Available Technology
Quality control for manufacturing of plastic articles
Technology:
Measurement of density and density distribution with magnetic levitation
Markets Addressed
Quality control (QC) is an integral part of manufacturing. It aims to:
(1) optimize the production process to reduce the number of defective parts produced, and
(2) prevent the distribution of defective products to the customer.
Typical categories of QC include static (electromechanical), dynamic (servohydraulic), hardness and impact testing, as well as dimension and shape inspection. The latter is typically performed manually or by coordinate measuring machines, which are often slow. Automation and speed improvement of dimension and shape inspection can reduce cost per piece examined and, in turn, improve QC by increasing inspection rate. This is especially critical for injection-molded plastic parts arts, where cost per piece is low.
Innovations and Advantages
Magnetic levitation (MagLev) allows suspension of diamagnetic objects in a paramagnetic fluid by application of a magnetic field gradient. The levitation height and three-dimensional orientation of an immersed object with respect to the gradient sensitively depends on its density, shape, and distribution of density. As such, MagLev is well suited for automated and contactless dimension and shape inspection as part of a QC process. We demonstrated MagLev’s sensitivity and specificity for various injection-molded plastic parts of complex shape (e.g., screws).
Additional Information
Publication: Unpublished
Website: The Whitesides Research Group
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Inventor(s):
Ellerbee, Audrey K.
Tricard, Simon
Whitesides, George M.
Categories:
For further information, please contact:
Mick Sawka, Director of Business Development
(617) 496-3830
Reference Harvard Case #3969