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Resistance Welding is a fairly
simple heat generation process: the passage of current through a resistance
generates heat. This is the same principle used in the operation of heating
coils. In addition to the bulk resistances, the contact resistances also play a
mayor role. The contact resistances are influenced by the surface condition
(surface roughness, cleanliness, oxidation and platings).
The general heat generation formula for Resistance Welding is:
Heat = I² x R x t x K
Where "I" is the
weld current through the workpieces, "R" is the electrical resistance (in ohms)
of the workpieces, "t" is the weld time (in hertz, milliseconds or
microseconds), and "K" is a thermal constant. The weld current (I) and duration
of current (t) are controlled by the resistance weldingpower supply. The
resistance of the workpieces (R) is a function of the weld force and the
materials used. The thermal constant "K" can be affected by part geometry,
fixturing and weld force.
The bulk and contact resistance values of the
workpieces, electrodes and their interfaces both cause and affect the amount of
heat generated. The diagram at the right demonstrates three contact and four
bulk resistance values, which, combined, help determine the heat generated.
Bulk & Contact Resistance Values.
Linear DC (Power Supplies)
DC25 Linear
DC Weld Control with Built-in Monitor
UB25 Linear
DC Welding Control with Built-in Monitor
High Frequency Inverters
HF27 High
Frequency Inverter
HF 25 High
Frequency Inverter
HF2/HF2S
High Frequency Inverters
Capacitive Discharge Welders
125DP
Capacitive Discharge Welder
250DP
Capacitive Discharge Welder
500DP/500HV/875DP Capacitive Discharge Welders
Weld Heads
Thinline Series Weld Heads
The Thinline Weld Heads consist of three families of
full-features products for precision metals joining:
80 Series - 20 lb. and 40 lb.
180 Series - 100 lb.
90 Series - 150 lb.
FEATURES:
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Adjustable Force-Firing
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Low Inertia Designs
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Air Actuated Option
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Adjustable Tare Spring
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Single Air Regulator
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Up to 1.5 inch (38 mm) stroke
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Up and Down Stops
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Rugged Design
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EZ-AIR Technology
Technical
data
60 Series Weld Heads
Miniature resistance welding applications require precise
control over electrode position and weld force. The 60 Series Weld Heads and
Automation Modules offer stable electrode positioning and accurate force
control. Traditional cable pedal weld head designs are subject to operator
overforce, resulting in variable weld quality. The unique actuator design of
the 60F Series Weld Heads eliminates overforce enabling all operators to
achieve the same welding results.
FEATURES:
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Manually actuated by cable pedal for precise electrode position control
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Unique actuator design eliminates overforce
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LED’s indicate firing signal and overforce protection
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Numerical force indicator for verification of overforce protection set point
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Includes cable pedal, base plate, and stand for quick set up
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Optional Optic Mounting Assembly holds stereo zoom microscope
Technical
data
70 Series Servo Motor Driven Weld
Heads
Designed for use in automation or benchtop welding, Miyachi
Unitek’s 70 Series Weld heads offer stable, repeatable electrode force for a
wide range of resistance welding applications. Two different models are
available, each equipped with an easy-to-program, state-of-the-art servo motor
controller which allows precise programming of electrode position and speed for
up to 32 different weld schedules.
FEATURES:
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Controlled, fast, repeatable servo motor actuation
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Extremely low-end force control (0.5lbs)
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Remote control I/O and PC communication
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Displacement and force options
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"Soft Touch" part clamping
Technical
data
Series 300 Electromagnetic Weld Head
System
The Miyachi Unitek Series 300 electromagnetic weld head
system is comprised of a linear magnetic force actuator and a
microprocessor-based electronic control, providing a precisely controlled weld
force profile for miniature parts welding. Weld-to-Displacement and
programmable follow-up force features ensure welding consistency and virtually
no splash when welding difficult materials such as copper, molybdenum, and
tungsten. The Series 300 can interface with direct current, inverter, and
stored energy power supply technologies.
FEATURES:
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Electronic Control
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Traceability of all Weld Head Functions
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Weld-to-Displacement
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Programmable Follow-up Force
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I/O Ports for Automation Applications
Technical
data
Series 400 Weld Head Modules for
Automation
The 400 Series are resistance weld head modules for
miniature and microjoining applications. Designed for integration into
automated assembly systems, two models are available: the 400M for opposed
welding and the 408SM for parallel gap or series welding. Both models are
constructed of high durability components for consistent, trouble- free
operation. Their compact size benefits integration by minimizing space
requirements while maximizing system design flexibility.
FEATURES:
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Stroke of 0.2 inches (5 mm)
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Two Weld Force Ranges
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Weld Force Setting and Adjustment are Tool-free
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Built-in Force Firing Switch
Technical
data
Series 500 Weld Head for Battery Pack
Manufacturing
Designed to meet the needs of high quality battery pack
manufacturers, Miyachi Unitek 508 Series Welding Head is ideal for joining thin
tab material to a wide variety of today’s advanced battery cell technologies.
This superior air-actuated weld head was specifically developed to work in high
volume production environments where quality, cost per part, and set-up and
maintenance are important.
FEATURES:
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Easy Force Adjustment with Fine Resolution
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Easy Set-up and Maintenance
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Capable of up to 3 Welds Per Second
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EZ-AIR Guarantees Repeatability
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1.5mm Electrode Rod Enables Fine Positioning for Small Cells
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Fine Gap Adjustment in a True Horizontal Plane
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Independent Electrode Force to Adjust for Polarity
Technical
data
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