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Choosing Welders

AC Micro Resistance Welding

Sunstone AC Resistance Spot Welders are AC welders with accurate controls that can be adjusted down to weld times as low as 1/100 second.  Typical welding applications range from sheets as thin as 0.05mm up to 1.2mm, depending on metal and orientation. Weld Metal Mesh and weld every wire for perfect results and excellent strength. Foil welding made easy using AC welding System.

Features of the AC Spot Welders

  • Available in a 2.2, 5, and 15 Kva Models.
  • Internal AC Transformer
  • Simple, User-Friendly Interface
  • Synchronous IC Control
  • Adjustable Heat Control

What is AC Welding?

Alternating Current Welding or AC welding refers to the type of power supply that is used in AC Resistance Welding. AC welding uses a constant flow of energy generated from an AC Transformer. This transformer can be controlled to generate very fine welds.

The AC welding systems are primarily used to create seam welds using the continuous flow of energy from the AC Power supply. This unit will continually flow weld energy as long as the trigger is pressed. This allows for hermetic sealing of pouch cells and any foil welding. This also allows for every wire in a mesh to be welded to the substrate, giving a strong, reliable and repeatable weld. Used for mesh welding screens, mesh basket welding, Filter welding, and Filter tacking.

Seam Welding Made Easy

The AC welding system is commonly used with the Roller hand-piece to accomplish seam welds. This wheel electrode allows for the weld to be generated as it rolls along the piece.

Pouch Cell & Foil Welding

Another great application for the AC Welding System is foil and pouch cell welding. The AC welding system allows you achieve a hermetic seal on foils. This allows for the creation of foil pouches. These pouches can be used to create custom sized pouches for your application. These can then be used for a Li-Po battery pouch cell. A pouch can be created and sealed for environmental protection, and safe storage over time.



CD Micro Resistance Welding

How does CD Resistance Welding Work?

Capacitive Discharge resistance welding or CD Resistance welding uses capacitors to store energy for quick release. A capacitor, like a battery, store energy for release. Unlike a battery, a capacitor has the ability to release energy at a much higher rate.

CD Resistance welding uses the microscopic gap between two parts to create heat in a very localized area. At the microscopic level, every metal has peaks and valleys ( See Picture to the Right). As two metals are placed surface to surface, peaks will touch other peaks. Depending on the force that is applied to these pieces, more or less surface contact will occur. As electricity passes through these peaks it causes heat to build up, and melt the peaks. This is the basic understanding of how a resistance weld is accomplished.

Pressure is Important

Pressure Plays a huge role in  CD resistance welding. As described above, the greater the pressure the more surface contact will be generated. Therefore, the great the weld pressure, the colder the weld will be. This is opposite of what many might think. Because there is more surface area, the resistance is lower, therefore it will create less heat.

In CD Resistance welding, repeatable results are one of the most important factors. To trust that when you complete a weld, it will not ruin your project or part, but complete the desired result. When done incorrectly Capacitive Discharge welding has the ability to blow up, or pop. This is due to not enough contact between the weld parts, and an electrical arc is created.

In order to get consistent results using Capacitive Discharge welding, both energy and power must be held constant. This is why the use of a pressure regulated hand-piece, or weld head is recommended. These will provide consistent and repeatable welds.

What is Needed in a CD Welding System?

Each of the CD Resistance welding systems come standard with a power cord (international converter included) and will a foot switch for weld actuation. Check out our CD Products Page CD200DP, CD400DP, CD600DP, CD1000DP.

Outside of the power supply, you will need a method to deliver the power to your workpiece. This can be accomplished in two different ways.


Weld Head:

The most popular method of delivering energy to a weld site is a weld head. Weld heads come in a variety of different operation types, including Pneumatic, servo, and manual actuation. Weld heads differ is pressure settings depending on your application. For more information on different weld head options check out our weld heads page.

