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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 from 1 to 30kVA
DC25
/ UB25 Linear
DC Weld Control with Built-in Monitor
HF
25/27 High
Frequency Inverter
Inverter Power Unit
ISQ20 Kompakt
High power DC Linear supplies from 180 to 1250kVA
ISA
SeriesMid-Frequency Inverter Resistance Welding Control
Capacitive Discharge Power Supplies
ADP 100,300 and
1000 ( ADP series)
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
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
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