Powder Coating efficiency increase for Mower Manufacturer

Maschinenfabrik Kemper GmbH & Co KG use modern systems and production plants, serving farmers and professional users. They offer harvesting headers, tractor-mounted choppers, and related parts.

“We are at a point where many of our customers receive their harvest attachments painted in their corporate colours right off the conveyor belt”, explains the System Operator at Kemper. “In addition to the short colour change times, the ergonomic design of the new booth is much better for our employees”, says the System Operator.

“We are using a total of ten automatic spray guns, whereby two can be used from underneath if demand requires it. Based on the geometry defined by the components scanner, the position of these spray guns can be optimised.

This is extremely important since at Kemper a considerable range of parts are suspended from the chain conveyor at random sequence and the geometries of the parts can be very complex. For instance, large drums can be very challenging. On average, the new booth makes it possible to coat 85% of the component’s surface automatically. Furthermore, the System Operator estimates that the new booth, when compared with the old Tribo system, saves approx. one-third of the compressed air required.

Safety and ergonomics in the workplace during coating of the large drawing-in rollers – this process is now be done by the automatic guns.

By using the dense-phase technology instead of the traditional Venturi Technology (Tribo Application) = Increased transfer efficiency and coating penetration thanks to softer spray, optimised electrostatic powder cloud, superior edge and corner coverage with one pass.

Thanks to dense-phase technology and the new Powder Feed Centre Spectrum HD – quality colour change in 4:15 min and highest first pass coverage efficiency.

The outline of the drawing-in rollers follows up by a third oscillator n Replacing 3 existing booths by 1 ColorMax3 fast colour-change booth enables an increased productivity speed also safe and clean environment: No need for the operator to enter the booth.

Substantial pretreatment

After suspending the components on an overhead track system, the parts are ready for a 13-zone spray pretreatment with zinc phosphate by Eisenmann. The cathodic dip coating process follows next.

During this process, a light grey is applied since Kemper uses many shades of light paints – and only slight fluctuations in the coating thickness would cause a darker CDC paint to shimmer through. The burn-in requires one hour at a temperature of 180°C; subsequently, the cooling process is started.

 Intensive quality control

Kemper does not leave the pretreatment, paint and process to chance. Each day, a metal test sheet and analyses are used to verify all process steps in our in-house paint laboratory. Each morning, four metal test sheets are painted and tested to verify that the zinc phosphating process is correct and the sequence is OK. Metal test sheets are moved through the CDC system, and coating thicknesses are analysed. The powder coating is not only tested for the proper colour hue, but a conical mandrel bend test, an impact and a cross-cut adhesion test are also performed. 

Colour change in 4:15 min

The dense-phase technology was new to Kemper since previously only one Tribo system was employed. From now on, only two people are required to proceed with the colour change – one person for the pre-coating and one for the post-coating process. If a colour change becomes necessary, the technician prepares a gap in the chain conveyor consisting of 25 links – equal to the length of a paint booth.

 As soon as the precoating is done and the powder is used, the technician closes the rear door and goes to the powder centre, where he interrupts the powder supply from the carton. He also places the previous powder carton underneath the hopper in order to collect the powder residue. 

 This is an impressive example how modernisation of application technology can increase the productivity and efficiency in a spray paint shop. At the same time, it becomes evident how demanding the painting requirements have increased in the agricultural machinery industry in the past years.