On the pulse with the right recipe

H. P. Kaysser GmbH + Co. KG, a specialist for metalworking processes, invested in a new powder coating plant to be able to coat more flexibly. Whether small or large workpieces in individual or series production - coating is now more efficient and economical.

H. P. Kaysser GmbH + Co. KG in Nellmersbach is a well-known contact when industrial customers want to keep their own vertical range of manufacture lean and outsource parts of metalworking for this purpose. H. P. Kaysser now has over 70 years of experience in this field and can offer its customers from practically all sectors of industry intelligent and economical solutions, from engineering through the complete sheet metal process chain to logistics. To this end, the company has set up numerous processes for the mechanical production and fully automatic machining of workpieces made of steel, cast iron, stainless steel, titanium, non-ferrous metals and aluminum on an area of around 30,000 square meters. Single pieces as well as small, medium or large series are possible.

Due to the high level of process competence, customers often benefit from quality, price and speed advantages compared to in-house production. However, H. P. Kaysser not only offers metalworking, but also coating services if required. In this respect, however, a need for modernization became apparent a few years ago, which is why the decision was taken to invest in a new powder coating plant.

Secure growth, increase flexibility

"We were looking for the right recipe for the highest-quality coating in an optimal process," recalls Timm Kaysser. "For this, we needed, on the one hand, the best ingredients for recognizing and coding the workpieces, for transport, pretreatment, masking and coating. And on the other hand, an intelligent control system that links everything together."

With regard to the technology and concept of the new powder coating plant, the specifications of the Kaysser engineers demanded a long-term and future-proof investment. In particular, flexibility in terms of the type of customer orders was to be as high as possible.

Maximizing environmental protection and sustainability also had a high priority. In addition, the aim was not only to create sufficient capacity to be able to coat all components manufactured in-house - regardless of their size and weight - in the company's own plant. It was also necessary to plan for additional capacity in order to be able to acquire external orders as a contract coater. In view of the size spectrum of the components to be coated and the resulting dimensioning of the plant, it quickly became apparent that this project would require an investment volume in the double-digit million range as well as the construction of two completely new halls.

For the planning and configuration of the coating technology, Kaysser relied on the many years of experience of CS Oberflächentechnik, which has already been involved in the creation of several large plants. In a first step, the first hall was realized at the end of 2018. The hall, with a floor area of 2,800 square meters, houses a continuous flow system on which components measuring 2.5 x 1.0 x 1.5 m and weighing 350 kilograms per product carrier can be processed in series and with a planned eight color changes per day.

Flexibility thanks to buffer and sorting accumulators

The workpieces first pass through a continuous pretreatment system with six zones to ensure optimum corrosion protection and adhesion of the powder coating. Despite a high degree of automation, a large number of buffer and sorting storage options provide the required flexibility in the process flow. The heart of the powder coating system is a modified ColorMax3 booth from Nordson, which is only 2.60 meters long and has a lower booth roof, so it is called ColorMaxE, where "E" stands for engineered.

Inside the booth, eight Nordson EncoreHD automatic powder guns with powder supply via dense phase pumps take over the powder application. In the interaction of the ColorMax booth, the EncoreHD powder guns and the SpectrumHD powder center, the eight color changes planned so far, without the operator having to enter the booth, are no problem. The resistant and particularly smooth surfaces of the booth components ensure very uniform light reflections and improve the illumination of the booth to make optical quality control easier for the coaters. At the same time, their texture, in conjunction with intelligent airflow management, helps to avoid the undesirable buildup of powder already during coating. This facilitates cleaning during a color change. During operation, a gentle airflow and regular blasts of compressed air feed excess powder to the center channel exhaust, from where it is conveyed to the twin cyclone for reprocessing.

Time savings due to easier accessibility

All system parts that have to be cleaned by hand are easily accessible, which helps to speed up the changeover even further. The Spectrum HD powder center with fresh powder supply ensures that the required color is available at the right time. The system conveys the powder from a box to the guns by means of the HDLV pumps. The overspray is extracted from the booth via a twin cyclone and, after separation of powder fractions that are too small, is fed to the powder center for reuse via an HDLV transfer pump. Before this, an ultrasonic sieve ensures a constant powder quality. This shows that, for reasons of economy as well as cleanliness, great importance was attached to efficient powder recovery. Only a small percentage of the powder in the circuit has to be separated. The entire coating plant is controlled by means of a PowderPilot HD touchscreen control system. An icon-based user interface provides the plant operator with relevant information on the status of the individual plant modules at any time, as well as step-by-step instructions when - for example during color change - his intervention is required. The largely language-independent control system, combined with the easy-to-understand guidance of the line operator through complex processes, largely prevents operating errors.

Additional manual coating

For individual pieces and for workpieces with very complex geometries that cannot be processed in the throughfeed system, an additional system is available for manual coating. Equipped with a glass booth from system integrator Rippert and the Nordson Color-on-demand system in combination with a powder management system for ten solid colors from iOS Industrieofen-Service GmbH, up to 15 color changes per day are planned here, coating is done at a loss.

Such a major investment is naturally linked to the expectation of long-term use. "Decision-makers of my generation no longer have to consider mainly technical and commercial aspects. Today, right from the start and at the same priority level, they also have to consider environmental, sustainability and energy issues," says the project manager and grandson of the founder. For this reason alone, wet painting was out of the question. The sophisticated cleaning and conveying processes minimize unnecessary powder waste.

Consistently, the new automatic plant was also configured to be particularly energy-saving according to the standards of the "Going Green Pro" package. Efficient equipment, in combination with an intelligent control system, ensures that consumption is continuously adjusted to the amount of energy actually required at any given time. For example, if the photoelectric sensor reports larger gaps in the feed to the booth, all powder guns are switched inactive, and the booth air flow is adapted and regulated down as far as possible - to the legally prescribed minimum exhaust air volume. At the same time, the output of the fan in the final filter is reduced.

Commissioning in 2018 proceeded without complications

After a planning and construction period of around 30 months, the first construction phase, which comprises the large hall with the throughput system inside, went into operation for the first time in November 2018. From the outset, the operators were struck by the improvement in coating quality. Whereas strongly fluctuating coating thicknesses of between 150 and 200 micrometers were the rule with the old coating systems, the new system consistently achieved 120 µm right from the start. Through further optimization, the applied coating thicknesses could then even be reduced to 80 µm. The large parts line, which will finally be completed at the end of 2020, will use product carriers with a load capacity of up to 2,000 kilograms. Part dimensions of up to 4,000 mm in length, 2,000 mm in width and 2,200 mm in height can be processed.

Better quality, lower material consumption

The significantly improved coating quality goes hand in hand with major material savings. For the H. P. Kaysser line, a reduction in powder consumption of 30 percent had been calculated in advance. Accordingly, a greatly reduced powder consumption was apparent right from the start. Another value also proves the particularly economical and sustainable operation of the plant. The recycling rate of 96 percent required for the automatic booth was already achieved during start-up operation. As a result, the BigBag collection station fills up only slowly with filtered-out powder coating residues.

50 percent capacity increase ensures long-term growth

The contractors also made the right decision when putting together the plant modules. The combination of efficient dense phase technology, highly automated components, integrated system control with barcode recognition of the product carriers and, last but not least, the 50 percent increase in capacity ensures long-term further growth for the Surface Technology business unit at the specialist for metalworking processes. In this sense, Timm Kaysser's assessment is thoroughly positive: "Everything looks as if we have set up something that really works well together with our industrial partners and craftsmen. The best ingredients and only a few cooks who agree on the recipe: That was the key to success here, too."

Nordson Germany GmbH
www.nordson.com