DIY CNC plasma cutting table - Making the right choices for interference free cuttings 

Thank you for your support my friend! Nothing stop me from sharing my experiences, as long as they are helpful to the poor hobbyists like we are.

I removed the RNRmotion board(the same one that I have been using on my milling machine) and replaced it with the NVEM board. And I do have a official license of Mach3.

@@minhsmancave9448 official license at $175?

@@joetke Not at $175, you can always find some discount somewhere. I paid $140. I always pay my software (SheetCam, LightBurn, Mach3) if I found they are worthy. But I can't deny that a hacked version is a good way for trial and I did start with it. If you buy the combo SheetCam+Mach3 (in case you have a plasma cutting table), you can get Mach3 for $120 I think. Mon ami, ou etais tu? Tu m'a inquiete un peu. Ca fait quelques jours que je voudrais t'envoyer un message pour demander tes nouvelles. On n'est pas sure de rien dans ce temps de pandemic.

@@minhsmancave9448 et moi alors? Avec les chiffres inquiétants du covid chez toi, je commençais à m'inquiéter aussi... Tout va bien, merci de ta part. Je suis plongé dans deux projets qui ont peu de chose à voir l'un l'autre: le design de logos et leur réalisation par broderie industrielle, d'une part, et de l'autre, la création - design aussi - de moules pour couler de l'argent/de l'alu ou autres, à partir d'un positif réalisé le plus précisément avec mes imprimantes SLA. Projets très prometteurs. Je suis surtout en panne d'employés ;) Pour revenir aux licenses software. J'ai été des deux bords: un pirate pour évaluer et ensuite par souci d'intégrité morale et professionnelle, une version officielle pleine. J'ai été 30 ans développeur hardware mais plus software en conduite de stations d'épuration en Alsace, pour un bureau d'études depuis disparu... et je tiens comme toi à être honnête malgré la tentation des logiciels piratés. Je vais acheter lightburn à $40, le seul software qui marche avec mon petit laser (eleksmaker A3 pro déjà dépassé). Leur version d'essai d'un mois est très pratique pour évaluer les compatibilités. Bien, je suis heureux que tout aille bien pour toi aussi. Je m'inquiétais. Un aussi actif que toi qui ne poste pas pendant 2 semaines, ça inquiète ;) Alors en attendant ta prochaine production, on va patienter. J'ai communiqué ton canal à quelques uns de mon entourage et ils l'ont apprécié. Ce n'est pas le moment de s'endormir ;) ;) Salut à toi mon ami et porte-toi bien avec tes proches.

Je suis en train de finir un autre projet sur le plasma cutter. Ce n'est pas facile car il s'agit d'installer le moins cher THC sur le marché en Mach3. Jusqu'à maintenant, je n'ai pas pu trouvé aucun instructions sur internet ou RU-vid. J'ai du tester chaque étape moi-même, heureusement, j'ai réussi et pense de finir aujourd'hui ou demain.

Don't buy it, it doesn't work very well for plasma cnc. It's OK for cnc mill but not plasma. It has a delay in starting and stopping of the torch which is very hard to fix and make it not usable for plasma

@@minhsmancave9448 any thoughts on the proma my plasma.... a little pricey but looks complete

I was talking about the breakout board. But the proma is surely easier to setup, the problem is that it is only compatible with certain types of mach3 breakout board (usually more official and expensive ones)

@@minhsmancave9448 hello minn av watched your video like the 10th time.. I have the same board.. An am having a problem with full cuts.. My cuts will cease 3/4 way.. Seems like a delay problem how did you fix it.. Please help me out am going insane.. Also I have a thc a Chinese sh hc31.. I won't bulge.. I can measure arc voltage in but no vout signal

It's not exactly removed. I made the shield that is isolated the nozzle from touching the plate. And after the torch is lifted off from the plate, I still have a few millimeters before the limit switch click again. It keep the torch at 1mm away from the plate if it warped. This way, the shield only scratch the surface from time to time, not all the time like the manual THC. The A141 torch definitely gave me better cuts compared to the p80 torch. That shows on thicker sheet metal. I can see that the arc is more focused and the kerf is smaller. This probably because the air in the a141 does swirl as I can see the burn marks inside the nozzle and the electrode. That is not the case with the p80 torch.

