Our 20” Heidelberg folder is quite sophisticated. It is configured in what is called a 4 x 4 x 2 configuration. What this means is we can make up to 4 folds on the first station, then 4 folds on the second station, and then 2 folds on the final station.
Sometimes we will place the first two stations in parallel. The most common configuration for this type of fold is a “roll fold”, where we take, for example, a 6”x20” flat sheet and make the first fold at 3”, then roll this into the second fold at slightly over 3” and repeat the process several more times. When the two stations are aligned in parallel we may make up to 8 roll-up folds in one pass.
After a simple half or trifold, the next most common type of fold is a right angle, or “combination” fold. In this case, the second fold section is set at 90 degrees (or a right angle) to the first section. Now you can take an 11 x 17 newsletter and fold it half to 11 x 8.5, and then feed it through the second station to fold it to 5.5 x 8.5. In this case, we are using one fold on the first station and one fold on the second station.
One complex fold we do routinely is starting with an 11 x 17 sheet, then fold to 8.5 x 11, then right angle fold to 5.5 x 8.5 and then fold in the third station as a trifold to 5.5 x 2.83. Here is that fold in action: