State of the art

“Smart tools” or also called “intelligent tools” for sheet metal forming become quite popular in the last few years. Many die producers, sheet metal part producers and large OEM companies are looking for smart solutions and they are trying to implement it in the tool. However, currently there are just a few tools on the market able to consider all costumer requirements and can be found in real process production. One of them is “electronic shimming” marketed by the company Hydraulico. This method is patented (Patent No.: US 6,691,545 B1) and can be found in production of stainless steel sinks for the kitchen. In general electronic shimming plate can be integrated in special sheet metal tools between blank-holder and press die cushion. The shimming plate than controls and optimizes blank-holder force during the deep drawing process.

In developmental phase there are a lot of “intelligent tools” however not available on the market yet. Among them is FP7 European R&D project named “Self learning Sheet Metal Forming System” (acronym: LearnFORM; NMP2-SL-2009-228346). In the project LearnFORM participates Gorenje as a project partner. The final result of this project is an intelligent self-learning tool with integrated sensors, actuators and controls for controlling deep drawing process in order to minimize scrap and improve quality of deep drawn sheet metal parts.

In SmartMForming project partners will concentrate mainly on bending and piercing operations, however we will focus also to sheet metal forming analyses. We will consider only high- strength steel sheet material. These materials are increasingly used because of their high-strength properties and other advantages. We are capable to achieve higher values of strength, but subsequently we reduce formability and increase sensitivity of spring-back effect. It is well known that high-strength steels usually behave as normal steel but the processes defects (failures) are here even more exposed. Therefore it is expected that the results of the project would be interested also for other materials.

In the area of servo systems in sheet metal forming when there is a necessity for precision control over a press process (forging, stamping, deep drawing etc.), a mechanical servo press machine is proven to be the best solution. The main advantage of these presses over the conventional presses (crank press, screw press, hydraulic press etc.) are: high flexibility for control of motion without decrease in production speeds (programmable stroke and velocity), accurate control by real-time feedback of ram position (sensors), increased energy efficiency and improved business management.

“SmartMforming” as an innovative R&D project idea differs from those mentioned above by using servo systems and control the status of the tool. Servo systems in SmartMforming tool will regulate the speed of the forming, stroke of the punches and two or even more forming operations will be merged into one operation.