Investigation of Surface Roughness in Incremental Sheet Forming of Conical Drawpieces from Pure Titanium Sheets

Abstract

The article presents the results of the analysis of the influence of incremental sheet forming process parameters on surface roughness measured on both sides of conical drawpieces made from pure titanium Grade 2 sheets. The experimental plan was created on the basis of a central composite design. The study assumed the variability of feed rate, spindle speed, and incremental step size in the following range: 500–2000 mm/min, 0–600 rpm, and 0.1–0.5 mm, respectively. Two strategies differing in the direction of the tool rotation in relation to the feed direction were also analysed. Analysis of variance is performed to understand the adequacy of the proposed model and the influence of the input parameters on the specific roughness parameter. The sensitivity of the process parameter on the selected surface roughness parameters was assessed using artificial neural networks. It was found that the change in the surface roughness of the inner surface of the drawpiece is not related to the change of surface roughness of the outer side. The morphology of the outer surface of the draw pieces was uniform with a much greater profile height than the inner surface that had interacted with the tool. Taking into account the outer surface of the drawpiece, the direction of tool rotation is also most closely correlated with the parameters Sa, Sz, and Sku. Step size and feed rate provide the highest information capacity in relation to skewness and kurtosis of the inner surface of the drawpiece.

The Influence of the Shielding-Gas Flow Rate on the Mechanical Properties of TIG-Welded Butt Joints of Commercially Pure Grade 1 Titanium

“…Due to the hexagonal close-packed crystal structure, titanium alloys exhibit a low ductility and formability at room temperature [ 10 ]. However, at elevated temperatures, the titanium and Ti-based alloys can be successfully formed [ 11 ]. Some titanium components require joining.…”

Improvement of the Dimensional Accuracy of a Ti-6Al-4V Ripple Disc During Electric Hot Incremental Sheet Forming

“…According to the above studies, some typical parts, such as cone and square cone, are adopted to analyse the optimal method of dimensional accuracy [21] to [23]. However, the heteromorphic part, namely a ripple disc, is still rarely reported in recent studies, and its forming defect, namely that is obtained due to the interaction between residual stress and thermal expansion, is shown in Fig.…”

Tribological Aspects of Sheet Titanium Forming

“…Generally, incremental forming, especially cold incremental forming, was developed as an alternative die-less sheet forming process, but it is effective only in prototyping drawn parts and small batch manufacturing. Additionally, product surface quality poses a big problem due to the surface roughness [ 23 ] and traces left by the forming tool on the drawn part surface. In order to improve the surface quality of products, lubricants such as a mixture of WS2 powder and oil [ 20 ] or self-lubricating coatings [ 24 ] are used.…”