IR oven speeds powder coating for sign maker

Edited by the Engineeringtalk editorial team Jul 17, 2007

a purpose-built medium-wave, infra-red oven was retrofitted into Hawes Sign's existing powder coating and curing line, between the coating cabin and the warm air oven.

A medium-wave infra-red oven from Heraeus Noblelight is helping Hawes Signs to achieve significant increases in production line speed in the powder coating of aluminium and steel panels at the company's Northampton headquarters manufacturing site.

The new oven was installed during an on-going, upgrade programme, which aims to see continuous improvement in all aspects of Hawes' manufacturing operations.

Hawes Signs offers design, manufacture, installation and maintenance of a range of external and internal signs for customers ranging from high street banks to car dealerships and supermarket chains.

The company's advanced manufacturing facilities include the latest in digital printing, vinyl cutting and flexible machine tool technology, so that it is ideally suited to handle large volume roll-out programmes as well having the capability to meet lower volume customised requirements.

Naturally, finishing operations are vital to the production of high-quality signage and environmentally-friendly powder coating is used to provide a sign surface which offers high gloss-retention and weatherability and is highly resistant to chipping, scratching, fading.

The powder-coating facility at Hawes Signs uses epoxy/polyester/pigment powders which are sprayed directly onto predominantly steel and aluminium panels of various sizes.

This powder must then be brought to a temperature which allows it to flow and fuse before being cured for a given time.

Previously, the sprayed-on powder had been pre-heated by a gas-fired infra-red system before entering a warm air convection oven for final curing.

However, this oven was starting to cause maintenance problems and to eliminate unwanted line stoppages while, at the same time increasing line speeds, it was decided to investigate alternative powder pre-heating methods.

Extensive tests were carried out at Heraeus' Neston Applications Centre and these showed that the powder coatings could be quickly and reliably heated to the required temperatures by medium-wave, electric infra-red.

As a result, a purpose-built medium-wave, infra-red oven was retrofitted into the existing powder coating and curing line, between the coating cabin and the warm air oven.

This consists of two parallel zones, a 50kW zone which heats the coated side of the panels and a 35kW zone which heats the rear, uncoated side of the panels to accelerate the heating effect.

Each of the zones can themselves be switched between two power outputs to accommodate two sizes of panel.

Since installation, the oven has helped to speed up the powder coating process as it heats the powder faster than the old system and it has also reduced the cure dwell time in the convection oven.

In addition, quality has improved, as the medium-wave heaters provide a uniform flow and fusion of the powders.

Heraeus Noblelight offers the complete range of infra-red radiation systems from NIR to medium-wave carbon infra-red (CIR).

It has over 40 years experience in infra-red technology and offers the expertise, products and systems to provide efficient and effective solutions to drying, heating and curing problems throughout industry.

If required, it can carry out proving trials with customers' own materials at its Neston Applications Centre and can advise on the selection of the optimum emitter to suit particular processes.