Do I Need a Diecutting Jacket?

To fully protect the platen, SHOULD one use a die cutting jacket when scoring and/or perforating or just when die cutting?

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yes, use a stainless steel jacket. also use a scoring matrix to acheive a real nice score (its like a mail and female).

A diecutting jacket will protect your platen when diecutting, scoring, or perforating. The exception comes when you are perforating along with printing. In this case I use perforating rule which is .909” high to avoid cutting the rollers and simply attach a thin steel strip (perf base) to the tympan to cut against. I believe all rules and supplies are available from NA Graphics who also can supply the die-cutting jackets for platens and cylinder presses.

I can only speak for Heidelberg windmills, but our steel jackets are only used for die cutting and perforating. Scoring, embossing and obviously printing are done with the soft packing. One of my Heidelbergs (1955ish) has been used primarily for die cut/score/perfing its entire life, and after hundreds of millions of impressions, the platen itself has absolutely no wear. Not even a mark. Scoring on a regular packing shouldn’t effect the platen, unless you are doing something seriously wrong. You won’t really need the matrix either, unless you are in a unique situation, or the stock requires it.

I’ve been scoring, die cutting and perforating on both a hand press and a Windmill for about 40 years. I use the die cutting jackets only for die cutting. To perf against a die cutting jacket can easily cut it up and mar the smooth surface. Dies, properly made ready, should only polish the surface as they cut. Straight perf rules cut too easily. Avoid any cutting into your die cutting jacket.

When scoring, I use special score channel matrix or build up a channel using many layers of paper or masking tape. When perfing, I use either Tiger base or thin strips of steel pallet strapping, held in place with double-stick tape.

Note also that score and perf rules are available in different heights - .906, .909, .911 and .918. I avoid using .918 for perfing and scoring when it’s in a mixed form.

- Alan

we are about to perf some 166# Wild paper on a windmill with a steel jacket. I was wondering if we need to put any type of protection on the jacket so the teeth won’t dull or if it is supposed to just kiss the jacket as it bites into the paper.
Thanks so much!

Die cutting and perforating on H platen
Press is designed to print with .918 type and a total of .040” on the platen including stock to be printed. To die cut with.918 rule you need .040” on the platen not including the stock to be cut. Most letterpress folks use .909 perf to protect the rollers when printing and perfing at the same time, often that is the only perf they have on hand but it requires .009 added to the platen just to get it to print plus the thickness of the stock to get it to cut. Banding iron and tape is one way to do this. A micrometer and various thickness of card stock, paper and metal and an understanding of the pressure control of the press is the key to success.
To use the die jacket when perfing only is up to the operator. The cut or perf rule should never bite into the jacket or damage the bed. Into diecutting using wood or poly is for the leather and related industries. I have had crease and perf rule ground to .888” in order to perf crease and print at the same time no ink on rule no damage to rollers.
I sell dies to clients that use H platens for diecutting they get .918 cut because that’s all they ever knew. I make my own for my platen using .927 down to .910 depending on the density of the stock to be cut or kisscut. .927 cutting rule in a folding carton die gives me .010” extra space on the platen for matrix or any surface makeready.
I could go on here but its time for a nap.