Hand Attachments:

Hand Attachments give you the flexibility to hold the weld tips in hand and have ultimate control. Hand-piece options vary from simple weld probes to more sophisticated pressure actuated handpicks. Depending on your application, and access to your pieces, Sunstone has the perfect hand-piece for you. Handpicks are grouped into three simple groups.

  • Single Probe – One Probe & A Grounding Pieces
  • Dual Probe- Two probes to accomplish a parallel weld.
  • Tweezer – Two opposing electrodes with the ability to apply force between them.

See our Hand Attachments page to find the perfect Hand-piece.

What is Opposed Welding?

Opposed welding is when the two electrodes are opposed to one another and pressing toward each other. This is like a tweezer. One electrode is on the bottom of the joint, and another is on the top. Pressure is applied from both sides, pinching the weld site. See the above graphic for a visual representation. Opposed welding is preferred to parallel and can accomplish better weld results. If you have access to both sides of your weld and can apply force to the joint, and opposed configuration is best. This configuration will create one spot on each side of the piece, where the electrodes came in contact with the piece.

What is a Step Weld?

A step weld is similar to a parallel weld in that there are two electrodes on the same side. The difference is one electrode is on the joint and the other is only on one single layer. This focuses the energy on one side of the electrode rather than on both. This configuration allows for a more powerful weld than a parallel weld, but not as powerful as an opposed. This configuration will result in one spot being created.

What is Parallel welding?

There are several different configurations to accomplish a resistance weld. Parallel welding is using two electrodes right next to one another in parallel. Both electrodes are on the same side of the weld, pressing down on the weld joint.  one electrode is positive and the other is Negative. The energy flows down into the workpiece through the one electrode and up the other to complete the weld. See the simple Graphic below for a visual representation. Parallel welding is used in battery pack welding. In battery welding a welding current cannot be passed through the cell, therefore a parallel configuration is required. In most applications, an opposed configuration will generate a better weld and require less energy. This type of weld will create two spots, where each electrode touched.


DC Micro Resistance Welding

DC Resistance spot welding joins metal pieces together by applying pressure and passing a large current through a localized area.

A DC welding system uses a Direct Current Waveform. This allows for a rapid upslope, a sustained peak, and a rapid downslope. This waveform is similar to a square, with a sharp increase in energy at the trigger, flat constant peak energy, then a sharp decrease in energy to finish. This allows for very fine control, especially on the lower end of the energy settings.

Why Use DC Welding?

DC welding is perfect for very small and fine wire welding. DC Power supplies have the ability to control the weld current very low & precise. One of the major applications for the DC Welding systems is Thermal Compression Welding. DC welding is also very useful in PCB repair, and trace welding. Additionally, DC welding is used anytime a very small wire, is being welded.

What is Thermal Compression Welding?

Thermal Compression Welding uses a DC Welding system, with a Thermal Compression Electrode. These electrodes have a very fine tip, that is bonded. This tip is specifically designed to heat up and transfer heat to the workpiece. Pressure is applied downward to the joint, and as energy is passed through the TCB Electrode. The tip of the electrode heats up, and with the pressure applied creates a weld. This process is primarily used in welding magnet and very fine wire welding. The tip heat will melt through the magnet wire coating and create a metal to metal weld.

What is needed in a DC Welding system?

Power Supply:

Sunstone offers 2 different DC Welding Power supplies. The Sunstone Linear DC, and The Avio Linear DC.

The Sunstone Linear DC Features an 8″ touchscreen display. This allows you to adjust your settings easily and quickly. This also gives you a graphic output of your weld waveform. Giving you the ability to see graphically what your weld will look like.

Weld Head or Hand-Piece?

With a DC Welding system, there are 3 major weld delivery options.

Weld Head:

The Sunstone WH2125A & The WH1125A are both options for delivery of DC welds. These are both Pneumatically controlled and allow you to adjust the pressure to perfectly fit your application. These are not the most popular options, due to the size of most DC welding projects. Depending on your application and access to your welding parts, as well as the amount of force that can be applied to your parts.

