Computer Solutions There are
almost as many different additive manufacturing techniques as there are materials, so outsourcing is the watchword.
Boom time for additive manufacturing
A
dditive manufacturing goes back a couple of decades. One company, Pera Technology, pioneered
one additive manufacturing method that involved a bath full of thermosetting resin where a laser adds layer by layer in two dimensions on a surface.
“We have been involved with 3D printing for over 25 years now, mainly in the areas of rapid prototyping using laser cured thermosetting. In the early days, you had large baths of thermosetting resins cured by laser with your solid structure growing out of this bath,” recalls Paul Tranter, chief executive of Pera Technology. “Since that time, we have been involved with a number additive manufacturing processes, latterly with the development of a process that creates 3D circuit boards using an additive copper process which has been commercialised in the US.”
Traditionally, a substrate with a copper film bonded to the top was etched or machined to reveal a track. By using additive methods, Pera claims it can reduce copper waste by about 70 per cent by pre-treating the polymer film in those areas where the tracks need to appear. This gives about 90 per cent of the conductivity of bulk copper, so thicker tracks are needed. Track width is a barrier so part of the reason for doing surface treatment of polymer film is to encourage liquid surface tension in a similar way that waxing a car causes a beading effect for water.
“We were effectively entering the surface of the polymer film in order to get surface tension so that the ink droplets would flow to the desired areas, so we are no longer restricted by droplet size in terms of copper track width,” Tranter explains.
“We can deposit say a 0.5 micron diameter copper droplet but with
Fig. 1. The design of a nebuliser helped to develop a 3D droplet printing technology.
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