Skip Feed, Dual Feed, Manuals?

Todd asks,

Our company recently purchased an older diecutter and no manuals were supplied with the machine. It’s much like one of our other diecutters, but a few controls/features are different. In particular, the feeder has the features we are told are Skip Feed and Dual Feed. Do you know what they are and what they would be used for?

I reached out to my friend and colleague Dwayne Shrader to help us out on this one. In addition to his experience on the converting side of our industry, he has written many user manuals for converting machines.

Todd says “older”, so I’ll assume it’s a gear driven machine. They have some limitations that many of the newer generation of servo driven machines don’t. He also says he doesn’t have manuals. Let’s quickly touch on that first.

For the safety of everyone… Call the OEM and request a set of manuals for that machine. If the OEM is no longer in business, research and find out who may have bought the company and/or the intellectual property rights. Make sure you have your machine serial and model number in hand when you make the call. Some may charge a nominal fee for the manuals, but many will… and should… at least provide a copy of the operating and safety manual for free if this machine is ‘new to you’. It’s in their best interest as well as yours that you have this documentation. If documentation can’t be located, you may want to have someone in your organization, or an outside resource, prepare operating instructions for your machine.

Now, the feed issue.

“Skip Feed” feeds one sheet for two rotations of the print or die cylinder. There are a couple uses for this feature. If you want to feed a sheet longer than your cylinder circumference. You might do this if you’re printing a repeating image on a sheet, or diecutting a repeating pattern such as vent holes. Another is if you need to double bump your printing plates for stronger coverage. So, your print plate is inked twice for each sheet fed.

With Skip Feed it is possible to print a single image on a sheet if the image is set back from the lead edge. I believe on a 66” machine that distance is approximately 21”. On 66” cambox driven feeders there is a maximum sheet length for Skip Feed around 82”. That may vary a little between machine manufacturers.

Of course, you can crease any length sheet you feed, but you likely won’t be able to slot inline unless you have a slotter that is specifically configured for Skip Feed, or a servo slotter.

One other thing to keep in mind is that the ancillary equipment in front and behind the press must also be able to accommodate the longer sheet or blank.

“Dual Feed” feeds two sheets for each rotation of the print cylinder or diecut drum. If you’re printing, the print plates will have repeated images, one for the first sheet and again for the second sheet. I guess they could be different images if you don’t mind the manual labor to sort them, or that’s what the customer wants.

I wouldn’t suggest Dual Feed on anything that requires close print registration because there is no way to adjust registration between two images on dual-fed sheets. Even if your plate maker is dead-on with registration, there are many other variables that can affect the registration between the dual-fed blanks.

As nicked bundle breakers/separators have become more popular, dual feed may have lost its popularity and usefulness. It is much easier to control the sheet, you can print and die cut blanks that are below press minimum, etc.

Servo driven machines on the other hand have some of the same limitations due to the physics of the print cylinders, etc., but in the case of the feeder and slotter they may have a greater range in through-machine sheet size.

Hope this is helpful.

— Dwayne