Highly controlled Blue Chip company manufacturing sensitive & hazardous material.

Brief

High accuracy batch filling pellet and grain products into automated assembly line.

Achievements

ATEX Compliant, double headed weighing system with course and fine vibratory feeders.
Fully automated and integrated into assembly line provided by others.

Benefits

Gain in weight batch weighing up to 170g to +/- 0.2g with divisional accuracy of 0.01g and standard deviations of 0.004g. Achieved Cpk >1.5.
Batch times < 15 seconds

Customer

Customer is an established manufacturer of hazardous components.

Challenge

The client needed a system to deliver weighments of a hazardous free flowing granular / pelleted material to receptacles positioned underneath an automatic assembly line.

A statistical confidence measurement determined that each weighment of up to 172g had to be less than +/-0.1g. This amounted to approximately +/-5 particles of the most frequently used material.

The required rate of weighment was 1 every 8 seconds with a fully automated control system monitoring the equipment. The ATEX requirements were for equipment that was Zone 21 compliant throughout.

Solution

Due to the relatively rapid weighment cycle a double weighing system was developed. The scales used were Sartorius ‘forced balance’ type which had an accuracy of 10mg. Such was the sensitivity of these scales that air currents and anything other than a freely suspended weigh hopper affected the stability of the signal.

The automation system used an algorithm of self learning in-flight correction so that the feeders were continually ‘tuned’ to subtle differences in the behaviour of the material.

Results

A fully automated weighing system integrated into complex conveying and assembly equipment. ATEX compliant to exacting and scrutinised standards and standard deviations of +/-0.004g for extended runs.

Through this project we have built a good relationship with the client who we continue to work with on further bespoke projects.