Adhesive bonding and mechanical joining techniques have
developed rapidly in recent years and they have
become more common joining techniques in sheet metal
product industry. New joining techniques have
become more popular because increasingly used precoated
sheet materials are difficult to weld. New joining
techniques can also be applied as well for precoated as
for uncoated sheet metal materials.
VTT Manufacturing Technology in cooperation with IVF has
carried out a research project of flexible
automation of joining techniques for sheet metals. The
project consisted of flexible automation of mechanical
joining and adhesive bonding of sheet metal parts.
The joining techniques studied can be applied to
supplement each other. The shape of a typical clinching
limiting the applications, because the tool must reach to
both sides of the joint like in spot welding. Adhesive
bonding without jigs can be used only for parts that are
locking each other when joined. If no constructive
locking appears the parts are kept steady in a jig or the
parts are secured by clinching or riveting. The adhesive
is also a sealing of the joint.
The research equipment was developed and built in the
laboratory of VTT, consisting of a robot with linear
track, clinching equipment, adhesive bonding equipment, a
flexible jig, a ventilation system and tables for
loading and unloading of sheet metal parts. The demands
for joint design and the economic effects of different
joining techniques were studied. Five industrial case
products were studied considering the utilization of
clinching or adhesive bonding instead of spot welding or
The results of the studies show that clinching and
adhesive bonding are possible to be automated flexibly.
Existing sheet metal products usually need some re-design
when a new joining method is applied. Sufficient
joint strength for most sheet metal products can be
produced by clinching or adhesive bonding.
Joining costs depend very much on jig costs. Clinching
reduces remarkably the lead time of adhesive bonded
parts and reduces also jig costs. Clinching and adhesive
bonding are very suitable joining techniques for several
material combinations, especially for thicknesses less
than 3 mm.
|Place of Publication
|VTT Technical Research Centre of Finland
|Number of pages
|Published - 1995
|MoE publication type
|VTT Tiedotteita - Meddelanden - Research Notes