PolyTecttm

OVERMOLDING PROCESS & MATERIAL

for

ELECTRONIC MODULE ASSEMBLIES

ELECTRONIC MODULEOverview

Electronic modules are encapsulated for various reasons, e.g., protection of delicate components due to environmental conditions including dust, dirt, and moisture, protection in thermally unstable environments, and to protect technologies and designs.

Applications: Hand held equipment, industrial controls, retail security, automotive components, electronic sensors (motion, photonic, etc..)

ELECTRONIC MODULE COMPOSITION

Electronic Modules may consist of:

• Populated Printed Circuit Boards

• Custom Components

• Input/Output Connectors

• RF Transmission Capability

• Mounting Hardware

Option 1:

Injection mold housing and insert PCB into housing. Then fill housing cavity with a potting compound and bake unit. Total assembly time up to 3 hours.

CONVENTIONAL ENCAPSULATION

Option 2:

Cast or formed housing and insert PCB into housing.Place seal or gasket around parameter. Affix coverplate with fasteners. Total assembly time 2-3 minutes.

CONVENTIONAL ENCAPSULATION

INJECTION MOLDING ENCAPSULATION

Process:

Typical injection molding cavity pressures

range between 1200psi and 2400 psi

Problem:

Shear stress of common solder (63%sn, 37%pb)

for mounting components to PCB’s is @ 500 psi

Result:

Component solder failure would occur during

injection molding due to shearing of solder joints

INJECTION MOLDING ENCAPSULATION

Process:

Typical injection molding material temperatures

range between 218 C (425 F) and 382 C (720 F)

Problem:

Melting point of common solder is 183 C (361 F)

Result:

Component solder failure would occur during

injection molding due to melting of solder joints

PCB ENCAPSULATION PARAMETERS

0500

100015002000250030003500

10 35 65 100 120 150 175 200 230 230Temperature (Deg. C)

Pre

ssur

e (P

SI)

Solder Failure Threshold

Thermoplastic molding

Epoxy molding

PolyTect tm

PolyTect molding pressures less than 500 psi

PolyTect molding temperatures less than 180 C

ADVANTAGES OF THE PolyTect PROCESS

• Low molding pressures of 100 psi

• Low material temperatures of 100F

• Low mold temperatures of 140F

• Use of solid or foam materials

PolyTect OVERMOLDING PROCESS

1. The populated PCB’s and any associated hardware components are placed into the mold base

Conventional multi-cavity mold

PolyTect OVERMOLDING PROCESS

2. The molding cycle takes between 30 and 120 seconds and monitors material temperature,pressure, velocity and shot size

Molding press closed during polymer injection

PolyTect OVERMOLDING PROCESS

The PolyTect process can be a single or multi-mold depending on the part size

Molds can be single or multi-cavity

Multi-cavity molds can be located in a single press,carousel-rotating press or a self-contained press

PolyTect OVERMOLDING PROCESS

3. Completed parts are removed and inspected

The PolyTect process allows parts to be molded clear then opaque sequentially providingfor preprogrammed QC inspection.

Parts can be molded with or without color providingpart security and/or identification.

PolyTect OVERMOLDING PROCESS

Mechanical and thermal properties are custom tailored for each application.

Materials used are proprietary multi-component polyurethane systems.

Tensile strengths range between 2500 psi and 9000 psi

Elongation values range between 20% and 300%

Operating temperatures range between –40C and +85C

Very low absorption rates

PolyTect MATERIAL PROPERTIES

PolyTect MATERIALS

Have the ability to be custom blended to provide:

•Foam (Low density and rigid)

•Solid (high density and rigid or very flexible)

•Soft or Hard (shore A 55 to shore D 95)

•Fast or slow reactivity (1 second gel to 45+ seconds)

PolyTect OVERMOLDING

PROCESS & MATERIAL SUMMARY

Developed to address the market need for an efficient way to encapsulate electronic modules. Modules consist of fully populated printed circuit boards

Eliminates the need to mold polymer housings used in conjunction with standard sealing methods with a one step molding process.

PolyTect OVERMOLDING

PROCESS & MATERIAL SUMMARY

Made of specialty-formulated materials to mold at temperatures and pressures below the shear stress of solder joints. Allows for over molding of delicate components without degradation of performance

Cost Reduction of traditional manufacturing and assembly methods