. IMHO I would have gone with candcnc.com for the controller it would have had thc with it.

[DZstar]

I couldn't find hybertherm in Algeria, what i found is the following:

Esab LPH 35
Esab LPH 80
Esab Powercut 650
Esab powercut 875
SAF ZIP 2.0
SAF ZIP 4.0
FIMER 40


I planning to cut 3mm to 5mm mostly and 8mm occasionally.

I will consider candcnc for the next order , i will contact them to see the shipping cost from the US to here.

[Weldtutor]

I couldn't find hybertherm in Algeria, what i found is the following:

Esab LPH 35
Esab LPH 80

Hi DZstar :wave: & welcome to CNC zone!

Great work on the construction of your CNC plasma table. The bearing mounting method is interesting & should work well.

Thanks for sharing the photos of your project which is sure to inspire others.

The Esab units in the quote above should work for your material thicknesses, with the #80 preferred for heavier sections.

Keep us posted as you complete your build.

[DZstar]

Weldtutor,

Thanks for the kind words, I wanted to give back something this forum where i learned a lot on the cnc plasma.

I will also post the cad files i designed for the Y axis ( it is not was finally came out because of my poor drilling technique, but should be helpful if someone wants to modify the dimensions)

the thing that I don't understand is the difference between LPH 80 and powercut 875 , both seems to cut similar thicknesses , can you please tell me what? is it something about the HF torch thing!! and why the HF is imporatnt (or not)?

[energyforce]

Does HF stand for high frequency. I know with TIG welding you have something called a high frequency start, and if you use that you can start welding without tapping the electrode onto the metal. The spark automatically jumps through the air and an electrical connection is made and the welding starts.

If you dont have high frequency start you need to tap the electrode to get a spark and get the welding going (like stick or arc welding). Maybe this is what HF stands for?

Crossing my fingers im right! Ill see what the pro's say after my post....

Erik

[DZstar]

i just managed to convert my mobile videos to .avi hope this benefits someone.

not good quality videos but well gives the idea.

[DZstar]

can someone tell me how to calculate the duty cycle of the plasma cutter? i dont understand what to set when trying to cut a door that Sheetcam says it will take 25 minutes on 5 mm plate when the duty cycle says 40% or 60% ? will that mean it will stop after 4 or 6 minutes and to do then?

thanks

[DZstar]

can someone tell me how to calculate the duty cycle of the plasma cutter? i dont understand what to set when trying to cut a door that Sheetcam says it will take 25 minutes on 5 mm plate when the duty cycle says 40% or 60% ? will that mean it will stop after 4 or 6 minutes and to do then?

thanks

[Torchhead]

DZstar: Duty cycle is one of those "loose" parameters. 40% Duty means you can cut 40% then you have to wait 60% of the period for it to recover. But 40% of what you ask!. Well, until it stops (. It's a function of heat. The power electronics get hotter the longer you cut. If you could wrap them in flowing ice water you could get 100% duty cycle. If the ambient temp is high your period will be shorter (i.e. it will get hotter faster and then it will stop faster and then you have to wait the 60% cool off period.

Put more airflow on the power components and it runs longer and cools quicker.

As you can guess there is no accurate way to predict the actual length of cut time you can get before it stops.

25 minutes!!! What in the wide world of sports are you cutting....an image of the Last Supper? If you have lots of objects you can break them into units and let the machine "rest" at intervals.

I have never had one job that lasted more than 7 to 10 minutes (and even that was not continuous cutting) but I don't cut much detailed (small pieces or cutouts) in 5 mm plate.

I can tell you the numbers (unlike the listed cutting thickness ,which is overstated by a lot) for duty cycles are conservative. It takes into account things like continuous cutting and high ambient temps.

Buy a bigger machine and the times go up. Add better cooling and the times go up. A bigger machine also means faster feedrates so less time to cut the same piece.

Also remember that the SheetCam estimate is total time and includes Z up and down while not cutting and rapids. Anytime the torch is off it is cooling down.

[Torchhead]

Does HF stand for high frequency. I know with TIG welding you have something called a high frequency start, and if you use that you can start welding without tapping the electrode onto the metal. The spark automatically jumps through the air and an electrical connection is made and the welding starts.

If you dont have high frequency start you need to tap the electrode to get a spark and get the welding going (like stick or arc welding). Maybe this is what HF stands for?

Crossing my fingers im right! Ill see what the pro's say after my post....

Erik

HF does indeed stand for High Frequency. Since plasma is basically burning air it occurs at high temps. The temp of a plasma flame is roughly 30,000 degrees. You can start the porcess one of two ways: Pass a "spark" of high frequency current and ignite the air of use a manual contack "arc" from touching the tip and withdrawing it quickly.

