CHAPTER 2: INSTALLATION
875DP/500DP/500HV DUAL PULSE
RESISTANCE WELDING POWER SUPPLIES
990-290
2-5
Air Actuated Weld Head Connections
Solenoid valve/regulator assemblies which are separate from the weld head, such as the Unitek Peco Models
80, or 82 Thinline Weld Heads, should be mounted at a convenient location on the bench.
Connect the inlet port on the air valve (solenoid) to a
properly filtered air supply
(65 psig maximum). Use
0.25-inch OD x 0.17” I.D. plastic hose with a rated burst pressure of 250 psi to connect the outlet ports of
the solenoid/regulator assembly to the flow controls on the air cylinders. Figure 2-4 illustrates a typical
single regulator installation for a Unitek Peco Series 80 Weld Head. Turn the regulator(s) fully counter-
clockwise to ensure minimum air pressure. Turn on the air supply. Repair leaks if necessary.
All Thinline weld heads are capable of cycling at a rate of 1 weld per second,
provided that the tubing
between pressure regulators and the air cylinder is kept as short as possible.
Increasing the length of the
tubing produces very sluggish mechanical motion.
Do not use lubrication on the input air line
because, as
the internal seals on the air cylinder wear, lubricating oil will leak past these seals and contaminate the
electrode and the workpiece with a fine oil mist. Once every six months or every 1 million operations,
whichever occurs first, remove the top flow control valve and place two drops of light machine oil in the top
of the air cylinder.