[WSS]

Here is a thread to post your Oxy/ Fuel cutting questions, ideas, problems and PHOTOS!

Let"s discuss codes, speed, gases, tips (consumables) or anything concerning oxy cutting.

And please don't be afraid to call "Dross" slag here. Oxy cutters will know what you are talking about!

Cheers!
WSS

[tinman13]

I have been looking for a way to ramp up the cutting oxygen, Something like a soft start valve, or........... ?

I have found Retro plasma makes a regulator assy. with "Ease on pierce rate control ". They describe it as "The rate that cutting oxygen pressure increases during the pierce is
set by the Pierce Rate Control knob".

I can't find much info on this type of system on the net.......... Anyone familiar with this type of system?

[jcc3inc]

Gentlemen:

I have attached (4) jpg's of a system and explanation. Hope it is of help to youall.

Regards,
Jack C.

PS: to print a decent sized page, click on desired page, right click on the result, then "print".
JCC

[amishmafia00]

i've heard of such setups. my torch is a victor mt 310 it has a manual valve on the torch to turn on the cutting oxygen. when i light my torch i open this valve. the regulator is on the tank with 25 feet of line away. when the cutting oxygen is off the pressure in the line goes to 0 when it comes on it takes time for pressure to build so it comes on slow. the thickest i've cut is 1.5 inch and i haven't had any problems.

I have been looking for a way to ramp up the cutting oxygen, Something like a soft start valve, or........... ?

I have found Retro plasma makes a regulator assy. with "Ease on pierce rate control ". They describe it as "The rate that cutting oxygen pressure increases during the pierce is
set by the Pierce Rate Control knob".

I can't find much info on this type of system on the net.......... Anyone familiar with this type of system?

[WSS]

I have been looking for a way to ramp up the cutting oxygen, Something like a soft start valve, or........... ?

I have found Retro plasma makes a regulator assy. with "Ease on pierce rate control ". They describe it as "The rate that cutting oxygen pressure increases during the pierce is
set by the Pierce Rate Control knob".

I can't find much info on this type of system on the net.......... Anyone familiar with this type of system?

Here is the page describing the process:

http://www.retroplasma.com/documents...%20Package.pdf

WSS

[millman52]

Here is the page describing the process:

http://www.retroplasma.com/documents...%20Package.pdf

WSS

I had looked on the retro plasma site before but didn't find their actual system.

I'd be willing to bet a dozen dough nuts against a boot heel their box has the same basic guts as mine other than regulators on the preheat as opposed to the flow tubes. They may control it a bit different.

On bench testing mine I really like the flow tubes. I probably cycled the system 30 times & the balls inside the tubes came to the same exact flow rate each time.

I also began thinking in terms of by-passing the cabinet if for some reason you would want to use the torch standard. I think all I need there is a toggle switch to turn the thing off. Everything inside the cabinet operates off 110V from a wall plug. The only command coming from the CNC table itself is pulled from the pierce relay on the table I/O card. NO SPECIAL POST PROCESSOR NEEDED.

[millman52]

This is interesting. I often have trouble piercing material above 1" thick

[scrambled]

I am setting up a oxy / fuel cutter. I need all the help I can get.

Steve

[millman52]

Steve, have you made any more progress with your port 2 installation to get your system going?

[matttargett4]

Hi Guys,

Ive never really done much mechanised oxy fuel cutting before this week but my plasma has failed and ive been using the gas to make up for it and ive found a few things id like to ask about.

My torch is a 3 hose harris machine torch and i have a solenoid on the cut oxygen, im using vvc nozzles, i only have a 1/2 and 1 to hand at the moment.

I have my fuel (propane) pressure regulated at the bottle, my oxgen regulated to the cut pressure at the bottle and the preheat pressure is regulated on the machine.

When i set the pressures to those specified in the cut charts i was imagining turn all three taps full on would produce a cutting flame but it seems way rich on fuel so my first question is, how do i set the correct cutting flame?

Second, how high from the material for preheat, pierce and cut?

How do pro's know how long to preheat for? Clearly too long melts your part, too short no penetration, i also find it makes a considerable difference where the pierce is and how many pierces have already been made in the plate, can i account for this in any way?

Clearly the nozzles are made for a material thickness but like i said i have only big nozzles on hand and the thickest ive cut is 15mm, cut quality was pretty good but can i turn the gas down and use them sensibly on thinner material? I have foud when going down as thin as 8mm that i cant really increase the cut speed above the max speed in the chart even though the material is half the thickness of that in the chart.

