Pierce Top Dross and DTHC Delay & Leads/Overcuts

[Rox]

Hi-
Few Questions:
Is this normal Top Dross at a Pierce?


DTHC Delay (sec) or Auto? Does any one prefer one setting to the other or what is the best way using this? Still trying to grasp operations on these.

And last. Two times my torch stopped just after finishing a hole or inside shape. I usually do an Arc Lead In and Lead Out and also added additional .25 over cut. Trying to smooth out start and stop points. I have the Rule applied slow 60% on small circles. Holes start in center . Im cutting 1/4" 45A Used .25 Arc lead in and went longer on my lead out .26 with .25 overcut.
Basically at my pierce point I have a bit of material still hanging.

Is my Pierce too close or too far?

Awe so many questions!
thanks in advance

[TJS]

I use what is in the loaded tool menu in Sheetcam that CandCNC has provided in their package. Basically, it is the book specs of Hypertherm, however I double check the delays and such with the hypertherm specs.
You did not list the specs in your post. Pierce Height, Pierce delay and cut height.
I do use overcut on thicker material. However, you might want to decrease that a little for 1/4" plate. The torch might be stopping because it has run out of material to cut and the voltage goes out of range. I make over cuts a little more than half of the material thickness when I am at 1/4" or over. Example for 1/4" plate I use about .150" overcut.
I use perpendicular lead in for holes. I use no lead out. I slow to 60% as you are. I also shut my DTHC off for thicker material and have a new configuration called "Thick Material" where I slow the speeds and accel rates down for X, Y and Z.
As far as the lava volcano you have in the pic: that does look a little big.
T.J.

[Deezl Smoke]

I use Arclight too. Your dross pic looks normal to my rookie eyes.
On the over cut, usually that is a case for air quality. I was having that same issue using the air condition system from Arclight. Once I got frustrated enough, I spent the money for a refrigerated air dryer and 95% of my cut issues went away. Now I only use over cut for thickness nearing the upper limits of the amperage chosen.
As TJS mentions, your torch may stop and shut off because it ran out of range of voltage when going into that long of over cut. Next time it does it, click on the tab "messages" and see if it tells you what happened.

[Rox]

I use what is in the loaded tool menu in Sheetcam that CandCNC has provided in their package. Basically, it is the book specs of Hypertherm, however I double check the delays and such with the hypertherm specs.
You did not list the specs in your post. Pierce Height, Pierce delay and cut height.
I do use overcut on thicker material. However, you might want to decrease that a little for 1/4" plate. The torch might be stopping because it has run out of material to cut and the voltage goes out of range. I make over cuts a little more than half of the material thickness when I am at 1/4" or over. Example for 1/4" plate I use about .150" overcut.
I use perpendicular lead in for holes. I use no lead out. I slow to 60% as you are. I also shut my DTHC off for thicker material and have a new configuration called "Thick Material" where I slow the speeds and accel rates down for X, Y and Z.
As far as the lava volcano you have in the pic: that does look a little big.
T.J.

Hi T.J.
Thanks for the response.
I was using out of book specs. What comes loaded with the tool set for 1/4" 45A. Thanks for the confirmation on the over cut, that is the 2 times it did stop. I have started using the perpendicular and that seems to have helped with the pierce points/end points.
Really appreciate the info.

[Rox]

I use Arclight too. Your dross pic looks normal to my rookie eyes.
On the over cut, usually that is a case for air quality. I was having that same issue using the air condition system from Arclight. Once I got frustrated enough, I spent the money for a refrigerated air dryer and 95% of my cut issues went away. Now I only use over cut for thickness nearing the upper limits of the amperage chosen.
As TJS mentions, your torch may stop and shut off because it ran out of range of voltage when going into that long of over cut. Next time it does it, click on the tab "messages" and see if it tells you what happened.

Hi-
Thanks for the tip to check messages. I did check codes etc but could not find anything. I AM still getting used to navigating tabs and such. So thanks for this.
I think our air quality is good but will advise with my husband about our system. We just changed out all the filters etc on it.

Thanks again!

[weldguy]

That top dross is pretty normal, should knock off easy but if lead in was a little longer you can keep this dross off the finished part entirely.

If your using an overcut to get rid of that last little bit of material at the end you may find it helpful to put your plasma cutter ( I am assuming your using a Hypertherm) in expanded metal mode so when the arc goes over open area it does not shut off.

Expanded.PNG (63.81 KiB) Viewed 5512 times

Expanded.PNG (63.81 KiB) Viewed 5512 times

[Deezl Smoke]

That top dross is pretty normal, should knock off easy but if lead in was a little longer you can keep this dross off the finished part entirely.

If your using an overcut to get rid of that last little bit of material at the end you may find it helpful to put your plasma cutter ( I am assuming your using a Hypertherm) in expanded metal mode so when the arc goes over open area it does not shut off.


Expanded.PNG

That's interesting. I had not thought about that. And I do use Hypertherm PM 105. But once I got the air dried out, as I am in a wet air area, the need for over cut went away. If I cut say 3/4" mild, I may still overcut .05" if the hole or part is small gets hot while cutting. But I used to have to over cut .15" or more as the tail of the plasma stream was lagging so far back. And that information came from this site. Which you likely participated in.

[Rox]

That top dross is pretty normal, should knock off easy but if lead in was a little longer you can keep this dross off the finished part entirely.

If your using an overcut to get rid of that last little bit of material at the end you may find it helpful to put your plasma cutter ( I am assuming your using a Hypertherm) in expanded metal mode so when the arc goes over open area it does not shut off.


Expanded.PNG

Oh thats great information! Thanks.

I went to perpendicular lead in and lengthened it a little. Shortened my overcut. Seems ok for now. I decided to throw a Fine Cut 45A and Swirl ring in and try out 12 Gage. No bueno. haha. Now trying to dial in Fine Cut Nozzles etc.