For L3Harris Technologies, a defence manufacturer in New Hampshire, manual epoxy and room-temperature curing applications were creating waste and variance in many of their defence production operations. This is because these processes were time consuming and created operator fatigue. Workers faced challenges from an epoxy pot life of 30 minutes to a small difference between applying too little epoxy or too much epoxy to the product. As a result, the organisation faced costly cleanup and rework with their hand-operated production process.
The manufacturing process for the night vision goggles requires multiple components to be bonded inside the product. To achieve this, the company uses a two-part epoxy with a thermal curing mechanism to bond the parts together.
Operators needed to fill syringes, and then manually dispense the epoxy onto various components. With a working time of just 45 minutes, the epoxy viscosity increased over time, requiring pressure changes on fluid dispensers. In addition, the tolerances for dispensing epoxy beads were exacting.
L3Harris had been assembling night vision goggles using hand processes since the company started manufacturing the product.
Seeking a more cost-effective solution, L3Harris approached Nordson EFD for solutions to the night vision goggles processing challenges.
Having collected data from L3Harris about their processes, fluid specifications and applications, Nordson EFD verified adhesive fluids, material substrates, and assessed automated fluid dispensing solutions.
Nordson EFD recommended an automated dispensing process and, where the manufacturing goals warranted it, an integrated vision system. The Nordson EFD engineers focused on three technologies to meet L3Harris’ production goals. First, to resolve the challenges facing the two-part epoxy adhesive dispensing process, Nordson EFD recommended using two 797PCP-2K pumps with an E3V series robot. Second, for the one component RTV, the company recommended using one 797PCP pump on a 3-axis robot. To address precise fluid dispensing tolerances, Nordson EFD recommended employing the E4V automated dispensing solution with a simple vision pencil camera.
The 3-axis EV Series dispensing robots, with integrated simple vision systems and DispenseMotion software, provided vision-based programming and other standard features such as DXF import, part presence/absence, and wrong part identification.
Dispensing software integrated with the inexpensive pencil camera allowed users to programme complex dispense patterns and arrays with high repeatability up to ± 8 µm (0.008 mm). The EV Series met L3Harris’ application requirements. The vision system ensured that components were in the right place and validated the parts were in alignment. The vision system would not allow dispensing fluids if it did not see the correct part in the proper location.
L3Harris Technologies started their automated dispensing system process enhancement with applications that were causing a high rate of operator fallout due to problems with the manual processes. Anything that was causing scrap and rework was scrutinized. With that in mind, L3Harris selected production lines with larger volumes because they would provide a faster return on investment.
The new equipment reduced the 2K epoxy dispensing step by an average of 65%, and nearly eliminated the cleanup time for this process. It improved throughput time, plus the repeatable, epoxy application benefitted the manufacturing process. Specifically for the epoxy process, the automatic dispense system was configured to use the exact amount of fluid for each specific step and mixed the two-part epoxy in real time. This capability reduced waste. The Nordson EFD system also used a vision system to self-align the automated dispense system for predetermined tasks. This level of accuracy served to reduce the need for cleanup and prevented defects.
L3Harris executives were impressed with the universality of the Nordson EFD software package, enabling their staff to learn and use the automated systems. The software made it easy for L3Harris to programme new applications, while maintaining repeatability and improving throughput time in the process. The automation benefitted the workers because it replaced the repetitive process requiring good fine motor skills. The automated dispense system eliminated extended periods of seated bench work, as using hand dispensing tools while holding parts or fixturing to apply bonds is no longer necessary.
