Lasers are employed in a tremendous range of plastics processing tasks, and Coherent, with the widest product portfolio of any laser manufacturer, can offer the right technology for best outcomes for virtually any application.
This includes CO2 lasers for cutting, slitting, and perforating, diode lasers for welding, and diode-pumped solid-state lasers and fiber lasers for marking. Plus, Coherent offers solutions from laser sources, to sub-systems, to fully integrated, turnkey machines. This is all backed up by extensive applications knowledge and support, ensuring that you get the right laser at the required level of integration, and the process know-how necessary to deliver maximum productivity.
There are several ways to mark colored, transparent or opaque plastics using lasers. Together with our decades of experience in marking applications, Coherent’s unmatched range of lasers and laser markers means that we can always provide a solution for your plastic marking application. A cost-effective marker or sub-system that is optimized to give you the results you want with the throughput you need.
Dark plastics can be marked with a laser foaming method which leaves a bright mark for good readability. Here the photothermal heating locally melts the material and creates tiny gas bubbles. The resulting plastic “foam” has a lighter appearance.
Colored and dark plastics can be marked by localized photobleaching. Here either green (532 nm) or ultraviolet (355 nm) laser light directly breaks interatomic bonds in the polymer by a photochemical process, thereby bleaching it to produce a white or light mark. In the case of ultraviolet induced photobleaching, the process is often called “cold marking“, as there is no noticeable heating of the material.
The use of laser-sensitive additives in plastics can generate considerable advantages. Additives in plastics are able to increase outline sharpness and contrast and thus enhance readability of the marking contents, e.g., for machine-readable codes. When used with transparent and semi-transparent materials, additives also result in excellent contrast uniformity and consistency. Plus additives in plastics increase the diversity of available product colors and are of crucial importance for the markability of certain materials.
Laser marking on plastics can leave a permanent mark by ablating (engraving) some of the material. This enables day & night marking of plastic parts which is
widely-used in automotive industry and consumer electronics. Here the laser
selectively removes specific layers from multilayer-coated transparent parts.
Laser transmission welding is a widely employed technique which produces particle-free, high throughput welds that are completely contained within the part. The basic principal of transmission welding is relatively simple. The material of the top part is transmissive at the laser wavelength, while the bottom part strongly absorbs the laser light. This allows the laser light to pass through the top material and be absorbed at the interface between the two parts, melting them and producing an interior weld. The pigments used in the bottom part absorb laser energy in the IR range, making diode lasers the ideal choice for this application. With different wavelengths ranging from 808 to 1470 nm, they are compatible with a variety of common pigments. The specific embodiment of diode laser welding depends upon the exact geometry of the parts.
Transmission welding produces joints within the part, resulting in minimal heat input and perfect surfaces. This makes it ideal for producing airtight welds in sensitive components – such as sensors. Another common application are car keys.
For this application, we recommend: ExactWeld 230 P
In the quasi-simultaneous welding method, even complex welding contours can be accommodated with the use of a galvanometer scanner head. The use of closed loop welding temperature controls delivers a high degree of process safety and control.
Compared to common separation methods, such as flame or hot knife cutting, laser technology offers enhanced flexibility and quality. Lasers, in combination with galvanometer scanner heads, are used for high speed, precision cutting of PMMA, PET and many other plastics. Due to the particular characteristics of the way the laser melts the material, the cut edge appears smooth and clean, and is free of micro cracks. And, non-contact laser cutting never suffers from tool wear, making the process consistent, and eliminating downtime for tool replacement.
Smooth, clean edge cutting of plastic-injection molded parts can be performed without color change or deposition of debris.
For this application, we recommend: Coherent CO2 DC Series
Rapid and precise cutting of fiber optic reinforced synthetic resin plates can be performed with a CO2 laser.