Thanks to new fiber laser technology it is now possible to weld clear and translucent polymers without requiring any specialized additives. Traditional through-transmission laser welding requires additives, whether pigments or specialized additives designed specifically to absorb the near-IR radiation. This was limiting, however, as it made bonding completely clear polymers expensive and the color was never truly. Read the rest of this entry »
“Transparent Laser Plastic Welding – Bonding of clear polymers without additives”
A breakthrough in laser plastic welding technology has opened doors for bonding of transparent polymers. Precision, flexibility and cleanliness already set laser plastic welding apart from other polymer bonding methods, but now the ability to bond clear polymers without special absorbers has expanded the list of potential applications. Find out how this technology will play a big part in the diffusion of laser plastic welding, especially in the mammoth medical device industry.
This chart displays the most common, weldable thermoplastics. Each sample of this study was done with the plastic materials in their natural state. Please take note of the color system which indicates weld quality.
Part 1 of a 3 Part Series
Transmission laser welding of polymers is a well-established industrial joining method, its reliability makes it particularly suitable for applications where very high weld seam quality is specified. A number of quality assurance methods are available when using this technology to safeguard the specifications demanded for the quality. These quality assurance methods are suitable for implementing a zero-error strategy, under very economically attractive conditions. This three-part series of articles discusses the different approaches.
Transmission welding or laser transmission welding also goes by a few other names, including: laser plastic welding, through-transmission welding (TTLW) and laser polymer welding. The names may be different but the concept is all the same.
Although, “laser plastic welding” is the term most often used to describe this technology, “transmission welding” is a much more descriptive term and more accurately portrays the process. This is because the basic principle of this joining method is passing, or transmitting, laser radiation through one piece of plastic to create a weld. Unlike standard welding where the energy is applied at the surface of the materials. Transmission welding aims to apply the energy in between two plastic pieces at their interface.
An interactive schematic showing laser plastic welded sensor housings and other electronics of a car.
Electronics make up roughly 1/3 of the cost of a car. Securely welded plastic housings ensure those electronics are well protected.
In the process of laser plastic welding an infrared laser beam is passed through an upper laser transmissive layer to a lower laser absorbing layer. The energy absorbed at the weld interface is conducted from the lower layer to the upper layer through conduction as the parts are clamped tightly together.
Hybrid laser welding is the same concept, however, in addition to the laser radiation a high-powered halogen lamp assists the laser. The polychromatic radiation from the halogen lamp helps pre-heat and soften both the upper and lower layer. This makes for faster welding, less stress on the part and stronger welds.
The increasing adoption of laser welding is due in no small part to the many technical advantages it offers. With regard to the economic advantages, prejudices still exist on account of higher investment costs for suitable materials. Any comparison with other processes must consider all aspects.
Laser plastic welding, also known as through transmission welding, is quite simple in its essence (see Basic Process Video). Laser radiation is shot through an upper transmissive plastic part and the energy is absorbed by the lower layer, creating heat at the interface and melting both parts.
However, the process does not always seem so intuitive. For instance when welding colored materials, specifically ones with opaque upper layers. Read the rest of this entry »
The process of laser plastic welding involves passing laser radiation through an upper transmissive layer to the surface of the lower absorbing layer. The absorbed radiation creates heat and contact between the two joining partners allows for melt and a weld at the interface.