More of an art-form than a machining process! Corrosion samples made at PH Tool are achieved by machining artificial defects in the workpiece rather than inducing actual corrosion. This keeps the features very controllable, repeatable, and most importantly, measurable. Corrosion patterns can be machined on any metal component and arranged in irregular configurations that closely simulate real-world conditions. Basic shapes include hemispherical holes, flat-bottom holes, square holes, hex holes, and custom-made irregular pits. Individual machined features are often grouped together into a pattern determined by the customer or even "randomized" by PH Tool (after which, a defect map is provided.) Specialized EDM electrodes are designed and made at the hands of skilled toolmakers. Electrode tooling can also be cast from real corrosion patterns and used to reproduce inspection conditions with an extremely high-degree of accuracy.
Once a custom electrode is manufactured, a particular pattern can be reproduced and plunged in an EDM machine to precisely-controlled depths. Having the same basic pattern machined several times, each at a different depth can be useful for gauging severity of corrosion in the field. Common applications are Ultrasonic Testing (Conventional and PAUT,) Eddy Current Testing, and Visual Testing. If you don't see the simulated corrosion pattern you need below, use your imagination... we'll figure out how to accomplish it!