Modification of Hard Chrome Plating by Yepco Surface Modification Treatment

1. Introduction

Hard chrome plating (HCr) is widely employed to extend the service life of molds and components, enhance corrosion resistance, and improve release properties. Whilst its surface may appear smooth and aesthetically pleasing at first glance, it actually harbours countless microcracks and plating nodules, which frequently cause issues during molding.

Addressing these challenges, IEPCO surface modification treatment is gaining significant attention. This process, utilising Swiss-made surface modification equipment, is a technology that can dramatically enhance adhesion, slip properties, and durability when applied before or after plating or coating.

This article clearly explains the effects, application examples, and technical background of IEPCO treatment, based on four technical documents.

2. Challenges with HCr Plating and the Significance of IEPCO Treatment

● Problems Caused by Surface Micro-Defects

While HCr plating offers excellent functional surface properties, residual stresses within the coating create countless invisible “microcracks”. Additionally, **nodular precipitates (plating nodules)** formed during plating, along with machining burrs and scratches on the substrate surface, are also causes of plating issues.

The representative problems these cause are as follows:

・Deposit (contamination) adhesion to molded parts

・Poor demoulding (resin or rubber sticking to the mold)

・Penetration of corrosive gases → Base material corrosion

Acceleration of plating delamination

3. Mechanism and Process of Iepco Surface Modification Treatment

Iepco treatment primarily consists of a two-step process:

　　① Cleaning process (e.g., MS300A)

• Irregularly shaped, angular particles are blasted onto the metal surface to remove plating burrs, work-hardened layers, contaminants, and fine particles.

  
  

  Process burrs and flash are also removed at this stage, creating a smooth and stable substrate.

  ② Peening process (e.g., MS550B)

• High-speed impact of spherical microparticles physically seals microcracks.

  
  

  Simultaneously, it forms a surface microstructure that enhances slip properties. This directly improves release properties and durability.

  
  

  4. Changes and Observation Results Before and After Treatment

  
  

  Comparing the HCr plated surface before and after Iepco treatment revealed the following distinct differences:

item	Before	after（Iepco）
Surface condition	Plating blisters and numerous fine cracks are present.	Smooth with no cracks or foreign matter
release properties	Deposits present, frequent mold release issues	Excellent slip properties, reduced mould release issues
corrosion resistance	Corrosion progression from cracks	Crack sealing to inhibit corrosion progression
Plating removal	Defects in the base material are susceptible to influence	Improved adhesion through defect removal

In particular, cross-sectional observations confirm that cracks are being sealed, representing a significant achievement directly linked to durability and release properties.

5. Application to Coating Removal: Regenerative without damaging the substrate

The scope of Iepco treatment extends beyond plating modification.

It is also effective for removing hard coatings such as PVD and CVD.

For example, when recoating tin-coated cemented carbide molds, the conventional approach often deemed them ‘unpeelable = scrap’. However, Iepco treatment offers the following advantages:

Minimal damage to the base material (less than 1μm)

Peeling possible within seconds

Ideal as a substrate for recoating after peeling. This enables reuse of molds previously discarded, contributing to cost reduction and SDGs compliance.

6. Optimal Utilisation Before and After Plating/Coating

● Pre-Plating Treatment

Applying Iepco treatment before plating yields the following benefits:

Removal of unstable layers and work-hardened layers from the substrate surface

Elimination of cracks and pinholes

Improved adhesion with the plating

Good plating take-up even after treatment (with appropriate peening selection)

● Post-Plating Treatment

Iepco treatment is also recommended post-plating to address challenges with HCr plating, such as removing micro-cracks and plating bumps, sealing cracks, and adding slip properties.

This delivers the following benefits:

Significant improvement in release properties

Reduction in deposit adhesion

Extended plating life and minimised issues

7. Comprehensive Technical Evaluation and Future Prospects

Iepco surface modification treatment is an effective plating and coating support technology for the following reasons:

- Non-destructive correction of plating defects (cracks, nodules, delamination)

- Applicable both pre- and post-plating

- Cost reduction and environmental impact reduction through mold reuse and performance enhancement

Furthermore, beyond HCr, it is applicable to coatings such as DLC, TiN, and CrN, as well as Ni plating and electroless plating, making it suitable for virtually all plating and coating systems.

Future applications are anticipated in fields demanding higher precision and reproducibility of surface properties, such as IoT and precision machining.

8. Summary

Issues stemming from surface defects in hard chrome plating significantly impact not only product quality but also the lifespan of molds and equipment. Iepco surface modification treatment offers an innovative solution to these fundamental challenges, addressing them non-destructively, highly efficiently, and with high precision.

‘Preventing invisible problems with visible treatment’ – true to this motto, Iepco treatment will likely see wider adoption as a technology supporting ‘invisible peace of mind’ in molding operations.