Engel: Tie-bar-less electric injection moulding machine processes LSR seal to tight tolerances

Sharp contours and tolerances down to hundredths of a millimeter: At Fakuma 2026, liquid silicone rubber seals for an inverter component will be produced – (Photo: Engel).

At Fakuma 2026, Engel will demonstrate the processing of liquid silicone rubber (LSR) on a tie-bar-less electric injection moulding machine of the “victory electric 1565/220” type. The machine produces a seal for an inverter component with tight dimensional and contour tolerances. The application focuses on uniform clamping force distribution, the prevention of flash formation, and the monitoring of material and process fluctuations.

The “victory electric 1565/220” has a clamping force of 2,200 kN and a size 1565 injection unit for larger shot volumes. The machine was first presented at K 2025 in a thermoplastics application and will be used for LSR processing at Fakuma 2026. The tie-bar-less design is intended to provide largely uniform platen parallelism and therefore an even distribution of clamping force across the mould surface. This is particularly relevant for low-viscosity LSR, as even very small gaps between the mould halves can lead to flash formation.

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A seal designed for zero-defect production: Measuring 484 mm x 202 mm x 29 mm, the LSR seal reliably protects sensitive inverter electronics from moisture – (Photo: Engel).

A seal measuring 484 mm x 202 mm x 29 mm is produced for an inverter component. The cycle time is around 70 seconds. The component is used to protect sensitive electronics against moisture. The contour tolerances are in the hundredths of a millimetre range, while the mould requires tolerances in the thousandths of a millimetre range. The material used is the two-component LSR “KEG 2003H-50 A/B” from Shin-Etsu.

The mould is supplied by Ach Solution and is equipped with the company’s “Servoshot” servo technology. The process design includes vacuum-assisted venting, a mould construction designed for leak-tightness and dimensional accuracy, and a cavity surface adapted to the material to reduce adhesion of the silicone. The still-hot component is removed automatically by an Engel “viper 40” robot using end-of-arm tooling developed by Ach Solution.

The victory electric 1565/220 equipped with a mold featuring ACH Servoshot technology. Part removal is handled by an Engel viper 40, with end-of-arm tooling supplied by ACH – (Photo: Engel).

For process monitoring, Engel uses standard pressure monitoring for the feed pressure of the dosing system. It detects deviations that may be caused, among other things, by fluctuations in viscosity or between material batches. An alarm is triggered at a feed pressure of 50 bar, allowing the process to be adjusted before a potential system shutdown occurs. In addition, the “iQ weight control” system is used to compensate for fluctuations in the injection process and thereby reduce scrap caused by changes in material viscosity.

The application is aimed in particular at the processing of large-format, tolerance-critical LSR components. From a technical perspective, the key aspect is the combination of tie-bar-less electric machine technology, mould design, automated part removal and process monitoring. The objective is to achieve a stable process with minimal flash formation and reduced rework.

Fakuma 2026
Friedrichshafen, Germany
12–16 October 2026
Hall A5, Booth 5203

More information: engelglobal.com

Engel Austria GmbH, Schwertberg, Austria

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