Circuit Board Protection with Low Pressure Molding

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Low Pressure Molding

Using an environmentally friendly hot melt adhesive, the low pressure molding process encapsulates parts safely in seconds, offering superior waterproofing and protection against temperature extremes, harsh chemicals, shock, and vibration. This makes it an ideal process for waterproofing electronics. Low pressure molding is uniquely positioned between potting and high-pressure injection molding. Unlike potting – which can take up to seven process steps – the entire low pressure molding process can be completed in three simple steps, effectively enhancing the waterproofing of electronic components. Based on the process-step reduction, fast-processing speed, substantially increased throughput, reduced material, shipping and labor costs, the cost for an overmolded part can be reduced to half the price of a potted part.

Low Pressure Molding Values
at a Glance

Protection against the Environment

Waterproof

Strain Relief

Impact and Vibration

Chemical Resistant

Weight Reduction

"Green" technology, No VOC & Low Waste

Cost Effective

Low Pressure Molding –
Improved Design Flexibility

Low pressure molding not only provides production benefits but also design benefits, such as skylining and an overall improved appearance.

Precision

Because of the tight overmolding tolerances, design engineers have more space and flexibility within the final assembled products.

Design

Low Pressure Molding offers design capabilities far beyond the form-fit-function of traditional circuit board protection materials.

Skylining

Low pressure molding materials can be skylined around components and electronics, reducing the material usage, the weight of the end product and provides more precise encapsulation.

Improved Appearance

Low pressure molding improves the aesthetic appearance of end products. The material becomes the housing, eliminating the need for additional parts.

Low Pressure

Low injection pressure easily molds around fragile components, and the material’s quick-cooling times during overmolding minimize the heat exposure to sensitive electronics.

Low Pressure Molding –
The Best Option for Part

There are numerous design, manufacturing and material benefits with low pressure molding, such as waterproofing protection, embossing/debossing and the materials’ inherent sustainable qualities. Experience the various technology advantages low pressure molding has to offer your production.
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Skylining

Material wraps the contours of components – with a minimum thickness of 1mm – encapsulating the PCB and reducing material usage through skylining.

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Single-part, No-cure Materials

Hot melt thermoplastic that does not require mixing or curing.

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Sustainable Materials

Low pressure molding materials are thermoplastics derived from plant-based fatty acids, are VOC free and REACH/RoHS compliant. The materials can be reworked and waste is
recyclable.

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Custom-material Options

LPMS USA’s custom Spectra-Melt line incorporates additives and low-density fillers to enhance material properties, such as color, optical clarity, UV resistance and thermal stability.

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Strain Relief

Mechanically bonds to protect wires and cables to provide a waterproof seal. LPMS USA offers wire and cable processing and attachment prior to overmolding.

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Overmolds Multiple Materials

LPMS USA’s dual-nozzle equipment platforms inject multiple materials at the same time, providing multiple PCB protection options.

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Eliminates Housing

Low pressure molding materials become the housing, reducing cost, part numbers and inventory.

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Bushings for Mounting

Compression-limiting bushings can be molded in place for parts mounting.

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Embossing/Debossing

LPMS USA’s mechanical design engineers can integrate logos, part numbers and time stamps into the material.

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Overmolds Batteries

Encapsulates and protects batteries withoutdamage.

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Waterproof

Low pressure molding materials provide waterproofing and meet sealing requirements up to IP 69.

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Shut Offs

Low pressure molding materials can shut off or mold around sensitive components, while still protecting electronics from moisture.

One Solution Provides
Multiple Protection Benefits

Low pressure molding provides the protection benefits of multiple technologies. It can be used as a potting, water­proofing electronics and conformal coating replacement.

Learn more by exploring the infographic.

