| Résumé : |
When it comes to dispensing adhesives for electronics assembly, hand-held and tabletop units have traditionally relied on pneumatics to "push" the material out of the syringue. There are problems with this type of dispensing; technicians have been required to live with its shortcomings and essentially work within the capabilities of the equipment. Production delays due to the need to calculate and recalculate settings, material waste, inconsistent performance and rejected parts have become expected and inherent factors in the process.
This article, suupplied by Fishman Corp., Hopkinton, MA., describes a mechanical dispensing system the company has developed that eliminates the vagaries of air pressure dispensing. The system combines the precision of linear drive technology with the intelligence of microprocessor control and the cost-effectiveness and flexibility of plastic syringues. As a result, exact amounts of adhesive can be dispensed without variations in applied pressure , the effects of moisture , changing viscosity and degradation in repeatability as the amount of material is reduced within the syringue during dispensing.
Before discussing the specific features and advantages of the new design, a point of reference will be established by reviewing how pneumatic systems operate. |
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Mechanical dispensing system offers precision and economy in ADHESIVES AGE, Vol. 41, N° 10 (10/1998)
