An innovative process that is halfway between casting and injection molding technologies

Low Injection Pressure
Improved Productivity
Superior Material Properties
Total Cost Reduction

What is Macromelt Molding?

Macromelt Molding is a low pressure molding process with hotmelt adhesives. It can achieve superior sealing, better protection of electrical/electronic components with higher productivity compared to those materials widely used in current sealing processes e.g. 2-component casting/potting resins or silicones. This notable process is environmentally compatible and contributes to total cost reduction due to improved productivity.

  • Macromelt Molding= low pressure, glue, injection molding.
  • An innovative process that is half way between casting and injection molding technologies.

Elecproy as a Henkel Iberian Technology Partner for MACROMELT applications, develops over-molding applications, starting from the design of the mold, injection tests and the possibility of manufacturing the finished parts if the client does not have sufficient means. Depending on the production, manual, semiautomatic or fully automated applications can be carried out.

Macromelt Molding Applications

The outstanding areas of application of the overmolding are the encapsulation of components, the filling of connectors and the injection of washers in situ. Deriving from them a multitude of solutions for different sectors, electronics, automotive, mobile telephony...

The featured applications of macromelt molding are electronic component encapsulation, connector potting and grommet injection molded in place.

Electronic component encapsulation

It is the low pressure applied during the molding process that prevents damage to the sensitive electronic components and
elements. The molding protects the electronics from external influences (moisture, mechanical stressing, etc.) and is capable of serving as a housing.

Connector potting

Hotmelts are used for sealing the plug and also for cable strain relief.

Grommet injection molded in place

The molding process can be used to mold grommets in place. This eliminates the time-consuming process of slipping the grommet on, which can cause repetitive strain injury. The molding can also include strain relief, which also enhances its esthetics.

Automotive Electronics

Macromelt molding can be applied to various automotive electronic systems and devices, such as tire pressure monitoring systems (TPMS), PCBs for seat occupant sensors, belt lock sensors, ECUs for motorcycles, air quality sensors, antennas for RF devices, smart entry (E-Key) systems, etc..

Mobile Phone Applications

Macromelt molding can be applied to the mobile phone battery, antenna, strobe flash, and other delicate components that require water-tightness, protection or encapsulation.

Molded connectors
Sensors with water-tightness & strain relief

Molding Machine & Mold Set

The molding system consists of the molding product, the mold set, the machine, and the melting unit. The melting unit for the hotmelt is usually used for injection of the hotmelt adhesive into the mold set at lower pressure compared to conventional injection molding machines.

The mold set, which is usually made from aluminum, facilitates the process to trial stage as it is lower in cost compared to conventional ones.

  • There are many types of molding machines available:
  • For small-scale production with manually opened mold set.
  • For production that needs higher productivity and output, with a sliding stage or rotary table for the mold set.


Manual gun

  • Suitable for testing or low volume production • Usual use 500 to 10,000 pieces / year
  • Regular size of the pieces 1-20 gr.

Automatic molding machine

  • Suitable for medium / high volume production
  • Usual use 20,000 to 400,000 pieces / year
  • Regular size of the pieces 1-50 gr.


Aluminum can be used as the material for making the mold set for Macromelt Molding due to

  • Lower injection pressure of the process
  • Better thermal conductivity of aluminum
  • No abrasive ingredients, e.g. fillers, glass fibers, contained in hotmelt

Steel can also be used as the material for the mold set. If the component to be over-molded has steel or hard
glass filled components, it is recommended to have steel inserts in this area of the cavity.

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ELECPROY AUTOMATIZACION Y ROBOTICA INDUSTRIAL SL - Pol. Industrial El Racó, Calle Tramuntana nº 7, 46612 CORBERA / Valencia - ESPAÑA