Digital Scanning Method for Thickness Analysis of Hollow Parts Manufactured by Incremental Forming on a CNC Lathe

Abstract

Incremental forming is one of the manufacturing methods which uses relative simple technological equipment and can assure a high rate of the process flexibility. These requirements can assure the efficiency demanded by the industrial market, in the case of small production batches, which occur more and more often nowadays. To ensure the stability of the process, the required quality and dimensional accuracy of the parts have to be well controlled. This requires the evaluation of the parts dimensions by certain measurements. For hollow parts, the measurement of their thickness is always a challenge, mainly when the dimensions are smaller and their depth is greater. This paper presents a digital method for the parts dimensional evaluation and analysis, which can be very accurate and does not need mechanical contacts with the part during measurements. The parts were scanned with a 3D blue light scanner, on their both sides and then the data was processed into specialized software, to obtain the parts digital surface from the 3D scanned data. The digital data was compared with the theoretical approach, to establish some conclusions on the validity of the sinus law and to point out the critical zones, where the thinning is strong and may cause fractures. The digital scanning method presented can be used also for quality control and inspection, as the processing steps are considered user-friendly and easy to adapt to certain specific requirements.

Incremental deformation: A literature review

“…The sine law materialised that the deformation in this case is the projection of the deformed sheet metal onto the final part surface [14] -see figure 9 [4]. In recent researchs, a single point incremental forming of a DC04 steel frustum cone on a CNC lathe machine, the sine low predicted the wall thickness in the deformed area with a precision less than ±0.1, without taking into consideration the surface near the fixing area who keeps his thickness [44]. Other researchers discovered that the thickness distribution is nonuniform in all formed area.…”