Graco Inc.

PR70™ applies Polyurethane in Precision Potting of Switches and Connectors



Potting of connectors and switches to ensure resistance to weather and water.
MOLEX is a Polish facility of international company that manufactures electrical devices. Their factory is located in the west of Poland in Sulecin. Switches and connectors produced by MOLEX require potting, which has to be done in small shots. Due to difficult-to-reach areas, potting is carried out manually, as cables don’t permit automation.

A two component no VOC polyurethane resin is used in this application. The mixing of this resin is difficult and is carried out with a static mixer, and exact, simultaneous pumping is extremely important. The potting process in this application is very demanding, as the product has a pot-life only 5-7 minutes (theoretically 10 minutes) at room temperature. In the beginning, manual mixing and potting was introduced. However, the result was a high amount of air entrapments, which resulted in very poor aesthetic joint. Also, the resin level control was difficult, as air was released a long time after the potting process, and the level of resin changed. The potential rejection of parts was considerable.

Molex’s requirements were to save material and limit its consumption.


The PR70™ is a fixed ratio dispensing system that accurately meters, mixes and dispenses two-component medium- to low-viscosity materials. This unit was proposed by AMB TECHNIC, a Polish Graco distributor, who also evaluated and tested the unit on site. The quality of the mixing of the resin and aesthetic potting was proven with the PR70.


MOLEX found the following features of the PR70 beneficial for their organisation:

  • Accurate and affordable plural component system,
  • Mix ratio range fixed, but easily chosen from available pistons in typical sizes.
  • Static mixing allowed good and stable quality of resin, without air entrapments.
  • Easy to use and understand user control interface for their existing operators.
  •  Simple process to introduce.
  •  Small shots realized by syringe potting of small parts.
  •  No solvent cleaning on the production site.


End User

Industry Market Sector
Electrical, electronics

Potting of connectors and switches

Material Specifications
Wevo Casting resin PU 552 FL/10

Typical Properties

  • 100 Parts A (Poly) to 20 Parts B (ISO) by weight
  • 100 percent Volume Solids
  • Pot Life: 10 minutes TDS, real on-site: 5-7 minutes
  • Room temperature potting

Graco Equipment


  • 5:1 Ratio BW
  • PR70
  • No filters
  • Basic controls
  • Static mixing
  • No heating
  • 8 litres tank agitator
  • 0,6 meter 3/8” high pressure hose set
  • 3/8” static mixers
  • MD2 mixing gun
  • Accessories:
  • Agitator in tank – electrically driven ensuring no air in the resin, even at low resin level

Graco Distributor Details
For your no-obligation to buy demonstration on a PR70 in Poland, 
please contact:
E-mail: ;