Origins and Evolution
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Conception
Incremental Sheet Forming was first proposed in the 1960s to address manufacturing requirements for complex sheet metal parts through deformations along a specified 3D toolpath. Key characteristics highlighted by inventors, such as Edward Leszak (1967), included that the process should:
Be carried out by an inexpensive and easily sourced (likely hemispherical) tool.
Strictly involve local deformations requiring a low forming force.
Have no need for dies, forms or mandrels.
Be capable of forming complex shapes that other processes are unable to form, or which are expensive to produce.
Early Development
ISF enables process automation for manufacturing prototypes and customised products, and ISF process development can be easily customised. The key steps of the generalised process include:
Product design: a CAD model of a desired geometry is produced.
Toolpath planning: a toolpath is generated from the CAD model.
Preparation: the workpiece (sheet metal or composite) is clamped into place.
CNC manufacturing: the desired geometry is produced through a series of localised, incremental deformations of the workpiece material.
Although the original patent was filed in the 1960s, ISF began to gain research attention following the popularisation of CNC technology in the 1990s. Thirty years of research and development have resulted in various process variants, from single-point, two-point and double-sided incremental forming to advanced processes such as laser-assisted, electricity-assisted, ultrasonic-vibration-assisted, and friction stir ISF.
A recent large-scale project led by Ford Motor Co and supported by the US Department of Energy estimated that the adoption of double-sided incremental forming could reduce energy consumption and material scrap by 70% and reduce low-volume production costs by up to 90%.
A 2020 study predicted that, in the US car industry, the implementation of ISF could lead to potential mean [energy and cost] savings of around 100 TJprimary and 60 million U.S. dollars per year by 2030.
Looking Forward…
ISF has process limitations which remain to be addressed.
The range of sheet materials which can be used in the process is still limited, and research is still being conducted to develop new methods to improve the formability of materials better-suited for a wider range of industrial applications.
Forming quality is difficult to effectively control and evaluate, so tolerances still need to be tightened to meet industry requirements.
Other issues relate to thinning and fracture, geometric deviation, and surface roughness.
Just like other early-stage innovations, today's developments are only a stepping stone to a promising future.