How many people here are using water tables? I have one for the plamsa but its empty just now but i seem to get lots of warping, is that just because i need a smaller nozzle or is there something i need to do to work round it?

I ordered some smaller nozzles from the grand old us of a with my hypertherm plasma parts, they are much cheaper and i figured i had to pay one lot of shipping, trouble is the plasma parts are on back order so my angle grinder is taking a pounding!!

Matt

[WSS]

Hi Guys,

Ive never really done much mechanised oxy fuel cutting before this week but my plasma has failed and ive been using the gas to make up for it and ive found a few things id like to ask about.

My torch is a 3 hose harris machine torch and i have a solenoid on the cut oxygen, im using vvc nozzles, i only have a 1/2 and 1 to hand at the moment.

I have my fuel (propane) pressure regulated at the bottle, my oxgen regulated to the cut pressure at the bottle and the preheat pressure is regulated on the machine.

When i set the pressures to those specified in the cut charts i was imagining turn all three taps full on would produce a cutting flame but it seems way rich on fuel so my first question is, how do i set the correct cutting flame?

Second, how high from the material for preheat, pierce and cut?

How do pro's know how long to preheat for? Clearly too long melts your part, too short no penetration, i also find it makes a considerable difference where the pierce is and how many pierces have already been made in the plate, can i account for this in any way?

Clearly the nozzles are made for a material thickness but like i said i have only big nozzles on hand and the thickest ive cut is 15mm, cut quality was pretty good but can i turn the gas down and use them sensibly on thinner material? I have foud when going down as thin as 8mm that i cant really increase the cut speed above the max speed in the chart even though the material is half the thickness of that in the chart.

How many people here are using water tables? I have one for the plamsa but its empty just now but i seem to get lots of warping, is that just because i need a smaller nozzle or is there something i need to do to work round it?

I ordered some smaller nozzles from the grand old us of a with my hypertherm plasma parts, they are much cheaper and i figured i had to pay one lot of shipping, trouble is the plasma parts are on back order so my angle grinder is taking a pounding!!

Matt

Matt, it has been a while since I have used a Harris torch but I believe the VVC tips are hi-speed machine type. They will have a smaller cut oxy orifice and use higher pressure, this will allow the higher speed.

To touch on the ipm question, oxy tips rely on the orifice size and psi to cut a specific range of sizes. An example would be a tip that is sized for 2"-3" plate that cuts at 10 to 7 ipm will not cut 1" plate at 18 ipm like a tip sized for 1" would, you might squeeze 12 or 13ipm out of the 2-3" tip but not much more, this due to the orifice size. Often though it is the best you can do because it is "what is on hand". The best bet is to have a few sizes of each size plate you cut on hand. A oxy/fuel tip will last a long time if you have pierce heights and delays set right.

Use a cut chart for your torch and tip combo to get close and fine tune from there. Getting the elusive "neutral flame" is experience. I remeber as a kid both my dad and grandfather hollering at me to get it "balanced" or "neutral" and not really knowing what they were saying but nodding OK. It is the point were the outer blue flame is A) not hissing and short but B) not long and whispy. Once pressures are set (free flow measured as close to the torch as possible) adjust the flame with the torch valves only. If you are running flashback protection, you may need more psi.

For knowing the right preheat delay amount, I will quote a comment made by Millman52: It is when the sparkles start to run across the plate. If you watch close to the outer PH flame, you will see the metal turn red and give up and blow away across the top of the plate in tiny sparkle looking balls, that is ready for pierce.

Hope that helps, look back further in the thread and there is a pdf made by esab that really gives some insight to oxy/fuel cutting. If you can't find it, I can re-post or send it to you, worth the read.

WSS

[scrambled]

Millman, I talked to Tom, and he said that I have the wrong version of the IO card. So I need to get the correct drivers installed.

I just finished replacing the 7/8 drive stem pinions with 2 1/4 gears. Now the vibration is gone, I am going to work on the IO card.


What Post processor is everyone using for Sheetcam?


Steve

[tinman13]

Thank you JCC,
That is exactly what I have been looking for.
Steve

[millman52]

Millman, I talked to Tom, and he said that I have the wrong version of the IO card. So I need to get the correct drivers installed.

I just finished replacing the 7/8 drive stem pinions with 2 1/4 gears. Now the vibration is gone, I am going to work on the IO card.


What Post processor is everyone using for Sheetcam?


