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The balance between consuming more paper and press time than absolutely necessary and providing appropriate bindery spoilage allowances is one of the most difficult parts of the graphic arts estimating and production process. Graphic Finishing Industries of Illinois (GFI) publishes a document called "Guidelines for Normal Spoilage Allowances."
Rickard Bindery recognizes that these GFI guidelines may be considered "generous" but nonetheless they are a good starting point. If you need to reduce the suggested spoilage allowances on a job-by-job basis, you will probably be OK most of the time. However, we highly recommend that you discuss your saddle stitching spoilage requirements with us in advance for all but the most routine saddle stitching jobs.
GFI Guidelines For Normal Spoilage Allowance
(Saddle Stitching)
Because spoilage occurs in every bindery operation, your finisher needs sufficient print overruns in order to deliver full counts. The following spoilage guidelines were developed by the Graphic Finishing Industries of Illinois to to help customers plan print production. Please bear in mind that these guidelines will not cover every job, so check with your finisher in advance.
Inserter/Stitcher/Trimmer
(Normal job on paper stock of 45# coated up to 100# coated)
1 pocket … 2% of the finished count, plus 500 signatures for make-ready.
2 pockets … 2-1/2% of the finished count, plus 500 signatures for make-ready.
3 pockets … 2-3/4% of the finished count, plus 500 signatures for make-ready.
4 pockets … 3% of the finished count, plus 500 signatures for make-ready.
Example: 500,000 finished books of four signatures. Spoilage allowance 15,500 of each signature, plus 500 (four signatures with binding laps; 4 pockets = 3% of 500,000 finished books 15,000, plus 500 for make-ready = 15,500)
Signatures with bent laps could increase this spoilage guideline.
Additional percentages:
- 1% per vacuum-fed signature
- 1-1/2% for one-up oblong books
- 1/2% for all two-up jobs
- 2% for 4-page signatures of 50# book weight or lighter
- 1/2% for each 8-page signature
- 2% for jobs on uncoated stock lighter than 45#
Additional Guidelines: The following factors could adversely affect these spoilage guidelines
- Condition of material as it is packed on pallets or skids going to finishing operations
- Numerous lots or codes
- Allowable overrun is an important part of the target figure; therefore, when no under run is allowed, an additional 10% beyond expected spoilage must be delivered to the finishers on most jobs.
Rickard Bindery Notes:
1) For saddle stitched jobs requiring five or more pockets (up to twelve-pockets) add 1/4% more spoilage per additional pocket. For example, if you have a nine-pocket job, our normal recommended spoilage allowance is 4-1/4% plus 500 of the finished count, plus 500 signatures for make-ready.
2) When your customer specifies NO UNDERS, the rules change. In these cases, it's much better to err on the side of conservatism than risk going back to press.
Make Sure Your Jobs Can Ride The Saddle
If you have any signatures with foldouts, such as gatefolds, accordion folds or roll folds, they need to be held together during automatic pocket feeding.
Usually, the best way to accomplish this is to apply glue in the trim-off margin. During layout, be sure to allow 3/8" head and foot trim so the glue will be completely removed during the final trimming process.
As Seen In Printing Views …
“In today’s marketplace, graphic arts companies must make a profit and remain price competitive. Good spoilage planning helps companies do both. Every significant printing job will incur some spoilage. Since spoilage rates aren’t consistent, it’s impossible to predict exactly how many sheets will be wasted during any given production run.
Many things cause bindery spoilage. Paper characteristics such as thickness, curl, brittleness, grade and coatings are very important. In general, thin sheets are more easily damaged than thicker ones. For example, when planning saddle stitched jobs, four-page signatures should be given twice the spoilage allowance of 16-pagers, if the paper is the same weight.”
– Excerpt from Kevin Rickard’s April 1999 Printing Views bindery column.
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