The HF approach works but causes a lot of RF noise during the process. The touch arc method is less noisey but useless for automated control.

The Hypertherm and TD units (some models) use a contact start but it occurs inside the tip. The electrode is spring mounted and with no air flowing its down in contact with the tip. When you fire, the current starts to flow and the air turns on and blows the electrode up and away from the tip and creates an arc start plasma event. That method is limited to units of 100 A or less but does work to reduce noise.

The really cheap units force you (the operator) to be the arc start by touching the tip....not good for CNC or machine cutting.

Tom Caudle
www.CandCNC.com

[DZstar]

Torchhead,

Thank you for the information,

I got the 25 minutes from Sheetcam estimation for cutting a 1 meter by 2 meters artwork tht I bought from ironshadow (it is a door). i just ran it again on another art work and it gave 18 minutes.

Can you please advise of what Plasma cutter from the ones available locally in Algeria should I buy to be used with my CNC table?

Esab LPH 35
Esab LPH 80
Esab Powercut 650
Esab powercut 875
SAF ZIP 2.0
SAF ZIP 4.0
FIMER 40

[DZstar]

well, it works! not as I hoped it will do but it works...

AFter A LOT of hours of work, finally I manged to get this table to cut some steel, but let me start where I stopped above, I finally got a good deal on this FIMER 40 plasma cutter (italian made, old version) it is a new machine but an old model, it should cut 8 mm but I hardly went through 5 mm. I paid $700 for this one. Image(923)

I had to attached a relay to BLUE cable inside the Machine itself ( though it was better than connecting to the torch handle itself) which I found it attached to the trigger. made a hole in the face of the plasma machine and fixed a socket for a wire connecting it to the controller box. images 919, 922 926 931 932 938 940

[DZstar]

then I made an enclosure for the PC and the Controller box, I prefred to use an old PC I had rather than the sony laptop (was afraid something will blow up ) image 964 965

Then found a good deal on this 2.5 Hp air compressor ($178). image 974

Connected everything and started the machine ......... image 961 962 949

[DZstar]

here is the first cuts I made..

[DZstar]

that was the GOOD NEWS, now the BAD NEWS is:

1. I used my house garage to build and run this table, so I used the house 220V-30A max electricity supply which Couldn't handle the power requirement of the plasma machine!!! Problem.. will need to somehwere with higher power supply.

2. I dont have a THC which made me unable to cut longer cuter as as soon as the Torch moves away from its referenced Zero the steel sheet(2 mm) had some up and downs . WILL NEED TO BUY A THC, CAN YOU PLEASE TELL ME IF THC 300 WILL WORK WITH MY PLASMA CUTTER?

3. Will need to build a stronger Z axis with afloating head to ref Zero in the Z direction, DOES THE THC 300 REF ZERO ALONE OR I NEED A FLOATING HEAD ?


i attached a video (3GP format) for one of the first cuts.

THANKS for all the help you all showed in this Forum,

[Torchhead]

You need the floating head (touch off) to establish top of material. If you use SheetCAM you can set it to reference Z before every pierce or up to several feet of travel between references. The THC300 should work with your plasma. It needs three signals:

Torch Switch (relay contacts run in parallel with the existinf torch swtich)
Tip Volts ( raw tip volts between the electrode wires and the workclamp lead)
Arc Okay (provided by a current sense trasformer in units without the signal)

The floating head assembly only adds a few pounds. It's just a short precision slide and brackets to mount it on the existing Z and hold the torch head.

Join our support forum. There are pix of the flaoting heads users have built and even some free plasma artwork. CandCNCSupport Yahoo Group

Tom Caudle
www.CandCNC.com

[EMMKAY]

Simple and good looking. Congratulations on the machine.

I did notice that you are running the longer axis with a leadscrew. Any problems on the whip of the screw for plasma cutting.. what is the length of the longer axis....

regards

EmmKay

[DZstar]

Torchhead,

Thanks for the info, i will sure check the group.

EMMKAY

The lonegr axis (x Axis ) is 238 cm of 2 mm / 14 mm Diameter. it it not rigid enough and vibrates on higher speed so I ordered a 22 mm diameter that should be stromger.

If that doesnt work I might go to rack' n' pinion

[EMMKAY]

In my table design I have a 10TPI 3/4 inch lead screw which is 2500 mm long. I am still reading of various issues I may have with it. I am looking at fixed mount designs from nook industries to stop the whipping. Will be interested in knowing how you get along as my table is still on paper and in heaps of iron bearings and screws at the moment.

cheers
EmmKay