Case Study
Introduction
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| Initial Site Survey |
Tarmac Concrete Products Limited manufacture aerated concrete blocks. One of the processes
in the manufacture of these blocks is the oiling of the mould that the concrete mix
sets in before being cut into the desired sizes/heat cured in large autoclaves. The
original process of oiling the mould cars used air pressure and a ring of spray jets.
The system was difficult to control and used excessive amounts of oil. Often the mould
car was not coated properly, this in turn affected the quality of the product and
often resulted in increased wastage and generated scrap that had to be recycled or
disposed of. The system also emitted a lot of undesirable airbourne pollution during
the application of the special mould release oil.
RobotSense were asked to review the then current set up at Tarmac's plant at Ford
Airfield Industrial Estate in West Sussex and determine any ways in which a new automated
system could improve the productivity of the process.
The Objectives
The main objectives that a new system had to meet were to develop a smoother more
efficient process for the application of the oil which would in turn improve productivity
and reduce wastage.
Initially RobotSense spent time working with oil suppliers and manufacturers of spray
equipment. Tests were carried out under controlled laboratory conditions, where a
replica system, including a mould car and robot cell, was constructed and tested -
the results were very positive and installation of the new automated method began
in late 2003.
How the System Works
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| Fully Commissioned Robot Cell |
The mould car passes into the cell where, once in place, it is locked and a robotic
arm is then activated. Mounted on the end of the arm is the spray technology to apply
the mould release oil. This arm then descends into the car where it can apply the
oil smoothly and evenly over all surfaces of the car.
The Features
The System uses a 6 axis Robot System, an electrostatic applicator gun assembly and
several other components. There are numerous safety features including a light curtain
system that operates whereby if the light beam is broken by an operator, it will deactivate
any robot motion until a reset pushbutton is pressed, there are also safety control
relays.
The system incorporates three analogue controls which give complete control over the
amount of oil that is applied, as well as full diagnostics which enable the monitoring
of oil usage.
Also the employees that were to maintain and operate the system were given full, practical
training before use. The installation and initial honeymoon period were very successful
and passed smoothly.
The Results
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| Robot Arm inside Cell |
The system was expected to meet the initial objectives - which it did. However nobody
was quite prepared for the results that were produced. Not only did the system function
as desired which improved the product quality and reduced wastage but there was a
substantial saving in compressed air usage and energy consumption. It was the reduction
in oil consumption by the system that was one of the greatest achievements - the new system
used a massive 67% less oil than the previous equipment. This reduction in oil alone
resulted in a financial saving of over £46,000 per year. Since oil prices have now
increased dramatically the system continues to save the company even more money.
The Health and Safety and Environmental impact of the system was also a major achievement
- workers reported a much cleaner working environment with improved air conditions.
The environment also benefited from reduced oil and energy consumption, as well as
the benefits of not having to transport the oil to the plant. Wastage was reduced
dramatically which also aided the company's environmental performance.
Following the success of the low pressure/water based system at Ford a second high
pressure system to apply mineral based mould release oil was commissioned for a plant
in Alfreton, Derbyshire.
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| Simulation of Spray Cycle |
Tarmac Concrete products entered the Robot Oiler into the British Precast Environmental
Awards in 2004 where the system won 2nd prize.
Indeed it is the benefits provided by the Robot Oiler to the plant workers Health
and Safety and also the environmental benefits that RobotSense are most proud of.
