May 18, 2008 
Ever more electronics manufacturers are required to economically dispense solder paste, isolating adhesives and placing LEDs on film substrates. Essemtec AG has developed a solution that can fulfill this growing need both efficiently and precisely.
Based on Essemtec`s proven placement machine FLX2010 MKL, a concept with a three-head system was designed. The head features a placement axis with an integrated component adjustment mechanism, as well as two independent axes with a piezo flow valve and a time-pressure dispenser gear. The dispensing valves are mounted on motorized, closed-loop driven precision linear axes to ensure an accurate movement in the Z-axis. The substrate is positioned on the machine table and is secured by vacuum. The spacious machine concept allows the handling of substrates in the format of 800 x 600 mm. The substrate is manually placed on the vacuum table and then adjusted to the positioning pins.
The vacuum is activated with a foot-operated switch, and the film substrate firmly sticks to the table. After the fiducials have been recognized by the vision system, the time-pressure dispenser applies three dots of isolating adhesive on the substrate � a larger one in the middle and two smaller dots aside. Then, solder paste dots are applied on the substrate solder pads using a high-precision, piezo-controlled PFV nozzle. The LEDs are then picked from Essemtec standard feeders, adjusted and accurately placed. The isolating adhesive, applied prior to the placement operation, eliminates any unwanted electrical contact between the solder dots.
The entire procedure at a glance consists of five steps:
- Apply film substrate, adjust and activate vacuum by foot switch
- Recognition of fiducials
- Dispensing of dielectric adhesive, three dots per each LED
- Placement of LEDs
- Deactivate vacuum, take substrate from the table.
The system was designed using only Essemtec�s standard placement modules. These modules feature high reliability and durability, and more than 600 are installed worldwide. Custom-specific adaptations and applications are planned and realized quickly and in cooperation with the users.
Essemtec is a worldwide leader in the manufacturer of Surface Mount Technology (SMT) production equipment. Essemtec specializes in high mix production equipment for Printed Circuit Boards (PCB) using Surface Mount Technology.
Essemtec is the only manufacturer to cover the entire production process, from Printers and/or Dispensers, to Pick-and-Place and Soldering equipment. Therefore, customers benefit from unparallel knowledge and the ability to select, from a single source, a complete process solution to meet their requirements.
