TECHNOLOGY | LASER MARKING AND WELDING


good marking quality. The additives are designed for marking of plastics that are inherently poor for laser marking — such as polyolefins — as well as PA, PET, PS, ABS, PC and PVC. Lasersafe additives are said to be suitable for most common marking lasers, with the company claiming that colour and transparency of the resins is not affected. The range of applications is broad — the additives can be used in coded and individu- alised plastic packaging as well as for tracking and tracing of shipments, and for anti-counterfeiting purposes. The Laser Mark Flex portfolio of masterbatches


from Ampacet are designed for high definition laser marking on to flexible films using Nd:YAG technology. The antimony-free product range consists of LaserMarkFlex 1081, which is formu- lated for black/dark grey marking, and LaserMark- Flex 1135, intended for lighter grey marking and carrying broad food approval status (EC and FDA). LaserMarkFlex masterbatches enable mono-


Below: Eckart’s Lasersafe additives are designed for effective use for traditionally difficult


polymers such as polyolefins as well as PA, PET, PS and PC


chrome permanent and anti-counterfeit markings to be applied to film surfaces. The markings are waterproof, light-fast and chemical and abrasion- resistant and, because it is an ink-free technology, no pre-treatment of the film surface is required, which reduces complication and saves energy. The masterbatches are suitable for use in monolayer as well as coextruded film structures and can be used to apply logos, barcodes, expiry or best-before dates, and serial numbers on labels or packaging. Ampacet has also recently introduced the LaserMark 1001074-E and LaserMark 1001088-E additive otptions, which it describes as cost-effective solutions that enable high definition, high contrast marking to be applied to clear and dark part surfaces using Nd:YAG laser systems. LaserMark 1001074-E produces sharp, dark markings on transparent or light-coloured plastic parts without affecting colour or transparency. It is antimony-free and suitable for food contact applications. Ampacet LaserMark


IMAGE: FRAUNHOFER ILT


Precision microfluidics can be laser welded without additives using Fraunhofer’s quasi-simultaneous irradiation technique


Fraunhofer aims to weld without using additives


Researchers at the Fraunhofer Institute for Laser Technology ILT worked with three industrial partners as part of the SeQuLas project to develop an additive-free technique for laser welding thin welds in transparent plastic components used in sectors such as medical technology and microfluidics. The process uses a 1940nm thulium fibre


laser, which offers a particular advantage in that many plastics absorb at that wavelength so additives such as carbon are not required. This means the transparency of the chip is not affected.


However, conventional absorber-free laser


transmission welding creates a heat-affected zone (HAZ) that extends vertically through the cross- section of the component. The associated thermal expansion during melting promotes the formation of blowholes and cracks, which can cause leaks in the seam structure. There is also a risk that the material will warp, especially in flat components. Fraunhofer ILT, together with German companies Amtron, Ortmann Digitaltechnik and Bartels Mikrotechnik, developed a quasi-simulta- neous irradiation technique that reduces the heat-affected zone. It involves guiding the laser at high speed several times along the weld contour to ensure simultaneous heating at all points. The developers say this reduces vertical expansion of the HAZ by up to 30% compared to contour welding. �www.ilt.fraunhofer.de


44 COMPOUNDING WORLD | July 2021 www.compoundingworld.com


IMAGE: ECKART


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