Professional Bench/Welding Technologies
Fixturing Using Tack- and Pulse-Arc-Welding Technology
Knowing how to tack-, fusion- and pulse-arc-weld at the bench saves time,
increases quality and drives up profits for your shop and service department
Fixturing is a technique of using tack- and/or pulse-arc welding technology to temporarily position parts before soldering, pulse-arc welding or laser welding. The technique makes you more proficient at repair, reconstruction, assembly, custom manufacturing and mass production. The following examples show applications of fixturing, how it was accomplished, the settings used and how it makes you more proficient.
18k Yellow Gold Ring Assembly
For this application of fixturing see Making a Yellow Gold and Platinum Ring Part 1: The Basic Steps, page 96. The two rings (A) and (B) will be soldered together. First, I lightly file the inside surface of the two rings. The metal raised by filing helps create the proper joint for tack-welding. Then I use the ABI Tack II to tack-weld them.
With the Tack II set at 45 volts on the high energy setting, I tack-weld the rings with the double pole tweezers (C). The tweezers have leads to the positive and negative terminals with a dielectric (non-conductive) insulator (D) between the tweezers arms. These hold and align the rings for tack-welding. After a single pulse of energy, the rings are tacked together. I inspect and find the alignment satisfactory. Otherwise, I would simply separate the rings and repeat the process.
Because these rings have a large amount of surface contact, I choose to strengthen the tack-weld using pulse-arc-welding technology. I use a single pulse of energy to spot-weld in a few locations, guaranteeing these heavy flat rings wont come apart during soldering. I use the ABI pulse-arc welder set on the high energy setting at 50 volts, a #2 tip and the alligator clip lead.
By using tack- and pulse-arc-welding technology to fixture this ring assembly before soldering, no binding wire or other cumbersome heat-sinking holding device was required, a tight joint was ensured and no parts shifted.
Platinum Earring Assembly
To attach and solder posts to platinum earrings, I rely on tack-welding technology. I use the contact pad (E) lead and pliers (F) lead to the positive and negative terminals of the ABI Tack II, set the Tack II at 40 volts on the high energy setting and fixture the post with a single pulse of energy.
I use 1500 platinum solder. Soldering is easier than conventional methods because no other holding device is needed.
By using tack-welding technology to fixture the posts for these platinum earrings before soldering, I ensured proper alignment and that nothing would shift during soldering, as often happens when using tweezers to hold the posts.
Repairing a Nose-Piece on Eyeglasses Frames
Bench jewelers still get requests to repair a broken nosepiece (G) on eyeglasses. In this case, I file both sides of the broken joint, then use the ABI Tack II set at 35 volts on the high energy setting. I use the alligator clip lead and the pliers lead to the positive and negative terminals.
The nosepiece is held in place firmly and is ready for pulse-arc welding. Ive experienced successful results tack- and pulse-arc-welding eyeglasses made from most alloys with various finishes other than titanium. To weld titanium frames, you need argon gas. Titanium eyeglasses are made of a variety of alloys, and results have been mixed. Research continues for reliable success with titanium.
By using tack-welding technology to fixture the nosepiece to the eyeglasses frame, I was able to pulse-arc weld the joint without having to use cumbersome holding devices. Using pulse-arc-welding technology and not a torch saved me an enormous amount of time. Lenses dont have to be removed, and frames dont need extensive refinishing.
Important: Tack-, fusion- and pulse-arc-welding equipment settings will differ and are based on the volume, amount of contact and alloy of the material you work with. Using like materials will give you a parameter for settings required for your application. Keep a record of settings and tasks for reference on future projects.
For questions on this process, contact Mark B. Mann at firstname.lastname@example.org or (406) 961-4426. To view related welding procedures, visit www.visual-e-communications.com.
This installment is sponsored by ABI, Cranston, RI. For general information on ABI equipment and procedures or for a list of distributors, call Janet Kirk at (888) 494-2663.
by Mark B. Mann
Photographs by Mark B. Mann