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Potting Replacemet

• No Housing; fewer part numbers
• Improved aesthetic appearance; skylining
• Design flexibility, beyond form-fit-function
• Weight reduction
• Fast processing, short cycle times
• Watertight encapsulation
• No cure
• Strain reflief
• Reworkable
• Low waste
• No VOC
• Environment, chemical, moisture, thermal protection
• Suitable for batch processing
• New IPC standard published

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Sealing Replacemet

• No Housing; fewer part numbers
• Improved aesthetic appearance
• No cure
• Moisture and chemical protection
• Electrical isolation

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Conformal Coating Replacemet

• Temperature, vibration, impact and chemical-restart material
• Environmental protection (85°C/85%RH) available materials
• No cure
• Green technology
• Suitable for in-line processing
• Ne IPC standard published

Low Pressure Molding – Simplified Manufacturing Process

Low Pressure Molding simplifies the manufacturing process significantly and helps you to:

  • Reduce your manufacturing steps (See Infographic)
  • Reduce weight for your part
  • Reduce your cycle time per part
  • Reduce your material consumption
  • Reduce your equipment & operations footprint
  • Reduce your total cost of ownership
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Low Pressure Molding –
Simplified Manufacturing Process

One of the major advantages of low pressure molding compared to traditional potting is its simplified manufacturing process. Instead of encapsulating a part in eight steps with potting, low pressure molding takes place in three simple steps.

Traditional Potting Process Flow

Mold Plastic Housing

Parts to Assembly

Insert Electronics

Parts Preheating

Potting Dispense

Vacuum or Settle

Oven Cure

Parts for Test

Low Pressure Molding Process

Insert Electronics

Mold

Test Device

Protect with Low Pressure Molding –
it’s that simple.

Learn more about low pressure molding and its advantages and applications!

Formulated Adhesive
Molding Resins

Low pressure molding is based on high performance polyamide, polyolefin and co-polyester materials, which provide outstanding performance, reliability and protection for your parts.

High-performance polyamide, polyolefin, and co-polyester materials

Thermoplastic materials, UL 94 V-0

80% of raw materials are based on renewables

No harmful fumes from molding process

Application viscosity from 1,000 to 10,000 cps

Application Pressure from 20 to 500 psi

Performance temperatures from -65°C to 200°C

Excellent adhesive properties to variety of substrates

Solvent-free, no safety labels

Long shelf life (2+ years)

RoHS and REACH complaint

Low Pressure Molding Compared
to High Pressure Injection Molding

The main advantage to low pressure molding is in its name: low pressure. When applied to a circuit board, high pressure injection molding’s highly viscous material would sheer off the components in seconds. Low pressure molding is perfectly suited for overmolding sensitive electronics, including sensors, switches and batteries.
High Pressure Injection Molding Low Pressure Molding
Pressure 25,000 PSI 100 PSI
Temperature 185–300+°C 180–220°C
Material Viscosity 5 grams over 10 min Melt Flow Rate

• Taffy
 2,000–10,000 mPa•s (cP)

• Pancake syrup
Applications
• PCB Housings
• Tooth Brushes
• Bottle Caps
• Pocket Combs
• Plastic Parts
• PCBs
• Sensors
• Switches
• Batteries
• Connectors
Equipment Injection Molding Machine

• Screw barrel system
 Low Pressure Molding Machine

• Gear pump system
Clamping Pressure 28–1,000 tons 1–10 tons
High Pressure Injection Molding
Pressure 25,000 PSI
Temperature 185–300+°C
Material Viscosity 5 grams over 10 min Melt Flow Rate

• Taffy
Applications
• PCB Housings
• Tooth Brushes
• Bottle Caps
• Pocket Combs
• Plastic Parts
Equipment Injection Molding Machine

• Screw barrel system
Clamping Pressure 28–1,000 tons
Low Pressure Molding
Pressure 100 PSI
Temperature 180–220°C
Material Viscosity 5 grams over 10 min Melt Flow Rate

• Taffy
Applications
• PCB Housings
• Tooth Brushes
• Bottle Caps
• Pocket Combs
• Plastic Parts
Equipment Injection Molding Machine

• Screw barrel system
Clamping Pressure 28–1,000 tons

Combined low pressures
and short cycle times

Low pressure molding is a safe and delicate process – positioned in between high pressure injection molding and potting. With its short-cycle times and low pressures, it is the ideal solution for circuit board protection.

