II - Customer service ÊÝqwurgxfwlrqÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝ ÍÍ ËÝgydqfhgsurmhfwùfrñhqjlqhhulqjÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝ ÍÐ ÌÝhdvlelolw|vwxglhvÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝ ÍÒ ÍÝhvwlqjÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝ ÎÌ ÎÝhfkqlfdovxssruwÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝ ÎÏ ÏÝqgxvwuldol}dwlrqdqgvhulhvsurgxfwlrqÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝ ÎÑ ÐÝrvwdvvhvvphqwprghoriqlvkhgsduwvÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝ ÎÒ @bnlokdsdq`mfdnerdquhbdneedqr9 ÊÝqwurgxfwlrq At each stage in the life of your tailor welded blank solution, a dedicated Tailored Blanks partner is available to provide you with a technical solution suited to your needs. Stage in the life of the product ArcelorMittal contact Preliminary design BIW experts Identification of application Preliminary blank concept Co-engineering development rg|lqzklwhuhylhz A multi-competence team consisting of Tailored Blanks development engineers, ArcelorMittal Auto resident engineers, ArcelorMittal design engineers and ArcelorMittal stamping engineers analyses the solutions of existing vehicles and studies optimizations with the following objectives: ı Weight saving. ı In-service and crash improved performances. ı Cost saving. ÝÍÏñhyhorswkhuljkwwdloruzhoghgeodqnvvroxwlrqvdffruglqjwrsulrulwlhvri wkhfxvwrphu Resident engineer Noble Intl. development engineer Blank optimization feasibility study Industrialization Noble Intl. plant project manager Detailed specification of part Series production 45 Client Technical Support (CTS) "$ t %! (laser welding, …) % % Safety (crash management, energy absorption, exceptional loads resistance) % y (stifffness) % % fe In-service performance Technical performance Quality follow-up ArcelorMittal has a development and technical support department which is dedicated to automotive customers. An engineering team, using tailor welded blanks experience of ArcelorMittal, can work on automotive projects and especially tailor welded parts from design to series production. Tailored Blanks requires from each customer detailed needs and priorities to optimize the tailor welded blank solution (see Fig.46). % #$ # ! Weight % % % Total cost of the function qñvhuylfhehkdylruvwxg| Beyond stamping feasibility study of the part, ArcelorMittal teams can design parts on the basis of speciÝcations and data provided by the customer, such as load analysis and main dimensioning criteria: ı DeÞection - stiffness. ı Plastic strains - resistance. ı Intrusion - crash. ı Steel grade and thickness optimization of the different areas of the blanks and comparison between the behavior of the tailor welded blank solution and the reference are examples of studies that can be performed (see Fig. 47 and Fig. 48). II - Customer service 44 ÝÍÐñudvkvlpxodwlrqridfrpsohwhyhklfohprghodqgvwxglhv pdghe|ufhorulwwdo ËÝgydqfhgsurmhfwdqgfrñhqjlqhhulqj 47 The results can be a comparison between reference and tailor welded blanks version in terms of deformation, stress, intrusion depth or fatigue resistance for instance. Of course, for such a study, CAD data of the part or the sub assembly must be provided by the customer. Studies can be made using generic or customer speciÝc load cases and dimensioning criteria. ËÝÊÝ lvnuhprydodqgfkdudfwhul}dwlrq ArcelorMittal experts can study applications and then prepare a design study by risk removal and characterisation in a Ýrst step (see feasibility study sub-chapter). ÝÍÑñ{dpsohrilqñvhuylfhdqdo|vlvdqgrswlpl}dwlrqlqfdvhridiurqwdofudvk rqdudlopdghzlwkwdloruzhoghgeodqn ËÝËÝ hvljqvxssruw Specialised software used by ArcelorMittal allows to take into account at an early stage the characteristics of each application and the manufacturing constraints. Generally, several different solutions are proposed to the customer together with in-service behavior analysis (crash, stiffness, etc), stamping, weight and cost estimations of the