Delft University of Technology

Delft Centre for Mechatronics and Microsystems

IntroductionMicro-gripping is an essential topic within the field of micro-assembly, i.e. the assembly of small and sometimes fragile parts into micro-products.

In industry the most commonly used principles for gripping are vacuum or mechanical (force or form closed) gripping. These principles have limitations for instance in terms of the flexibility and the suitability for handling the small parts that companies expect to see in the near future. Scientific research has mainly focused on exploring and modelling fundamentals of grip principles, and demonstrated this in prototypes. There is a lack of systematic, quantified and applicable knowledge on micro-gripping for industrial use.ObjectiveThe main research objective is to increase the portfolio of solutions for micro-gripping in industrial assembly application. This includes systematic and quantified research on grip principles, considering the specific demands from the micro-domain.

ApproachThe figure illustrates the followed approach.

Industrial studies have shown the following issues. The complexity of micro-assembly operations is often on such a level that current micro-gripping technologies and research have difficulties to match the application requirements.

The current micro-gripping solutions and the intention to re-engineer the conventional mechanisms will approach their limitations. The need for broadening the technology portfolio is clearly indicated.

Results• Systematic understanding on the process

windows of a variety of micro-grip principles

• Liquid Solidification gripping technology for operating mini- to micro-sized components made from diverse materials, and with complicate geometries.

• Fully functional industrial handling system with high flexibility, fast grip-release cycle down to 1 second.

Liquid Solidification gripping has been tackled in the research. A series of prototypes of liquid solidification based grippers were built and tested. The experiments showed that fairly great gripping force can be built up in a small contact area; the gripper can adapt to a variety of parts shapes; small parts made form different materials can be successfully picked up and released.

Defeng Lang

Delft University of Technology

Precision Manufacturing and Assembly

Mekelweg 2 NL-2628 CD Delft

Tel: +31 15 2781814 Fax: +31 15 2783910

Email: d.lang@tudelft.nl

Technology for micro-

gripping

Demonstration of micro-grip-module

Experimental research and evaluation on models

Industrial application related criteria analysis

Investigation and modelling micro-grip

principles

Industrial cases based research

1mm1mm

Welding spots

Assembly hole

Small parts raise big challenge for assembly

Picture courtesy Sonion Nederland B.V. & Integrated Mechanization Solutions B.V.

Heat Sink

TEC

Gripper Tip

AcknowledgementThis project is part of the Delft Centre for Mechatronics and Microsystems, and is a co-operation with Integrated Mechanization Solutions B.V.

Gripper unit on basis of Liquid Solidification principle

The structural sketch (left). The design of an industrial prototype (right)