TD A60 Cutting

[islander261]

Hello

I have a TM2 table with the blue screen TM ATHC. My torch is an SL100 machine torch. My air supply is dry (both refrigerated and desiccant dryers) and clean. I very rarely cut anything other than 14ga HR steel. All my work is garden art and other small artsy parts with lots of pierces and short cuts, no FAB shop type long straight cuts. I use a water table for fume control. I want to improve my cut quality (narrower kerf, less dross) and consumable life but seem to be stuck. I have been using the 40A stand off tips (nozzles) with and without shield. What I have done:

1. Modified X axis drive to be like TM3 table, now I get good acceleration without loosing steps;
2. Starting with manual parameters have trial and error tested to get present best performance, 40A, 97V, .2 pierce no delay (control program has plenty even when set at 0),.16 start, 100ipm, 75lbs air by front panel, ground clamp directly to to work;
3. I get a kerf that is about .045 to .050 at the bottom and .060 to .065 at the top;
4. I get variable bottom dross heavy to light depending on tightness of curves, long straighter cuts nearly dross free, all dross easily removable with wire cup brush on angle grinder (I get tired of this some days);
5. I get from 100 to 600 pierces, average about 200 per tip and double that per electrode, some times really short tip life because of splatter from pierces.

I think that part of the variable dross problem is because the TM software and ATHC cannot compensate (freeze torch height) for corners and tight curves is this correct? The actual distance the ATHC moves in manual mode is hard to measure because I have found no way to freeze it other than switching the power switch off. Will I get the biggest improvement from abandoning the TM control system and using one from say CandCNC that can compensate for curves and corners?

I have thought about replacing the SL100 torch with a Hypertherm Duramax and using the finecut consumables. This is about a $750 experiment and I am not sure I want to do it, though it is cheaper than a new Hypertherm plasma unit. Has anyone tried to put a a Duramax torch on a TD machine?

Ok, I know that there are experienced TD users here and at least one factory guy. Am I looking in the wrong places to get cut quality improvement? Does anyone have any other suggestions for cut quality improvement? From reading other posts it seems that the A60/SL100 torch combo should be able to give cut quality equal to everyone's nice pictures of cuts with Hypertherm units posted here. I really don't want to buy both a new plasma unit and controller only to find out there are adjustments that will solve these issues. Thanks in advance for any tips, feel free to PM me if you don't want your replies on the public forum.

John

[srp]

Some suggestions:
I cut with a Pak master 75 xl plus. I like to use the 30 amp tip even though td does not recommend for a machine torch. I don't often cut heavier than 16 ga but sometimes 11ga. I still use the 30 amp nozzles. When everything is working right the results are great. I don't have Athc but have a floating head which works just fine in the gauges I cut. .13 pierce and cut. This 30 amp nozzle is classified as a drag tip.

One thing I think you need to determine first is your actual pierce and cutting height. It should be .13. You will need to calibrate your arc voltage to that height.

TD makes two 40 amp nozzles. If you do use the 40 amp be sure it is the one for a standoff situation suchas a machine torch. The 30 amp are drag nozzles. The 40 amp machine number is 9-8208. I use a 9-8218 end cap without any of the splash shields.

Other folks on the forum also like using the 30 amp nozzles on their machines.
I get about 1500-1800 pierces and 15,000-18,000 inches per electrode and nozzle(when everything is working good). My machine has a hi-freq start which might make a difference.

I thought about a HT torch an my td machine and got a "no-way" from HT.

My read on your post is a problem with cutting and pierce height. Clean dry air is a must. There is no reason you should not be able to achieve a perfect cut. Work away a do a routine process of elimination. document as you go. - John T.

[mlinehan]

Like srp says, for a narrower kerf, use a smaller tip. 20 amp is probably too small and slow, but the 30 amp does give a narrower kerf.

The dross is influenced most by cut speed, then by torch height. Dross which is easy to remove is usually low speed dross. You are more likely to see this in corners and curves. You also will get more dross where 2 cuts are close together, more heat in that part of the plate.

Try cutting with the AVHC turned off and set torch height by hand.

[Brand X]

Like srp says, for a narrower kerf, use a smaller tip. 20 amp is probably too small and slow, but the 30 amp does give a narrower kerf.

Talking on-line to a Thermal rep about the 20-30 amp consumables for the one torch.. (About 12 years ago) He said the orifice size for the 20 amp, and the 30 amps tips are the same.. Is that correct or not? I found 30 amps ones work better for cnc stuff I tried with them.. Been a long time since I used either one.. (Cutmaster 101/machine torch)

[mlinehan]

AS you say, the orifice size is the same for the 20 and 30A tips. Other dimensions are different. In my experience, the difference between 20A and 30 A tips is very small. 20 A does allow you to move a little slower.

[islander261]

Hi

I did a bunch of testing and really couldn't get consistent results with the 30A drag tips. I had the height set at .130 and checked it several times with gauge pins. I tried with both fixed height and with the AVHC on with no real change. See 30A photo,DSC02720.jpg and DSC02719.jpg.

Then I went back to 40A standoff tips using book setting. I check height with gauge pins to make sure it is correct. See 40A photos. As you can see the test lines came out pretty good with a kerf of about .060. Then when you look at the actual cuts at the same speed as the good ones on the speed test you can see the difference in cut quality between this and the speed test and between different parts of the same piece.

John

Added photo labels

[Brand X]

I picked up some 20 amp tips for my A-120. I like the results,even though the machine does not dial down to 20 amps.. Very nice results cutting .060 steel. Right at .030 kerf.. low dross too. I was right at 70 ipm overall . Love the slower speed with the 20 amp tips.. 75 psi air pressure. Can't remember the Arc volts right now, but have it in SheetCam.

[srp]

My most recent experience with cutting results were very similar to what I view in your pictures. 40 amp stand off tip - good results but the 30 amp was like yours. I suspected that the electrode and the nozzle were not always concentric which might have been giving me the variable results with the 30a nozzle. My torch was 7-8 years old and I thought it would be worth changing the torch body to see if it made any difference. Cleared up the problem with the 30a and is cutting great. I suspect the 40 a standoff is more tolerant of misalignment. This problem drove me nuts. It would be cutting great and I would change one of the consumables and quality would go to hell. Genuine td part - wondered if they had a qc problem. Most of my hair is gone now but it now looks like I may get to keep what little I have until the next go around.

[Brand X]

Just tested it again with my A-120- 20 amp tips work really well. Used the new SheetCam shape library to make this.. 16 ga. and 75 ipm,20 amps,100 arc volts.. My A-120 must dial down pretty well, because the tip looks prefect after quite a bit of test cuts.. My Esab will cut at 150 ipm (Slowest) with it's 20-30 amp nozzles at 30 amps.. I used the 20-30 amp tips with my other Thermal machines,101/151 but never cared for them.. That was almost 10 years ago, but funny how I like them now..