Session: 03-06-01: Advanced Material Forming – Mechanism, Characterization, Novel Processes, and Control

Paper Number: 145610

145610 - Influence of Tool Diameter in Single Point Incremental Forming of Polymeric Materials 

Single point incremental forming (SPIF) is a versatile and cost-effective manufacturing process used extensively in prototyping and low-batch engineering components. It involves the precise movement of a tool over a thin sheet of material, incrementally deforming it into the desired shape. SPIF offers several advantages, including flexibility in producing complex geometries without the need for specialized tooling, reduced material waste, and the ability to manufacture small batches economically. Additionally, SPIF enables rapid prototyping and customization, making it ideal for various applications in industries such as automotive, aerospace, and consumer goods.

The process parameters in SPIF significantly influence the quality and formability of the formed component. Factors such as spindle speed, feed rate, toolpath geometry, and tool dimensions impact material deformation, surface finish, and dimensional accuracy. Optimal parameter selection is critical to avoid defects like springback, wrinkling, tearing, or excessive surface degradation, particularly in polymers. Adjusting process parameters enables SPIF to accommodate a wide range of materials and geometries, making it a versatile manufacturing solution for various industries.

One of the critical parameters affecting the formability of polymers in SPIF is the tool geometry. Tool diameter in SPIF directly affects the achievable feature size and geometrical accuracy of formed parts. A larger tool diameter allows for faster material deformation due to increased contact area, enabling the formation of larger features with reduced forming time. However, larger tool diameters may induce excessive material stretching, leading to thinning and necking. It also comes at the expense of intricate detail and sharp curvature, limiting the deformation of formed parts. Conversely, a smaller tool diameter provides finer detail and higher geometrical accuracy but demands longer forming times and possibly increased forming forces. It may also result in localized heating due to increased friction, potentially causing thermal degradation and reduced formability. Therefore, the choice of tool diameter must strike a balance between forming efficiency and geometrical precision. For polymers, where material softening and viscoelastic behavior play significant roles, selecting an optimal tool diameter becomes crucial.

Additionally, step size, defined as the incremental advancement of the tool along the forming path, profoundly influences the surface finish and mechanical properties of formed polymer components. A smaller step size allows for finer control over material deformation, minimizing surface roughness and enhancing geometrical accuracy. Moreover, reducing the step size mitigates the risk of material springback, ensuring that formed parts maintain their intended shape after unloading. Furthermore, finer steps enable the accommodation of complex geometries with smoother transitions between forming stages, facilitating the production of intricate polymer components with superior surface quality. However, decreasing the step size increases forming time and energy consumption, impacting process efficiency and productivity. Thus, selecting an appropriate step size involves a trade-off between surface finish, forming efficiency, and mechanical performance, necessitating careful consideration in SPIF of polymers.

The work presented herein investigates the effect of process parameters, namely tool diameter and step size on the formability of polymeric materials. The material investigated in this study is polycarbonate. Several experiments will take place to include a full factorial design of experiments. Tool diameters will vary between 8 mm and 20 mm and step sizes will vary between 0.5 mm and 2.0 mm. The feed rate and wall angle will remain constant throughout the experiments.

To evaluate the formed components, various measurements will take place, such as thickness distribution and profile evaluation. The outcomes of the work presented herein are expected to contribute to understanding the impact of process parameters on SPIF of polycarbonate material, which can be expanded to different polymeric materials.

Presenting Author: Ihab Ragai Penn State University, Erie

Presenting Author Biography: Dr. Ihab Ragai is a professor at Penn State University, The Behrend College. His research area focuses on the advances in manufacturing processes and systems.

Authors:

Rachel Diefenderfer Penn State University, Erie
Chad Vanderwiel Penn State University, Erie
Ihab Ragai Penn State University, Erie
Mark Rubeo Penn State University, Erie
Natalie Barkley Penn State university, Erie
Conner Best Penn State University, Erie
Kristofer Laser Penn State University, Erie