​@@minhsmancave9448 Can you make a video about your new THC solution? I'm very interested in :) Anyway I'm using RNR board and you are right it's weakest point is the USB connection. I have the original board the blue one which came with high quality shielded usb cable with ferrite core which helps a bit against noise. But it's crucial to have some kind of THC because if plasma tip is getting too far from the plate it starts to emit a lot of noise which is too much even for the shielded usb cable and the board restarts

@@peterpasti This shield I made is customized to my A141 torch and I had to cut it using my milling machine. If you have a decent CNC machine that can mill Aluminum, I'll send you the CAD file. What torch do you have?

@@minhsmancave9448 I've WSD-60P torch. Currently I'm using the wire guide ring which fixed with a hose clamp to the torch. It works ok but because of the slag on the top of the plate it sometime stuck and leave marks in the cut line. My plan to replace it with 5mm thick stainless steel ring which can go through the slag easier. But I'm qurious for other solutions :)

To avoid getting stuck on the slag, I made a conic shield with the angle is 30 degree from flat surface. This way, it will bump the torch up when hitting the slag. You can see my original shield design (mechanical THC) and cut something like that with your plasma table, make it conic with a hammer and find a way to fix it on the torch. It worked quite well for me.

It's not enough for CNC plasma.

It's like the spark plug in the engine. Each type of spark plug has a spark gap is optimized for a type of fuel, amount of fuel. Not sure what will happen but I do believe that the manufacturer did some testings to find the optimized gap for their machine.

@@minhsmancave9448 I use the plasma source of the eutectic castolin brand. But I'm always having a little electromagnetic interference. Today I tried to regulate the spark, everything was fine without interference, but after a while it started to cause another type of problem. When you start to cut, immediately afterwards the electric arc goes out .... do I need to readjust the spark? Hugs and thanks for helping !!!

Maybe try to increase the gap a bit, too close gap also not good. I can't be sure, but sometime call the support tech and ask what the gap should be might be helpful

It seems that MAch4 is more advanced Mach3 with supports (ArtSoft stopped supporting mach3). So, maybe Mach4 is the way to go depending on what type of function you think to have on your milling machine. If you only use normal, basic milling, I don't think it matters that much. Mach4 breakout board might be more expensive since there are not many chinese boards for it yet.

as long as it's a blowback pilot arc, it won't have the problem with interference from the HF pilot arc

The output signal of the NVEM is active low, make sure your relay is also active low. You can use a multimeter to test the voltage of the output pin to see if the pin actually works or not

I tried with the tester but nothing. I set the output 1 as port 2 pin 1 and then tested with the multimeter : 0v. Then tried with another pin but nothing same result.

Before start cutting (moving the torch in X and Y), you will need to pierce through the sheet metal. The pierce height usually higher than the cutting height because the melted metal doesn't have anywhere to go other than being blown back up. To avoid it getting stuck to the nozzle of the torch, you will have to set the pierce height at enough distance and have certain piercing time delay. That's what you see at the beginning of each cut.

You can still buy it on AliExpress

@@minhsmancave9448 Did you buy the Hero? Today I will Order Hero Cut 55i or LOTOS LTP5500D-CNC, I can not tell the dirrerence, They both have a 1:1 Output, What part number is yout Straight Torch? Are you in Vietnam, I am an ExPat in NhaTrang

I got a used Hero Cut 55i from ebay for under $300 but haven't gotten time to put it on the CNC machine yet. I have been paying more attention to my milling machines and my fishtank filter business. Both machines are the same, buy the one that is convenient for you to get parts and warranty. Yes, I'm from Vietnam, but luckily was born in peace time.

