Forging is the manufacturing process of shaping metal by using localized compressive forces, either cold (near room temperature) or hot (higher temperatures for ease of metal shaping). To achieve a finished part, forged parts usually require further processing such as heat treating and machining.
Forging is typically a harsh manufacturing process. Metal contacting metal, expecting one to change, and the forming tools to stay intact and dimensionally accurate can be difficult at the best of times!
3D scanning, such as white-light scanning or laser scanning, can be extremely helpful for tooling development to assist both in archiving "good" tool shapes, and in measuring tool wear over time to help support preventative maintenance programs and to optimize tool change out cycles.
For the forged parts, 3D scanning offers a powerful technology to better understand the dimensional impacts from the process the parts undergo during the post-forge procedures. Heat treating for the purposes of stress relief or hardening affects the molecular structure of the metals and can cause distortion in the parts. ‘Colour map’ deviation reports can be readily applied using 3D scanning technology to compare the ‘before’ and ‘after’ states and how the parts change.
One of the challenges for the quality inspection of forged parts is the alignment or datum structure on the parts when comparing measured 3D data to 3D CAD data. More specifically, it is the variability of these datums prior to machining which can be complicated. Typically, parts that are forged have extra material left on the piece to allow for later machining, and that means these alignment features can be ‘buried’ inside the material. The challenge is to set up the part for the machining operation and ensure that there will be enough material everywhere to create the finished piece, given that "new" datums are about to be created. 3D scanning of the forging and generating 3D colour map inspections, using offset conditions and go/no-go criteria can eliminate the uncertainty with these processing steps.
If multiple machining operations are done, measuring the parts at relevant steps can also help to ensure that the parts are within specifications for that stage and that there is still enough material for the next operations. The earlier in the manufacturing process errors can be found, the less expensive it is to fix them and avoid the costs of unnecessary operations and machine/process time.