Looking for some help dialing in a Proma SD on a new machine

[xnaron]

I've been building cnc machines like mills, routers, laser cutters and 3d printers for many years. I decided I wanted a cnc plasma machine. I was going to build but I found a used deal on an unused langmuir crossfire without the plasma cutter. As this is a hobby and right now I can't justify the cost of a hypertherm so I bought herocut HC6000 plasma cutter with cnc ports on it. I added a floating z to the crossfire with both a floating head limit switch and 3 proximity sensors from automation direct (ksk-ap-4h). I am using a Proma SD THC.

I am trying to get the Proma SD setup. I am running 3 inch test cuts at 0.060" from material at 150 ipm and 45amps air pressure 53 psi. You can see in the picture below I highlighted these 2 cuts with arrows. The z axis stepper is off during the cut and I read the voltage on the Proma at 86V. I have the proma speed setting at 80.

I set the proma to 86v turn on the stepper and get setup for a cut using the proximity sensor as the probe. It is set to detect at 0.060" off the surface. I took a video below showing the behavior of the Proma SD. It seems to have a hard time trying to keep the head to the target voltage. Maybe this is normal?



There is way more slag on my test piece than on the straight test cut. My thinking is if the THC was doing a good job keeping the head at the right height I should have hardly any slag on my cut.

Any insight appreciated. Thanks

[robertspark]

what material thickness?

bottom dross... too slow feedrate....maybe your acceleration is too low... what acceleration

you also have to consider that 150ipm is 2.5 inch per second....there was only one cut in my opinion that the thc would have been active because it needs time for the voltage to stabilise once acceleration begins at the start of the cut... also if the feedrate slows in the corners which it probably will the voltage will rise, more bottom dross and you probably don't want the torch to dive....

only the outer offset cut imo would have had the thc to actually do anything useful.

everyone has an opinion and they will all be different.... the proma is a bit clunky... I am not sure about the SD having never owned one though but the 150 is very clunky and did not work well on thin material for me.

(shouldn't be making bottle openers anyway.... if you can't open it with your hands you shouldn't be drinking it.... yes that's bottle tops not screw caps or ring pulls either I'm talking about, and no don't use a door or your teeth..... coming of age thing .... if you can't open it (without a bottle opener or other device)... you're not old enough to drink it I was told... man I learnt to open them quick after that and still a party trick

[adbuch]

That 53 psi seems low, I run 100 psi at the machine on all 3 of my plasma cutters. You might also try reducing your cutting speed to see if that helps. What material thickness are you cutting?
David

[acourtjester]

From the star image in the video there are a few other things to look at you have some that did not finish the cut. If you use SheetCam there is an overcut setting to help with that. You may want to add lead-ins and lead-outs. The dross is from to slow cut speed or from the low air pressure. In your video the up or down light is on to long can you adjust the sensitivity lower so it reacts quicker. Also use a longer cut to find you cut voltage like 8 to 10 inches to get a more stable arc voltage.

[xnaron]

I was cutting 0.060 inch steel. Now I don't know what kind of steel as it was in the bin at metal supermarket. I think it had ATSM 1001 on it.

Today I spent some time doing more test cuts. I cranked up the pressure to 70 psi and then down to 65 psi. My plasma cutter says 70 psi is max on it. I am not sure why that is. The electric valve inside is rated for 115psi and has been tested working to 175psi. I will have to run some 10" test cuts as suggested. It didn't seem to matter what speed I went as the dross on the bottom was pretty consistent. Experimented with amps from 30 to 50 and speeds 50 to 150 varying based on amps. I changed to a new electrode and nozzle and it did not make a difference (I tried the 1.0mm nozzle vs the 1.1mm that was on it.

I decided to try a thicker piece of steel. It looks to be the same finish as the 0.060". I did some test cuts and settled at 50amps, 65pi, 100ipm. Bottom dross was similar to the 0.060".

In mach 3 both x and y are set too 300ipm at 40in/s accel. I have tried different speeds on the Proma SD from 60 to 120. It seems to be all over the place. It has a hard time trying to keep the voltage at the set value. The documentation on the proma is pretty poor. I probably should try another THC but not sure what is better?

I have tried increasing cut speeds for a given amperage until it no longer cuts through. The bottom dross seems the same on all of the cuts. Maybe this steel is bad for dross? I can't for the life of me repeat the 2 test cuts I made that were dross free.

I'll try more cuts tomorrow. I really appreciate all of the advice.

[xnaron]

Ironically my first cut had the least dross.

[xnaron]

I found a good deal on a used Powermax 45xp and a Powermax 85. Neither have a machine torch. I only have 240V @50A that I can use to supply power to the plasma cutter. That being said I don't know if going with the Powermax 85 would get me that much more over the 45xp?

[adbuch]

I own and use both the 45xp and the 85. I use the Duramax hand torch for machine cutting with both the 45xp and 85, with great results from both. I am running my 85 on 100 amp 3 phase power, and the 45xp on a 50 amp 240V circuit (although the 45xp rated input current is 32 amps @ 240V). I don't think you have the power available to run the 85 to its full capacity, and the 45xp offers plate marking (not available on the 85). I run the Hypertherm FineCut consumables for all my cnc cutting 10 ga. and thinner material. For your setup I would definitely recommend the 45xp - you should see a tremendous improvement in the quality of your cuts vs. your current machine.
David

https://www.hypertherm.com/en-US/learn/ ... s/marking/

[acourtjester]

Another thing with the 45 XP is you can use a fine cut nozzle for the 0.060" metal you are cutting, it could be the 1.0 and 1.1 mm nozzles are causing the dross problem the combination of the lower air pressure and nozzle opening has less of a velocity .
Here is a little info for you I have a Hypertherm 65 the fine nozzle orifice is about 0.80 mm ( i used an OA tip cleaner for a gauge 0.79 mm go through and 0.83 no go) and the 45 amp nozzle had a 0.93 mm snug fit. And the air pressure for the hypertherm is much higher so you can see the cutting ability would be much better.

