Pressure Balance Characteristic of a Double Structure Blade under Quasi-Statically Reciprocal Loading Condition

Abstract

One of the blades that are widely used for cutting of paperboard in paperboard converting industry is called ‘double structure blade’. Other than a hardened center bevel cutting tip, this blade has a soft tapered bottom for pressure adjustment. This paper reports on pressure balance characteristics of this blade under a quasi-static reciprocal loading condition in small number of cutting using a crank type press machine that has four load cells mounted under its cutting table. From this research, the following results were observed: (1) The four load cells force difference method was proposed in order to evaluate pressure unbalance of a blade under reciprocal loading condition. (2) A plastic deformation has occurred on the blade bottom tip at a certain applied force and has resulted in reducing the crank machine force balance. (3) In any number of cutting, the first cutting was found to have the biggest load cell force different (max-min) before stabilizing in the subsequent cutting. (4) The blade bottom tip pressure has decreased at certain applied forces caused by upsetting and lateral bending deformation of the bottom tip. (5) The blade crushed tip thickness tangency measured along its cutting line has showed reducing at a certain high applied forces caused by the cutting tip hazard layer and the bottom tip plastic crushing.