Voltage divider is to be connected to the THC, not mach3

I'm finishing installing and testing a new thc system sf-hc25g on mach3. In a few days, I will be able to publish a video and manual on how to make it work with Mach3. It's a cheapest THC system on the market and so far it works quite well for me. I'll let you know when the new video will be ready.

@@minhsmancave9448 perfect I will be waiting

@@andrescastropineda8348 Video is ready, I'll post the installation guide very soon (maybe a few days). ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-O_cJlMhwqmY.html

@@andrescastropineda8348 I have the link to download the manual now available, check the description of the video

Should be 0.8mm, mine was about 1.5mm

@@minhsmancave9448 thanks for the info ...

I tried to adjust the gap distance, but I can not unscrew the points to adjust the point distance. The screws are tight, maybe glued. It seems it can not be adjusted, I just make it like that for years, now machine fire intermittently, can you share experience to loosen the screw ...

I'm not sure how your system is like. Are your components in a metal shielded (grounded) box? The USB breakout board is very sensitive to the HF signal, especially when the arc doesn't start right away. Try to get your plasma cutter and your controller unit on different line of power (at least your plasma cutter should have its own breaker from your breaker box). You can also un check the option "use driver watchdog" in Mach3,config, general config. The start gap only help to make the arc start faster so the HF signal has less interference but won't remove it completely.

And I'm not trying to advertise for the Chinese, but one thing will definitely help is installing the Thc system sf-hc25g. This system has the arc voltage divider board that has a relay on it. The breakout board doesn't communicate directly with the plasma cutter anymore. I have been using it with my RnRmotion board and no problem with interference anymore.

Hi, thanks for the quick answer. I'm using an metal shielded grounded box, and all wires are shielded and grounded. I use Mach4.

What breakout board do you have?

Hi, I don't know the model at the moment, when I'm in the workshop next time I write it down. In a last video from you you have a white wire to the burner nozzle, which you meaned it stops interferences? Where is this wire connected? Doesn't it worked right? Best regards

Not very easy to get rid of the HF frequency. Some people said that they were successful using shielding, filtering. For me, the solution is to use blowback pilot arc plasma cutter, not HF pilot arc.

@@minhsmancave9448 what would the pilot arc with recoil be like?

Which THC do you have? Novusun only work with stand alone THC (step/dir mode, not up/down mode)

Output #1, and 12v, active low. You will have to buy a relay that you can choose active low or high

@@minhsmancave9448 thank you wery much

The solid state relay type is for ac load, it doesn't work for the trigger of the plasma cutter. Unless you can suggest one that can use for DC load.

Hi sir, i have buy the same nvem like yours, but do you have a clue wiring diagram and mach 3 setting? With nvum, where i do suppose connect the relay for pilot arc trigger (which port)

Today i try to run the motor but failed, maybe i'm not familiar yet with mach3

Output port is #2, input ports is number 1. You can chose the output port to trigger the arc but usually it is output #1 (near spindle). I don't have a diagram yet, will try to make one in the future.

@@minhsmancave9448 hai there, my board already got issue after used for 2days, it runs ok, but then it show upgrade bin file in mach3, at the motor tuning cannot set the velocity, so the motor cannot run at all, in the plugin config show axis0 freq 0 too, and seems to be alot of people got this problem too.. do you have tried to isolate 5v usb with usb bob red board?

It's not easy to isolate the red board. I did many things and the intègrent still come back from time to time when cutting with high amperage. Until recently, I installed the Sf-hc25g thc, this THC has an integrated relay on the voltage divider board. So the USB board doesn't interact directly with the plasma cutter anymore and that seems to help. I haven't had any problem with the interference then. Maybe if you wanted to use the red board, try also the Thc system.

There's no delay pin, you will have to buy a relay and control it using an output of the controller

Please can you help me setting it up

I have the relay but how to connect it

@@aabtech32 The output of this board is active low, make sure you have this type of relay that you can choose the input is high active or low active: www.amazon.com/Willwin-Channel-optocoupler-Support-Trigger/dp/B077TLWQ5G

Hi, I have that type of relay but how to wire