Dispense air-free, accurately metered, mixed and dispensed epoxies and urethanes into APT vacuum chambers for superior penetration and void-free vacuum cast parts.

Vacuum-potted components ranging in size from automotive ignition coils to large MRI body- imaging coils often require air-bubble and void-free penetration of the mixed epoxy—around every turn of wire and under hard-to-reach overhanging ledges.

When connected to one of our ECS-Series or HT-Series metering, mixing and dispensing machines, our complete vacuum potting and encapsulating systems are equipped to precisely control your formulation’s ratio, shot-size and output rate — to deliver air-free material into your molds at precisely preset and controlled vacuum levels. The resin degassing tanks connected to the dispensing machine can be equipped for either batch or continuous thin- film resin degassing.

Typically, digitally-controlled vacuum at better than 0.5 mmHg is continuously drawn on the resin materials in the supply tanks, while high-voltage components to be potted inside the vacuum chamber are also digitally maintained at a precise vacuum level to insure bubble-free casting of on-ratio, abrasive-filled mixed material, into those mold cavities. High-voltage electrical and electronic components demand vacuum potting, however other critical air-free applications, including vacuum-assisted RTM, utilize vacuum casting to produce void-free parts.

APT’s metering and mixing systems feed air-free mixed material to both standard and custom- built vacuum chambers to produce the highest quality, void-free parts. What size or type of chamber is right for your application? Our people can work with you to select one of our existing manual or automatic chambers or we can design one that meets your specific application requirements.

Your vacuum chamber can be as simple as a small chamber with a front-opening door. On the other hand, for high volume output, if you need to minimize the time spent cycling from vacuum to vent, our continuous flow-through vacuum chamber includes three chambers and four automatic doors. This system allows the center chamber to be maintained under constant vacuum (i.e., no vacuum/vent cycles) to maximize pour time inside the center chamber. These systems include automatic valves for connection to the vacuum pump and for venting vacuum to ambient pressure.

Shown below is a dual-box vacuum chamber. While parts are being automatically poured inside the chamber on the left, an identical chamber on the right lowers its automatic elevator base to permit finished potted parts to be removed. Note that there are four individual shutoff nozzles at the top of each chamber to allow the system to sequentially pour into each mold cavity. Due
to the absence of air, it can take a while for the mixed material to flow by gravity and fill voids down inside the assemblies. Multiple-pass pouring eliminates over-filling by allowing you to make a series of programmed shot volume displacements into each mold cavity (including a final “top-off” shot), just prior to opening the chamber and removing the parts.

The two chambers shown below have front-opening doors, lighted sight-ports, automatic vacuum valving and mixed material inlet valves. The vessel on the left has a manual turntable inside the box, plus a vacuum-sealed horizontal rod running through the chamber, which lets the operator accurately position the shutoff nozzle over each mold cavity. The larger chamber on the right has a 36″ diameter hinged door.

When potting trays of parts with numerous cavities, digitally controlling a single pour nozzle often answers the need to eliminate maintenance on multiple pour nozzles. In the fully automatic vacuum boxes shown below, a single pour nozzle is driven from part-to-part with a servomotor- controlled, X-Y-Z Axis, pour tube positioning system. With these systems, automatic conveyors index a mold or tray of molds into the pour chamber or the operator simply places a long tray of parts to be potted on the z-axis base inside the chamber and presses the start button. Sensors at the edge of each tray detect that tray’s identifier and communicate with the PLC to automatically
preset the ratio, shot-size, output-rate and all indexed movements of the pour nozzle from one mold cavity to the next. At the end of the automatic sequence, the chamber is vented, the door automatically opens and the tray of parts is removed for post curing.