No Notch Curving of Rotary Rules-Technical Bulletin

    Zimmer Industries of Hawthorne, New Jersey obtained a US Patent on its No Notch Curving
    Process many years ago. At that time, it appeared that the industry was not ready or open to
    such a product. Today, even more than in the past, curved rotary rules without notches, create
    some very significant advantages for both the diemaker and the diecutter. Part of the reason for
    this is the advent and increased use of automatic rule processors. Additionally, recent
    refinements to this unique curving process, have made those advantages even more significant
    and important.

    No notch curving can be used on any type of rule- cutting, creasing and perforating. The process
    creates tighter tolerances of inner diameters, making the rule more stable and secure on the
    cylinder, thus, less likely to “bounce” and eventually crack from work hardening. Most cracking of
    conventionally notched curved rules occurs right next to a bridge or a notch. The absence of
    notches significantly reduces rule breakage and allows the rule to have increased contact with
    the cylinder, also reducing the chances of the rule “bouncing”. No notch rule is a more truly
    circular shape, in contrast to conventionally curved rule, which is not actually a true circle, due to
    how it is made. A more circular curved rule runs in a “smoother,” less bouncing and stressing
    manner.

The no notch rule also presents more rule surface area for the dieboard to “hold on to,” thus improving
the security, permanency and stability of the rule in the dieboard. Conventionally curved rules have a
tendency to spring back toward their original straight forms, because in essence, they are simply bent
or curved. No notch rule is virtually a “formed” piece of steel, rather than curved or bent. Thus, any no
notch curved rule is less likely to “pop up” at the ends.

Some diemakers have stated that no notch curved rules are hard to drive into the dieboard in relatively
long pieces. This can be true, but is easily overcome by the strategic placement of a notch or two into
the rule. In some cases, this may be done automatically with rule processors. It is also said that no
notch curved rule does not “open up” as easily as conventional rule does, but diecutters will also
acknowledge that conventionally curved rule that is significantly “opened up” or “stretched”, is much
more likely to break in the diecutting operation. Again, this is because of the rule “bouncing “ on the
cylinder. No Notch rule can be ordered in any inner diameter desired, to specifically deal with many of
the cylinder sizes and degrees most commonly used.

Several diemakers using automatic processors have reported that no notch curved rules perform more
consistently and more efficiently (especially regarding not hanging up or jamming) than conventional
rules in processors. Right above every notch used in conventionally curved rules, there is a slight bump
or swelling, where the actual bending or curving takes place. This may occasionally cause problems in a
processor, (not to mention the potential reduction of rule surface area contacting the dieboard.

No notch curbed rule- a product whose time has come. Give it a try. It works!