Changing their adhesive dispensing process saved a manufacturer of low-pressure air switches almost $70,000 a year.
The company offers dozens of standard configurations that can be factory-calibrated to each manufacturer’s specifications.
The calibration screw sits in a small well. After the screw is adjusted, the well is filled with adhesive to keep the screw in position and discourage tampering. Since screw height and displacement vary with the configuration, the amount of adhesive is different for each job.
Squeeze bottles caused bottlenecks:
Until recently, the application/curing process was a lengthy batch operation with frequent bottlenecks.
Operators used squeeze bottles to fill the wells with water-based adhesive. Since there was no way to control the amount dispensed, they often applied too much and wiped off the excess.
Although the adhesive was inexpensive, waste and cleanup were significant.
Once all the switches in the batch were filled, a fan was used to speed curing. At least five minutes was required for the adhesive to skin, so the switches could be boxed. Since final curing and quality control audits were required before shipment, there were usually lengthy bottlenecks.
Taking advantage of new technology:
To reduce work in process, the company investigated changing from water-based to UV-cure adhesive and replacing the dispensing tables with automated dispensing/curing lines.
Even though the new adhesive by Nordson Australia cost ten times more and capital investment was required, analysis showed the expense would be more than offset by higher productivity.
To minimise cost and expedite implementation, off-the shelf equipment was used wherever possible. Application-specific components such as universal fixtures that could accommodate the various switches were fabricated in-house.
Pneumatic dispense valves from EFD, Inc. (East Providence, RI USA) provided the accuracy and cycle speed needed to rapidly fill each well with a consistent volume. Each valve was paired with an EFD ValveMate controller that made it simple to adjust shot size for different configurations without stopping production.
The controller also eliminated the need to reprogram the main computer when changing products valuable when dealing with so many styles and specifications. Adhesive is cured with a system from EXFO Photonic Solutions Inc. (Mississauga, ONT).
Fast results and multiple benefits:
The new dispensing/curing lines eliminated the bottleneck by providing faster throughput with minimal handling. Now, calibrated switches are handled only once when placed in the fixture that moves them to the dispensing station.
As the switch moves into position, the computer signals the EFD controller to begin dispensing and in less than a second the well is filled with the correct amount. Curing takes another four seconds.
The company’s investment saves more money per year through higher output, less work in process and greater overall efficiency:
- Process time has dropped from more than 5 minutes to less than 5 seconds
- Productivity has increased 25-30%
- Bottlenecks and non-value-added activity have been eliminated and
- Switches are packed as they come off the line, cured and ready for shipment