CI Electronics microbalance has been incorporated into an automatic instrument for mechanical analysis of human hair samples and other fibres
Dia-Stron is a specialist company that builds automated instrumentation for the analysis of human hair and other fibres.
Unilever recently approached the company with a requirement to improve and automate the measurement of stiffness of human hair samples.
Dia-Stron responded by designing and building a fully automated system that, once the sample cassette of up to 50 samples has been loaded, can analyse the fibres without further operator intervention.
Each sample is transported for analysis from the storage cassette to the measurement module by a single axis robotic arm.
Once in the measurement module, the fibre is clamped at one end and then moved down so the free end applies a load to the force measurement device.
The bending moment of the hair can be determined by measuring the load applied and the distance moved by the clamped end of the fibre.
Furthermore, because human hair has a cross-section that is more elliptical than round, the instrument is able to rotate each hair around its own axis for further measurements to be taken.
One key element in the success of the instrument is precise force measurement and for this Dia-Stron selected the Mk4 microbalance head from CI Electronics.
This has an electronic control system that maintains the measurement position regardless of the load, which is vital for an application where force and displacement are being measured.
Only minor modifications were required to the standard CI Electronics controller to suit Dia-Stron's design of instrument control system.
Dia-Stron added a specially designed loading wire of less than 0.5mm diameter against which the fibre sample acts, and the system was ready to measure the small forces associated with bending a single hair.
Nigel Winsey, managing director of Dia-Stron, explains: "We had a choice of suppliers for microbalance heads, but we selected CI Electronics because this company's technology is so much more robust.
"The instrument we developed is going to be shipped around the world, and also users might knock the head while loading the samples.
"This means that the microbalance head has to be robust, and all the evidence so far indicates we made the right decision with the Mk4.
"If it receives any knocks, the electronic control system automatically resets the head, whereas many alternative balances have delicate wires and other features that would simply not survive this type of treatment.
"This instrument has been very well received at Unilever and the microbalance head has worked well within specification.
"CI Electronics was an excellent supplier throughout the project, and we are looking forward to selling more systems, incorporating the micro-balance heads, into our international customer base."
