An analytical cost estimation model for the design of axisymmetric components with open-die forging technology

Abstract

Open-die forging is a manufacturing process commonly used for realising simple shaped components with high mechanical performances and limited capability in terms of production volume. To date, an analytical model for estimating the costs of components manufactured with this technology is still an open issue. The paper aims to define an analytical model for cost estimation of axisymmetric components manufactured by open-die forging technology. The model is grounded on the analysis of geometrical features available at the design stage providing a detailed cost breakdown in relation to all the process phases and the raw material. The model allows predicting product cost, linking geometrical features and cost items, to carry out design-to-cost actions oriented to the reduction of manufacturing cost. The model is mainly conceived for design engineers, cost engineers and buyers, respectively, for improving the product design, the manufacturing process and the supply chain. Cost model and related schemas for collecting equations and data are presented, including the approach for sizing the raw material and a set of rules for modelling the related cost. Finally, analytic equations for modelling the cost of the whole forging process (i.e. billet cutting, heating, pre-smoothing, smoothing, upsetting, max-shoulder cogging, necking and shoulders cogging) are reported. The cost model has been tested on eight cylindrical parts such as discs and shafts with different shapes, dimensions and materials. Two forge masters have been involved in the testing phase. The absolute average deviation between the actual and estimated costs is approximately 4% for raw material and 21% for the process. The absolute average deviation on the total cost (raw material and manufacturing process) is approximately 5%.

Key features and novel trends for developing cost engineering methods for forged components: a systematic literature review

“…The forging time required to produce the part is strongly related to the shape and the time necessary to perform auxiliary operations (i.e., heating, cutting, machining). It would be beneficial from a technical point of view to link product features with the analysis of CAD models used to derive geometric information (data input) [122]. This practice will permit to fill up the cost models with geometrical inputs automatically.…”

An Investigation for the Performance of the Design of Hot Forging Die and Workpiece

“…(Maarefdoust and Kadkhodayan, 2010). The closed die hot forging process and the process affecting the cost improvements are shown in Figure 1 (Campi et al, 2020).…”

“…Figure 1. Hot forging process in a closed die (Campi et al, 2020) Tool costs in hot forging can constitude 30% of the total process cost. Besides, tool production costs (die production cost) can directly affect the process parameters (repair, press downtime, scrap, rework, etc.).…”

“…Figure 2 shows the die steel and machining costs according to the total tooling costs. (Chander and Chawla, 2017) Cost estimation is a design task that provides the classification of cost items of both materials and processes prior to the manufacturing process (Campi, 2020). Today, companies have to provide product, and tool costs in a quality manner at competitive prices.…”

Transfer of Ausforming Parameters TO SCALED Forging tools

“…Hot bulk metal forming is used for industrial serial production and is considered highly efficient, since components can be produced almost without material loss in short cycle times [1]. Open die forging enables the production of simple shaped components with high mechanical performances and limited capability in terms of production volume [2]. The amount of load bearing cycles a tool system can operate without failure is decisive for the economic efficiency of the forging process and defines the tool´s service life time [3].…”