Jewelry Welding Basics
The Orion is a micro pulse arc welder and a capacitive discharge resistance welder in one. This combination of abilities allows for infinite creative possibilities. The Orion can be used as a tack welder to temporarily position parts before welding or soldering. By increasing the power output it can also be used as a permanent fusion welder (resistance welder, spot welder). In its pulse arc setting the Orion can be used to perform permanent welds, add metal, and do a variety of other amazing and time saving applications.
What is a Pulse Arc Welder?
A pulse(d) arc welder is a special case of a Tungsten Inert Gas (TIG) welder. In TIG welding a sharpened tungsten electrode is used in combination with electrical power to start and sustain an high temperature plasma stream - an arc. This plasma arc is used as a heat source to melt the work piece metal. Filler metal can also be added to build up joints and create strong and reliable weld “beads”, or weld seams.
TIG welders can use AC (alternating current) or DC (direct current) energy to initiate the plasma arc. Sunstone Engineering has chosen to build on our extensive experience with DC welding technology. The Orion uses industrial capacitive discharge technology to produce the pulse arc weld. AC wall voltage can vary up to 20% during the day. Capacitive welders have the advantage, over AC technologies, of precisely storing energy before the welding process. This means that the Orion will produce a repeatable weld independent of AC power fluctuations.
The Orion pulse arc welder is a micro TIG welder and allows extremely fine control over all welding parameters. This control allows everything from prong re-tipping to seam welds in moderately sized steel work pieces.
What is resistance welding (also called tack, fusion and spot welding)
Resistance welding, often called tack or fusion welding in the jewelry industry, takes place using a very different process from that of TIG welding. In resistance welding a large electrical current is passed through two work pieces to join them. At the contact point between the two materials there is a resistance to the flow of the electrical current. As electrical current is passed through this contact point resistive heating takes place. When enough current passes through the work pieces the temperature (especially at the interface between the two pieces) can become hot enough to melt the metal in a spot. The terms resistance welder and spot welder are descriptive of this process.
If you limit the amount of power and electrical current going into the weld you can create a temporary or weak weld called a “tack” weld. Tack welding is very useful in jewelry making. It provides the ability to temporarily position a part before permanent welding. This ability opens a multitude of creative possibilities. It also helps eliminate the need for complicated binding or clamping of parts before permanent welding or soldering.
Permanent resistance welding is also useful in jewelry making. The Orion can weld ear posts and wires, tie tacks, catches, domed or dapped parts, joints pins, bolo backs and much more. Because the heart of the Orion is an industrial capacitive resistance welder, everything from one time custom pieces to production welding is possible.
Why is protective welding gas necessary?
During the pulse arc welding process high temperature plasma quickly melts metal into a molten pool at the weld location. If room air is allowed to come into contact with the molten metal, oxygen from the air will quickly react with the hot metal. The result is a metal oxide that is brittle, porous and burnt looking.
If we use a protective weld gas, such as pure Argon (99.9% pure, Argon 4.6) we can prevent these effects. The argon is used to displace any oxygen at the weld location. As the arc is performed, the protective gas acts as a barrier to prevent oxygen from entering the weld zone. After the weld has cooled the protective gas is turned off.
Using the Orion pulse arc welding stylus
The Orion pulse arc welding stylus has been designed for ease of use. In automatic trigger mode, when the stylus electrode gently and lightly touches the weld surface, the Orion will start the welding process for the user by pre-flowing protective gas (argon). Just before the Orion is about to make a weld it will sound an audible beep alert. Removing the electrode from the work piece before or during this beep will abort the welding process. If the weld is allowed to continue the arc will be initiated. During the welding process the stylus electrode is automatically retracted to prevent electrode contamination of the work piece.
Most users can become proficient on the Orion pulse arc welding stylus after a few minutes of practice. We recommend performing a series of practice welds on some stainless steel or titanium material (or whatever is available). These welds will help the new user learn the tip pressure requirements, the use of gas flow, and a range of power settings available. In the Orion Master Jeweler Plus the user can select a tip retract preference to better match contact pressure preference.
During welding your hands should be kept steady. Shaky hands may distort the finish of your weld. Rest your hands on a surface to steady them. We highly recommend a pulse arc welding stylus stand or the use of the stereo-microscope to help overcome shaky hands.
