What is Low Pressure Overmoulding?
Low Pressure Overmoulding is an innovative encapsulation process positioned between traditional potting and injection moulding technologies. It is a complimentary technology. It does not replace all potting applications and typically does not compete with traditional injection moulding.
LPO is an injection process whereby a PCB assembly, for example, is placed in a specially manufactured aluminium mould tool, and completely surrounded ( overmoulded ) with a liquid compound that effectively forms the housing for the device
Use of specialist raw materials and mold equipment form the key elements in the process.
The molding compounds used are called ‘ hot-melts ‘. These are typically polyamide materials that are heated to 210C, forming a low viscosity material that can be injected at low pressure ( typically 50 – 200 psi ) into the mold cavity to encapsulate the electronics.
It is the low injection pressure that is paramount in preventing damage to the electronics.
The injected material starts cooling as soon as it comes into contact with the mould cavity, thereby producing a short curing time cycle. Its excellent adhesive properties forms a watertight seal ( IP 67 rated ) around the PCB without any chemical reaction, ensuring that no toxic fumes are produced.
Unlike traditional potting applications, there is no need for a separate housing.