摘要 |
<p>Moulding machine (10) according to the invention comprises an upper platen (12) and lower platen (14). Upper platen carries a female mould part (16) while lower platen carries a male mould part (18). Machine further comprises an ultrasonic generator (20) connected by leads (22) to a controller such as a computer (24) for controlling the frequency, phase and marked spaced ratio of the on and off pulses for the ultrasonic generator. The ultrasonic generator is partly embedded in platen and also in part of the female mould part. The lower horn region (26) is located adjacent the mould cavity (28) such that in use ultrasonic vibrations are communicated via horn into the cavity and hence into the liquid and pulp material contained therein. Female mould part (and part of upper platen) preferably comprise vent holes (30) to allow evacuation of steam from mould cavity.</p> |