Taper

[gsi]

I'm getting a weird taper at the end of a section of cutting. I'm using a Dynatorch SuperB with TD A80. I'm cutting 5/16 A-36 using 80amps, 65 IPM, and torch height control. My consumables are brand new factory thermal dynamics. The rest of the part cuts out pretty good but these last couple of teeth have a lot of taper. I've cut 6 of this part and all of them have done the same thing. I don't have a moisture problem as my filters are very dry. I checked them to make sure after cutting these. I've cut other parts with the same consumables and they cut out fine. I'm using corner slowdown for arcs with a radius less than 1". Any ideas?

Thanks,
Griff

[jimcolt]

If you had a Hypertherm I would suggest using the 45 amp shielded consumables, cut at about 32 inches per minute at a cut height of .06", pierce height of .15" and a pierce delay time of .8 seconds. Arc voltage would be about 138 to 140 volts.

With the T-D unit I would recommend using a 60....or maybe even the 40 amp nozzle.....and look up the book specs. 80 amps is too much power for 5/16" thickness if you are looking for best cut quality. Jim Colt Hypertherm

[Brand X]

Ditch the 80 amps tips.. with 50-55 (9-8209) and the 60 amp 9-8210) Tips.. Shielded with 80 psi, and 85 for the 60 amp tips.. You will probably not like the 40 amp as well.. You are looking at .1900 pierce (maybe .2000) and a cut height of .1700 (55 amps) and .1800 on the 60 amp ones..

With the one torch you cannot get too far out of range in thickness to amps cut.. Gets ugly in a hurry.. Set your speed by looking at the arc. Book can be way off.. I generally get better cuts with the 70 amp tips over the 80 amp ones... Unless you need more power to pierce. Cuts 0.500 MS much straighter then with 80 amps.. It's funny ,the older holdover amp sizes from the old school Thermals (not in the book) 50-55, 70 amp tips are some of the best you can use in a A-80... No book specs at all, just what works..even the 20 -30 amp un-shielded work sweet.. These machines have stumped a lot of People.. Got to be stubborn, to get performance out of them. They have a lot of great qualities to them, but following some of the book specs is not one of them.. I am not sure what you run in acceleration, but that is another thing that helps to be set right.. Don't really have clue about setting up a Dynatorch, but seems like a nice machine. I like the looks/ features of them anyway.

[gsi]

Thanks a ton guys! I dropped down to a 60A tip and used close to Jim's settings. The cut quality improved by a huge amount. The book specs were way higher IPM. I think it was 55 IPM. Seems like slowing it down got the cut quality way up. As a plus, the hole quality seemed to go way up as well.

[gsi]

Here it is all cleaned up. You can kinda see the hole as well.

[exapprentice]

Hi gsi

you must be happy as Larry, looking good, very good

[gsi]

I'm very very happy. Thanks again guys. I've been able to cut some parts that I had previously tried but I wasn't happen enough with the cut quality.

[Brand X]

Looks a lot better. You are in a good range with the amps to thickness being cut.. The older torch design design can do a nice job, if you pay attention to what it's telling you.. If you don't, it's really frustrating as all get out.