Efficient
Paint Spraying in the Automotive Industry
An integral
component in the manufacturing of vehicles is painting the bodywork.
Particularly during the early period of car manufacturing, high-gloss
bodywork finishes were associated with high cost and time expenditure.The
first electrostatic rotary atomisers were developed in the 1980s
and 90s.
The advantage of rotary atomisers (also known as paint robots)
are their economic use of material: thanks to the high-voltage
paint charge, 90 per cent of the paint is applied directly onto
the bodywork and is no longer wasted. Rotary atomisers of this
kind merely require a rotating disc.
The paint to be atomised forms a film on the disc which becomes
increasingly thinner towards the edges and dissolves into droplets
whose size is controlled via the speed of rotation.A nozzle ring
is required around the atomiser to direct and shape the paint
jet.The atomiser can therefore be operated in any position and
can be used for external as well as internal finishings.This
type of rotary atomiser is therefore ideal for the car industry.
SAFE PRESSURE TRANSMITTER FOR THE SPRAY HEAD
Keller was able to supply intrinsically safe pressure transmitters
and intrinsically safe temperature sensors to a client who produces
paint robots for the car industry.
You make ask why they are intrinsically safe. Even though non-flammable
water-based paint is usually used on bodywork parts, the mist
that is created during atomisation can take on a flammable state.
Although hazards only occur in the rarest case during paint spraying,
rotary atomisers must be equipped with explosion-proof technology.
Some pressure transmitters are fitted in the spray head of the
robot where they measure the spray pressure in the paint spray
system and detect quick pressure changes which are caused, for
example, through the placing of hoses.The pressure transmitters
are located in a high-voltage field and communicate with the
robot control mechanism via a fibre-optic cable, whereas 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
means via copper conductors.
December 2020
