Orbital Forming of Flange Parts under Uncertainty

Abstract

Uncertainty in the properties of semi-finished parts can cause fluctuations in the product properties, especially if they have a strong effect on the process and cannot be compensated by process adjustments. Incremental forming processes have the potential to react to changing conditions by adapting the tool movement during the process. This paper analyzes the feasibility of controlling material flow in an orbital forming process in order to selectively fill those geometric elements which were specified with narrow tolerances by the designer. The effect of different process parameters on the mushroom effect and the degree of mold filling are analyzed by FEM simulations and experiments. In order to realize online monitoring and control, an estimation model is introduced, which maps signals from sensors and the process control to the geometric target values.

Our Specific Approach on Mastering Uncertainty

“…One prominent case of special processes is orbital forming. During orbital forming a tool with small contact areas rolls over the workpiece and progressively shapes it [8]. Forming forces are reduced drastically in orbital forming presses, the translatory ram motion is extended by an additional rotary motion.…”

Methods and Technologies for Mastering Uncertainty

“…At the same time, the lower rolling friction between the workpiece and the punch enables a radial material flow, also known as the mushroom effect [187]. This effect can be controlled by varying the tool angle, the feed rate and the rotational speed in order to counteract fluctuations in the semi-finished product [58]. The forming machine we use is a 3D Servo Press (as described in Sect.…”

“…During the forming process a perforation with a nominal diameter of 7.5 mm is added to the centre of the bevel gear. The influence of the parameters tool angle, infeed speed and form of motion on the resulting material flow is investigated and variables for process control are identified [58]. At the same time, variations in the angle at a constant tool angle lead to a deviation of the height profile.…”

“…3.6.3. By having the complexity of the actuators in the machine, new processes can easily be developed [58,160], and passive standard processes, such as deep drawing, can be enhanced [51].…”

“…The latter depends strongly on the material properties of the current workpiece. By measuring the geometry after springback while still clamped, the bending operation can be adjusted and iterated to the desired geometry, as we demonstrated in [58].…”