Instrumented roll technology for the design space development of roller compaction process

Roll compaction process modeling: Transfer between equipment and impact of process parameters

“…A similar model compared to the normal stress model from P2 only, was obtained, where hydraulic roll pressure, screw to roll speed ratio and the interaction term between them had significant effect on the average normal stress. These findings are consistent with those reported by Meyer et al (2005) and Nesarikar et al (2012b). Bindhumadhavan et al (2005) reported that the peak normal pressure decreased as the roll speed increased.…”

“…This was attributed to heterogeneity of feeding pressure in the last flight of the feed screw and this has been previously reported in the literature (Simon and Guigon, 2003). Several researchers (Miguelez-Moran et al, 2009;Cunningham et al, 2010;Nesarikar et al, 2012b;Simon and Guigon, 2003Miguelez-Moran et al, 2009Cunningham et al, 2010Nesarikar et al, 2012b;Simon and Guigon, 2003) have shown that normal stress decreases and ribbon porosity increases near the ribbon edges due to side seal friction, resulting in variation of ribbon porosity across ribbon width. The variation of normal stress across the ribbon width leads to variation of the ribbon porosity.…”

“…The variation of normal stress across the ribbon width leads to variation of the ribbon porosity. The tip of the Alexanderwerk 1 feed screw is approximately 10 mm and is consistently delivering uniform flow of the powder blend into the nip zone (Nesarikar et al, 2012b) and therefore, it is applying a steady feed pressure resulting in steady normal stress at the center of the roll. Hence, normal stress values from sensor P2 recorded at various combinations of hydraulic roll pressure, roll speed and feed screw speed were used for data analysis.…”

“…Only normal stress data from the center (P2) and front (P3) were used since the back (P1) was malfunctioning at the time of measurement. Detail information about the instrumented roll technology can be found in Nesarikar et al (2012b). …”

Modifications to Johanson's roll compaction model for improved relative density predictions

“…Compressibility constants between 4.5 and 5.9 were reported by Bi et al [16] in their experiments using formulations consisting of several materials, including Avicel PH-102. Nesarikar et al [22] also reported compressibility constants of between 4 and 6 in their formulations, which contained equal amounts of Avicel PH-102 and lactose as well as other components. Figure 5.4.…”