different solutions proposed. ËÝÌÝ wdpslqjihdvlelolw|vwxg| SpeciÝc tools for numerical analysis developed by ArcelorMittal allow the customer to achieve an accurate analysis taking into account the desired safety margin in the Ýnal design of the part. Exclusive ArcelorMittal tools are based on: ı SpeciÝc forming limit curves for the welding areas of tailored welded blanks. ı SpeciÝc methodologies to analyse forming operations by Finite Element Model (FEM). ı SpeciÝc numerical tool to predict and compensate springback after stamping named Outifo (examples of results are shown in Fig. 49). Stamping feasibility studies rely on the Forming Limit Curves (FLC) of the welded area model developed by ArcelorMittal: ı The FLC of the weaker material is not sufÝcient to predict the behavior of the tailor welded blank during stamping. ı The recognized ArcelorMittal FLC model of the welded area has been presented in numerous congresses: - 40th Mechanical Working and Steel Processing. - ISS congress. - International Deep Drawing Group Congress. ı FLCs are further explained in chapter III. II - Customer service 46 ÝÍÒñodvvlfuroorxwrighvljqvwxg|riwdloruzhoghgeodqnvlq xdoskdvhÎÒÓðxowlskdvhÊÓÓÓ ÌÝhdvlelolw|vwxglhv 49 ÌÝÊÝ dvhuzhoglqjihdvlelolw|dqdo|vlv Experts from ArcelorMittal R&D can study tailor welded blanks and parts in order to provide data preparing the design study in an optimum design. These Ýrst studies are characterizations and risk removals. Input data Results ËÝÍÝ wkhuvshflfghvljqvwxglhviruwdloruzhoghgeodqnv With the CAD data of the Ýnished part and data of the stamping tools, the Tailored Blanks team can supply: ı Development of the minimum blank shape for stamping. ı Validation that welds are located in non-critical zones. ı Complete stamping simulation to validate blank shape and keep costly prototyping to a minimum. ı Quick feasibility analysis and risk removal study. ı Detailed analysis. ı Zones of thinning and thickening. ı Strain Ýelds. ı Minimum blank dimensions and optimized tailor welded blanks. ı Tailor welded blanks deÝnition after tailor welded blanks optimization. ËÝÎÝ dloruzhoghgeodqnvrswlpl}dwlrqirufrvwvdylqj Tailored Blanks performs Ýne tuning in a systematic way in order to: ı Optimize thickness and grades to decrease weight. ı Develop nesting solutions to reduce steel consumption. ı Optimize blank shape to a maximum of parts in a weld cycle. Deliverables: blank shape, gross and net weight, tailor welded blanks price, steel grades and thickness. liihuhqwremhfwlyhv ı Compare performance of tailor welded blanks with different steel grades. ı Obtain a Ýrst feasibility assessment of a part. ı Provide data for analysis of numerical stamping simulations of a tailor welded blanks part. Such data are usually completed by the Forming Limit Curve of the Laser welded area. The objective is an experimental evaluation of the formability of the laser welded seam; the acceptable value depends on the part severity. Such analysis is composed of different steps: ı Blanking quality analysis. ı Hardness measurement in the weld area. ı Weld geometry. ı 180¡ Bending test. ı Erichsen test. ı Tensile test. ı U-forming test. ÌÝËÝ odqnlqjtxdolw|dqdo|vlv The objective is to judge if the cutting edge quality of the sub-blanks is acceptable for laser welding and deÝne the blanking procedure and cutting parameters to obtain sufÝcient cutting quality (see Fig. 50). ÝÎÓñrrewdlqvxiflhqwfxwwlqjtxdolw| Cross sectional view Parameter measurement ZD ZL ZA P Definition ZD (%) Rounded height ZL (%) Sheared height ZA (%) Breaking height P (mm) Breaking depth II - Customer service 48 ÌÝÌÝ dugqhvvphdvxuhphqwvlqwkhzhogduhd The objective is to determine the hardness proÝle across the seam in order to estimate the formability (see Fig. 51 and Fig. 52). In the laser welding process the heat is very localized. As a consequence, the heat affected zone is thin and the quenching speed very high. The presence of steel grades with carbon and alloying elements gives martensitic microstructure with a very high hardness. However, the dilution of the molten area, by another metal for instance, results in a less quenched metallic structure with reduced hardness and better formability during assembly (orange curve). ÌÝÎÝ ÊÑÓĂehqglqjwhvwõÏppgldphwhuö In order to analyse the bending behavior, the laser seam is bent at 180¡ at the maximum and it is determined whether and at which angle it cracks. Obviously a real part is not subjected to a 180¡ bending. The test can thus be considered as conservative. 