Hard anodization issues in quarter turns: Why it’s not recommended and better alternatives

When specifying Turnlock receptacles to be hard anodized, it’s important to consider the potential challenges this process may introduce.

Issues with Hard Anodization

In our production qualification process, both we and our customer observed that the hard anodization began to chip after just a few cycles of locking and unlocking. Once the anodization is chipped, the effectiveness of the plating is compromised. In the context of avionics and electrical panels, the customer raised significant concerns regarding microscopic Foreign Object Debris (FOD) that can arise from such chipping.

Despite our attempts to mitigate FOD through various treatments, we encountered numerous difficulties. Ultimately, we discovered a silicone spray that provided temporary relief, allowing us to pass the customer's qualifications. Impressively, we had no concerns, recalls, or warranty issues over a span of at least ten years. However, after approximately 25 cycles, FOD reappeared.

It's noteworthy that engineering departments often focus only on the initial cycles, overlooking long-term performance.

Comparing Hard Anodizing and Standard Anodizing

Unlike hard anodizing, which is more brittle, standard anodizing demonstrates greater resilience and less chipping. My experience suggests that while anodizing, in general, can be done cost-effectively, hard anodizing tends to escalate costs without delivering long-term durability.

Recommendations

Before opting for hard anodization, consider the impact on performance and longevity of your parts. Here are some specific parts to be cautious about:

• Part: 212-12A-H
  • Recommended Alternative: MT-HR25A
• Part: 26R1-5
  • Recommended Alternative: MT-HRPM25A
• Part: 26R2-5
• Part: 26R3-1
  • Recommended Alternative: MT-HRPM2HA

Conclusion

In conclusion, hard anodization may seem like a beneficial choice for durability and corrosion resistance, but the realities of performance in avionic applications indicate otherwise. It is essential to ensure that both cost and longevity are carefully balanced when making these decisions.