Under head surface inspection 24 August 2023

GEFRA has modified the design of its OPTISORT ST standard steel disk machine in order to inspect underneath the head of screws, based on requests from customers. 

GEFRA explains: “One of our customers contacted us and said: ‘We need a system that can also inspect the surface underneath the screw head.’ After receiving similar requests from other customers, we decided to make it our new challenge.” 

By tighten the screw with a defined torque, or if the screw also has a sealing function, it is mandatory to have a specified surface condition under the screw head without any impurities, cracks or adhesions of zinc. In some production processes it is not always possible to avoid any defects on this surface. For this, GEFRA’s customer asked for a sorting machine that was able to do all the well known testing of the fastener and additionally inspect the surface underneath the head of the screw. 

GERFRA was able to solve this task based on its standard steel disk machine, OPTISORT ST. “The modified design enables the inspection system to take a look underneath the head of the screw, during the same single inspection cycle through the machine,” explains GEFRA. “For evaluation of the defects, all the familiar tools of our reliable and easy to use inspection software AUTOCONTROL can be used.”

GEFRA’s OPTISORT inspection and sorting machines are available in two different basic machine types: OPTISORT ST with steel ring disc for testing fasteners, screws, blind rivets and long rod shaped parts; and OPTISORT W with glass disc for testing nuts, washers, rivets and other flat parts. 

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Will Lowry Content Director t: +44 (0) 1727 743 888


Will joined Fastener + Fixing Magazine in 2007 and over the last 15 years has experienced every facet of the fastener sector - interviewing key figures within the industry and visiting leading companies and exhibitions around the globe.

Will manages the content strategy across all platforms and is the guardian for the high editorial standards that the Magazine is renowned.