In-mold decoration technology enables plastic product decoration at molding process instead of secondary process.
It made the luxury designs and metal-like texture applicable to a wide variety of products.
Products like cosmetic compact cases used the aluminum vacuum evaporation directly onto plastic materials to add metallic shining, because they got heavier and more expensive if they used real metals.
We soon received requests from our clients, to implement the same wonderful designs also to their cell phones.
However, there was one problem. It was of no matter as long as cell phones had a single antenna, but we found that with the high functional features, the traditional aluminum deposition would block the cellular radio waves.
Which metals other than aluminum would not interfere radio waves? We found two such metals: tin and indium.
Since tin or indium deposits non-conductively, it does not cover the entire external surface of cell phone and therefore prevents radio interferance. The easiest method could be to deposit tin or indium using the VM chamber, in the same way as with aluminum.
However, this method requires high cost due to lower yield.
Yukiyasu Arakawa, our engineer thought of NCVM In-mold Decoration, which uses a scratch-resistant hard coat foil.
If we apply aluminum deposition in-mold technology, we should be able to reproduce the luxury designs and metallic texture with other metallic materials.
However different metals shows different performance. It is hard to create a beautiful metal-like texture even if the functional requirements were satisfied.
After a continuous process of trial and error, we finally achieved to create the metal-like texture with no signal interferance, achieved both design and functionality.
One of the advantages of NCVM In-mold decoration is that you can enjoy a variety of designs by combining a Sn deposited and a graphic foil onto the front and rear side of a transparent panel.
"With only a single idea, you'll get amazing designs -- this is one of the pleasures of us as technical engineers," -- Arakawa mentioned.
Even the NCVM In-mold has the exellent feature of design, it still has problems. The advantage of NCVM In-mold is high yield, short lead time, low cost in manufacturing, however, it looks suffer by comparison with the shiny metal-looking products deposited with the VM chamber directly.
The In-mold technology is made by both the in-mold foils and the molding technology.
"We want to continue to pursue the ultimate metallic texture by working together closely with the printing factory who produces the In-mold foils," Arakawa concluded.