Title:
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Adhesive bonding of metal cutting tools
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The aim of this work is to develop techniques and
to optimize the process of bonding of cemented carbide metal
cutting inserts. This replaces the common methods of clamping
or brazing. The first stage was to-survey and test structural
adhesives to select the most promising adhesive for metal
cutting applications. This resulted in a choice of toughened
epoxy heat cured adhesive.
A comparison between bonded and brazed joints,
from the damping capacity point of view was made. In this
comparison adhesive bonding resulted in, a higher damping
capacity when compared with brazing. The bond line thickness
proved to be significant in increasing the damping capacity
of the bonded joints.
A comparison was carried out between the heat flow
through bonded and brazed tools, and demonstrated pronounced
heat insulation in the bonded tool, which depended mainly both
on the thermal conductivity of the adhesive material and the
thickness of the bonded layer. The effectiveness of the bond
line thickness, from the points of view of thermal
conductivity and developed thermal stresses was investigated.
This showed that the thinner the bond line the better is the
performance of the bonded joint.
The effect of coolant on the temperature of the
bond line as well as the tool tip was also investigated.
Mixing metallic powder with the adhesive material
in order to increase the thermal conductivity of bonded tools
was investigated. A new apparatus for measuring low thermal
conductivity is proposed.
Extensive cutting tests were carried out in order
to assess the performance of bonded tools with and without
coolant, reground tools and bonded tools having copper powder
mixed with the adhesive. The assessment of cutting
performance when using bonded tools compared with brazed
tools showed that not only a better surface finish could be
obtained with bonded tools but also far less tool flank wear
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