TECHNICAL FIELD

The present disclosure relates to vibration-assisted free form fabrication, for example, of metal sheet.

BACKGROUND

Sheet metal forming is generally performed using a stamping process in which opposing tools having a desired geometry press the sheet metal into a desired shape. Stamping may be a very efficient and cost-effective process for high volume manufacturing. However, for low volume manufacturing or prototyping, the cost and energy required to produce stamping tools for each component design iteration may be prohibitively high. A sheet metal forming process that can produce cost-efficient prototypes in a timely manner would be highly beneficial.

SUMMARY

In at least one embodiment, a system for forming a workpiece is provided. The system may include a fixture assembly for receiving a workpiece having opposing first and second surfaces, first and second tools, and a vibration source configured to vibrate the first tool. The first and second tools may be configured to move along first and second predetermined paths of motion as the first tool is vibrated by the vibration source and to exert force on the first and second surfaces to form the workpiece.

In one embodiment, the first and second tools are configured to move along the first and second predetermined paths and to exert force on the first and second surfaces to form the workpiece without penetrating the first and second surfaces. The vibration source may be configured to vibrate the first tool at a frequency of 5 to 70 kHz. The vibration source may be configured to vibrate the first tool at an amplitude of 1 to 50 μm.

In one embodiment, the vibration source may be configured to vibrate the first tool in a direction substantially parallel to the first surface. In another embodiment, the vibration source may be configured to vibrate the first tool in a direction substantially perpendicular to the first surface. The system may include a manipulator including a tool holder configured to hold the first tool, wherein the vibration source includes a transducer that is attached to or integral with the tool holder.

The first and second predetermined paths may be complimentary such that pressure is applied to the first and second surfaces in a local area of the workpiece. In one embodiment, the vibration source is a first vibration source and the system further comprises a second vibration source configured to vibrate the second tool. The first and second vibration sources may be configured to vibrate the first and second tools at the same frequency.

In at least one embodiment, a system is provided including a fixture for holding a workpiece, a first tool, and a vibration source configured to vibrate the first tool. The first tool may be configured to move along a first surface of the workpiece and to exert a force on the workpiece against a second tool as the first tool is vibrated to form the workpiece.

The system may also include a first manipulator configured to move the first tool along multiple axes along the first surface of the workpiece and a second manipulator configured to move the second tool along multiple axes along a second surface of the workpiece. The second tool may include a mold having a surface contour. The vibration source may be configured to vibrate the first tool at a frequency of 5 to 70 kHz and at an amplitude of 1 to 50 μm. The system may include a manipulator including a tool holder configured to hold the first tool, wherein the vibration source includes a transducer that is attached to or integral with the tool holder.

In at least one embodiment, a method of forming a workpiece including opposing first and second surfaces is provided. The method may include positioning first and second tools, vibrating the first tool using a vibration source, and moving the vibrating first tool and the second tool along first and second forming paths along multiple axes such that the first and second tools contact the first and second surfaces to form the workpiece.

The first tool may be held by a tool holder and may be vibrated by a transducer attached to or integral with the tool holder. The first tool may be vibrated at a frequency of at least 1 kHz. The first and second forming paths may be complimentary and pressure may be applied to the first and second surfaces in a local area of the workpiece. The method may include vibrating the first tool at a frequency of 5 to 70 kHz to heat a local area of the workpiece to a temperature of 20 to 70% of a melting temperature of the workpiece.