51 ÝÎÌñ{dpsohriehqglqjwhvw ÝÎÊñdugqhvvsurohdfurvvwkhzhoglq Hardness (Hv) 500 400 300 200 100 Distance from weld seam 0 -3 -2 -1 0 1 3 2 Homogenous welding Effect of the dillution of the carbon content ÌÝÍÝ hogjhrphwu| The objective is to measure the geometry of the seam to compare it with the customer speciÝcations and verify if there is a risk of stress concentration. It may result in an optimization of the process parameters. ÌÝÏÝ ulfkvhqwhvw The tailor welded blanks are blocked and deformed according to an equibiaxial strain path. A comparison between the height obtained with the base metal and the tailor welded blanks is made. Such a test gives an idea of the formability of the weld compared to the base metal. Generally a requirement of Erichsen ratio (see Fig. 54) higher than 70% is recommended. It may be discussed according to customer speciÝcations and part difÝculty. It is important to point out that this requirement alone has its limits when we consider the formability of welds in ductile UHSS. The weld may well present a sufÝcient elongation for a given application, even though the 70% Erichsen criteria is not met due to the excellent elongation of the base metal. In such a case another test has to be preferred and a deeper study of the formability requirements of the part is recommended. ÝÎÍñulfkvhqwhvw Height of the stamped specimen 27 +/- 0.05 BM LW ÝÎËñ|slfdoplfurvwuxfwxuhlqwkhzhogduhdri Cross sectional view Parameter measurement Í 20 +/- 0.05 LE 33 +/- 0.1 Dqhbgrdmsdrs a`rdlds`k Dqhbgrdmsdrs k`rdqvdkcdcak`mj LE % Erichsen = LS ZF LT = 0,25 LE + 2xLM + L S Height of the stamped weld Height of the stamped base metal x 100 II - Customer service 50 ÍÝhvwlqj ÌÝÐÝ hqvlohwhvwv Tensile tests on laser seams are performed in the longitudinal and transverse directions. Such measurements of the Ultimate Tensile Strength (UTS) and Elongation (E%) give an idea of the formability properties in the respective deformation directions (see Fig. 55). ÝÎÎñ{dpsohrifrpsdulvrqehwzhhqedvhpdwhuldodqgzhog lqorqjlwxglqdodqgwudqvyhuvhgluhfwlrq UTS E% Longitudinal Transverse Longitudinal Transverse Steel grade A and B Weld ÌÝÑÝ ñiruplqjwhvw The objective is to analyse the stamping behavior of a U-shape (representative of the local shape of B-pillars or rails). For this test, the U-shape is made by stamping. The sides of the blank are blocked under blank holders. The punch goes up until cracks appear on Þange along the weld seam. The U-shape is stamped and it is analysed at which depth cracks appear. Stamping parameters can be adjusted to be as representative as possible of an industrial part. ÝÎÏñ{dpsohriñiruplqjwhvw 53 Nesting is the process of maximising the number of blanks that can be cut from a steel coil. It is basically a geometrical exercise but some other aspects must be respected to optimize the nesting: ı Rolling direction imposed by the formability requirements of the part or its in-service behavior. ı Tool constraints such as feasibility of the press geometry, evacuation of the blanks and the scrap, and the cutting quality of the edges to be welded. ı Coil width feasibility and economics. ı Tailor welded blanks production process (number of parts per weld cycle, edge preparation, linear/non-linear welding). The blanks can be divided into two families depending on their shape (see Fig. 57): Êñlpsohvkdshgeodqnvzklfkduhuhfwdqjxoduruwudsh}rlgdoÝ These blanks can be cut on a shear line and require no part speciÝc investments. This process is well suited for low and medium