TECHNOLOGY | LASER MARKING
Above: A moulded plaque in an Akro-Plastic laser-transpar- ent compound photographed with a normal camera (left) and with an infrared camera (right)
required colour for the manufacturer’s branding and an additive for UV protection.” At another major compounder, RTP Company,
Strategic Account Manager Joe Hennessey says use of laser marking is growing among producers of medical devices such as injection pens, partly because of FDA requirements. It offers three laser marking masterbatches in LLDPE and PP carrier resins suitable for placing dark marks on a range of polymers including polyolefins, TPEs, TPUs and POM.
Laser transmission welding Lasers are not only used to mark and decorate plastics parts – they are also increasingly used to join them. The choice of masterbatches and compounds for laser welding is now quite broad, particularly from suppliers of engineering plastics, but continues to broaden – and properties continue to improve. Several months ago, for example, Lanxess added to its laser-weldable Pocan PBTs and Durethan PA6 grades, claiming for its Pocan B3235 LT and a hydrolysis-resistant variant Pocan B3235 HR LT that “virtually no comparable products with the same high level of laser transmission and the same high level of properties are sold on the market.” It is also an area of high interest back at Gabriel-
Chemie. “Laser transmission welding has become increasingly important over the last few years, so we are dedicated intensively to the development of this product line. The company offers optimised laser welding masterbatches for all types of process variants,” a spokesperson says. Unlike other welding processes, laser welding
generally requires the use of parts made in two different materials or one material incorporating two different additive systems: one that transmits laser radiation (so the radiation can pass through it on the way to the joint) and one that absorbs it (and so heats up and melts the plastic). Laser wavelengths of 808nm, 940nm, 980nm and 1064nm are used. A typical example is the housing of a waste gate
actuator for automobile turbo chargers by Hella, which is laser-welded from two parts based on two
68 COMPOUNDING WORLD | February 2018
different grades of Evonik’s Vestamid HTplus polyphthalamide (PPA). The cover is made from a specially developed laser-transparent Vestamid HTplus M1034 grade, while the body is made from the laser-absorbing Vestamid HTplus M1634; both grades contain 40% glass fibre. “Laser welding has several advantages over the
more commonly used ultrasonic welding,” says Evonik. “No damage to internal electronic compo- nents, homogeneity, narrow heating zone, high welding seam strength, and no welding spatter in the housing.” Other products taking advantage of the technol- ogy include window frames with integrated panes, vehicle lights and bumpers, and microflow reactors for gases and liquids. Technical compounder Akro-Plastic offers various masterbatches and compounds suitable for the laser welding process. “With increasing use of plastics in automotive, electrical, medical and industrial markets, precise, fast, flexible and clean joining technique of the highest quality standard is required,” the company says. Akro-Plastic offers a range of compounds based on various polyamides, unreinforced and reinforced, impact modified, black or coloured, that are transparent to laser. The company measures the laser transparency with a laser having a 980nm wavelength at regular intervals during production of its laser transparent compounds using an LPKF TMG 3 measuring device and states the laser transpar- ency value on the certificate of analysis (COA).
CLICK ON THE LINKS FOR MORE INFORMATION: �
www.evonik.com �
www.lati.com �
www.budenheim.com �
www.eckart.net �
www.gabriel-chemie.com �
www.merckgroup.com �
www.silberline.com �
www.polyone.com �
www.rtpcompany.com �
www.lanxess.com �
www.akro-plastic.com
www.compoundingworld.com
PHOTO: AKRO-PLASTIC
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