SUNSTONE PicoDC User manual

Direct Current Resistance Welder Users Guide
20210615 • PART #1230
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Users Guide
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ATTENTION: Read the Safety Guide before operating this welder!
Operator assumes all liability.
REVISION DATE VERSION NO. DESCRIPTION OF CHANGES
1 08/2021 Original Content
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Contents
Chapter 1: Overview ....................................................1
Welding Tips and Recommendations ................3
Common Electrode Types......................................4
How to Maintain Repeatable Welds ....................5
Chapter 2: Setup and Installation ............................7
Safety Precautions ...................................................7
Voltage and Power Requirements .......................7
Exploring the Welder’s Front Panel.....................8
Exploring the Welder’s Back Panel .....................9
Exploring the Side Panel...................................... 10
How to Set Up Your Welder................................. 10
Chapter 3: How to Use the Software Interface . 12
Run Screen Operation .......................................... 13
Selecting Weld Schedules........................... 13
Trigger Weld ..................................................... 13
Comparator Monitoring................................ 14
Displacement Monitoring ............................ 14
Weld Head Position........................................ 14
Force ................................................................... 14
Weld Head Control Screen Operation ............ 15
Mode Select...................................................... 15
Force ................................................................... 16
Position .............................................................. 17
Timing ................................................................. 18
Speed.................................................................. 19
Displacement ................................................... 20
Weld Setting Screen Operation ........................ 21
Waveform Graph ............................................. 21
Turn Pulses On or O .................................... 21
Set Voltage........................................................ 21
Set Pulse Duration.......................................... 22
Set Delay Between Pulses........................... 22
Save/Load Screen Operation............................. 23
Communications Screen Operation................ 24
PLC ....................................................................... 24
Alarms................................................................. 26
Importing/Exporting Weld Settings......... 28
Systems Screen Operation................................. 29
Interface Panel................................................. 29
Lock Panel ......................................................... 29
System Panel.................................................... 31
How to Update the Pico’s Software ................. 32
Appendix A: Pinout Details ..................................... 34
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Users Guide
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Chapter 1: Overview
The Sunstone Pico is a closed-loop feedback, direct-current, resistance welder engineered for thermocom-
pression and other ne welds. With built-in force and displacement monitoring, the Pico provides unmatched
precision, energy control, and monitoring using a color touchscreen interface.
The Pico provides you with many advantageous benets, including built-in weld monitoring, SPC tools, PLC
communication, closed-loop feedback, and more—all controlled with a 100% digital interface. The touchscreen
provides easy access to all weld parameters in addition to a visual representation of the weld waveform graph,
weld histograms, alarms, and warnings.
For automated production settings, the welder has basic PLC protocols. A cloning feature provides a simplied
method to set up multiple identical welders. Cloning copies all parameters and settings from one welder and
quickly exports them to other welders.
DC resistance welders, like the Pico, can provide consistent and repeatable energy discharges with accurate
controls and ne adjustments. DC resistance welders are ideal for thermocompression applications and small
wires due to the lower peak currents and maintainable energy discharge.
The Pico provides the following features and benets:
• Small heat-aected zone during the weld
• Ability to monitor Force and Displacement during the weld (coupled with the Micro E weld head)
• Versatility to weld very small, thin, and delicate metal parts
• Single or Dual Pulse operation
• Low maintenance required
• Touchscreen Interface
• Weld Monitoring
• Weld Head Controls
• Remote Schedule Select
• Weld Counter
• Histogram of weld results

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• Weld Comparator
• Full welder parameter cloning
• Lock-Out Mode
• PLC communication ready
• Software Updates
• Multiple Languages available
• Alarms and warnings
What is Direct Current Resistance Welding?
The Sunstone Pico welder converts the AC power coming from the wall to DC power and utilizes an internal
control system to regulate and maintain the weld discharge for accurate, repeatable welds. The control system
allows for ne tuning and manipulation of the weld energy to adjust for various welding applications. DC power
can be ideal for very ne wires and thin components that need the precision other welding power supplies do
not provide. The peak current of DC welders is lower than that of CD welders, but more sustainable throughout
the weld process. The sustained peak currents are ideal for using thermocompression electrodes because the
constant current provides a more even heat during the length of the weld.
DC RESISTANCE WELD FORMATION
Resistive spot welding relies on metal resistivity to heat and fuse metal. Current is generated by the DC power
supply and is passed through the workpiece metal. Energy is dissipated in the form of heat due to the metal’s
resistance to the current. This resultant heat melts the weld materials, fusing them together. There are two
phases to the melting process and the welder must overcome both the “Contact Resistance” and the “Bulk
Resistance” of the material.
Contact Resistance
On the micro scale, surfaces of materials are rough and uneven, resembling peaks and valleys, as shown in Fig-
ure 2.1. When two surfaces are pressed together, contact is only made in a limited number of locations (where
the peaks meet the peaks), instead of across the entire surface. These contact points act as resistive bridges
for the current to ow across and create contact resistance. During the rst few milliseconds of weld formation
these bridges melt, allowing other bridges to come into contact to continue the melting process.
Figure 2.1. Surface roughness limits surface-to-
surface contact. More contact points result in a
lower contact resistance.

