A new machining centre for rimless lenses from Alphamatic is poised to reduce waiting for a new set of spectacles when they are rimless
A computer numeric control machine cuts holes and slots down to as little as 1mm diameter in plastic lenses as thin as 1mm, with high accuracy, to provide new levels of reliability in rimless spectacles.
Further it's more economic, machining both lenses in the same programmed operation.
One critical problem overcome by the unit is that of maintaining mounting holes perpendicular to the variably curved surfaces in the relatively soft materials.
The tilt cradle, which provides this fourth axis of alignment, uses aluminium components manufactured by Norse Precision Castings, a company in precision sand casting, a company which also works in rigid polyurethane.
Rigid polyurethane is used for the base platform, front moulding and main top cover, each with close tolerance interfaces and demanding shapes.
The processes at Norse Precision Castings have allowed prototype quantities of up to ten individual aluminium components to be made economically.
However once design is proven, the sand casting process will enable parts to be combined, providing further economies.
The sand cast process will still be economic in supplying production quantities.
The components for the outer enclosure, made in rigid polyurethane are based on models similar to those used in sand casting which allows the designer the freedom of style without surrendering functionality or ergonomics.
With extensive experience of both rigid polyurethane and aluminium, Norse Precision Castings is in an almost unique position of being able to advise on component design in plastics or metal, or in this case a combination of the two.
