Page 14 - Industrial Technology EXTRA - 22nd June 2020

SENSORS...

Miniature sensors help robots

get a grip on silicon wafers

During automated production of solar cells, compact two-finger grippers transport

trays of silicon wafers between operations. To avoid impacts on the wafer’s surfaces,
process engineers require reliable confirmation that gripper jaws are fully open
before the gripper descends to pick up a tray. Contrinex’s Ultra-miniature inductive
proximity sensors, mounted directly above the top faces of the gripper fingers, sense
the position of the jaws in the fully open position, eliminating avoidable scrap costs

liminating avoidable scrap costs has to be
at the top of any production engineer’s to-
do list, particularly when rectifying
Ecomponent damage also means
interrupting a fast-moving automated production
line. When the component in question is a costly
photovoltaic silicon wafer, designers often turn to
automated handling systems, although relying on
these to achieve perfect alignment isn’t always the
answer.
In a manufacturing cell, handling systems
assemble solar cells before presenting them for
automated testing. To start, trays of silicon wafers the gripper fingers; attempts to pick up a wafer tray
are transported between operations by two-finger with the jaws only partially open result in fingers
edge-grippers. If gripper malfunctions occur, scrap impacting on the wafer surfaces. A cost-effective
costs can mount rapidly, with mechanical damage hardware solution is required to provide overriding
caused by impacts on the wafer surfaces being a inhibition of picking routines if this situation arises.
common cause Designers specified two-finger grippers fitted
with Contrinex Ultra-miniature inductive sensors as
Position of the gripper fingers a reliable and cost-effective means of detecting the
Analysis showed that open/close errors account for position of the jaws at the extremes of travel. Before
a significant proportion of gripper malfunctions. the gripper descends to pick up a tray, these
Software routines alone can’t identify the position of miniature proximity sensors, mounted directly

June 2020 • INDUSTRIAL TECHNOLOGY EXTRA! • p14