Prototype door access control uses a complex combination of materials and processes
Star Prototype has resurrected a finishing process used on Spitfire aircraft cockpit canopies to polish polycarbonate parts for a door access security control.
Star described the vapour polishing method as potentially “highly dangerous, but extremely effective.”
The Chinese company, owned by Teesside businessman Gordon Styles, was called in to deliver a prototype of a finger vein biometric door access system for a Canadian company. The prototype needed to be both functional and photorealistic.
Star used a complex mix of processes including vacuum casting, CNC plastic machining, sheet metalwork, silk screening, painting and engraving as well as vapour polishing.
The vacuum cast parts of the prototype were made from two different grades of polyurethane supplied by Axson. The first of these is similar to ABS and the other to rubber. The dark grey castings were produced in the correct colour and picked up their texture from that of the mould surface. Styles described this as “very unusual for
The keypads were also made out of polycarbonate. At first PMMA was considered. Styles commented: “This would have required a lot of manual sanding and the parts were too small for this to be feasible. Instead the parts were made from PC and finished by vapour polishing. This … process was used to make Spitfire cockpit canopies clear again after repairs.”
They keypads were vacuum cast in blue-tinted ultraviolet-stable PU resin and then painted. After painting, the letters were laser-engraved into the surface, allowing a translucent keypad display.