Heidelberg Doubles Production Speed with ‘Frog Fold’ Technique
I’ve been dying to write about this. When I was at the PRINT show, I got a call from Dan Maurer, Heidelberg’s VP of Postpress Product Management, asking me to come take a look at the new “frog folding” technique they were demonstrating on the show floor. He said they were nearly doubling the production speed for signature folding. I wanted more details, but he said I had to come and see for myself.
Of course I broke land-speed records to get to the booth (not an easy thing to do in heels, by the way). When I got there I was shocked at what I saw. Heidelberg developed a way to increase productivity for signature work by rotating the sheet to feed oblong with a special twin lay attachment and pneumatic gate in the first folding unit. They call it “frog folding” because the sheets “leap frog” one another into two parallel side lays. Confused yet? It’s a little hard to explain.
Steven Calov, Heidelberg’s Postpress Product Manager sent me an explanation of the process:
“Our ‘frog fold’ solution achieves both top folding quality and dramatically improved productivity by combining lower-speed production with a high number of cycles, based on a simple turn of sheets in the feeder. Here’s how it works:
Sheets are fed oblong at the feeder. Depending on the sheet format, this can lead to an increased performance of approximately 30 percent at the same machine speed, due to the shorter infeed length of the sheet (see Illustration 1).
Illustration 1: Rotating sheet to oblong fold, gain 30% productivity at the same mechanical speed.
Until now, the limitation of oblong feeding has been transferral of the speed problem to the second folding station, because there was no reduction of the infeed length and the full sheet length still had to be transported (see Illustration 2).