Finishing Equipment
THE ROLE OF COLOUR IN DEFINING EMBOSSED PRODUCT SURFACES
By Tom Kerchiss, Science and Technology of Advanced Materials, RK Print
more to converting than packaging. This can include complex plastics, specialised planar films, non-woven textiles, synthetic papers/boards, foils and other materials which are manufactured and are then subject to a variety of converting processes: including coating, laminating, slitting, printing, die cutting, creasing, folding, gluing and embossing – all of which can improve the overall performance of a finished product and in some cases enhance product appearance. Of course one must not forget that at the end of the day the finished product still has to be packed and wrapped and the item securely contained – so packaging and labelling is still very much part of the converting remit. Many of the processes traditionally
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associated with packaging and prime labelling production are, sometimes with modification and changes in configuration used in the production of finished goods destined for agricultural and horticultural usage; medical/scientific purposes, electronics and electrical applications, automotive, building, construction and civil engineering. Let us consider a process that strides the divide between packaging and industrial and consumer goods, embossing, and the embosser. A wide range of products may be embossed. Within the realm of packaging, an embossed carton creates a textured surface, attractive to look at and touch. Typically an embossed surface tends to be associated with premium products such as gifts, chocolate boxes or tinned biscuits. Wallpapers, decorative wraps, kitchen
towels and napkins are perhaps, apart from packaging the products that most noticeably come to mind when one thinks about embossing. Functionality and aesthetics are motivators for using embossing and embossers. In pharmaceutical applications, embossing can be used for the raised surface synonymous with braille dosage instructions. Embossing is used at times as part of a security program, it can add an extra layer of complexity for counterfeiters and others engaged in forgery to overcome. An application area for embossing
techniques is tissue and towelling. Though some of the paper towelling and toilet tissue produced remains un-embossed the trend amongst brand leaders of kitchen towelling is to opt for four-colour printing
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and an embossed design as part of their marketing strategy. The embossing unit comprises varying numbers of embossing rolls and is designed to provide the product with volume as well as personalising it. Embossing techniques range from using a steel engraved roll against a flat counter roll, which may be rigid or elastic depending upon the design criteria. Other methods include using a steel
engraved roll positioned against a negative steel engraved roll or alternatively a steel engraved roll can be used in conjunction with a paper roll or steel/rubber roller. Tissue, towelling, non-woven rolled goods
may be embossed and also flexographically printed. Not withstanding the difficulties associated with printing colour designs at speed on a fragile absorbent substrate, the converter has to make provision for higher levels of linting and dust than in other applications and processes. Inks have to be closely matched and must perform well on press. Controlling process variables is a must. Dot gain can be made more
Embossing can be used for the raised surface synonymous with braille dosage
instructions
noticeable due to the substrate, careful fingerprinting is essential, and attention must be paid to graphic layout and fidelity of colour. In the past, one or two colour printing at speeds in the region of 300m per minute was the norm. Today, a combination of productivity demands and commercial consideration necessitates speeds in the region of 700m and four colour printing. Various quality control devices ranging from off line proofing or colour communication devices to inline automatic inspection systems enables printers and converters to tackle problems that are simply unacceptable such as poor colour registration, streaking, spotting, pin holing, problems associated with inks; colour variability, printability issues and much more. Products that depend not only on how
they perform but how they look to manufacturers and their suppliers, use a variety of process monitoring and quality control devices for trialling inks, coatings and substrates. Devices aid product development, determining what is possible and what is not. Pilot coating/printing and laminating
systems such as RK Print Coat Instruments Rotary Koater and customer bespoke VCM have a part to play as do proofing and colour communication devices such as the FlexiProof for users and producers of flexographic inks and the K Printing Proofer.
rkprint.com
convertermag.com
ackaging may be the mainstay of business for the majority of converters but there can be much
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