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Bulk Resistance
Once all the bridges have fused, the contact resistance nears zero. At this point the second phase of the
melting process begins and the bulk resistance of the materials plays the nal role in weld formation. The “Bulk
Resistance” is the inherent resistive nature of the material and varies depending on the type of material. As
conductivity increases, resistivity decreases. Conductive metals such as copper require much larger amounts
of energy to form a weld compared to more resistive materials such as steel.
What is Thermocompression Welding?
Thermocompression welds utilize the resistive nature of the electrode material to generate the heat for fusion
instead of relying on the resistive nature of the materials being welded. Thermocompression electrodes (gener-
ally made of tungsten) are specially designed to be fused at the very tip. As current is passed through the resis-
tive tip of the electrode, heat is generated. Constant contact between the electrode and material being welded
must be maintained with the correct amount of compressive force to create fusion with the substrate material.
Welding Tips and Recommendations
Remember that every weld application is dierent. Several factors must work together and be balanced to
achieve successful welds. Sometimes experimentation and tweaking is required to get just the right weld. As
previously discussed, the resistivity of the materials and contact resistance play a major role. Other important
factors include the force being applied, the weld discharge energy, the weld discharge length, and the elec-
trodes being used.
WELD FORCE
Since contact resistance plays such an important role in the weld process, the weld force being applied by the
electrodes is critical. The larger the contact resistance, the hotter the resultant weld.
As more force is applied, the contact resistance is reduced due to an increased number of contact points be-
tween the two surfaces at the weld spot (more contact points result in lower contact resistance). More contact
points results in a cooler weld.
Conversely, too little force can lead to arcing between the two surfaces, which causes undesirable weld results.
Too much force can lead to weaker welds and part deformation.
Note: Weld force, as specically described above, applies to resistance welding only. Thermocompression
welds are not aected by contact resistance and therefore lighter forces do not lead to increased weld heat.
In fact, higher forces are sometimes necessary to create good contact fusion (hence the term “compression”
used in the name).
WELD ENERGY
The weld energy is adjusted using the welding power supply. Sunstone recommends that you rst try a weld at
a low energy setting and then increase energy until the desired hold strength is achieved. This tactic helps pre-
vent destroying the workpiece by having too much energy to start out. With thermocompression welds, when
set too high, energy settings can even lead to electrode tip degradation/failure.

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WELD LENGTH
Some applications require longer weld times than others to achieve good welds. Keep in mind that the longer
the weld lasts, the larger the heat aected zone will become. Weld length plays an important role in Thermo-
compression welding because the electrode tip must remain heated long enough for the coating and wire to
melt.
Common Electrode Types
Thermocompression
Thermocompression electrodes are typically used to weld magnet wires or other coated wires. Thermocom-
pression electrodes typically have an 1/8” diameter shaft body; dierent tip sizes/shapes can be available to
cater to various applications. Larger tips require more energy to heat suciently while smaller tips can be more
fragile and require less force.
Parallel Adjustable Gap
Parallel adjustable gap electrodes can be used to weld thin foils and strips and oer exibility in gap distance,
also allowing for a step conguration if required. They are available with a variety of tip sizes and come in Glid-
cop® or molybdenum.
Fixed Gap
Fixed gap electrodes can be used for similar welding applications to the adjustable gap but have the advantage
of easily maintaining the exact same gap for every weld with no need to adjust the gap. They have a smaller gap
that can often be achieved by the adjustable gap electrodes (but cannot be used for step weld congurations).
They are available in molybdenum.
Opposed
The opposed conguration is ideal for cross-wire welds and welds that oer access to both top and bottom of
the material. Electrodes come in Glidcop, Molybdenum, and Tungsten, with a variety of tip shapes.
Electrode Tip Ratings
Dierent electrode tip sizes can handle dierent amounts of force. Use the following as a guide:
• .01” x .01” – 40-1000 grams
• .015” x .025” – 125-1500 grams
• Anything larger – 400-2000 grams

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Direct weld (Opposed)
Current passes from one electrode through both
workpieces and out the opposing electrode. Typically
the easiest conguration to achieve good weld nuggets
and strength. See Figure 5.1.
Step (Adjustable Gap)
The electrode is placed on both materials, but from the
same side. A step or adjustable gap electrode congu-
ration can be challenging when maintain proper pres-
sure at each electrode due to possibly uneven surface.
See Figure 5.2.
Series (Adjustable Gap/Fixed Gap)
The electrodes are placed on the surface material only.
Because the current is split between both materials,
sometimes this conguration requires more weld ener-
gy than a direct weld would. See Figure 5.3.
Thermocompression
In a thermocompression conguration, the current
does not pass through the materials being welded, but
rather the current passes through the electrode tip. A
thermocompression conguration is most useful for
coated surfaces like magnet wire. See Figure 5.4.
How to Maintain Repeatable Welds
Consistent weld results require a consistent and
repeatable process. A few suggestions for ensuring
repeatable welds include:
• Keep a weld logbook documenting the process
once a successful weld has been achieved. Try
to keep track of the following:
• Force applied
• Electrodes (tip size/shape, electrode
material, etc.)
Figure 5.1. Direct
(opposed) electrode
conguration.
Figure 5.2. Step
(adjustable gap) electrode
conguration.
Figure 5.3. Series
(adjustable gap/xed gap)
electrode conguration.
Figure 5.4. Thermocom-
pression electrode cong-
uration.

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• Measured gap distances (between electrodes, between the tips and workpiece, etc)
• Electrode placement in electrode holders (ush with top, extending “X” amount, etc.)
• Welding Power Supply settings (energy, length, etc.)
• Make sure there are no impediments to shaft movement.
• Make sure all the screws and connectors are tight.
• Make sure the weld head is placed on a stable, level surface that does not wobble.
• Try to make sure the materials being welded are clean and free of contaminants like dirt and oil.
• Whenever possible, xture the parts being welded to ensure repeatable positioning and stability during
the weld.
• Keep electrodes clean (create a process of maintaining the electrodes after a predetermined number of
welds.