AUtomating a HF cheapie, spot welder

[Dawai]

OKAY, I can't count, 1,2,3,5 and come up with the same thing, wanted something I could just stick in and push a footpedal..

Mounted a air cylinder on it, got out first a pair of timers and a relay and air solonoid and opto22 cube relay.

THEN, since I had a shop automation system I just added it into that.

LOGIC: Pedal press =true
(1)timer to clamp, air solonoid on
When timer(1)=true
(2)timer to weld
While timed out = true, opto22 relay on, weld
Timed out, current off..
Pedal press = false, release all..

Spot welding is a combination of pressure and time/current
Since current is not adjustable, pressure and time are.

Thin stainless sheet, 20ga=2.5 seconds or 2500 milleseconds at 40psi on 1" cylinder on 4" radius.

14 ga steel= 8.5 seconds or 8500 milleseconds at 40psi on 4" radius from welder hinge.

TOO much air deforms tips.. A weld nugget should look hot and bubbly gum all around meaning was molten. WHEN you shear the weld it should tear one part or the other..

IF your shop is not automated: you need:

1"x8" stroke air cylinder, regulator, guage
1 2 second timer on delay
1=0 to 10 second timer on delay
solonoid
foot switch..
opto22 cube relay
2 pole relay..
24vdc pwr supply if cube relay requires it..

foot switch activates solonoid and 2 second timer, once timed out, weld timer is energized along with the cube relay, (check voltage input) and once times out, cube off. FOOT up, all off.

My welder is on a swivel stand, if I had floor space I would prefer a tripod.

[whateg01]

I don't do any spot welding, but this sure sounds neat. I wonder how many other tasks that could be adapted to?

Dave

[rsanter]

I love my spot welder. I have used for years for pannel replacemets on cars. it will really cut the work time espically on the front collision cars that need the rad support and inner pannels replaced.
all I do now is trim away the old pannel and use a grinder or die grinder to kill the old spot welds and remove the remaining metal. clean the area a bit and fit the new pannel. hit it with the spot welder and then go over the weld spots with a wire brush and it goes to the paint guy for prep and paint.

bob

[firstgenbird]

That's a great idea David. When you control processes, you get repeatability. With careful notebook notes and weld testing, you'll end up with settings and processes that always act as wanted.

[Dawai]

Welds better welds than I ever could counting..

Problem? as welding tips deteriorate, the time must be changed slightly.

I need a good source for tips. I got a lathe, but....
I highly recomend changing these over to timer control. Even if it is just a time on control in a box and you manually do every thing else. I used to put stitch timers into migs for body shops.. weld, 1,2,3 off.. press trigger, weld 1,2,3.....