[xnaron]

Thanks guys that is great info! I looked at the specs for the 45xp and it looks like the max I can pierce is 1/2" therefore that would be the max size I could cut on it with the cnc. Is that correct? Just curious if maybe they under spec'd it and it can pierce a bit thicker?

[acourtjester]

What you find from the manual is the pierce thickness and and there are what is called edge start for thicker metal, you can download their manual from the web.
As to you looking for another THC the Price CNC avhc-10 if a great unit for the money. They are listing out of stock may be a corvid-19 hick up
https://www.pricecnc.com/product-page/avhc10
video I mad 2 years ago on the Price

[acourtjester]

Here ae images of cuts I made today 0.067" mild steel 79 volts 200 ipm 45 amps fine cut nozzle, 110 PSI at the back of the hypertherm. A 2.5" circle in a 3.25" square, very little dross, straight out of the water table.

circle in box 3.25.zip

(911 Bytes) Downloaded 55 times

[adbuch]

Thanks guys that is great info! I looked at the specs for the 45xp and it looks like the max I can pierce is 1/2" therefore that would be the max size I could cut on it with the cnc. Is that correct? Just curious if maybe they under spec'd it and it can pierce a bit thicker?

You can cut 5/8" thick material using pre-drill or edge start.
David

[xnaron]

I wanted to get the price THC but it was sold out Your cuts look really good with hardly any dross.

I've been looking for options for a machine torch for the 45xp. I see hypertherm sells a mini machine torch and a duramax lock machine torch. I'll have to research them.

[xnaron]

I did manage to get this out without any drama tonight. It is for my daughter's birthday. 16 inch diameter.

[adbuch]

I did manage to get this out without any drama tonight. It is for my daughter's birthday. 16 inch diameter.

598222D8-22CC-45F0-AFF2-BB9898040DB7.png

Looks great! If you can do that level of work with your current setup and cutter, then perhaps you really don't need to upgrade
David

[xnaron]

Thanks. It's the dross that is an issue and my difficulty trying to get it dialed in.

[adbuch]

Thanks. It's the dross that is an issue and my difficulty trying to get it dialed in.

I'm wondering if the water splashing all over the part might have anything to do with creating more dross? I have a water table/tray under my table, but the water level is about 10 inches below the part being cut and I don't get any water splashing up onto the material.
David

[djreiswig]

I don't think the water level will cause dross. I run mine right under the material and don't get excessive dross. If you run it 10" below the material it won't capture very much smoke.

[adbuch]

The water doesn't capture the smoke, my draft system does.
David

https://www.youtube.com/watch?v=pLLiygynHaU

[robertspark]

I added a floating z to the crossfire with both a floating head limit switch and 3 proximity sensors ....

Off Topic (but the topic has probably run its course now from the original topic)

Impressed with your use of 3 prox sensors.

what is their purpose, collision avoidance or touchoff?

Are they active all the time or only during the touchoff sequence?

I have been using them for limit and home switches but have had intermittent issues with them triggering on occasion when the plasma is fired (so was impressed with you using them in close proximity to the torch) [not a discussion for my issues as I know how to overcome them], but interested in what you are using yours for and how you have wired them? (all to 1 input, do you use inline diodes?)

thanks for your time

[acourtjester]

AS to the THC matter you may start another post about your quest. Ask members for their input and experiences with the one they have. Some post their unit names in the signature at the bottom of their posts. There are many out there with a good price spread, and as you have found some are not that good, or hard to get functioning. With the Price you may see if you can find out when they will be back in stock and if you want to wait.

[robertspark]

THC >> the miniTHC has proved to be a nice THC for me + simple and is available shipping from the US and is a little less than the price THC I believe

https://minithc.com/

[xnaron]

I added a floating z to the crossfire with both a floating head limit switch and 3 proximity sensors ....

Off Topic (but the topic has probably run its course now from the original topic)

Impressed with your use of 3 prox sensors.

what is their purpose, collision avoidance or touchoff?

Are they active all the time or only during the touchoff sequence?

I have been using them for limit and home switches but have had intermittent issues with them triggering on occasion when the plasma is fired (so was impressed with you using them in close proximity to the torch) [not a discussion for my issues as I know how to overcome them], but interested in what you are using yours for and how you have wired them? (all to 1 input, do you use inline diodes?)

thanks for your time

The 3 proximity sensors are used for touchoff. They sense any metal at 18mm. At least that is the theory. I am having a few issues with repeatability. I am finding with thinner gauge sheet that they detect at different heights depending on whether it is over a slat or not. I believe I also am getting a little interference from having the aluminum torch holder so close. I did revise the mount to move them further away but I don't think it was enough. There is a guy on youtube called Tool Junkie that uses these sensors but he uses a delrin or 3d printed mount for the sensors with a machine torch. I will try that when I get my hypertherm upgrade and machine torch going.

I also have a floating z axis for a touch off (see pics). I can switch between Proximity and Floating in Mach 3. I also have a button that lets me turn off the z stepper for when I do test cuts to get the right voltage on the THC. I used a spring to take a lot of the weight off the floating Z. I put a scale under the head and it has 300grams on it when it triggers the floating Z.

[xnaron]

AS to the THC matter you may start another post about your quest. Ask members for their input and experiences with the one they have. Some post their unit names in the signature at the bottom of their posts. There are many out there with a good price spread, and as you have found some are not that good, or hard to get functioning. With the Price you may see if you can find out when they will be back in stock and if you want to wait.

Yes that is a good idea.