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Enhanced shelf life, readability, cost, paper selection, use of certain kinds of adhesives, and the binding machine itself are all vital considerations in producing a well-crafted perfect bound book. With each of these criteria in mind, a number of key strategies and processing steps must be part of spine preparation.
Spine Preparation
Improving page pull and binding strength is particularly key in books that are manufactured for the academic market, where products must withstand rigorous use from semester to semester. That's not to say that durable performance isn't critical throughout the general commercial book market. Naturally, publishers don't want books returned or rejected because pages fall out. Another factor is the ability of the book to be utilized by the end user most conveniently. Proper spine preparation will make a big difference in how easily the book can be opened, and how well it closes.
Of course, also very important is production expense. Like almost anything else in the manufacturing world, if shortcuts are taken, the end product will suffer and the expense for producing books will likely increase because of the need to correct quality imperfections. One of the more common mistakes is using too much glue, which not only could negatively affect the overall integrity of the binding, but will also dramatically increase the unit cost per book.
Now, let's take a closer look at some of the specific considerations you should keep in mind to help you ensure proper spine preparation.
Paper
The characteristics of the paper used in a perfect binding job can play a pivotal role in page pull and binding strength. Coated papers are typically more difficult to bind than matte papers, while newer papers with roughened surfaces, introduced in the late 1990s, can provide exceptional production efficiency, as well as highly durable performance.
Also a major factor is the use of papers containing increasing percentages of recycled fiber content. For instance, leading publishers Simon & Schuster and Random House will be shifting from 10 to 25 percent recycled content by the year 2012. Surely, environmentally-friendly book production is a rapidly expanding trend in the book manufacturing industry, and rightfully so. However, recycled papers present the challenge of providing less material for adhesives to grab onto. Thus, preparing the surface to obtain good contact becomes even more important.
Among the steps to keep in mind, both with recycled and non-recycled papers, is to make sure that the edges of the papers are not damaged. Another step is "fiber roughening," whereby the fibers are literally roughened, and the clay content is removed to give the fibers maximum exposure—resulting in improved surface area, and an enhanced material for the adhesive to bond to.
One more caveat: Bulky book papers should not be notched, because notching destroys the fibers. Instead, these kinds of papers should be processed with one or two sanding discs, with the second disc rotating in the opposite direction of the first.
Dust
As every bookbinder knows, if dust finds its way into the perfect binding process, it minimizes what the adhesive has been designed to do. Binding adhesives are formulated according to very specific chemical equations, and there's no room in the equation for dust.
The fact is, if dust is not removed before book manufacturing, it will go somewhere. Either it will stay on the spine, or, in faster machines, it could be entrapped in the air surrounding the moving book...eventually moving downstream and contaminating the gluing operation. A correctly functioning exhaust system is of paramount importance in diminishing and/or removing dust during the perfect binding process.
Adhesive Considerations
When using hot melt glue binding (one-shot or two-shot), notching should be performed except as stated above, when bulky papers are involved. Notching effectively increases the contact surface of the glue, and improves page tying. When binding with PUR adhesives, there is generally no need to use notcher heads. This results in enhanced layflat characteristics.
Maintenance and Testing
To ensure optimal sustainability of the adhesive binding process, the milling station must be well maintained. Although this seems obvious, such steps as cleaning components regularly, keeping tools sharp and level, and continually adjusting/re-setting backup plates are sometimes overlooked in the interest of saving time.
Also obvious, but at times skipped over, is periodic testing in a meaningful manner. As an example, binder operators often want to test product for strength immediately after the product comes off the line or shortly thereafter—even though the adhesives have not had the proper opportunity to set up. This is especially true with some of the newer adhesives like PUR, which do not set up right away.
Careful and comprehensive spine preparation is indeed crucial to the quality of the end product, and ultimately to the profitability of a perfect binding operation.
It should also be underscored that choosing high-quality adhesives will lead to the production of higher quality books. The same holds true for choosing quality-engineered binding equipment. It can add up to the building of a better book...and a stronger business.
James Kaeli is division manager of Book & Publication Binding at Müller Martini. In this role, he interacts with customers, sales, and their factories to help define and configure highly automated and integrated manufacturing systems. Kaeli joined RR Donnelley in 1981 as a project engineer and worked in several plant locations, with management responsibility for manufacturing, engineering and maintenance, and information systems. He joined Müller Martini in 2001. He is a member of the adjunct faculty of Penn State, and is a frequent speaker at book industry conferences, including the R&E Council for Finishing Technology and Book Tech.
author: By Jim Kaeli