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Trying to understand new procedure.

Posted: Wed Mar 25, 2015 5:43 pm
by gnabgib
WPS for TIG states; Current and Polarity, dc, -ve to torch and I haven't seen that before. I'm doing stainless, so dc-.
It also lists Arc energy range to 2.5 kj/mm and Voltage range of 11-12V? Both of which I've never seen when talking TIG.

Re: Trying to understand new procedure.

Posted: Wed Mar 25, 2015 6:27 pm
by weldin mike 27
Kj/mm refers to your travel speed for a given setting. For tightly controlled heat input. On some ss it is ruined if held above a certain temp for too long.

Re: Trying to understand new procedure.

Posted: Wed Mar 25, 2015 6:55 pm
by gnabgib
Thanks and is dc,-ve to torch possibly just a technical way of saying dc-?

Re: Trying to understand new procedure.

Posted: Wed Mar 25, 2015 8:14 pm
by Otto Nobedder
gnabgib wrote:Thanks and is dc,-ve to torch possibly just a technical way of saying dc-?
Yes.

Some newbie weld engineer was trying to use his new vocabulary. All he really said was, "DC-"

Steve S

Re: Trying to understand new procedure.

Posted: Wed Mar 25, 2015 9:03 pm
by gnabgib
Otto Nobedder wrote:
gnabgib wrote:Thanks and is dc,-ve to torch possibly just a technical way of saying dc-?
Yes.

Some newbie weld engineer was trying to use his new vocabulary. All he really said was, "DC-"

Steve S
Ha!..Thanks Steve, confirms my suspicions. Thinks...Must remember to read between the lines.

Jeff

Re: Trying to understand new procedure.

Posted: Wed Mar 25, 2015 9:05 pm
by weldin mike 27
No worries.

Re: Trying to understand new procedure.

Posted: Thu Mar 26, 2015 5:06 am
by Markus
There should be given the amperage range to follow. For example 70-90 A. That kj/mm is heat input and it's bit weird that it is given if amps are not.

Voltage does affect to the heat input as well, but usually that is not given for hand welding due to change of your tungstens hight. 10 volts refers to very small cap between workpiece and tungsten. Couple of mils or so.

Also how to determine your welding speed and track that in every single weld? Impossible with hand welding...

Re: Trying to understand new procedure.

Posted: Thu Mar 26, 2015 5:58 am
by gnabgib
Markus wrote:There should be given the amperage range to follow. For example 70-90 A. That kj/mm is heat input and it's bit weird that it is given if amps are not.

Voltage does affect to the heat input as well, but usually that is not given for hand welding due to change of your tungstens hight. 10 volts refers to very small cap between workpiece and tungsten. Couple of mils or so.

Also how to determine your welding speed and track that in every single weld? Impossible with hand welding...
I was given all the details including the amperage range and travel speed, I just haven't included all of that here.

Re: Trying to understand new procedure.

Posted: Sun Mar 29, 2015 11:24 am
by TRACKRANGER
gnabgib wrote:
I was given all the details including the amperage range and travel speed, I just haven't included all of that here.
It would be great to see all of the settings. Might put everything into perspective a little better for others to follow.
Thanks
Trevor

Re: Trying to understand new procedure.

Posted: Sun Mar 29, 2015 4:45 pm
by gnabgib
TRACKRANGER wrote:
gnabgib wrote:
I was given all the details including the amperage range and travel speed, I just haven't included all of that here.
It would be great to see all of the settings. Might put everything into perspective a little better for others to follow.
Thanks
Trevor
Well, the procedure was supplied 'In confidence' so if I gave you all the details I might have to kill you :lol:

Re: Trying to understand new procedure.

Posted: Sun Mar 29, 2015 8:27 pm
by Otto Nobedder
gnabgib wrote:
TRACKRANGER wrote:
gnabgib wrote:
I was given all the details including the amperage range and travel speed, I just haven't included all of that here.
It would be great to see all of the settings. Might put everything into perspective a little better for others to follow.
Thanks
Trevor
Well, the procedure was supplied 'In confidence' so if I gave you all the details I might have to kill you :lol:
That said, the Kj/mm is an upper heat limit, or travel-speed quantity, as was mentioned by another. Just stick with the WPS amps, and move fast enough you don't make it black, and you should be fine.

Steve S

Re: Trying to understand new procedure.

Posted: Tue Mar 31, 2015 6:17 am
by gnabgib
That said, the Kj/mm is an upper heat limit, or travel-speed quantity, as was mentioned by another. Just stick with the WPS amps, and move fast enough you don't make it black, and you should be fine.

Steve S[/quote]

Thanks, but I have to admit it's got me in a knot and I'm thinking now of making a micro rotator, because of the small size and it being a critical weld.
Jeff

Re: Trying to understand new procedure.

Posted: Tue Mar 31, 2015 7:10 pm
by Otto Nobedder
If you build that "micro-rotator", please share what you build!

I envision a variable-speed geared electric drill (Max 500 RPM, DeWalt makes one) with the trigger replaced with a potentiometer, for speeds as low as 5 RPM, clamped in a vise.

Without knowing the specifics of your project, this is the cheapest accurate rotator I can imagine.

Steve S

Re: Trying to understand new procedure.

Posted: Tue Mar 31, 2015 9:30 pm
by weldin mike 27
Sewing machine motor. Already has a foot control, and lots are connected via belts and not built in. So easy to adapt.

Re: Trying to understand new procedure.

Posted: Wed Apr 01, 2015 2:45 am
by gnabgib
I'll probably get a geared 12v servo motor, with maybe 5rpm at the shaft and gear accordingly. Need up to 26mm per minute but next question is that of the return contact. Maybe a small copper arm, spring loaded to maintain contact while the work piece is turning. I think I have the purge attachment worked out.

Re: Trying to understand new procedure.

Posted: Wed Apr 01, 2015 9:47 am
by MinnesotaDave
A little back ground on heat input may help you determine your speed needed for your weld positioner.
Just solve for "S"
heat input Kj.GIF
heat input Kj.GIF (29.01 KiB) Viewed 524 times

Re: Trying to understand new procedure.

Posted: Wed Apr 01, 2015 10:24 am
by TRACKRANGER
gnabgib wrote:I'll probably get a geared 12v servo motor, with maybe 5rpm at the shaft and gear accordingly. Need up to 26mm per minute but next question is that of the return contact. Maybe a small copper arm, spring loaded to maintain contact while the work piece is turning. I think I have the purge attachment worked out.
"Up to 26mm per minute"?

Just asking. Are you sure that's not missing a zero or something?

If it was e.g. 12mm diameter rotating at 5 RPM, the travel distance would be at least 188 mm per minute.

To get 26mm per minute with a 12mm diameter job, you would need a rotation speed of ~0.7 RPM. While I don't know the diameter being used, it somehow seems awful slow.

This 'secret' job is getting more and more intriguing ...

Trev