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Through Optimum Use and Innovation of Welding and Joining Technologies
Improving Global Quality of Life
A range of processes are used for joining, including mechanical fasteners, welding, brazing, soldering and
adhesive bonding. The choice of process tends to be made on an assessment of the materials, joint design,
mechanical/environmental performance and cost. Unique features of the medical device field are that
most products need to be tolerant to sterilisation techniques (e.g. autoclave, radiation) and some require
surfacing techniques to make them biocompatible or anti-soiling. Additionally, the technology employed in
these devices is developing very rapidly and assembly techniques (e.g. joining) have to adapt accordingly.
Welding techniques are currently used on a range of products such as:
Laser welding of precision instruments and hermetically sealed cases/
packages.
Benefits
:
Low distortion, Reduced machining, Reduced thickness of casing/
materials.
Arc welding catheter guide wires.
Benefits
:
Rapid heating/cooling cycle allowing the joining of difficult
materials and heat sensitive devices.
Ultrasonic and thermosonic welding for electronic device interconnection.
Benefits
:
High speed, Low temperature, Reliable.
Resistance welding for heated catheter tools.
Benefits
:
No additional materials, Will withstand high temperatures.
Laser welding polymer fluid transfer devices (e.g. blood and colostomy bags, lab-on-a-chip):
Benefits
:
Rapid assembly, no additional materials (e.g. adhesives), Recycled–improved sustainability,
Avoids cross contamination and enables
Welding PEEK optima for orthopaedic joints:
Benefits
:
Replaceadhesive,whichreducesnumberofmaterials,retainsmaterialpropertiesandavoids
re-qualification.
“
Welding” processes are now also being adapted to provide surface engineering and 3D shape generation e.g.
Laser Direct Metal Deposition – orthopaedic and dental implant generation,
customisation or surface texturing.
ElectronBeamsurface texturing/sculpting - enhance implant toboneattachment,
provide drug release surfaces.
Thermal/Cold Spray - orthopaedic implant coatings (e.g. hydroxyapatite) to enable
bonding to the bone.
The new medical products that welding assists in manufacturing can have a profoundly
beneficial effect on patient life-style, well being and reduce healthcare costs: Surface
engineering can extend implant life, miniaturisation can reduce surgical trauma. Smart implants/monitoring
systems can restore a more active life and reduce time in hospitals.
Challenges include
:
increased miniaturisation, “smarter” systems, longer life implants, improved surface
coating (e.g. bio-implant and wear-resistant interfaces).
Cardiac pacemaker-
laser welded case
Orthopaedic
hip joint
9
Needs and challenges of major industry sectors for future applications
