What is Perfect Binding?

Perfect binding is a popular binding method for printed books, including paperback and softcover books, magazines, and catalogues. It is favoured for its cost-effectiveness and clean, professional appearance. Perfect-bound books use melted EVA or PUR glue (PUR Binding) to bind the book blocks with the covers. Let’s discuss the perfect binding process and the kinds of applications perfect-bound books are most typically used for.

Advantages of Perfect Binding and PUR Binding

Perfect binding offers many advantages for many publications, such as paperback books, reports, catalogues, and magazines. Here are some of the key benefits:

1. Professional Appearance: Perfect binding provides a clean, sleek look with a square spine, giving publications a professional, high-quality appearance.
2. Cost-Effective: Perfect binding is generally more affordable than other binding methods like hardcover (case binding), especially for medium to large print runs. This cost efficiency makes it accessible for projects with budget constraints.
3. Printable Spine: The flat spine of a perfect-bound book allows for spine printing, which is impossible with other binding methods like saddle stitching. This feature is crucial for books and publications that will be displayed on shelves, as it makes the title and author visible for easy identification.
4. Flexibility in Page Count: Perfect binding can accommodate a wide range of page counts, making it versatile for various project sizes, from thin reports to thicker novels.
5. Durability: When using quality adhesives, perfect-bound books are durable and can withstand frequent handling. This makes them suitable for publications that will be used repeatedly, such as manuals and textbooks.
6. Ease of Stack and Display: The square, flat spine allows perfect-bound books to stack neatly and align evenly on shelves, creating an organized and appealing display, whether in a bookstore, library, or personal collection.
7. Adaptable to Various Sizes and Formats: Perfect binding is not limited to standard book sizes. It can be used for publications of nearly any size, offering flexibility for unique and custom projects that may not fit traditional binding specifications.
8. Efficient Production: Modern perfect binding machines, like our BQ470, have streamlined the binding process, allowing for quick turnaround times and the efficient production of large quantities of books.

EVA vs PUR Glue for Book Binding

The choice between EVA and PUR glue in book binding often comes down to the specific requirements of the project and the desired balance between cost, durability, and production efficiency. EVA may be preferred for projects where cost and speed are priorities, and the books are not expected to endure extreme conditions. On the other hand, PUR is often chosen for higher-end projects where the durability and longevity of the binding are paramount despite the higher cost and longer curing time.

Ethylene Vinyl Acetate (EVA) Glue

EVA glue is a hot-melt adhesive widely used in the bookbinding industry, particularly for perfect binding processes. It is known for its ease of use, quick setting time, and flexibility, making it a popular choice for many standard bookbinding projects.

Here are some key features and considerations of EVA glue:

• Quick Setting: EVA glue sets quickly, allowing faster processing and handling times in production environments.
• Cost-Effective: Generally, EVA is less expensive than PUR glue, making it a cost-effective option for many binding projects.
• Flexibility: Books bound with EVA glue tend to be flexible, benefiting the user experience.
• Temperature Sensitivity: EVA glue is more sensitive to temperature extremes, which can affect the longevity and durability of the bond in certain conditions.

Polyurethane Reactive (PUR) Glue

PUR glue is a reactive adhesive that offers superior strength and durability compared to EVA glue. It has become increasingly popular in bookbinding for applications that require a stronger bond or will be subject to more rigorous use.

Here are some of the characteristics of PUR glue:

• Stronger Bond: PUR glue creates a stronger bond than EVA glue, making it suitable for books that must withstand heavy use or adverse conditions.
• Flexibility and Durability: The bond formed by PUR glue remains flexible and is more resistant to temperature extremes and other environmental factors, enhancing the durability of the bound product.
• Longer Setting Time: The curing process for PUR glue is longer than the setting time for EVA, which can impact production times. However, the bond continues to strengthen over time.
• Cost: PUR glue is typically more expensive than EVA glue in terms of the adhesive itself and the equipment needed for application. However, its durability can justify the cost of high-quality products.

Equipment Needed for Perfect Binding

When we prepare to bind a book, we need the following equipment:

• A stack of book blocks, uncut, usually in digitally printed sheets
• A stack of laminated book covers on single sheets
• Perfect binding machine, we use a BQ470
• Guillotine cutter (for the 3-knife trim after binding)

The printing for perfect binding is pretty straightforward—you need a set of book blocks (the interior sheets) and covers that are usually laminated to protect the print. Most spines for perfect-bound books can have a design on them; anything under 3mm is usually left blank. We can pind paperbacks with a maximum spine of around 65mm.

Step 1: Print and prepare the text pages

The first step is to get the text printed. We print on Canon Titans to produce all our mono books; any colour printing is produced on our Canon 1350. The internals of the books are printed on large sheets of paper, usually SRA3, and then cut into individual book blocks slightly larger than the finished book size.

Step 2: Print and prepare the book covers

Before binding the books, the covers need to be laminated and trimmed to size. We make sure to have a large glue trap on the covers. Perfect-bound books can also have gatefolds on the covers. This part of the cover extends beyond the book block and is folded inside the cover. It’s similar to a dustjacket on a case-bound book.

Step 3: Perfect bind the covers and book blocks

The binding process uses our 4-clamp BQ470 binding machine. We use either EVA or PUR for all our paperbacks. EVA is an affordable option for books on regular, uncoated paper. PUR is used for all books on coated paper or for heavy usage. Book blocks are inserted into one end, and the covers are inserted into the other. When the text is inserted into the machine, it is carried along the binder, and 2mm of the book block is milled off (we add this 2mm when we impose the book for printing) before passing over the glue rollers. The milling roughens up the book block so the cover has better adhesion.

After the book block has passed over the milling blades and the glue rollers, the cover gets fed from the other end. The cover is creased and automatically enters the binder’s nipping station. When the book block gets to the cover it, the nipping station presses the cover onto the book block and holds the cover in place for a second. This ensures proper adhesion to the book block.

The book is then passed around the binder, where it drops out and is put onto the conveyor for trimming.

Step 4: The 3-knife Trim

The last part of the process is known as the 3-knife trim. Until now, the book blocks and the covers have been done on larger sheets of paper. Perfect binding is done on larger sheets of paper and then trimmed down so that the final cuts make the books crisply clean on all the edges—no unevenness and no excess glue.

The conveyor transports the books to the three-knife trimmer, which takes roughly 30 seconds. This allows the glue to cool. Our three-knife trimmer cuts the books to their final trim size in two cuts. First, we cut the foredge, the opposite side of the binding, and then the head and tail.

This process is called a 3-knife trim because there are 3 cuts to be made: the head, the tail, and the foredge.

Step 5: Quality control and packing

After the books leave the trimmer, they are inspected and packed into single-wall cartons. When we inspect the books, we look for the correct trim, any text or images cut off, correct margin spacing, scratched covers, crushing on the spine, glue marks, indentations, and any damaged corners. If everything is okay, the books will then be packed. We place all books in single-walled cartons with bubble wrap. These cartons are then packed into double-walled cartons ready for shipping.

Perfect binding tip: Shrink-wrap your books before shipping

Alongside our standard practice of packaging all orders in single and then double-wall cartons, it is advisable to shrink-wrap your perfect-bound books before dispatch. This effectively prevents cover damage and scratches, and confining the books in compact shrink-wrapped bundles minimises movement during transportation, further enhancing protection.