Practical considerations before welding
To help make your welding project successful we recommend that you consider and follow these steps:
- Consider the physical properties of the materials to be welded
- Practice welding on a parts with similar size and composition (until you feel comfortable)
- Consider the joint and part to be welded
- Use the Metal Information Table as a guide
Consider physical properties
Different metals and alloys can respond quite differently during the welding process. To help determine the correct starting parameters it is helpful to understand some physical properties associated with the metal. For example does this material conduct heat away quickly (high thermal conductivity). If so you may need to start with more energy to get the same spot size as a less conductive material. Does the material have a low melting temperature? If so you may need to turn down the power but extend the time of the weld. Adding to much weld current (directly related to the power setting) to a low melting temperature metal may cause it to vaporize.
After a short time welding on a variety of metals the user will gain an intuition about selecting a weld setting. It is always advisable when welding a new material to start with very low power and work upward as needed.
Practice on similar sized material
Work piece size can play a large role on weld properties. Practice on a test piece of similar size and geometry to help find the exact settings desired. During your practice welds phase, hold the work piece with a welding attachment and not directly with your fingers. This will help you get a feel for the final temperature of the part. The temperature of the work piece will depend of material properties - especially the size of the work piece vs. the amount of weld energy. If the piece is large its overall temperature will likely stay low, regardless of the weld energy. If the work piece is small and the energy input is small (e.g. micro mode) its temperature will also stay low.
Consider the joint and part to be welded
Remember that some materials, such as solder, perform poorly when welded with the pulse arc setting. If your joint contains solder you should remove it prior to welding. If your joint has cracked you may consider adding filler material out past the cracked area to restore metal strength. Consider the type of joint (I, X, V, Y etc.) and plan to use an appropriately sized filler wire if needed.
Determining the best power settings for a particular weld application
In Pulse Arc Mode metals will weld according to thermal conductivity and melting point. For example, a metal with lower thermal conductivity (e.g. stainless steel, titanium, cobalt alloys) will weld easily because the weld heat stays concentrated in the spot. Therefore, less power is required to weld one of these metals than other metals of the same thickness that have a higher thermal conductivity.
Metals with higher thermal conductivity (e.g. copper, silver, gold) will require more power to create the same spot because much of the heat is conducted away quickly.
The melting temperature of the metal is also very important when determining the necessary power setting for a weld. Knowing the approximate or relative melting temperature of your working metal will enable you to estimate the amount of energy require to create a spot. High melting temperature translates to a large amount of energy required. Low melting temperature translates into a smaller amount of energy required to make the weld.
In Tack Mode, power is important but there are two other important factors that need to be remembered. These factors are electrical conductivity and contact pressure. In Tack Mode the Orion is a fully fledged resistance welder. This means that the Orion uses a metal's electrical resistance to create the weld heat. Metals that conduct electricity well (e.g. copper) are more difficult to weld in Tack Mode and require special Tack attachments to obtain a proper weld. The second important factor when in Tack Mode is the weld contact pressure. The weld contact pressure can be controlled by how much force you apply to the two pieces that are being welded together. The harder you push the pieces together the lower you make the electrical contact resistance between them and the lower the created heat. Conversely, light pressure will result in high contact resistance and high heat.
For all welds, the size and thickness of the metal will play a significant role in the power settings that you choose. Sunstone Engineering recommends that users start at a low power and work upwards until an appropriate power setting is found. Please check the Orion Jewelry Welders forum for job specific power setting information and please post your preferred settings as well.
Power vs. time adjustment
The Orion Master Jeweler and Master Jeweler Plus allow the user a great deal of flexibility to control the penetration and size of the pulse arc weld spot. The power adjustment control can be generally thought of as a control of spot size while the time adjustment can be through of as weld penetration. In addition power can also be considered a measure of welding current and heat. The time can be considered the time that welding current or heat is applied.
Because the Orion is based on a capacitive discharge resistance welder the welding output pulse will have a smooth welding current decay. The pulse will start with a peek current which will decay to a final weld current value. The curve will look very similar to a triangle. If the weld pulse is allowed to decay fully to its low state the actual weld will look smooth. This decay behavior allows the weld pool to solidify more slowly and provides an extremely fine, smooth finish. If the weld pulse (and time) are short the pulse will approximate a square shape. The weld current will rise quickly and stay relatively constant and then stop. This type of square pulse behavior is an excellent choice when the weld electrode must be placed at a shallow angle. The square pulse (short weld time) provides a stable arc as the weld electrode is retracted.
The welding electrode
The Orion pulse arc welding stylus can accept two electrode diameters, 0.5 and 1.0 mm. Weld current is related to the diameter of the welding electrode. For small, low power welds, especially in micro-mode, the 0.5mm electrodes can be used. The 1.0mm electrodes are preferred for large, high power welds, but can be used for low power welds as well.