PMMA (polymethylmethacrylate) led lens
PMMA, also known as acrylic,Plexiglass,and Acrilite brand names,is the most widely used plastic material.
Compare to the PC(Polycarbonate),key features of PMMA led lens as following;
- low cost – making it very affordable;
ease of molding into any shape;
- high light transmission – 93 % as compared with 88% for Polycarbonate;
- “green” material – it is recyclable and BPA free;
high UV transmittance.
PMMA is widely used for total internal reflection (TIR) lenses,led lighting, led lens profile and so on.
Customer shoule be also noted that some disadvantages are reported,such as yellowing under prolonged UV exposure,higher water absorption,and lower scratching and heat resistance when compared to other plastics.
Why is Acrylic used so often for led lighting lens?
Acrylic is an incredibly useful plastic for applications requiring transparency where high impact resistance is not an issue. Acrylic is very scratch resistant compared to other clear plastics. It is a lighter alternative to glass and an economic substitute for polycarbonate in applications where strength is not a crucial factor. It can be cut into extremely fine shapes using laser cutting technology because the material vaporizes upon impact with the concentrated laser energy. Because of its brittle failure and relatively low strength, we don’t often use Acrylic. Instead, we prefer to use PC or PETG. PC and PETG might not be as clear as Acrylic, but they are usually “clear enough”. If optical clarity is of extreme importance, than we will use Acrylic. We have machined Acrylic on the CNC, and also made hand-formed pieces. Usually after machining, the parts need to be polished to remove the tool marks and restore the optical clarity. A few examples include the following:
- as a led lighting lens
- as a general replacement for glass
- fashion accessories (e.g. we worked on a project where we produced cuff bracelets made of acrylic. We were machining the flat shapes, then heating and bending the bracelets on a forming machine we made).
- display products (e.g. we hand fabricated a large scale model of a clear iPhone case for a tradeshow. Because it was roughly one foot by two feet in size we needed a material that was simple to machine. PC would have been too expensive and because it was a show piece, the clarity and finish of the parts was important.
Post time: Jul-27-2020