Steve

Steve I had gone to the manuals on CandCNC's Yahoo site & done a bit of reading on installing the MP3000. Somewhere in there it mentioned the version of one of the cards needing to be current. It was yesterday evening when I was reading it & by now I can't remember the details.

Knowing your project has been a lengthy one just kind of assumed something slightly out of date might be your problem. I'm probably the worlds worst to buy something then let it lay for weeks or months before using it.

I started building an actuator type "Z" lifter & an new HT 1250 plasma nearly a year ago & still don't have that installed & am paying to have thin materials plasma cut. I can't really say I haven't had the time I just haven't made it happen.

Tom will get you through it. He has always had the answers I needed. Sometimes I can be shch a bonehead that it takes a week or 2 for what he is telling me to sink in.

I am using the Mach2 plasma.post for my oxy set up. (again I am running 2006 or so vintage MP1000 candcnc equipment)

[tinman13]

...... It just dawned on me what you are describing!

The air cylinder could be controlled with shop air and it wouldn't need to be oxygen clean.
I will have to experiment with force requirements to see how big of a cylinder it would take.

The beauty of this is I have most all the stuff laying around to build it with!
Thanks for the idea!

Steve

[WSS]

...... It just dawned on me what you are describing!

The air cylinder could be controlled with shop air and it wouldn't need to be oxygen clean.
I will have to experiment with force requirements to see how big of a cylinder it would take.

The beauty of this is I have most all the stuff laying around to build it with!
Thanks for the idea!

Steve

Steve,

Kind of, One side would have oxy running through it. The idea is to replace the dome in the drawing. This would be variable according to how far back the plunger (piston) is. 1/2-10 acme is nice because it is .100" per turn, easy to gauge. The more volume you have in the chamber the softer the start.

We are using a Thermco gas mixer here to mix argon and oxy. One of the problems we had when using liquid argon was the hard start and stop when the solenoid cycled. This caused the dewar (spelling?) to over pressure and vent. Even with the pressure builder off the shock would build pressure on its own.We ended up putting a 10 gallon tank in line to absorb the shock, a soft start/stop so to speak. The air cylinder would do the same and be adjustable. I am thinking a 2" bore bimba or rexroth type about 10-12 inches long would supply the needed drop for a soft start. I notice the longer the hoses are between my solenoid and torch valve the softer the flow starts. I had always believed you wanted to "snap" the pressure, but this looks like it might be worth a try.

If you notice in the drawing posted, the HP cut line is the smallest. This is due to the dome being able to supply the needed volume for a short time then switch to the larger, non stored supply of oxy flow.

Who wants to try it first?

WSS

[WSS]

I wonder if this could be done with a small bore "oxy safe" air cylinder that has had the piston converted to a plunger and the rod changed to a 1/2-10 acme thread for adjustment? It would serve only one torch for the ramp up oxy. but might be doable. The ramp pierce is pretty handy to keep slag traveling in a rearward or away direction. The Hi PH could be done with a separate set of 3 way Asco type solenoids and a extra set of regulators. Once you found the right combination you could manifold the whole deal to pull from one (of each) bottle.

I converted the jpgs from jcc3inc's post to a pdf (Big thanks Jack!)

Here is a link:

http://files.me.com/izonltd/id43n2


WSS

[tinman13]

"air cylinder that has had the piston converted to a plunger and the rod changed to a 1/2-10 acme thread for adjustment? "

I'm afraid you lost me on that one!
Steve

[scrambled]

OK--

Time for some questions. Since I am wiring my single solenoid valve in, Is there that much of a difference using a soft start?

I have been trying to understand the piping schmatic, and to me it looks like I would need 9 solenoid valves. Is this correct?

Any other info on this that you have is greatly needed


Steve

[WSS]

Thinking about this, The goal is to pre-heat faster and keep the tip debri-free during and after pierce.

The ease on my be secondary to the hi-lo PH and a code controlled ramp pierce. I have done a version of hi-lo, and that was to use a rosebud to help the pre-heat along. The version shown in the drawing would be better of course, due to the smaller HAZ. The rosebud spread the heat around too much.

Another use for the hi-lo PH is to anneal areas on AR plate that will be machined later. You could go into that mode and circle the area or spiral out with great control.

Has anyone seen the ease on pierce in action or on video?

Steve,

You may be able to use 3 or 4 way solenoids to cut the number of solenoids down. Do you think you will try it?

I don't want to sound like a pest but make sure the solenoid you use for the oxy is oxy safe.

WSS