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MEL 423 : Micro-Manufacturing

Topic:Design of a micro injection moulding machine

for thermosetting moulding materialsBy: W. Michaeli, T. Kamps

A Presentation by: Sajeed Mahaboob

2011ME1111

Instructor:Dr. Anupam Agrawal

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Prototype

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Introduction

Outline of the process

Detailed description of the process

Importance and conclusion

What’s all there to discuss?

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Micro products made of thermosetting polymers

enable innovative applications since thermoplastics do not always meet the desired properties.

Thermosetting moulding grades offer advantages in thermal durability and chemical resistance in comparison to thermoplastic resins.

Processing smallest quantities of polymeric material for applications in micro system technology require high process accuracies.

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Highlights..

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Introduction

Micro system technology has grown up drastically during the last decade.

Micro system technology has great potential for the future.

Growing rates of about 16 % per year are regularly predicted.

The mainstream trend is the increasing use of polymer parts in the micron range.

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Contd...

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Thermosets offers great advantage over thermoplastic materials.

Thermosets has…Good chemical resistanceHigh temperature durabilityGood flowabilityHigh rigidityMuch Lower viscosity

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Concept of using two plungers unit was

followed in this process.

During the plasticizing phase, the upper plasticizing plunger pushes resin through a die heated at melting temperature as the injection plunger is cored back at the same time.

Details of the design

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Machine requirements for thermoset materials

1. Clamping unit:Similar to thermoplastics, only small clamping forces are needed in micro injection moulding with thermosets due to the small dimensions of micro parts.

2. Plasticizing unit and injection unit

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Design of Injection and plasticizing unit

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Plasticizing and injection unit

The plasticizing unit of the micro injection moulding machine is designed for the processing of free flowing thermosetting moulding compounds.

In the plasticizing unit, temperature peaks have to be avoided in all cases, for prematurely curing material can put the entire machine out of action.

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Contd..

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The requirements for the plasticizing

unit can be summarized as follows:• adaptation on the existing machine body,• ensuring constant plasticizing temperatures,• avoidance of a peak temperature,• fast plasticizing,• avoidance of resin fluctuation in the injection system for high process accuracy.

• flexible shot volumes.27-042015

Contd..

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Contd.. Similar to thermoset injection moulding

machines in the macro scale, a common heating via liquid medium was chosen for its temperature control.

The high thermal capacity of liquid heat carriers enables temperatures to be kept at a very constant level, for pre-curing resin in the machine’s injection section has to be avoided.

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Important finding

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Not suitable for complex moulds Slower process time Controlling peak temperature Resin fluctuation in injection system

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Limitations

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Application made of thermosetting polymer grades are

advantageous over thermoplastic grades, where inappropriate can be substituted, like the use of nickel in bio-medical devices.

In micro injection moulding for thermosets, the properties of thermosets provides the opportunity to take benefits from its characteristics.

In order to process smallest amount of thermosets, an already existing setup is available. It is based on a prototype designed at IKV.

Thermoset micro parts with a shot weight in the area of 0.05g to 3g can be manufactured with this setup.

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Conclusion

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So… Gentlemen

Thanks for your Patience!!!