Kaba Group, a global security firm, is a longtime ESI Engineering Specialties customer. We have been producing unlocking slides—important components of many of Kaba’s high security locks—for them for several years.

Portfolio-2-Unlocking-SlideIn the past, we had used high-carbon steel to produce the .5 inch wide, 3 inch long unlocking slides. Though tight tolerances of .0015 inches were required, our precision tooling and 150 ton press was able to reliably stamp unlocking slides within specifications.

The Challenge

Recently, however, Kaba approached us with some unexpected design change requests.

They required 350,000 unlocking slides of the same dimensions but with different physical characteristics. The high-carbon steel originally specified has magnetic properties, which were no longer suitable for Kaba’s requirements.

Not only did they require their unlocking slides to be manufactured in a non-magnetic material, but the material had to maintain a very high surface hardness of Rc 65. They also required the order within four weeks. With an established rapport, Kaba was confident in our ability to come up with an effective and cost efficient solution in a timely fashion.

The Solution

We solved the magnetism problem almost immediately by switching from high-carbon steel to type 304 stainless steel. Type 304 stainless steel is a steel alloy that includes nickel as roughly 8% of its composition. The addition of nickel modifies the molecular structure of the steel and eliminates the metal’s magnetism.

The change to 304 stainless streel required us to modify the tool for the 150 ton press. 304 stainless steel is harder than high-carbon steel, so the tool for the unlocking slide had to be updated to withstand the higher cutting and forming forces and avoid die wear, which could slow or stall production.

We turned to a specialized coating technique to satisfy Kaba’s surface hardness requirement — the unlocking slides had be rated at Rc 65. Our engineering team, which is well versed in both current and emerging production techniques and processes, was able to identify plasma ion nitriding as an ideal coating procedure for the unlocking slides.

In plasma ion nitriding, nitrogen gas is electrified, resulting in nitrogen molecules ionizing to the surface of the metal. This process is very effective for surface hardening, but it can warp parts with thin cross-sections.

For its use in high security locks, the unlocking slides have to be uniformly flat within a tolerance of only .005 inches. To counter the warping caused by the plasma ion nitriding process, ESI engineers devised a specialized rack, sandwiching the stamped unlocking slides in such a way as to maximize plasma exposure but minimize distortion.

We were able to engineer a new process in order to meet Kaba’s updated unlocking slide requirements without sacrificing quality, production time, or cost.

Contact us today to learn how we can engineer solutions for your next project.