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Manual inspection of tablets

The problem

This process involves visual inspection of tablets prior to packing. Operators sit in front of a small conveyor belt in order to inspect the tablets. There were two operators working at each conveyor. The tablets are automatically fed onto the conveyor and passed in front of the first operator. The operator would check for any defaults and remove any tablets deemed to be unsuitable. The tablets were then automatically turned and fed onto the next conveyor where the next operator must inspect the other side of the tablet and remove any unacceptable ones. Tablets that are discarded are placed into a trough at the front of the conveyor. Suitable tablets are then collected at the end of the conveyor in a bag in a small bin.

The posture adopted by the operators when performing this task is particularly poor. Due to the intricate detail of the work, operators need to be close enough to the tablet to identify minute flaws. The conveyor was positioned in the centre of the unit at a depth of 400mm. This meant that operators had to lean forward to view the tablets on the conveyor resulting in a stooped head and neck posture over the unit and conveyor.

Person leaning over inspecting tablets

Operators often remained in this posture for up to one hour, which produced shoulder and back discomfort in the employees.

Surrounding the conveyor is a stainless steel unit. The inspection light reflects off of the steel and into the operators eyes, which was not only irritating to the operator but could also result in eye strain and headaches.

For this task it was a requirement for all of the operators to wear overalls, overshoes (or white shoes), hat, beard mask, goggles and gloves. Wearing such PPE can be uncomfortable, especially when potentially worn for long periods. Being uncomfortable can often result in decreased concentration.

The inspection task requires great attention to detail and concentration; however it is very monotonous and repetitive. Towards the end of a shift, operators feel tired and this could affect the quality of their work.

Person leaning over inspecting tabletsThe solution

The feasibility of an automatic inspection machine is being investigated. The benefits of incorporating such a machine may outweigh the potential high costs of purchase and installation. The inspection task requires 6 months training per operator to reach a consistently high standard, and only certainly staff make the grade; this would not be necessary if the task were to be automated.

As an interim measure changes to the workstation and work organisation were introduced to mitigate risk. An appropriate foot support was made available to allow operators to adjust the seat to the appropriate height for working as well as being able to gain adequate support for the feet and legs. The height of the foot platform was set to be 720mm below the top of the work bench. The platform has an open front face to allow clearance for the seat legs and a non-slip surface.

A plastic tray was also introduced to hold the tablets during inspection as an alternative to the moving belt. This allowed the operators to angle the tray towards then which improved head/neck posture and removed the time pressure of the machine-paced belt inspection.

Increased rest breaks and job rotation were also introduced to further reduce the postural strain and monotony of the task.

The benefits

Updated 2008-12-05