High speed laser micrometer measures circumference, diameter and ovality of cylindrical objects

A manufacturer of inspection equipment has applied a high speed, non-contact laser micrometer to measure the circumference, diameter and ovality of cylindrical objects, including cigarettes, filters and cigars. The company is also utilising the same sensor to measure the shape of shoulders for extruded laminate tubes.

Cerulean, based in Milton Keynes, designs and manufactures a range of quality assurance systems and instrumentation for applications in analytical laboratories and manufacturing processes of cigarette and filter rod producers.

Cerulean’s CD Express is a bench top instrument that measures and displays the circumference, diameter and ovality of cylindrically shaped objects. At the heart of the CD Express is a non-contact laser micrometer, supplied by precision sensor manufacturer Micro-Epsilon UK Ltd. 

Micro-Epsilon’s optoCONTROL ODC 2500-35 sensor is a non-contact, laser-based measurement system with an integral, high resolution CCD camera for measurement of dimensions. The sensor offers high sampling rates, outstanding accuracy and excellent resolution. As Steve Frankham, Sales & Marketing Director at Cerulean states: “We selected the Micro-Epsilon sensor for its robustness and ease of use; particularly the fact that it could be easily configured to fit the required application.”

With the CD Express, the sample under test is simply dropped into the machine and held in the path of the laser beam using a custom made rotary chuck. 100 individual measurements are taken during one complete 360-degree rotation. From the results, the minimum, maximum and average diameter or circumference is calculated and can be displayed together with the ovality. Batch statistics are also available and the individual results can be exported via an RS232 interface. The sample is then ejected automatically.

Cerulean’s CD Express system uses a special version of Micro-Epsilon’s ODC 2500-35 laser micrometer, with modified software inside the controller module to suit the customer’s application. Chris Jones, Managing Director at Micro-Epsilon comments: “The unique aspect about this application is that our ODC 2500-35 sensor controls the complete CD Express system via its modified software, which enables it to send and receive signals to start and stop the mechanical components and record the measurements. This means that no additional control hardware was needed to make the system function correctly.”

The CD Express was originally designed to measure and display the circumference, diameter and ovality of cigarettes, filters and small cigars. It was specifically designed to provide the tobacco industry with a simple, fast and easy-to-use, manually fed, non-contact measurement instrument compliant with ISO standards. According to Frankham, the machine has been “readily accepted”, both as a primary measurement device for small and independent producers, as well as by larger producers who have been looking for a manual instrument to provide a rapid check of circumference on start up.

However, Cerulean has realised that instruments such as the CD Express have applications in other industries besides tobacco. The first such application to be investigated was a requirement to measure the ovality of shoulders for extruded laminate tubes. “With only minor modifications the CD Express quickly demonstrated that it was capable of meeting these requirements,” says Frankham.

Cerulean is now working closely with Micro-Epsilon to identify and exploit new applications for the instrument. “We’re currently investigating a wide range of potential applications for the instrument, including how it can be used to measure the dimensions of wires, rods, plug gauges and tubes,” continues Frankham.

Micro-Epsilon’s optoCONTROL range of sensors measure the dimensions of a target or the position of an edge by using the shadow principle. optoCONTROL consists of a sensor unit and a controller. A parallel light curtain is generated by using a laser light source. The CCD camera in the receiver section measures the target contour formed by the shadow at high accuracy. The sensor unit is controlled and evaluated by an intelligent controller with graphical display for the operation and measurement function.

For more information on Micro-Epsilon’s optoCONTROL 2500 range of laser micrometer sensors, please call the sales department on 0151 355 6070 or email: info@micro-epsilon.co.uk

For further details on the CD Express please contact David Walker on +44 7739 541951 or at david.walker@cerulean.com

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