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Limitations of injection Moulding


1. Intense industry competition often results in low profit margins.

2. Mould costs are high.

3. Moulding machinery and auxiliary equipment costs are high.

4. Lack of knowledge about the fundamentals of the process causes problems.

5. Lack of knowledge about the long term properties of the materials may result in long-term failures.

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Breaker Plate & Screen Pack :

Breaker Plate - 1. This is performed metal disk,  with a multitude of small diameter holes. 2. The breaker plate is placed in between the screw and the die assembly. 3. It's principal function is to provide support for the screen pack . 4. The breaker plate helps also to convert the spiral flow of the polymer melts leaving the screw into a linear, axial one. Screen Pack - 1. Screen Pack is usually a multilayered,  nearly symmetrical sandwich of metallic wire screens.  2. It is placed between the screw and the breaker plate,  using the latter for physical support. It's  role is to eliminate the particulate contaminants.  3. The screen pack composition is always based on trade-offs, there is need to eliminate particulates using screens with high mesh,  but at the same time this create flow restriction,  it reduced the throughput, thus low mesh would be preferred.  4. Decision should be made as for as the maximum tolerabl...

Barrel & Hopper Cooling System (Elements) :

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