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Abstract

An actual analysis in the tool and mould making sector showed that methods and programs insufficiently support the manufacturers of pressure die casting moulds in the quotation costing process. The primary aim of quotation costing is to generate many first-class bids in order to gain a high quantity of profitable orders. For this purpose companies have to achieve a high calculation precision with low expenditure. In addition, a comprehensible calculation is of great importance in order to enable an internal and external comparability and analysis as well as to permit the customer to assess the performance offered. In order to support companies of the tool and mould making concerning these matters, a working group from industry and science analyzed the quotation costing made by manufacturers of pressure die casting moulds. The article discusses the results of this analysis and describes the development of a rule-based calculation approach.The generation of first-class supplies is of special importance for enterprises of the tool and mould making sector since the fast submission of qualified offers represents the prerequisite for competitiveness [1]. At the same time, the calculation of an estimated price is, as a rule, carried out free of charge. For this reason, the creation expenditure of bids should not increase proportionally with the precision [2]. Apart from the demand for an effort-free creation with simultaneously high calculation quality, the qualitative representation of the performance profile represents another important task in the area of quotation costing. It is decisive for the success of a bid to communicate the competence of the company to the customer. A convincing technical description of the mould with logically presented costs supports an easy internal and external evaluation. It enables the customer to judge whether the offered conditions are superior to those of competitors regarding price and performance [3].Since present concepts and programs do not offer a sufficient solution for manufacturers of pressure die casting moulds, a working group consisting of 10 companies of the tool and mould making was founded in March 2007 at the Institute of Production Engineering and Machine Tools (IFW) of the Leibniz Universität Hannover. The group aims at analyzing the difficulties of quotation costing of pressure die casting moulds and developing a geometrybased quotation costing system. In order to develop this system, a method has to be found that renders possible to use the geometry information of the casting part for an accurate calculation.The following chapter shows the results of an analysis conducted by the working group regarding the quotation costing process of pressure die casting mould manufacturers. Furthermore, these results provide a basis to summarize the challenges of the quotation costing process of pressure mould producing companies.

Current methods of technology assessment seldom include the manufacturing processes and organization around the investment target. As most interdependencies cannot be quantified, companies predominantly assess technology investments via methods which exclude monetary evaluation of technological aspects. Moreover, future costs and benefits of the manufacturing technologies are rarely considered systematically when making conventional investment decisions. This procedure does not necessarily lead to an optimal investment choice. In order to invest in low life-cycle costs technologies, the costs within the manufacturing processes and organization around the investment target, as well as all future costs and benefits, have to be carefully considered. The following paper introduces a new approach to analysing Total Costs and Benefits of Ownership (TCBO) using process chain simulation models. A representative manufacturing concept provides a practical insight how to use simulation in order to generate a database for technology assessment. Furthermore, the article discusses how future costs and benefits as well as the Net Present Value method, could be integrated within the TCBO-approach.

This article introduces a method for generating and analyzing CAD models of mould cavities to compute the tool accessibility. Using information about the surface curvature, a determination of working areas for different milling head geometries becomes possible. Relating groups of surfaces with milling heads and specific cutting data allows calculating the manufacturing time of roughing and finishing operations, including the tool change time. Determining the working areas, inaccessible for milling heads, enables to estimate the volume of material that needs to be eroded. A CAD-based application of the calculation tool 'Visual Form Calculator' (VFC), developed at IFW, is presented. Using the VFC, companies of the tool and form making industry are able to generate a virtual model of the contour element in order to analyze the accessibility of the working areas of the cavity and calculate manufacturing costs.