© 2016 Nelson Stud Welding, Inc.
Page 7
All Rights Reserved.
February 2016
Part No. 729-110-042 v1.03
1 Overview
The Nelson NCD+ stud welding guns are made to be used with Nelson NCD+ stud welding power units, which
utilize the capacitor discharge principal of stud welding. This system is designed to use fasteners, which are
manufactured with a small projection on the weld end and are welded by either the Contact or Gap method. Heat
for fusion is obtained from an electric arc, which is established by flashing away the small projection. The
discharge of the welding current or energy stored in the capacitors produces an arc that melts the end of the stud
and a portion of the base material. The stud is forced into the molten metal before the conclusion of the arc cycle.
Upon cooling, a uniform cross section bond is achieved. A special advantage of the capacitor discharge process
is the limited heat generated, and low penetration which allows the fasteners to be welded to thin and/or coated
parts opposite the weld side.
Selection of the “gap” or “contact” welding mode is application dependent. Gap welding usually provides superior
weld reliability with aluminum and other non-ferrous metals. Contact welding is generally used with carbon steel
and stainless steel especially when weld appearance is not a prime consideration. The contact welding setup is
easier to make and the contact mode is somewhat more tolerant to work piece flexing.
The welding guns in this series are a “contact gun” which is suitable only for contact welding and an “auto-gap
gun” which is suitable for both gap and contact welding.
NOTE: Depending upon the weld setup established for any particular stud size or material, the noise generated by the
flashing away of the stud tip may exceed the allowable level established by the Occupational Safety and Health
Administration (Section 50-204.10 of the Federal Register, Part II). For this reason, it is recommended that the stud
welding operator and anyone working within the immediate area of the stud welding operation use proper ear
protection.
SAFETY SYMBOLS
ATTENTION! BE
ALERT! Your safety
is involved.
Used to call attention to immediate hazards which, if not
avoided, will result in immediate, serious personal injury or
loss of life.
Used to call attention to potential hazards which could
result in personal injury or loss of life.
Used to call attention to hazards which could result in minor
personal injury.