Micro-Weld Head:

The most popular option for delivering DC welds is a Micro-Weld head. These have very fine control over the pressure being applied and allow you to adjust this pressure in a matter of grams. This ultra fine control allows the user to adjust the pressure to fit any application. These weld heads are both pneumatically, servo, and manual foot pedal control. The Sunstone Micro Weld-Head has a foot pedal that manually moves the weld head down for extra precision. This weld head also uses the Thermal Compression Electrodes, to complete thermal compression welds. This weld head holds the electrode and applies force to complete these types of welds. The Sunstone Micro-Weld head also includes a free-floating arm Mounted microscope that allows you to see the very small wires that you are welding.

Hand Attachment:

The last option to deliver DC Welds is through the use of a Hand Attachment. These can vary in function and form. Hand Attachments vary from simple welding probes to tweezers, and pressure actuated hand-pieces. The most popular hand attachment used with DC welding systems is the Dual Probe Hand Piece- Micro (DPHP-Micro). This hand-piece allows you to deliver Thermal Compression Welds by hand. This is the only Hand Attachments that uses the TCB electrode.

What Thermal Compression Electrodes Are Available?

The various TCB electrodes have a specific function to help you get the desired weld.

  • TCB-FL – Most Common TCB Electrode – used for all-purpose welds. The flat tip allows for an even weld.
  • TCB- SMFL – Similar to the FL, but with a 25% Smaller tip surface.
  • TCB-2525T – Has the smallest tip of any TCB electrode at .010″ square- flat tip for even welding.
  • TCB-SY – 5-degree slant side to side. This allows for the electrode to weld with deeper penetration on one side.
  • TCB-SL – Designed to weld and cut a wire, the SL has 7-degree tip angle from front to back. To cut the wire at the front, and weld at the back.
  • TCB-U – The most robust TCB Tip – Used for higher power/ higher heat applications, thicker magnet wires, or in high production applications.




HF Inverter Micro Resistance Welding

High-Frequency Inverter Welding (HF Inverter) uses a specialized power supply to complete highly repeatable resistance welds. HF Inverters are used primarily in automation due to the high repeatability of the welds. An HF Inverter power supply takes an AC input, and rectifies it to a DC wave, then switches to an AC weld during the primary weld current. Similar to a DC weld, but with a low-level AC wave at the top of the waveform.

Why Use HF Inverter Welding?

HF Inverter Welding produces very consistent and repeatable results. This makes it a primary candidate for use with automated welding systems, and in automation. The Avio HF welding system that Sunstone Provides, uses closed-loop feedback, that allows monitoring of each weld. This monitoring allows you to measure each and every weld to ensure that they are consistent and perfect. Additionally, the HF Inverter’s closed-loop feedback provides you with the ability to setup envelops or ranges that the welds can fall within. This allows you to set how strict you need your weld controls.

What Else is Needed for an HF Inverter Welding System?

Due to the high repeatability of the HF Inverter Power supply, a highly repeatable weld delivery source is recommended. This would be through the use of a weld head. Two different weld options are available.


The use of a servo weld head is the highest level of precision of any type of weld delivery system. The servo weld head gives you ultimate control of pressure, duration, and displacement. Simply, you can control how fast you want the electrodes to move, how much force to apply, and even control how much the electrodes move during the welding process. This is the ultimate welding head for use in Automation and semi-automated systems. If you are looking for the ultimate weld head that can be used by any user and get amazing results, look no further than the servo is driven head.


A Pneumatic head will provide you with the level of control and precision necessary for use with the HF Inverter. Simply supply a compressed air line, and set the speed that you want it to descend and ascend, and you are ready to weld. With adjustable height and pressure, a Pneumatic weld head will give you great results.

What Applications Use an HF Inverter Welding System?

Applications include:

  • Resistors to Terminals
  • Aluminum & Copper Lithium Pouch Cell Terminals
  • Many Layers of Small Foils
  • Capacitor Leads
  • Brazing
  • Battery Pack Manufacturing
  • Large Magnet wire
  • Honeycomb Welding
  • Medical Device
  • Aerospace
  • And Much More!


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