| 摘要 |
<p>A method and apparatus for smoothing and levelling a thermoplastic coating on a substrate by a utilization of ultrasonic energy. The coated substrate, which may for example be wax coated paperboard, is conveyed past an ultrasonic generator which directs ultrasonic vibratory energy onto the thermoplastic coating. The ultrasonic energy heats and works the coating thereby resulting in its levelling and smoothing. The coated substrate is conveyed over an idler roller located immediately below the ultrasonic generator which functions to precisely position the substrate relative to the generator.</p> |
