Weld Stud Location - Nelson Stud Welder

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Howdy all:Where I work, we have a Nelson stud welder and we use both 3/8 and 1/2 weld studs.I'm trying to increase efficiency and throughput of our fabrication process a little.  Owner wants to ditch the studs, it's their perception that it takes too long.  I disagree totally, but I do agree, that the time that it takes to weld the studs currently takes longer than the time we save on assembly.We use a HAAS CNC to drill all our tubes.I want to use a "drillpoint" to mark the stud's location.  The idea is, to just drill a shallow hole, deep enough to mark the location and allow the tip of the weld stud to center on it, then they can pull the trigger and be done.Has anyone done this?  Any suggestions on doing it right, avoiding pitfalls?Thanks muchCM
Reply:Sounds like it would work fine, easier than a punch markVantage 500's LN-25's, VI-400's, cobramatics, Miller migs, synch 350 LX, Powcon inverters, XMT's, 250 Ton Acurrpress 12' brake, 1/4" 10' Atlantic shear,Koikie plasma table W/ esab plasmas. marvel & hyd-mech saws, pirrana & metal muncher punches.
Reply:I think they should get rid of that stud welder. I would come and get it so it is out of their way.In all seriousness what type of welder is it Capacitance Discharge or Arc. There may be a newer better faster technology out there.
Reply:Colonel-MonkNote - the conical point is integral to the studs' arc-initiation.CNC operations are to save labor.  A very shallow 'spot-point' may be efficacious for 'sight' location.  But a hole - of depth & diameter to make manual placement of thestud quicker - will/may adversely effect the arc-initiation burn-in;and result: with inadequate fusion - weld failure.The conical point, and it height is an engineered feature of the StudGun process.  Experiment - but thoroughly test.Opus
Reply:I used to run a Nelson stud welder years ago for mounting studs of several sizes to tracks, and tubes of elevator cars. Those things take a lot of power and this one used a separate engine generator for it's power supply. I'm thinking it generated 3K amps and was powered by a Hercules engine driving a DC generator. Anyway in the early days I used to punch mark the stud locations with a prick punch which the process was later modified into using a ball end punch radius ground to match the contour of the studs to be welded in a pneumatic hammer. Again this was modified into a radius ground ball mill once NC type equipment became available and the production went much faster. A single guy could complete a stud weld cycle every five seconds with the manual loading, placing, clamping, and triggering the welder.SlobPurveyor of intimate unparalleled knowledge of nothing about everything.Oh yeah, also an unabashed internet "Troll" too.....
Reply:I work at a shipyard and we use Nelson stud welders for every size stud imaginable, thousands a day.  We use center punches to mark the locations for shooting, works well enough here. Do you have the stud guns that ensure the stud is held perpendicular to the surface? Makes it almost impossible to shoot it crooked
Reply:Hey AllThanks for the replies.I called Nelson and talked to a guy yesterday that had some good info I'll share.First, I didn't realize that there was a flux ferrule or something involved in the process - he told me that it creates a shielding gas area around the weld.He told me that the idea of using a drill point or such was sound but that the diameter of the point shouldn't be more than a mil or so bigger than the diameter of the ferrule.  I might still consider this, but won't be back at the plant for a few weeks, and I don't want to rely on this before some testing.  I'll need to be there where I can get my hands on the stuff.He brought up the idea of using templates which also seems like it would work.  Since I don't have the stud or ferrule in hand just now, it wasn't easy to follow, but he said to use a NON-magnetic material like stainless steel or phenolic about 16 ga (1/16") thk and to make the holes big enough for slip fit over the ferrule.  1/2" ferrule is .795 and 3/8" is .640, so he said to use .800/.645 respectively.That might be a better way, but we'll try both and see.This stud type isn't the type that has a small nub on the bottom that you could locate on a punch dimple.  It's just flat on the bottom, type CFL.  These are threaded all the way to the bottom.  Not sure why they were spec'd this way, we don't really need threads to the bottom.  So far as I know, they draw an X and locate stud best they can.  The gun on the welder appears to be the type that holds it vertical, I haven't seen a single bad one so far.I might look into changing the type to one that is easier to locate.  We'll see how this works.thanks
Reply:Just out of curiosity,what was the owner suggesting you use in place of the stud?---Meltedmetal
Reply:going back to using a thru-bolt and nut, or tapping for a bolt (which would only work in a few spots.)I'd actually like to do more studs, not less.  But that's going to be an uphill sell unless I can make it look faster and better.
Reply:Our fabricators use both a dimple/punch mark, and others laser etch a 90 degree "L" so you align the stud in the crotch of the L.  The dimple/punch mark did not adversely affect weld quality, as the fusion zone extended far beyond the dimpled area.
Reply:You guys don't use the ceramic rings that go around the stud when you shoot it? I am surprised, I have never seen anyone do it without them. I would think the stud would oxidize pretty badly without the shielding ring.
Reply:Originally Posted by fsisnerosYou guys don't use the ceramic rings that go around the stud when you shoot it? I am surprised, I have never seen anyone do it without them. I would think the stud would oxidize pretty badly without the shielding ring.