3 Types of Conversion Made Possible by Machine Knives

It’s a fact: somewhere between the source and the shelf, materials need to be cut and converted to enter their next stage of “life.”

In the most general sense, this happens one of three ways: slitting, perforating, and cutoff.  Three simple actions that are repeated various times in the process of raw material to end product.  Three simple actions that, without knives to make it happen, would leave us with a whole mess of material and not a lot to show for it.

I should mention that there are, in fact, other ways of cutting and converting materials – via wires, needles, lasers, and other technology.  But, for a majority of the products we use day to day, it’s machine knives that make it all possible:

  1. Slitting for the Sake of Manageable Materials

    Circular knives slit brown paper into thinner strips.
    Circular knives slit brown paper into thinner strips.

    Who wants a 15′ tall roll of brown paper to feed into their home printer? Or better yet, how about a half-ton mass of bread dough looming in your kitchen, just waiting to be broken into loaves?

    Not me, that’s for sure!

    Machine slitting is the process of breaking down a larger material by cutting it into smaller strips lengthwise.   Circular knives are the most common slitting weapon of choice in this step of the manufacturing process – but straight knives can be used as well.

    In some cases, a Slitter Rewinder machine not only slits the material, but rewinds it into smaller rolls at the same time – think of paper, textiles, films, and other flexible materials that are often transported elsewhere for further processing.

    It’s often one of the first steps in the conversion process, as materials need to be broken down to be turned into salable product – and without  knives to help along the way, well, we’d be stuck!

  2. Cutoff: Form, Fill, Seal (and Slice!)

    Circular cutoff knives
    Circular cutoff knives are highly configuarble.

    Slitting and cutoff go hand in hand. Remember that 15′ roll of raw paper? Well, first circular knives slit it into something more manageable, but a smaller roll of paper isn’t going to fit into your printer, much less make a nice birthday card or cupcake box. Now, is it?

    Enter the cutoff knife. Cutoff knives can be straight or circular, beveled, toothed, or whatever you please.  And they are everywhere.


    I can’t think of a single manufacturing process that doesn’t use a cutoff knife of some kind at least twice. Take the paper example, first it’s cut into sheets off the roll, and likewise its packaging is cut to fit those stacks of sheets.

    Shark tooth blade

    Speaking of packaging – consider the Form Fill Seal machine. This beauty is the bread and butter of the flexible packaging industry; without cutoff knives, all you’re left with is unbroken strings of potato chip bags, juice pouches, and who know what else stretching from here to Pluto and back. Twice.

    Either that. Or someone’s going to lose it splitting each of those apart with only a pair of scissors to keep him grounded.

  3. Perforation: The Dark Horse of Conversion

    Perforating straight knives
    Perforating straight knives can be configured many ways.

    Perforating is the conversion we probably take the most for granted.   From toilet paper to plastic bottles caps to spiral notebooks – perforations are everywhere. They make our jobs easier and our lives a little less stressful in ways we often forget to notice.While perforating machines sometimes employ lasers or pins to get the work done, in many others it is, in fact, perforating knives that make everything from stamps to checkbooks possible.

    Think about it, how would you like a world without perforations?

Remember this next time you… well …next time you do anything.

Even when you don’t see them, knives are everywhere. They slit the fabric that goes into the clothes you manufacture.  They perforate cardboard cases for easy retail display of your latest product.  They cutoff rewound rolls of paper into receipt tape that will fit into your customer’s cash register.

They even do things like take the corn off cobs for canning, and mash up paper pulp for recycling – but that’s a story for another day.

Either way, once you stop and think about it, it’s hard NOT to see the knife behind every product you make, and the importance of making sure you’re using the best possible knife for the job.