SAE EPR2020019

Currently, inaccuracies in machine tools are often not detected until after they have produced nonconforming parts, causing reworking or scrap. For high-value aerospace parts, a single rejected part is a significant cost. Low-value parts are often inspected less frequently, allowing many nonconforming parts to be produced before the issue is detected, also resulting in high cost.

The alternative to relying on part inspection is to run frequent tests on the machine itself, but established calibration and health-check processes take between 20 minutes and several days. Emerging rapid and automated verification (RAV) processes enable machine tools to check their performance automatically in just a few minutes. These RAV processes can be performed frequently throughout the day, allowing machines to operate without human intervention for long periods of time. When an issue is detected, the machine may be able to recalibrate and then continue automatically. Where this is not possible, the machine stops and provides diagnostic information enabling the operator to efficiently get the machine back into production.

For many machines, especially smaller ones, artifact probing is the most cost-effective and easily implemented method. Combined with probing of roughing cuts, it can also verify spindle and dynamic errors at the micrometer level. Inertial measurement has a lot of potential to provide continuous monitoring during operations, and significant research efforts are therefore justified to validate and improve diagnostic capability. Noncontact triple-probing of spheres can provide highly accurate RAV while also enabling some compensation to be achieved in a very rapid way. This equipment is costly when dedicated to each machine for RAV but may be justified for very high-value machines and processes.

NOTE: SAE EDGE™ Research Reports are intended to identify and illuminate key issues in emerging, but still unsettled, technologies of interest to the mobility industry. The goal of SAE EDGE™ Research Reports is to stimulate discussion and work in the hope of promoting and speeding resolution of identified issues. SAE EDGE™ Research Reports are not intended to resolve the challenges they identify or close any topic to further scrutiny.