volume vehicles. Ëñrpsoh{eodqnvruvkdshgeodqnvÝ Blanking is made with tools on press line. The tools are dedicated to a speciÝc part. For this reason, this process is efÝcient for high volume series where the investment is low per vehicle. ÝÎÐñrjlfdofkduwvkrzlqjwkheodqnlqjsurfhvvdffruglqjwryhklfohyroxph dqgeodqnvkdshfrpsoh{lw| Complex shaped blanks Simple shaped blanks High volume car > 400,000 vehicles/year Tool blanking Tool blanking for increased productivity Low volume car < 50,000 vehicles/year High tool cost per part, try to review the design of the tailor welded blanks Shear blanking khdelolw|wrsurgxfheodqnve|wkhprvwfrvwñhiihfwlyhsurfhvvzloodozd|veh ghwhuplqhgehiruhwkheodqnlqjwrrovduhrughuhg Some cases are worth being dealt with in more detail: ı rzyroxphyhklfohvzlwkfrpsoh{vkdshgeodqnvÝ The part cost is signiÝcanly increased if a tool investment is required. Therefore it is often better to review the design of the tailor welded blank and replace the complex shaped blanks by simple shaped blanks. As a consequence of this there will be a gross weight increase of the tailor welded blank and some more engineering scrap will be generated during stamping. But as long as the cost of the increased gross weight is lower than the tool cost per part, this approach is still advantageous. II - Customer service 52 If the volume is only about 10,000 vehicles per year, laser cutting may be an efÝcient alternative. This gives us the possibility to reduce engineering scrap and to avoid tool investments: ı ljkyroxphyhklfohvzlwkvlpsohvkdshgeodqnvÝ Even though it is possible to blank on a shearing line, it may be advantageous to use tools as two or even more parts can be cut in one stroke. Tools mean investments and scrap between the blanks in the cutting process but the costs generated by these aspects are compensated by a signiÝcantly increased productivity. Blanking tools have the beneÝt of a stable and repeatable process with minimised geometrical tolerances. The cut edges will be of good quality. This is important in particular for the edge that has to be welded, for which special attention has to be taken. ÝÎÑñ{dpsohriqhvwlqjirudorzyroxphfdufrpsduhgwrdkljkyroxphfdu rzyroxphfdu + No investment needed - More scrap - Less productivity wdpshgsduw ljkyroxphfdu + Investment per part is low thanks to the high volume + Minimised scrap + High productivity as many blanks can be cut in one stroke ÍÝÊÝ swlpl}hgpdwhuldoxwlol}dwlrq Material utilization rates are affected by product design, blank nesting and drawing die developments. For parts requiring a drawing die operation, material utilization rates as high as 80% and as low as 30% are common. This can be estimated by the product development in the early process and design stages. Parts that are more rectangular in outline normally have higher utilization rates. In general, rectangular or trapezoidal shaped parts lend themselves to signiÝcantly improved nesting efÝciencies. ÍÝËÝ dwhuldovdylqjvsrwhqwldoriluuhjxoduvkdshgeodqnv Parts which are rectangular or trapezoidal blank shapes (such as Þoor panels) will have a higher yield than parts that require irregular shaped blanks. For example, some elements of the body side inner have such irregular shapes that the blanks cannot be nested efÝciently. Very low yield rates such as 30% for monolithic parts have been seen in the industry for these parts. This means that 70% of the purchased sheet steel ends up as engineering scrap. ÝÎÒñrg|vlghlqqhuzlwkqhvwlqjriwkhgliihuhqwsduwv 55 1.0 mm 2.0 mm 1.5 mm 2.0 mm This can be optimised by using a tailor welded blank. Splitting the blank into pieces gives a very effective nesting. Later on, using the tailored blanks technology, the welding will produce the desired irregular shaped blank (see Fig. 59). Cost savings and yield rate will be improved considerably. ÍÝÌÝ hvljqjxlgholqhviruqhvwlqj The design of the blanks is always strongly related to the welding process. Big or small sizes of the blanks need different space on the welding line. Sometimes