CoolTherm SC-324 is a two-component, addition-cure silicone encapsulant from Parker LORD, rated 4.0 W/m·K and UL 94 V-0, used to pot electrical and electronic assemblies. At a specific gravity of 3.25 it is one of the heaviest potting materials on the market, so the filler wants to settle out of it. Short answer: we dispense it with a Material Feeding System (MFS) feeding a PDP-1500A-HF two-component progressive cavity metering pump.
Recommended: a Material Feeding System (MFS) feeding a PDP-1500A-HF two-component progressive cavity metering pump.
Material at a glance
| Manufacturer | Parker LORD |
|---|---|
| Type | 2K thermally conductive silicone encapsulant |
| Chemistry | Silicone |
| Thermal conductivity | 4.0 W/m·K |
| Mix ratio | 1:1 by weight or volume |
| Viscosity | Resin 37,000 cP; hardener 43,000 cP; mixed 30,000 cP @ 25 °C; specific gravity 3.25; working life 30 min |
| Cure | 24 h at 25 °C or 60 min at 125 °C |
From Dispense Robotics test records and the manufacturer's published data. Always work from the current technical data sheet.
How we dispense it
CoolTherm SC-324 is running in production on a Dispense Robotics Material Feeding System (MFS). The MFS keeps resin and hardener agitated and recirculating so the filler stays in suspension, and feeds a PDP-1500A-HF two-component progressive cavity pump that meters it 1:1. Pump size depends on your shot size and cycle time.
- Settling: at a specific gravity of 3.25, the filler drops out of suspension in a pail. Agitating and recirculating both sides, all the way to the pump, keeps every pour the same.
- Hydrogen: SC-324 gives off small amounts of hydrogen gas, so Parker says don't store it in unvented containers. Tanks and feed systems need to vent, and the work area needs ventilation.
- Air: unless the material is mixed in a closed system, air gets in. Vacuum degassing in the MFS and a static mixer at the valve keep voids out of high-voltage parts.
- Abrasion: tungsten carbide rotors, wear-resistant stators and slow pump speeds (8 to 12 rpm) hold up to the filler.
- Ratio: each side is metered to within ±1%; check it weekly by weighing a shot from each side.
- Cure inhibition: amines, sulfur and tin salts stop it curing, so keep them out of the system and off the parts.
See our PDP two-component metering pumps and the Material Feeding System (MFS), or use the pump configurator.
How the MFS keeps filler in suspension
The Material Feeding System agitates and recirculates the material so heavy filler stays mixed all the way to the pump. Watch how it circulates the product:
Frequently asked questions
What pump should I use to dispense CoolTherm SC-324?
CoolTherm SC-324 is running in production on a Dispense Robotics Material Feeding System (MFS). Pump size depends on your shot or bead size and cycle time; send us those and we will size it.
Can CoolTherm SC-324 be fed from pails or drums?
Yes. For production volumes we feed it from bulk containers through a Material Feeding System (MFS), which agitates and recirculates the material so the filler stays in suspension, and degasses it under vacuum.
How do you keep CoolTherm SC-324 on ratio?
Each side is metered by its own progressive cavity pump, held to within ±1% per side. We recommend a weekly check: weigh a shot from each side and adjust, because filled materials vary from batch to batch.
Will CoolTherm SC-324 wear out the pump?
Thermally conductive fillers are abrasive. With tungsten carbide rotors, wear-resistant stators and pump speeds of 8 to 12 rpm, stators typically last 6 to 12 months and rotors up to 24 months, and a pump rebuild takes under an hour.
Talk it through with us
Running CoolTherm SC-324, or about to? Send us the technical data sheet, your bead or shot size and your cycle time, and we'll recommend a pump and feed system. We can run an application test on your material before you buy. Contact us
Related materials
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CoolTherm SC-324 is a trademark of Parker LORD or its affiliates. Dispense Robotics is not affiliated with the manufacturer; the name is used to describe the material our equipment dispenses.