Abstract
Injection tests of mixed wood powders of Cryptomeria with Japanese cypress were carried out at various temperatures and moisture contents of wood powders in order to achieve near net shape forming of wood powders. Effects of cavity temperature and moisture content of wood powders on the injection pressure-punch stroke curve and the mechanical properties of injected products were discussed. The experimental results showed that the wood powders could not be injected into the cavity when the moisture content was 12%. In this case, the profile of injection pressure-punch stroke curve is similar to that of compaction process of wood powders. The bulk density and bending strength of product increase with increasing the cavity temperature. However, maximum relative density became 0.8-0.9 under the cavity temperature of 175±5 ℃. The bending strength of the products made from powders with moisture content 200% tends to be small. On the other hand, the bending strength became max when the powder with moisture content of 50% was used. Finally, it was also found that if the arbitrary cavity was using under appropriate injection conditions, it was possible to obtain the wood powders products with arbitrary shape.