a small reduction of the size of the blank can result in a big gain on total welding costs as the production plant can weld one more blank in the welding cycle. In that case the productivity increases and the costs for welded parts are less expensive. Therefore, a close cooperation between the development engineer and the customer is recommended. Furthermore it is also recommended to locate the weld in low stress areas in order to avoid stamping problems. In general the weld does not move too far perpendicularly to the stamping direction, especially in the case of a big thickness difference between the two blanks. This important fact should also be considered when the design and the nesting are deÝned. II - Customer service 54 ÎÝhfkqlfdovxssruwirulqgxvwuldol}dwlrqdqgvhulhv surgxfwlrq ÝÏÊñhulfdwlrqrivwudlqohyhoridvsrwñzhogrqdsdwfkñw|shzhoghgeodqn 57 Forming limit True values Major strain Safety strain 0.317 0.330 0.344 0.357 0.371 0.384 0.397 0.411 0.424 0.438 0.451 0.465 0.478 Tailored Blanks has developed a whole range of services offering speciÝc solutions for these products. This support is based on the utilization of tools speciÝcally developed to analyze and optimize the forming behavior of welded blanks. These actions are aimed at ensuring reliable production at lowest cost and at achieving zero defects from the outset of part series production. 0.8 0.7 0.6 FLC FB450 0.5 0.4 Safety margin ÝÏÓñursrvdoiruwkhlqyroyhphqwridloruhgodqnvdvriwkhxsvwuhdpyhklfoh ghvljqskdvhâlqrughuwrpd{lpl}hjdlqv 0.3 0.2 5 years + 2-5 years < 18 months Current vehicle 0.1 Weld spot Minor strain Step 1 Advanced engineering Step 2 Vehicle concept and design Step 3 Tool development and prototyping 0 -0.4 Step 4 Production -0.3 -0.2 -0.1 0 0.1 0.2 0.3 0.4 ÝÏËñhulfdwlrqrizhogolqhvwudlqohyholqdodvhuñzhoghgeodqn Simulation without LWB FLC for material A1 and B1 Fracture on real part > Innovative solutions > Development planning > Introduction of new steel products and technologies > Stamping > Monitoring of working groups for the industrialization of new solutions > Forming and joinin g assistance: - Stamping - Simulation - Tools design - Tools optimization - etc. Major strain > Quality management 0.5 > Production assistance 0.4 > Cost reduction 0.3 A1 B1 0.2 > Parts and process design support Part feasibility seams OK 0.1 0.0 Thanks to its cooperation with tool manufacturers, welded blank production sites and stampers, ArcelorMittal is in a position to take part in the industrialization of these parts. This work, which supplements the work carried out in the design phase, will reduce tool adjustment times and tool manufacturing costs, as well as optimize the tool integration cost and time at the series production site. Possible actions during this phase are for instance: ı Delivery of prototype drawings. ı Transfer of ArcelorMittal welded blank know-how to tool manufacturers Ï simulations and tool design. ı Supply of data needed to perform stamping simulations - FLCs of the various materials and weld areas, tensile curves, etc. (further explained in chapter III). ı Support for stamping sequence design (Fig. 61 and Fig. 62). ı Performance of forming simulations (if required). ı Support for interpretation of stamping simulations. ı Stamping analysis by strain measurement with a type-approved device (Fig. 61 and Fig. 62). ı Acceptance and validation of tooling. ı As required, optimization of the blank shape and/or weld position in case difÝculties arise with tool adjustment. 