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Aircraft painting with ProBatch™ at Pilatus in Switzerland

Precise mixing and dosing saves money

Only special two-component coatings fulfil the extreme demands placed on durability and safety of aircraft coatings. Due to the high paint prices of up to 40 euro per litre, material losses during mixing must be avoided. 

Our GRACO partners, Retech GmbH, from Oberriet/Switzerland, have installed a ProBatch™ batch dosing system at the Pilatus Flugzeugwerke AG in Stans/Switzerland. The aircraft manufacturer Pilatus has had particular success with the PC-12, a single-engined turboprop machine, which can be equipped as a business, transport, rescue or recreational aircraft. The paintwork on these aircraft must be able to withstand cold and heat, atmospheric impact and mechanical assault. 
A PC-12 goes through the paint shop in Stans every third day. There are also other models and repair work.

Complex paints 
Aluminium, keflar, glass or carbon fibre substances are used as substrates. The paint structure consists of an epoxy primer and a high solid polyurethane finish for aluminium and an epoxy base, a polyurethane acrylic filler and the polyurethane finish for plastics. In the past it was very difficult to mix precisely the correct amount when mixing by hand. The result was high costs: Too much paint mixed and loss of time to achieve the correct viscosity. Manual mixing means insufficient process security and health and safety concerns. 

Calculation instead of hit-and-miss testing 
During manual work on "exotic" mixing ratios, errors constantly occurred when calculating the ratios (e.g. resin : hardener : thinner 2.5:1.3:1.8). Useless waste at material prices of 30 - 40 Euro/litre represent real extra costs. If the viscosity is not exactly correct and the paint is used regardless, flawed coatings are the result, which subsequently require expensive correction. It was possible for Probatch™ to eliminate all sources of error in one sweep. The required final amount of material is precisely dosed and thus eliminates material losses and reduces preparation time. Moreover, the solvent requirement is determined automatically, which reduces the administrative effort when calculating the VOC output. All of this is efficiently recorded. These protocols, and the resulting traceability they provide, are of great importance to Pilatus, as they are repeatedly requested during audits and ISO certification inspections. 

Low paint consumption, fewer errors, better working conditions 
The system amortisation was calculated based on the paint savings and the shorter preparation times for the mixed materials. Even employees with little PC experience have no problems navigating the user-friendly menus of the ProBatch™ controller. The paint preparation time should also be kept to an absolute minimum because the pot life lies between 2 and 4 hours; the processing window is thus increased. ProBatch means less paint waste plus improved health protection and less reworking. 

Flexible system 
Six principal components are processed by Pilatus. ProBatch™ can manage up to 250 different formulations. For special paints, ProBatch™ is used to dose the hardener and thinner precisely as required to a preselected volume of resin. The system is also used, then, to add controlled amounts of components by hand. 

Peter Lauber, paint shop manager and responsible for the investment decision, judges from today's perspective: "We are a satisfied Retech customer. Not only because it was possible for us to lower our internal costs and decrease the error rate, at the same time increasing quality, but also because we have increased the attractiveness of our workplace." 

More information from: Mr. Remo Heule, Retech GmbH management, Tel.: 41 71 7600313, Fax : 41 71 7600315,

Features & benefits

Probatch™ batch dosing system


  • No. of materials: Max. 6
  • Dosing range: 120 ml to 19 l
  • Weight: max. 22.7 kg or 20 l
  • Formulations: max. 250
  • Mixing precision: 1percent
  • Mixing range: 1:99