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Chief Folding Fanatic

Trish Talks Finishing

By Trish Witkowski

About Trish

Trish Witkowski is Chief Folding Fanatic at the online community She holds a bachelor of fine arts degree in graphic design and a master of science degree in Graphic Arts Publishing from Rochester Institute of Technology's School of Printing Management and Sciences (now the School of Print Media).

An award-winning designer, Trish held the position of creative director for a Baltimore-based agency for six years, and has taught design and desktop publishing at the college level. She has a specialized expertise in the area of folding and is the creator of the FOLDRite™ system, a 2004 GATF InterTech™ Technology Award winner.
Trish frequently publishes articles for graphic arts industry publications, and has written three books on the topic of folding: A Field Guide to Folding, Folding for the Graphic Arts: A Teacher's Handbook, and FOLD: The Professional's Guide to Folding.


PUR ‘Spine Cam’ and Nozzle Technology Ensures Consistent Glue Application

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Heidelberg has newly-engineered its PUR gluing systems for the entire Eurobind perfect binding line and is now offering an innovative camera recognition system for the EB4000 perfect binder.

The enhanced PUR system for the Eurobind line uses a volumetric application system with a closed-loop gearing pump and nozzle-based applicator to ensure even application of glue to the book spine. The system efficiently regulates glue by opening the width of the glue nozzle based on the spine width of the book (an automatic adjustment). The operator can easily adjust glue start and stop length.

Some of the other functions the operator can control are the independent temperature adjustments on the melting plate, storage tank, nozzle tube and return tube. The height of the PUR nozzle can be adjusted manually, allowing the operator to change glue film thickness between 0.2-0.3mm.

The system is engineered so that the PUR circulates through the width of the nozzle to ensure a consistent heat temperature at the point of application. The glue that is not used is circulated back to the gearing pump to be reused.

Their new PUR system greatly improves upon a traditional open tank or roller-based PUR system, creating less waste and drastically reducing clean up time. Open tank systems or roller-based systems expose the PUR to the environment, which reduces the life cycle of the glue. These systems also require that the pot is emptied at the end of the day for cleaning. Heidelberg’s closed-loop pump system does not expose the glue to the environment and requires simply that the nozzle be sealed with wax or grease when not in use.

The “Spine Cam”
In the application process of PUR, Heidelberg has developed a camera recognition system for its EB4000 model to monitor the quality of the application of glue film on the spine of the book. The set up is very easy. The operator selects the “Camera Monitoring Function” on the touchscreen then runs one book without PUR to measure the surface of the spine and then two additional books with PUR to set the sample book for the recognition system. The operator looks at the glue film thickness across the book and then acknowledges the sample is OK on the touchscreen and the system is set.

The camera then reads each individual book after the PUR is applied against the sample taken. The system is an important quality control mechanism to ensure the consistency of the glue film and the integrity of the finished product.

“In the traditional world of hot melt, you would wait a few minutes for the book to cool and then perform a pull test,” says Steven Calov, Postpress Product Manager for Heidelberg USA. “PUR, however, cures with time and moisture to create the chemical bond. In this case you may need 2-4 hours to perform the same test based on the manufacturer’s recommendation for the glue. To overcome this obstacle, we developed a system to monitor the glue application to the spine to ensure that each book is the same as the sample taken when the system is set up.”

Cool stuff. To learn more about these devices, please contact your local Heidelberg Postpress Specialist, or contact Steven Calov directly at

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