Case Study: Why S136 ESR is the Superior Choice for High-Volume PC Injection Molding

Case Study: Why S136 ESR is the Superior Choice for High-Volume PC Injection Molding Project Background & Client Requirements In a recent precision project involving Covestro PC grade AL2447 , our en

Case Study: Why S136 ESR is the Superior Choice for High-Volume PC Injection Molding

Project Background & Client Requirements

In a recent precision project involving Covestro PC grade AL2447, our engineering team was faced with three non-negotiable technical requirements:

• Optics: Stable transparency and high-quality mirror surface appearance.

• Precision: High structural strength and strict dimensional consistency.

• Scale: An annual production target of approximately 500,000 pieces.

The Challenge of Processing Covestro PC AL2447

While Covestro PC AL2447 offers excellent flowability and thermal stability, the material itself poses a challenge to the mold's longevity. Processing this PC grade requires temperatures exceeding $300^\circ\text{C}$, which can be "aggressive" toward standard mold steels.





Why S136 ESR? The Decisive Engineering Factors

We moved beyond standard P20 or 718H steel, opting for S136 ESR (Electroslag Remelting) for two critical reasons:

1. Superior Corrosion Resistance

Under high-temperature PC processing ($300^\circ\text{C}$+), PC materials can release corrosive gases. Standard steels often suffer from "gas etching," leading to surface micro-pitting. S136 ESR’s high chromium content provides a protective shield against this chemical wear.

2. Long-term Polish Stability (Mirror Finish)

For a 500k-cycle project, maintaining a "Grade A" mirror finish is non-negotiable. The ESR process ensures an extremely high level of steel purity with minimal inclusions. This allows the mold to be repolished less frequently, avoiding costly downtime and ensuring the 500,000th shot looks as clear as the first.

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Conclusion: Engineering as Risk Management

At Jeancen Mold, our engineering logic is simple: We didn’t select S136 ESR to "over-specify" the project. We selected it as a risk management decision.

By investing in the right steel up-front, we ensure process stability, protect the client’s brand reputation for quality, and guarantee a lower total cost of ownership over the project's lifecycle.