Painting the bodywork is an integral aspect of vehicle manufacturing. During the early period of car manufacturing, high-gloss bodywork finishes were associated with high costs and time expenditure. The first electrostatic rotary atomisers were developed in the 1980s and ’90s.
One advantage of using robots for spray painting in automotive manufacturing is that they handle the material economically.
Rotary atomisers (also known as paint robots) offer the advantage of using paint material economically. Due to the high-voltage paint charge, 90% of the paint is applied directly onto the bodywork, so waste is minimised. Rotary atomisers of this kind simply require a rotating disc.
The paint to be atomised forms a film on the disc that becomes increasingly thinner towards the edges and dissolves into droplets – and their size is controlled by the speed of rotation. A nozzle ring is needed around the atomiser to direct and shape the paint jet. The atomiser can then be operated in any position and used for external and internal finishing. This type of rotary atomiser is, therefore, ideal for the car industry.
Intrinsically safe pressure transmitters
KELLER has supplied intrinsically safe pressure transmitters and intrinsically safe temperature sensors to a client that produces paint robots for the automotive industry.
How are they intrinsically safe? Although non-flammable water-based paint is usually used on bodywork parts, the mist created during atomisation can become flammable – and although hazards occur only rarely during paint spraying, rotary atomisers must be equipped with explosion-proof technology.
Pressure transmitters fitted in the robot's spray head measure the spray pressure in the paint spray system and detect quick pressure changes which may be caused, for example, by placing hoses. The pressure transmitters are located in a high-voltage field and communicate with the robot control mechanism via a fibre-optic cable. In contrast, additional pressure transmitters and temperature sensors monitor the dosing system and the pumps of the axes. These pressure transmitters communicate with the control system through conventional analogue connectivity via copper conductors.
KELLER’s equipment manufacturing team develops automation solutions that are tailor-made for the requirements of its production department and meet its high standards of quality and precision. This has enabled KELLER to improve its products and process stability and efficiency continually over the past 50 years.
Keller is represented locally by Instrotech, which supplies the rotary atomisers for efficient paint spraying to the South African market.
For more information visit: www.instrotech.co.za
