Friction welding

I am working on a project that involves the welding of end caps on the ends of tubes. The material is a tube of 304 SS and two end caps also of
304. The end caps are turned to have two diameters, the smaller diameter fits into the ID of the tube and the other diameter is slightly larger than the OD of the tube.
The end caps are welded and then the whole tube is ground and polished (this is an appearance part) to the proper OD and finish.
We talked to a friction welding Company they gave us a quote of about $2.00 per tube, but I was wondering if there might be a different welding method (TIG, MIG) that could be automated and produce welds at a lower cost.
We do anticipate having to grind and polish for the final finish, no matter what process is used.
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Tube diameter and wall thickness??
Greg Postma wrote:

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RoyJ wrote:

DUH!!! The tube diameter is .750" and it is 16 guage so the wall should be about .065"
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The orbital welders others mentioned should do a good job on this but I doubt if they will be cost effective. They do take some time to clamp them up, not meant for the kind of volume you are planning.
We ran 100,000 plus per year for a single weld on 1/2" tube using a rotary fixture and manual TIG welding. Production rates per hour were fairly impressive but the job was a total turnoff for the operator. This project had the advantage that we did not need to hide the weld.
I'd consider a rotary fixture with twin TIG heads (2 machines) run with a cheap PLC. Machine the end caps so there is some extra metal that will supply the needed filler. You might be able to get your cycle time down to less than 60 seconds, the operator sticks the caps on, shoves it in the machine, hits the go button, inspects the one that just came off.
Your secndary finishing costs to grind down the TIG weld should be in the equation. I suspect the friction weld will have minimal metal removal.
Cheers.
Greg Postma wrote:

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An orbital TIG unit could weld those very quickly with a minimal cost per part, however the orbital TIG machine for be a tad expensive.
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Ernie Leimkuhler wrote:

Hi Ernie, Define "tad" expensive.... We plan on making 200K pcs times 2 welds per unit quite and lot of welds in the next 3 years, so a major purchase is not out of the question. Thanks Greg
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Give AMI a try at http://www.arcmachines.com/Pages/screen1.html
You can lease if you care not to purchase. Company I work for purchased one for am 8" stainless steel line for Perrier-Arrowhead in Cabazon a few years ago. Unbelievable results. They will even setup training classes for you.

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On Mon, 02 May 2005 18:24:16 -0500, Greg Postma

I agree with Ernie, orbital welding would easily do the trick for the size tubing you are talking about. Look at the following 2 sites for info.
http://www.pro-fusiononline.com/products/orbital.htm http://www.pro-fusiononline.com/products/orbital.htm
google on orbital welding for more links.
My guess is that prices would range from around $2k for a simple unit on up depending on bells, whistles and automation desired. LemonArts Metal Works
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Starting money for an orbital TIG unit would be around $2000 - $3000 for a basic power supply and around $1500 for the orbital head.
There are a few companies that sell nothing but orbital TIG gear and they could give you a much better price range for what you are doing.
The most time consuming part of orbital TIG is setting up the machine, but since you are only doing one weld the setup could be locked in. After that you would just pop the parts ijnto the jig and hit the start button.
Here is a part of my links list that has many orbital suppliers.
<http://www.stagesmith.com/Metal-links.html#OrbitalRoboticPlasmaElectron BeamLase>
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How exactly does orbital welding work?
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It uses a robotic welding head that is basically a clamp that wraps around the pipe or tube. Inside the clamp is a track that allows a small TIG head to travel around the pipe. All of the weld parameters are set by the machine control. Weld amperage, travel speed, and pulser settings can all be dialed in so the weld is performed exactly the same way every time. The TIG head uses small pre-ground tungstens so welding is very consistent.
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Cool!
Reminds me of some welds I saw at the UIUC engineering open house; pipe welds for pharmaceutical applications. Blew me away...
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Manufactured bikes: a lot of the mid-range bicycle frames appear to be tig welded with great consistency. How are these made? By hand or automation?
Ciao, David Todtman
wrote:

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All hand fed TIG welds. Most of the low and midrange aluminum bikes are made in China.
Orbital only works well for pipe and tube joints where the connections are simple inline or right angle desings.
Most orbital TIG is done using no filler metal (aka "Autogenous"). There are orbital heads that have a cold-wire feed built in.

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Greg,
By 'friction" you mean ultrasonic? The ultrasonic welders use frequency amplitude, time and pressure to weld the metals. Costs are up($10-25K) there for a welder but in a production line they can pay for themselves as little as 1 year. At my job we use "Sonobond's and Stapala's" to sonically seal refrigeration systems.
Luck, Brian

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Bulletsnbrains wrote:

Brian, I wasn't aware of ultrasonic welding for metal,we currently have some plastic parts joined using ultrasonic welding, but I didn't know you could weld stainless this way. It is something I will looking. Thanks for the tip
Greg
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Bulletsnbrains wrote:

Brian, I contacted SOnobond this AM.They said that their technology probably would not work fro my application. Their strong point is non ferrous metals, foils and spot or stitch welding. I'll add them to my data base just in case.... Thanks for your help Greg
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news:hridnU3is9wL4urfRVn-

It was a stretch on that thought. Luck
Brian
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Greg Postma wrote:

BIG SNIP Update on project spent some time on the phone this AM with MTI and American Friction Welding learning about their processes and limitations. Although both know they could make the joints I need, they could maintain the overall length tolerance demanded by the end user. So tomorrow I will be contacting the orbital welding companies and an electron beam welding company to see what they can offer.
BTW, Ernie, how do you find any time to weld? I mean you promptly answer questions in this newsgroup (some times over and over again, you've put together an amazing reference of welding knowledge on your website, but just studied for and got your welding inspection cert. so when do you find time to melt metal?
To those of you who have not taken the time to see Ernies site, you are missing alot. If portfolio of work is amazing and his compendium of welding resources is like .......well it's kinda hard to explain. Let me put it this way.... In this group instead of telling someone to go"Google" we should instead tell them to go "Ernie it"..... Thanks fo all for your helpful info. I will keep you updated
Greg
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Well I actually have a HUGE update planned for the links list. I have about 400 links to fix and 600 links to add.
The gallery is going to be updated to add all the stuff from the last year. And I will finally add the reference section with all my TIG advice in one place.
As to when I weld... Right now mostly at school when teaching. Most of my own shop time is spent in planning, CAD drawings, logistics, discussions with clients and hunting down materials.
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