EFFECTS ON FORMATION, RETENTION, AND MECHANICAL-PROPERTIES OF FORMING BLADE SEPARATION IN A TWIN-WIRE ROLL-BLADE FORMER

A short blade separation makes a compact design of the blade section possible, which is favourable since it reduces building size requirements. However since the blade distance is a component of the hydrodynamic conditions in a blade section, if may influence the forming result. in a pilot twin-wire roil-blade former the effects or blade distance for two different blade pulse forces were investigated over a range of jet to wire speed differences, using TMP. The shortest blade separation employed was 46 mm, and the blade pulse force was included since it might influence the pulse extension; Formation, retention, tensile stiffness including in-plane anisotropy, fracture toughness and Z-toughness were evaluated. No adverse effects of a shorter blade separation were established. A short blade separation can thus be chosen. The blade pulse force had an adverse effect on retention. otherwise there were no major effects of the blade pulse force.