Ask the experts

ES Nov15 Pg28 Hammond2Considering in-house or third-party modification? Asking the original manufacturer to configure an enclosure can be more economical, explains Hammond Electronics’ Russell Irvine.

Using standard enclosures has its advantages: products are on the shelf ready for immediate delivery and unit costs are attractive. Standard products, however, are exactly that: standard. To suit a specific project, they typically have to be machined to accept switches, displays, connectors and keyboards. They may need to be printed with legends and logos or finished in a non-standard colour to meet branding requirements.

To modify a standard enclosure, there are three options. Firstly, purchase standard products and modify them in-house, however, few electronics OEMs have the resources. Alternatively, buy standard products and outsource the modifications. Unfortunately, there are costs, time penalties and logistics complications associated with sub-contracting, with each process requiring extra units to allow for first-offs and set up wastage. By far the best option is for the original manufacturer to modify the enclosure.

As a supplier of moulded plastic, metal, extruded and die-cast aluminium enclosures to the electronics industry, Hammond Electronics offers more than 5,000 different standard designs and sizes. It also boasts the equipment, people and systems to support modifications. The latest investment of over £100k in CNC machines increased modification capacity by some 35 per cent, improving service levels and reducing lead times.

Made to measure

So what kind of modifications can be undertaken? Using CNC XYZ milling machines, Hammond is able to create cutouts and rebates. Choose from a library of standard apertures or create custom shapes. Modern drilling equipment ensures large and small holes can be positioned to tolerances of 0.005mm relative to each other. Alternatively, in sheet metal enclosures, punching is an economical way of creating apertures in flat panels.

Legends can be engraved in both plastic and metal using traditional techniques. Other marking options include screen printing, which enables single or multiple solid colour legends in a durable finish that resists erosion.

Plastic, unlike metal, offers no radio frequency (RF) attenuation. If radiation susceptibility is a potential problem, Hammond offers electromagnetic compatibility (EMC) coatings. A variety of materials can be applied to the inner surfaces of a plastic enclosure to give different degrees of attenuation depending on project requirements.

Plastic enclosures are available in ABS, flame retardant ABS and polycarbonate, in any custom colour. Alternatively, aluminium die-cast enclosures are available as standard in natural and black finish. Different finishes and colours can be applied to both enclosures and panels. Overlays can be added to any size of front panel to give a durable and attractive appearance.

To help specify modifications, PDF drawings or CAD files for all products are available online.