Temperature and injection time

The typical temperature profile during injection shows the fast-hardening process of low pressure molding material. The material cools quickly within the mold set – never approaching solder reflow temperatures.

Low Pressure
Molding Setup:

Injection temperature:
425°F (218 °C)
Mold set temperature:
70°F (21°C)
Cylindrical PCB over mold:
0.5” x 2.5” (1.27 cm x 6.35 cm)

Strong protection

From material and design flexibility to IP 65-68 submersion protection – low pressure molding provides excellent protection for your parts or devices.

Protection Ratings

Most submersion product testing is rated using the Ingress Protection (IP) scale
First Number:
protection against solids		 Definition Second Number:
protection against liquids		 Definition
0 No protection 0 No protection
1 Protected against solid objects over 50 mm (e.g. accidental touch by hands) 1 Protected against vertically falling drops of water
2 Protected against solid objects over 12 mm (e.g. fingers) 2 Protected against direct sprays up to 15° from vertical
3 Protected against solid objects over 2.5 mm (e.g. tools and wires) 3 Protected against direct sprays up to 60° from vertical
4
Protected against solid objects over 1 mm (e.g. tools, wires and small wires)
4
Protected against direct sprays from all directions – limited ingress permitted
5 Protected against dustlimited ingress (no harmful deposit) 5 Protected against low pressure jets of water from all directions – limited ingress permitted
6 Totally protected angainst dust 6 Protected against strong jets of water (e.g. for use on shipdecks – limited ingress permitted)
7 Protected against the effects of temporary immersion between 15 cm an 1 m, Duration of test 30 min.
8 Protected against long periods of immersion under pressure
First Number:
protection against solids		 Definition
0 No protection
1 Protected against solid objects over 50 mm (e.g. accidental touch by hands)
2 Protected against solid objects over 12 mm (e.g. fingers)
3 Protected against solid objects over 2.5 mm (e.g. tools and wires)
4
Protected against solid objects over 1 mm (e.g. tools, wires and small wires)
5 Protected against dustlimited ingress (no harmful deposit)
6 Totally protected angainst dust
Second Number:
protection against liquids		 Definition
0 No protection
1 Protected against vertically falling drops of water
2 Protected against direct sprays up to 15° from vertical
3 Protected against direct sprays up to 60° from vertical
4
Protected against direct sprays from all directions – limited ingress permitted
5 Protected against low pressure jets of water from all directions – limited ingress permitted
6 Protected against strong jets of water (e.g. for use on shipdecks – limited ingress permitted)
7 Protected against the effects of temporary immersion between 15 cm an 1 m, Duration of test 30 min.
8 Protected against long periods of immersion under pressure

Protection Levels of
Circuit Board Protection Technologies

CBP
Protection
Conformal Coating
Light mechanical protection
Sealing
IP 65-68 submersion protection
Potting
Robust; wide range/spikes in operating temperatures
Low Pressure Molding
Material and design flexibility (features); vibration dampening; IP 65-68 submersion protection

Protection Levels of
Circuit Board Protection Technologies

CBP
Conformal Coating
Protection
Light mechanical protection
CBP
Sealing
Protection
IP 65-68 submersion protection
CBP
Potting
Protection
Robust; wide range/spikes in operating temperatures
CBP
Low Pressure Molding
Protection
Material and design flexibility (features); vibration dampening; IP 65-68 submersion protection

Waterproofing electronics

Securing Your Electronics from the Elements

Want to learn more about how Low Pressure Molding waterproofs your sensitive electronic components? You can read more about it here.
READ MORE

Further Topics

Cost Savings Calculator

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LPMS USA
1441 Branding Lane, Suite 110
Downers Grove, IL 60515 USA
Tel: +1 (800) 353-7773

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