microCAD 2006 pp.99-104.
1
COMPARISON OF WEB-BASED MOULD QUOTATION SYSTEMS Balázs Mikó PhD, Assoc. Prof. Budapest Polytechnic, Bánki Donát Mechanical Engineering Faculty Department of Manufacturing Engineering,
[email protected] Summary The cost estimation in mould making industry is rather a complex problem and therefore a great challenge. This process is aided by those web-based systems, which are compared in the current article. Keywords: manufacturing cost estimation, plastic injection mould
1. INTRODUCTION The role of the engineering plastics is increasing in our days in the automotive industry. Aluminium and steel parts are replaced by plastic parts, which generates less overall mass, reduces production costs and environment pollution. Due to these trends the mould maker companies face a considerable challenge not only in terms of productivity of design and manufacturing, but also in trying to meet the increased demand in quotation. For increasing demands companies have to process data in large quantities. The state is well marked by this example: a medium size tool workshop, which can produce about 40-50 moulds per year, makes about 1000-1200 quotations. The quotation has a strategic role for the mould manufacturer, because it has a serious effect on the company’s operation. The main question here is how the manufacturer can balance between profitable production and the customers’ budgetary considerations. Some additional problems are the unknown details of construction and manufacturing process, the confidential budget and the several rivals. In addition to several unknown parameters a further difficulty in the quotation process arises, that is how to give accurate data by minimal work, however this expectation is inconsistent. The flavour property of the known quotation methods ([1], [2]) is that the invested work is in direct proportion to the accuracy. For the fast process of quotation requests and the short deadlines there is little time for detail analysis of the problem. Furthermore, in the case of unsuccessful project the invested work is lost, and therefore this work can be defined as “waste”. The current industrial practice utilises the personal experiences, whereupon it is vulnerable and doubtful. Based on these considerations we can determine the requirement list of an ideal quotation system: it is easy to use, requires short processing time, yields accurate results, its actual design and manufacturing environment is considered, and the results are not under the influences of the user’s experiences. To the best of my knowledge there is no such system.
microCAD 2006 pp.99-104.
2
There are several initiatives which provide support for the quotation process. The three systems which are presented in this article are linked to internet-based technology and are free to use.
2. IPLAS MOLDCOSTER The „MoldCoster” was developed by the American International Plastic Laboratories and Services (IPLAS) Ltd. The homepage of the system is www.iplas.com [3]. The knowledge of the “MoldCoster” comes from statistical processing of industrial case studies. The user interface is simple, clear, uses 13 parameters to describe the problem and the parameters can be selected from combination boxes.
Fig. 1. User interface of the „MoldCoster” The parameters, which are described by the moulding exercise are the following (the numbers show the number of choosing facilities): (I) product size (7), which is characterised by the mass of the product, (II) product complexity (5), (III) the cavity sets (4), (IV) the cavity finishing grade (8), (V) number of cavities (5), (VI) the type of runner system (5), (VII) cavity texture (4), (VIII) engraving (5), (IX) required tolerance of the product (4), (X) type of the material of the mould (4), (XI) type of plating (3), (XII) region of mould built (8), (XIII) kicker (7). The effects of each parameter are well controlled, hence if you select the product size, the given based cost is modified by different percentages, and the latter is shown in the user interface.
microCAD 2006 pp.99-104.
3
3. UFE MOLD COST ESTIMATOR The “Mold cost estimator” was developed by UFE Inc. The company has been satisfying his costumers since 1953 by engineering services from product concept to production. The homepage of the system is www.ufeinc.com [4]. The cost estimation in “Mold cost estimator” is driven by the following parameters: (I) the size of the product (volume and mass) (5), (II) the complexity of the parting line (4), (III) the number of 3D features like ribs, holes etc. (7), (IV) the number of lifters and sliders for undercuts (5), (V) the number of cavity (7), (VI) the tool life in numbers of shots (5). The output of the system consists of five data: the minimum and the maximum cost of production and the minimum and the maximum time of production in weeks.
Fig. 2. User interface of the „Mold Cost Estimator”
microCAD 2006 pp.99-104.
4
4. COST ESTIMATOR The “Cost estimator” was developed by David O. Kazmer for research based empirical models and statistical data. The system can be retrieved from kazmer.caeds.eng.uml.edu [5]. D. O. Kazmer is professor of University of Massachusetts Department of Polymer Processing, and has substantial industrial and research experience in this area. In “Cost estimator” there are eight input parameters: (I) type of plastic raw material (6), (II) the tool life (6), (III) the number of cavity (6), (IV) the complexity of the plastic part (3), (V-VII) the overall dimensions of the part, (VIII) the wall thickness. These results are very sophisticated, but unlike the other two systems the objective of the estimation is the price of the moulded part, and the tooling cost is just one component. If you click to on to “Details…” the list of results can be studied. Out of 14 data 13 are related to the plastic injection process.
Fig. 3. User interface of the „Cost estimator”
5. CASE STUDY To compare the systems’ capabilities several tests were carried out. Figure 4. shows one of the test parts. The overall dimensions of the part are 56x39x19 mm, the material of the part is ABS/PC, and because of undercuts the mould has two slides in the longer size. The numbers of the cavities are 4, and the runner system is a heated manifold with four nozzles.
microCAD 2006 pp.99-104.
5
Fig. 4. Test part Table 1. shows the input data and the results of the test execution. The numbers of the input data are equivalent with those on the previous lists. For better comparison we made a quotation with an empirical figure, which is created by a mould shop’s cost expert. This figure takes into account the cost of material, the cost and type of runner system, the cost of engineering design and the complexity of the mould. The estimated cost was 31.400, - $. Table 1. Results MoldCoster Input (1) – Extra small (