0.1 -0.3 -0.2 -0.1 0.0 0.1 0.2 0.3 Minor strain LWB FLC allows to predict rupture by stamping simulation Simulation with LWB FLC for material A1 and B1 Major strain 0.30 0.25 0.20 A1 B1 0.15 0.10 0.05 0.00 0.05 -0.10 -0.05 -0.00 0.05 0.10 0.15 0.20 0.25 Minor strain Rupture prediction II - Customer service 56 ÏÝqgxvwuldol}dwlrqdqgvhulhvsurgxfwlrq Strain levels must be veriÝed at the end of tool adjustment, as they are crucial to ensure optimum tool productivity. This requires the use of a speciÝc tool (welded blank FLC) and detailed analysis of the behavior of the materials in the weld area. Analysis is required to ensure the quality of mass-produced parts. This assistance, as well as cost reduction proposals, continuous quality improvements and any product modiÝcations, is provided throughout series production. The project manager based at the plant to which the part has been assigned takes over from the Tailored Blanks development engineer, who works with the customer plant in order to Ýne tune the technical speciÝcations and packaging of the welded blanks. The human and technical resources (order of speciÝc cutting tools, welding tools, etc.) needed to ensure the proper start-up of series production are deÝned in conjunction with the Client Technical Support and the quality and logistics managers of the Tailored Blanks plant. Delivery of initial compliant samples validates the launch of series production. ÝÏÌñwdqgdugruvshflfphwdosdoohw ÐÝrvwdvvhvvphqwprghoriqlvkhgsduwv 59 ÐÝÊÝ khvhuylfhriihu Together with industrial partners active in the automotive industry, ArcelorMittal has developed a model for estimating the total cost of production of a part in order to support the choice between different technical solutions as early as in the design stage. The cost structure will of course vary from one customer to another but as the model aims at comparing different solutions rather than determining nominal costs, the differences between the modelÔs and the customerÔs real cost structure will be eliminated to a large extent. The model, which allows an evaluation of the whole production process, is validated in discussions with customers and on the basis of numerous examples, made for both tailor welded blanks and other types of solutions. Tailored Blanks has drawn up a catalogue of generic parts based upon several years of experience of working with all the major OEMs and subcontractors in Europe. These parts have been designed to give the same technical performance as the monolithic post-assembled alternative. Once the design is validated, the production process of the tailor welded blanks is optimized according to the number of parts to be produced. Finally the costs are estimated and compared to those of a conventional monolithic post-assembled solution. Tailored Blanks also performs cost assessments on real customer projects in order to determine whether an application is economically viable as a tailor welded blank or not. Data needed from the customer: CAD Ýle of part and potential reinforcements to be integrated with the tailor welded blank. ÝÏÍñrvwgulyhuvfrqvlghuhglqwkhprghoriufhorulwwdoÝwkdvwrehqrwhg wkdwqrghyhorsphqwdqgsurwrw|slqjfrvwvduhlqfoxghg lqwklvprghoÝrzhyhuâwkhvhvwhsvduhjhqhudoo|ohvvh{shqvlyhiruwdloruzhoghg eodqnvdvwkhuhduhihzhusduwvwrehghvljqhgÝ Materials Engaged material ÏÝÊÝ xdolw|prqlwrulqj The ArcelorMittal Customer Technical Support engineer (CTS) at the customer plant works closely with the quality manager at the Tailored Blanks plant to ensure quality monitoring. They are supported by ArcelorMittalÔs stamping and welding specialists. ÏÝËÝ doxhfuhdwlrq The CTS proposes studies aimed at reducing cost, weight and part forming operations. These studies are carried out by a multi-disciplinary team and, if appropriate, with the support of R&D and ArcelorMittal Auto product processing experts. ÏÝÌÝ rjlvwlfvfkdlq The logistics manager at the Tailored Blanks plant and the ArcelorMittal Auto sales team ensure day-to-day service which is measured by service ratings and safety inventories. Scraps > Including tails of coils Rejects Scrap and rejects recycling Matic addition Cutting Stamping Machines > Depreciation > Maintenance > Consumables (including energy) > Surface area used Assembly Logistics Machines > Depreciation > Maintenance > Consumables (including energy) > Surface area used Machines > Depreciation > Maintenance > Consumables (including energy) > Surface area used Tools > Depreciation > Maintenance Tools > Depreciation > Maintenance Tools > Depreciation > Maintenance Labour > Operators > Supervisors > Absenteeism rate Labour > Operators > Supervisors > Absenteeism rate Labour > Operators > Supervisors > Absenteeism rate Process > Capacity utilization > Speed > Added value loss due to rejects Volume Process > Capacity utilization > Speed > Added value loss due to rejects Cost of capital Taxes Taken into account in ArcelorMittal Auto cost approach Process > Capacity utilization > Speed > Added value loss due to rejects Specific development cost (engineering studies, prototyping, fine tuning time of tools) Inventory costs > Surface area > Inventory value > Consignment inventory Handling > Labour > Packaging > Pallets (delivery and intermediate inventories) Flow management cost > References management > Invoicing > Quality control II - Customer service 58 Steps: Compare the designs (monolithic vs tailor welded blanks) technically to validate that the performance is equal, optimize the tailor welded blanks solution from a production point of view and determine the sales price. Finally the costs are compared for the respective processes by the customer: For the post assembled monolithic case (composed of 2 different parts): ıCoils cost + coils storage + 2 x blanking + 2 x stamping + 1 x assembly. For the tailor welded blanks case: ıTailor welded blanks cost + 1 x stamping. ÐÝËÝ hwdlohgghvfulswlrqriwkhfrvwdvvhvvphqwprgho This cost assessment model focuses on a comparison of the secondary processing costs of the various material solutions. It takes into account the full range of cost structure elements of a Ýnished part or sub-assembly to be mounted on an assembly line at the premises of a car manufacturer or sub-contractor. These elements are divided into: ıFixed costs: capacity equipment, speciÝc tools, maintenance, buildings, etc. ı Variable costs: labour, materials, consumables, etc. The approach taken by this model is based on a comprehensive and chronological description of the manufacturing sequence used to form and join the various elements making up the part or sub-assembly from the tailor welded blanks supplied (or from coils in the case of a monolithic part). Each stage of the manufacturing sequence or forming (cutting, stamping, roll forming, etc.) and joining (welding, bonding, crimping, etc.) processes is thus covered by a detailed description of operating costs integrating all cost elements mentioned above, which constitutes the input data for the assessment model. The accuracy of the input data determines the relevance of the Ýnal assessment result and thus the cost of the solution. Assessment model input data: 4 data input categories can be distinguished: ÊñdwhuldovñgdwdghvfulelqjÞ ı Dimensions of the used blank or of the coil, in the case of the monolithic solution. ı Rate of material engaged, resulting from nesting optimization. ı Ex-works cost of the product and cost of recycling generated scrap. Ëñdqxidfwxulqjsurfhvvñgdwdvshflfwrhdfkpdqxidfwxulqjsurfhvvâ fryhulqjlqirupdwlrquhodwlqjwrÞ ı Capital investment costs (machines and tools). ı Depreciation of capital investments. ı Cost of consumables, including cost of energy. ı Cost of labour. ı Production speed of lines at their productivity level. ı Reject rate. ÌñrjlvwlfvñlqsxwgdwdlqfoxglqjÞ ı Cost of storage. ı Cost of packaging. 61 ÍñlqdqfldofrvwñlqsxwgdwdfryhulqjÞ ı Return on capital employed. ı Business-related taxes, etc. All this data is entered into the model at each stage of the manufacturing process, generating an assessment of the cost of the Ýnished part for a given volume of parts to be produced over a given period of time. This approximation of the overall cost makes it possible to quantify the economic advantages of the proposed Tailor Blank solution by comparison with a reference monolithic solution. Furthermore, the model provides a detailed description of the cost structure to support the technical arguments, and it can be used to identify additional optimization of the proposed solution. II - Customer service 60
© Copyright 2024