Water-based paints contain few organic solvents and are very environmentally-sustainable. These paints are regarded as durable and yield impeccable results. They are used in vehicle painting around the world.
High-speed rotation atomizers with electrostatic paint charging ensure an even application of water-based paint. In order to apply the procedure with low overspray losses to interior painting as well, a compact atomizer is needed to quickly and easily reach all surfaces. To answer this need, Dürr has expanded its product family by adding the high speed rotation atomizer EcoBell3 Ci.
High application efficiency and low complexity
“We can make the painting process more efficient if we consider not only the investment costs for the customer, but also the personnel costs, the consumption of resources, the environmental burden, and the costs for maintenance and servicing when developing new products,” says Dr. Hans Schumacher, president & CEO of Dürr Division Application Technology, describing the requirements for product development. “It is our goal to sustainably increase productivity in the paint shop with modern paint application technology.”
This involves coordinating the cleaning unit along with the atomizer, the color changer and the dosing pump during the development of an automated, electrostatic water-based application for interior painting - and creating them as a complete system.
In order to reduce the material usage for paint application, Dürr initially optimized the bell disk with the shaping air ring system on the high-speed rotation atomizer EcoBell3. Concurrently the arrangement of the electrode ring was changed. The spray jet can be aligned with exact focus in the vehicle interior, visibly producing less overspray and self-contamination. This adjustment ensures also a noticeably compact shape of the new atomizer and it can reach the interior surfaces of the car body very well.
Without using complex voltage block systems the atomizer applies the water-based paint with high quality and improved application efficiency.
Atomizer cleaning within cycle speed
“Modern paints dry very quickly. Because a small part of the overspray always lands on the atomizer, it can lead to contamination. That is why the atomizers have to be cleaned often,” says Frank Herre, head of Development Application/Process, describing a crucial particularity of water-based paints. Dürr supplements its atomizer with the EcoBell Cleaner D2 for this cleaning task. “We fulfill the high demands concerning cycle time and flushing agent consumption with our automated solution,” says Herre, summarizing the system’s advantages.
The EcoBell Cleaner D2 completes cleaning the exterior of the atomizer within the cycle speed. Changing color and cleaning the paint channels in the atomizer’s interior take place simultaneously, allowing the system to begin painting the next car body in fifteen seconds.
Reduced VOC emissions
In terms of VOC emissions, the EcoBell Cleaner D2 is setting new standards with a flushing agent consumption of a maximum of 50 milliliters per cleaning process. The predecessor model required ten times the amount of flushing agent for one cleaning process. In the clear coat application solvents are used as flushing agents. This means 500 milliliters of VOC can be saved per cleaning process. In the base coat application the EcoBell3 Ci can also save VOC, which correspondents to the share of solvents in the flushing agent (ca. 10%). The EcoLCC2 color changer along with the EcoPump9 dosing pump ensures high productivity in fully automated interior painting. Both have ample space on the robot’s second arm. Yet the robot arm remains flat and can access all areas of the car body interior.
The EcoLCC2 color changer flexibly provides the desired color in automatic paint shops – in the shortest color change times (<10 seconds) and with the lowest paint losses (ca. 10 ml). The color changer activates the individual colors by docking onto the respective paint valve. Color mixing is prevented by design, because each of the 36 colors has its own paint channel. The paint hose from the dosing pump on the 2nd arm connecting up to the atomizer is equally short for all colors, which has a consistent positive effect on color loss when changing color. The low complexity of the system, which only needs five pneumatic valves in total to control all of the color changer’s colors, permanently lowers the servicing and maintenance costs.
Depending on production volume and plant fittings of the interior painting zone, this system can result in savings of up to one million Euros per year by low paint osses and less flushing agent consumption.
There are sustainable advantages for automobile manufacturers in the process sequence. The Dürr system’s simple design of electrostatic exterior charging does not require additional installations in the booth wall. There is no need for complex pigging technologies, docking systems, canister technologies or dosing cylinders for voltage block systems mounted on the atomizer arm.
Everything points to electrostatic charging in vehicle painting with water-based paints. With Dürr’s automated system, lower VOC emissions and higher productivity in interior painting is now possible.