Vero Electronics choose Gardobond LH pretreatment for new £2m finishing plant

Citation

(1998), "Vero Electronics choose Gardobond LH pretreatment for new £2m finishing plant", Anti-Corrosion Methods and Materials, Vol. 45 No. 5. https://doi.org/10.1108/acmm.1998.12845eaf.002

Vero Electronics choose Gardobond LH pretreatment for new £2m finishing plant

Vero Electronics choose Gardobond LH pretreatment for new £2m finishing plant

Keywords Finishing, Pre-treatment

Vero Electronics Ltd recently made a £2m investment in a new finishing plant for its range of electronics cabinets produced at the Uxbridge factory. A key feature of the new finishing system is the choice of Chemetall's Gardobond LH phosphate pretreatment to give outstanding corrosion resistance plus compatibility with the subsequent anodic electropaint coating.

Vero Electronics' Head Office and Electronic Packaging Division is located at Eastleigh, Hampshire, UK, with a Circuit Board Division near Southampton, and a Power Conversion Division at Bremen in Germany. There are seven other Vero Electronics subsidiary companies in Europe, with others in the USA and India. An extensive distribution network of agents covers the rest of Europe, the Middle East, Africa and Asia Pacific.

The company's products include the Imrak 700 multi-practice racking system, which was a Design Award winner at Hannover in 1997. In fact, Vero Electronics finds that such is the demand for its electronic racking systems generally that the finishing plant at Uxbridge is now working 24 hours a day. Products are designed to meet a wide range of network installations, from wall mounted enclosures for offices to 800mm × 800mm free standing electronics cabinets. Cabinets are also supplied to customers' own specifications, including colour choice.

Three years ago there was a management buy-out at Vero Electronics by a number of its UK directors and managers. With healthy support from its bankers the decision was made to keep the company in the forefront of its market place. This included the purchase of extensive robot welding facilities at Uxbridge and then, 18 months ago, the £2m pretreatment and finishing plant.

Previously, the finishing system at Uxbridge consisted of a transporter which carried cabinets and components through an aqueous alkaline dip tank: a rinse stage and then into an anodic electropaint primer tank. This was followed by conventional airspray application of wet paint. Although quality control ensured that a good quality durable finish was obtained, it was felt that long-term corrosion resistance could be improved even more with a better pretreatment and that production and quality control would be further enhanced with a computer controlled fully automatic plant.

Vero Electronics technical staff looked long and hard at the pretreatment systems on the market, with numerous tests being carried out by potential suppliers and by Vero at Uxbridge. The decision was made to use Chemetall's Gardobond LH, which is a combined cleaner and lightweight amorphous alkali metal phosphate. It produces a markedly higher coating weight than conventional pretreatments of this type, and is suitable for the treatment of steel, other ferrous metals and zinc surfaces.

Another important reason for the choice of Gardobond LH is that anodic, as opposed to cathodic, electropaint coatings are sensitive to the type of phosphate coating they are applied to. A form of cissing can occur whereby the electropaint pulls away from the pretreated surface. Gardobond LH proved to be the best in being completely trouble-free in this respect ­ and it has never given a problem since it was first used. At the same time it is giving a corrosion resistance of 96-100 hours salt spray test at Uxbridge. Vero Electronics has stayed with anodic electropaint because switching to cathodic would give them colour stability problems, i.e. the primer coat would grin through the subsequent powder coat in corner areas, due to the Faraday cage effect during powder application.

The new £2m pretreatment and finishing plant, now running non-stop on three-shift working, was designed and installed by Electropaint Ltd. Jude Burke, product manager at Chemetall Ltd, worked closely with Vero and Electropaint in the design of the pretreatment section.

Moving on a conveyor at 21Ž2m/min, the cabinets and components enter the 30 metre long, seven stage spray pretreatment tunnel. The first stage is a Gardobond 535 alkaline cleaner operating at 60°C, foilowed by two mains water rinses. The next section is the Gardobond LH phosphate pretreatment, operating at 45°C. Both the cleaner and the Gardobond LH are automatically dosed into the pretreatment tunnel via Astles control units which also control the temperature.

Some 98 per cent of the work handled is mild steel. The remainder, Zintec and aluminium, still goes through the Gardobond pretreatment process.

Following the Chemetall phosphate pretreatment there are two more mains water rinses plus a final demineralised water rinse before wet entry into the anodic electropaint tank. This boat-shaped tank holds 55,000 litres and is one of the largest in Europe outside of the motor industry.

After dry-off the cabinets are then powder coated, using Nordson roll-on, roll-off electrostatic booths, then cured.

Further details can be obtained from Chemetall Ltd. Tel: 01296 399233; Fax: 01296 399211.