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Low Pressure Moulding

Efficient protection for sophisticated electronics

The Low Pressure Moulding process has its origin in the sealing of cable harnesses in the automotive industry - today it is used in many areas for the protection of electrical and electronic components.

At 5 - 60 bar, processing takes place at a significantly lower pressure than in the classic Injection Moulding process. This makes it possible to directly encase sensitive components such as circuit boards, sensors, etc.

The cycle times are limited to the moulding cycle, which, depending on the size and contour of the components, is around 10-60 seconds. Direct further processing is then possible, which means a clear time advantage compared to e.g. 2-component potting.

The adhesive properties of the materials used enable the components to be protected up to IP68 with the right combination of materials.

Thanks to an optimized material flow, hotmelt molding with the thermoplastics used can also be implemented for temperature-sensitive components.

Different material properties and processing variants, combinations of different materials and, if necessary, further process steps enable a wide range of applications.

LPM in a nutshell

  • Low pressures
  • Short cycle times
  • No curing or reaction times
  • Housings can be replaced
  • Suitable as strain relief
  • Applicable for temperature-sensitive components
  • Operating temperatures -50°C - + 150°C
  • Impermeability up to IP68
  • Wide range of applications

The Technology

The Low Pressure Moulding technology is generally based on simple principles. It is made successful by the combination of special properties of the moulding materials in processing and effectiveness, technological processing options taken from the application and injection molding technologies as well as adapted tool technology and system control.

Materials

Amorphous polyamides are used, which, in contrast to crystalline polyamides, on the one hand have excellent adhesive properties (adhesion) and on the other hand are very suitable as a housing replacement due to their significantly higher mechanical strength compared to other hotmelts (cohesion).

The amorphous structure also results in a relatively low processing viscosity, which allows these materials to be processed in a moderate processing temperature range (190 ° C - 250 ° C) at comparatively very low pressures (5 - 60 bar - in individual cases up to 100 bar).

In addition, specially structured polyolefins are occasionally used. Wherever the adhesion of the polyamides reaches its limits, they offer good properties both with the amorphous polyamides and with a large number of crystalline and strongly cross-linked materials.

The properties of the materials can be varied in a targeted manner through various combinations of raw materials and special requirements, such as UV resistance, hydrolysis resistance and increased thermal conductivity, can be implemented with the appropriate additives.

Machine system and toolings

Due to the intersection of material- and adhesive-typical properties, the processing equipment used can rely on adhesive application technology and the classic injection molding process 

and these can be combined and modified in such a way that a specific machine technology is created. 
The corresponding extensive knowledge about the possibilities and requirements of the Low Pressure Moulding process enables to create an effective, clean and cost-effective production platform for the process and the system control.

The structure of the materials enables the use of modified tank devices in combination with piston or gear pumps as well as hotmelt extruders with special dosing systems to avoid pressure peaks.

In tool technology, mainly aluminum is used in order to take into account the adhesive properties of the materials and to ensure demouldability, in combination with steel inserts to increase the stability where abrasion occurs in the process, e.g. through insert parts. The entire structure of the moulding tools in Low Pressure Moulding also takes into account the specific process-optimized number and arrangement of moulding cavities and the injection direction.

Project specific solutions

The entire technology offers many options for adaptation. Due to the systematic modular design and a large number of possible variations of the individual components, the processing systems can be adapted to almost all project and production-related requirements. This means, on the one hand, individual workstations can be largely individually designed, and on the other, more complex moulding stations can also be integrated as modules into overall production processes, as required. In almost all cases this leads to a simple and clean process and to significant cost advantages.

We would be happy to organize technology trainings for you and your colleagues to get to know the possibilities and evaluate the use cases in your company - on site or online from the OptiMel Studio.

Fields of application

Connectors / Grommets

Housing and sealing with integrated strain relief and kink protection can be implemented for plug connections and grommets. A defined position of the components and, if necessary, plugging is implemented in the tool by means of a specially manufactured moulding cavities, clamping plates and mating connectors.

Sensors

Sensors are protected from a multitude of external influences without affecting their functionality. They can be completely encased or, by using the adhesive properties of the materials, important measuring areas can be kept free from encapsulation and at the same time important electronics areas can be protected against media. In both cases, component damage is avoided thanks to the low pressures of the LPM process.

Housings

Individual shaping and sealing in one process step, which results in - additionally to the technical advantages made possible by the sealing - in particular the possibility of higher production quantities per time unit and thus significant cost savings.

PCBs

The encapsulation serves to protect the components from vibration, moisture, contamination, contact and mechanical stress without influencing or damaging them within the processing.

Micro switches

Low Pressure Moulding is in this case mainly used to ensure long-term functionality, by protecting against humidity.

We deliver the complete technology

1
Technology consulting

The introduction of new technologies begins long before the required production equipment is purchased. We will advise you from the start, share detailed knowledge of the technology and carry out feasibility analyses.

2
Prototyping

We analyze the matching moulding material based on your requirements, carry out spot tests for adhesion analysis and create prototype tools for test samples and pre-series production.

3
Tool design

At the heart of every project, many details are crucial for a stable and efficient process. We advise on component design, manufacture high-quality tools and carry out mold flow analyzes.

4
Process design

Cycle times, pressure, processing and mold temperatures play a decisive role in project-related process design. We determine these parameters and advise on the optimization of ongoing projects.

5
Equipment configuration

Suitable equipment is defined by the specification of the project, production conditions and, if applicable, future projects. The configuration is aligned to your requirements based on the modular machine program and extensive accessories.

6
Allround service

With advice on process optimization, training for your staff, various maintenance options and spare parts service, you can also make use from our know-how and support during a running production. 

7
OptiMel Studio

Would you like to get to know us or use our services without the effort of traveling ?! - We switch you into our studio and it's almost like you're there.

8
Contact

Whatever demands and challenges your project has - our team is here for you:

+49 2371 - 1597 0
info@optimel.de

Further questions?

Would you like to find out more details about the technology? Do you have any projects that you would like to discuss with us?

We are looking forward to hearign from you!