Pneumatic Shear Cut Knife Holder With Optimized Cutting Characteristics

Nowadays high or speed converting equipment is being designed increasingly to perform a very specific slitting operation in order to maximize the winders efficiency. This is also true for the pneumatically operated shear cut knife holders.

A new Dienes pneumatic holder, PSG-DF, is a holder specifically designed to function at slit widths as narrow as 2 inches, at high speeds such as in excess of 7000 fpm, and with heavy weight paper and board basis such as 175 lbs./1000 sq.ft. The paper and packaging industry are the typical users.

The features of the PSG-DF, in addition to those mentioned above are:

• Dovetail design is a separate two-piece design. This allows the holder to be removed separately without sliding adjacent holders off the dovetail. This component being separate also allows various dovetail design or linear bearing support possibilities.
• Two vertical shafts provide extreme rigidity after pneumatic extension of the lower head. This rigidity and vibration dampening leads to extended blade life and quality slit edge.
• Bearings in the upper and lower head are pre-loaded "ball cage" design. This same style bearing exists in ball screws of precision motion equipment such as machine tools and coordinate measuring machines. This design eliminates the condition known as "stick-slip" and provides the possibility of low cutting forces at lower air pressure and forces that are very repeatable.
• CANT angle and vertical penetration of top knife blade are critical settings when shear cutting. This holder employees a self-locking large micrometer type knob on the top of the holder to perform the depth setting. DIENES recommends .8mm or .030". The knob contains 10 divisions, each .006" in value. CANT angle is positively set by an angle plate mounted to the backside of the holder body. Plates are graduated in _ degree increments and the value is clearly visible even while slitting.

The lower head is modular and allows for various design possibilities of blade and guarding.Blade diameter 130mm, 150mm, 180mm and 200mm are all available. Guards that provide automatic 360 degree hand protection in the non-run position or a guard with a swing-down tab for setting lower female knife are just two possibilities.

Despite a 360° safety knife guard, a BG approved quick-change knife head makes it possible to change the knife without even touching it, and without the means of any tools.

State of the art sensor technology can be applied to precisely adjust the cutting force between the bottom and the top knives.