Perspex, Acrylic PMMA (including Perspex & Plexiglas brands) is well suited to the lenses, light guides and prisms. Acrylic is half the weight of glass and offers very good resistance to component breakage through shock or impact, with excellent light transmission properties like glass.
It is vital to fully heat treat the Acrylic prior to machining to pre-shrink it and de-stress it to avoid cracking, crazing and tolerance issues later down the line. Carville have over 80 years’ experience heat treating plastics, and have multiple, modern, fully controllable ovens to enable optimum heating and cooling cycles adjusted for material types and sizes
Precision CNC turning and milling
Acrylic lenses, light guides and prisms often require very tight tolerances to be maintained, and Carville have the experience and equipment to achieve these. We can receive data for complex lens surfaces including parabolic profiles, Fresnel lenses and complex aspheric lenses.
Carville have a range of processes and tools, including diamond milling, diamond tipped specialist tools and diamond turning, to produce high quality, accurate lens surfaces.
As well as vapour polishing capabilities, Carville has a wealth of experience with hand mop polishing lenses and prisms to get the finest possible finish. We can achieve a surface finish of Ra 0.03
Acrylic and Fibre Optic Light Guides
Light from a single light source can be captured and guided by means of acrylic and fibre optic light guides. Carville manufacture these for a number of applications, including use in medical, scientific and specialist industrial equipment. Light guides can be simple components such as a round acrylic light pipe or may be more complex components which have been fabricated and formed. Light guides can be wrapped in reflective materials to ensure optimum light transfer from the receiver to the output.
Carville specialise in aspheric lenses, working with clients to ensure we capture the profile requirements accurately, either from drawings or digital data. We use 100% cast acrylic as this is the highest quality, and can also source specialist optical acrylic. We also offer coating options either for additional hardness or specialist coating. We also use visual calibration guides for some lens applications to ensure a consistent level of quality for demanding applications.
Acrylic prisms usual require precision CNC milling followed by flat diamond milling and mop polishing to achieve the required dimensions and finish. Correct heat treatment is especially important as these can often be quite large parts. Applications are very broad ranging from industrial equipment for food processing through to military periscopes.
Prism and Lens Coating
A range of specialist coatings are available such as hardness coating on prisms or lenses. For example we can provide an OptiguardTM lens coating which is a clear, UV curable silica modified hardness lens or prism coating to provide significant abrasion resistance. Hardness levels of 8H can be achieved.
Acrylic CNC machined prisms have a wide range of applications. For example, Carville have experience manufacturing parts for applications such as military vehicle periscopes, medical imaging systems and optical laboratory instruments.