Tweco 400 MSTP Arcmaster - Manual (Page 40)

34
LOAD (retrieve) a Program to Control Panel
• Press and HOLD the LOAD button. Beep will sound and Digital Meter display will show a number 1.
• Select a memory location by rotating the control knob, 1 to 5 is displayed on the meter.
• After selecting the desired memory location (i.e. 1 to 5), press the right scroll button and the machine
will give a beep to confirm the weld parameters are loaded onto the control panel.
4.06 Pulsed GMAW
General
Pulse-GMAW (referred to as Pulse-MIG) is a welding process that involves the pulsing of the
welding current from a high value (peak current) to a low value (background current) to produce a
clean spatter-free weld. The intent of this manual is not to present a comprehensive coverage of this
welding process, but to give an explanation of the terms used and how they apply to the 400MSTP
power source.
Explanation of Terms: (See Figure A)
Ist: Ist is the amplitude of the initial pulse of current during the arc starting interval.
Ipk: Ipk is the amplitude of the high pulse of welding current (peak current).The current is forced to
this high value by the power source for a brief time (Tpeak). The peak current melts the wire and forms
a droplet. This droplet is then propelled to the weld pool.
Vpk: Vpk is the amplitude of the arc voltage during the high pulse of weld current.
Tpk: Tpk is the amount of time that is spent at the peak current. This time must be sufficient to form a
droplet.
Ibak: Ibak (background current) is the low value of the weld current. The background current
serves to preheat the wire and work piece. The background current must not be allowed to go too
low or the arc will become unstable and difficult to maintain.
Vbak: Vbak is the amplitude of the arc voltage during the background time.
Tbak: Tbak (background time) is the amount of time that the weld current is at the low value.
Normally, this would be a larger amount of time than is spent at peak current.
Pulse Rate: The pulse rate is the number of pulses of current that produced per second. The
400MTSP allows a pulse rate of approximately 30-300 pulses per second.
Pulsing Frequency: Pulsing frequency is the same as pulse rate. A pulse rate of 60Hz means that
the power source produces 60 pulses of current per second.
Ibak (min): Ibak (min) refers to a minimum background current level. If the current falls below this
minimum level, it will become difficult to maintain a stable arc.
Arc Length: The distance between the end of the wire electrode (the wire being fed through the
torch or gun) and the weld pool. This distance is usually set to give a smooth, spatter-free weld.