Transparent Plastic Laser Welding
Transparent Plastic Laser welding or what is commonly know as clear-on-clear welding is new and innovative way to achieve bonding of polymers without additional fillers or additives.
Traditional plastic welding also known as Transmission or clear-on-black welding involves a transmission of laser beam through the upper clear (to the laser) or natural colored plastic part to the lower or what’s commonly known as absorbent part. Typically lower part contains absorbents such as carbon black. In all transmission plastic welding there has to be the upper (Tranmissive) and lower (absorbent) part. When laser beam passes through upper part, usually at 800nm -1020nm wavelength, it is absorbed by lower part. Consequently, this absorption creates heat energy that allows absorbent layer to fuse with trasmissive layer creating a molten weld seam.
In contrast to traditional clear-on-black welding, Transparent Laser Plastic Welding is partially transmitted to both parts because of a longer laser wavelength of 1400nm-2000nm. However, most of the energy from laser will be concentrated on the joint and therefore both parts will be welded simultaneously.
This is a completely different concept from traditional plastic laser welding. While it was possible to achieve clear-on-clear laser plastic welding with Transmission welding, it required translucent absorbents. In contrast, Transparent Plastic welding removes dependency on additives or absorbers. Another traditional way of achieving clear-on-clear weld is Edge Welding or clear-to-clear polymer edge laser welding. Edge Welding involves shining laser beam through the edge of transmissive layers and onto the joining edge of absorbent layer. The problem with this method is that laser does not have a deep penetration which is usually at around 10,000 nm.
Clear-on-clear polymer laser welding is a revolutionary idea especially for industries such as medical. Medical devices typically demand more precision and accuracy much more so than other industries. As medical devices become smaller and more complex, clear-on-clear welding would achieve much cleaner weld without introduction of foreign additives or absorbents.
Highly regulated industries such as medical device production would benefit from Transparent Plastic Laser Welding. Every time new additives or absorbents are introduced, FDA requires additional steps for approval. This can create costly delays and frustration. Furthermore, additional additives could cause contamination and functional defects. Clear-on-Clear welding solves that problem due to the fact that there are no additional additives and risk of contamination by foreign materials is virtually non existent.
As with all polymer welding, fixturing, and joint design are crucial to fast and robust welds CMS Laser can build a system for your specific needs. We offer FREE sample processing in our state of the art Application Lab. Send us your sample today!