SmartMForming

About

Sheet metal forming is one of the most important processes in modern industry production. Today many component parts from different technological fields like aerospace, airline, automotive and household appliances industry are made out of sheet metal material. Sheet metal forming processes are very complicated processes and require very careful planning. Over the last few years this has become an even bigger problem because of more complex drawn-products, higher demands on product quality and due to development of new higher and high-strength materials. Today in the automotive industry more than 35% sheet steel parts are made of higher and high-strength steels and this number is still increasing [1].

Main advantage of using higher and high-strength materials is in higher values of strength, which consequently lead to higher strength of the product. That means that the same product can be made with lower thickness, but consequently it will decrease weight of the end product. But introduction of new higher and high-strength steels into the industry presents new challenges for toolmaking companies. When we use high-strength steels we are facing with complex problems, like spring-back. Many authors have the opinion that spring-back is one of the most difficult problems during the sheet-metal production. Spring-back in sheet-metal forming can be described as the change in sheet-metal’s shape compared to shapes of the tools after the forming process [2]. We distinct following types of spring-back when considering the geometry of a product: angular change, sidewall curl and twist [3].

On the basis of the above presented demands have toolmakers today a lot of challenges when designing sheet metal tools and manufacture sheet metal products with high quality. Over the last years it is becoming more and more important the stability and optimization of the process. Suppliers of the tools are facing with pressure for lowering the cost of products and increasing productivity, therefore we are looking for every possibility, which can reduce costs. Optimization and process automation are solutions that can greatly influence on the lowering of product costs and increasing the productivity of manufacturing.

Nowadays, there are some new methods to optimize production of sheet metal forming. One of the often used methods nowadays is hot-forming, but the cost of setting up such production process and manufacturing costs are enormous comparing to the standard cold forming methods. In most cases hot-forming can be suitable only for large companies while smaller companies like SME`s keep asking for more affordable solutions. In project SmartMForming we want to develop the method and solution of “smart” forming of high-strength steels using servo systems. Servo systems are already used in the sheet metal forming process but they are mostly integrated into the presses (so called servo press) and there are a lot of advantages using of servo presses. Our idea in this project is that servo systems will be part of the sheet metal tool and therefore their advantages can be used in all manufacturing environments (mechanical and hydraulic presses). The main advantage of this concept will be that there is no need for investing into additional equipment or machines (servo-presses). With servo systems in the tool there will be also other advantages such as shortening technological time, increasing product quality, reduction costs of the tool during the life time cycle and the most important, higher capability of manufacturing more complex products.

Servo systems in “smart tools” will regulate the speed of the forming, stroke of the punches and most important will be merging the two or more operations into one operation. For example; in some cases bending and calibration operations can be merged by using servo systems. Consequently the tool will be shorter, the weight of tool will be lower and also the cost will be lower. One of the main advantages of using servo systems in “smart tools” is also flexibility, because with using servo systems it is possible to influence on the product quality and spring-back effect. The tool will be less dependent on variation of sheet material properties and therefore in the production will be less low quality products and scraps. “Smart tool” should also have integrated sensors for ON-LINE controlling of the process parameters, the tool and product quality. With ON-LINE controlling it will be possible to monitor “health” status of the sheet metal forming tool, to prevent damages of the tool and to optimize sheet metal forming processes.

[1] www.france-metallurgie.com, boronextrication, Volvo V70 Body Structure [2] Y. Tongxi, Plasticity Bending Theory and Application, Beijing Science Press, 1992. [3] Deželak, M.: Finite element method combined with machine learning for spring-back prediction, 6th International Conference and Exhibition on Design and Production of MACHINES and DIES/MOLDS, Turkey, 2011.