FREQUENTLY ASKED QUESTIONS (faq)

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For ease of use, our FAQs are divided into categories. This page is updated regularly, so please check back to learn more.

If you have a question about our products or services that is not listed here, please email: sales@metcase.co.uk with your question and our team will get back to you as soon as possible.

DESIGN-IN RESOURCES:

• How do I download an METCASE drawing or 3D model?
• Where can I download METCASE brochures, assembly instructions and certifications?

CUSTOMISING SERVICES:

• How do I ...?
• How do I ...?

SPECIFYING METAL ENCLOSURES:

• How do you earth a metal electronic enclosure?
• Are ventilated rack enclosures enough for heat dissipation?
• Are custom 19 inch aluminium enclosures expensive?
• Which finish is best for aluminium electronic enclosures?
• Are aluminium enclosures suitable for display-mounted electronics?
• How can I reduce the cost of a fabricated enclosure?

DESIGN-IN RESOURCES:

HOW DO I DOWNLOAD A METCASE DRAWING OR 3D MODEL?

Drawings are available for all METCASE products. This is how to download them:

1). Go to the individual product page of the part number you need (e.g. M6219145).
2). Open the 'DRAWINGS/INFO' tab at the bottom of the page. Here you can download the files.

NOTES:
- For 2D drawing files (.dwg/.pdf) you do not need to register, you can download them straightaway (.dxf files can be supplied on request).
- For 3D models (.stp/.x_t/.sat) you need to register and then login before you can download these files.
Register and login here >>

Where can I download METCASE brochures, assembly instructions and certifications?

Downloads available:

• brochures and publications
• assembly instructions
• certifications such as ISO 9001:2015, REACH, RoHS.

Download these from our technical downloads page here >>

CUSTOMISING SERVICES:

How do I ...?

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How do I ...?

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SPECIFYING METAL ENCLOSURES:

How do you earth a metal electronic enclosure?

There are different methods for earthing a metal electronic enclosure. METCASE strongly recommends the use of self-clinch stainless steel fasteners for the highest level of reliability – for both the strength of the insert (to ensure that it does not fall out) and for the earth bonding compatibility over long periods of time.

Best practice is to provide a dedicated protective earth (PE) stud formed using a self-clinching stainless-steel stud or nut installed directly into the primary structural chassis. This is typically the base or a main side wall but many METCASE enclosures feature earthing studs as standard on every panel. Inserts must be mechanically permanent, resistant to rotation/pull-out and located close to the mains entry point.

Stainless steel is preferred for the insert itself due to its mechanical robustness and long-term stability under thermal cycling and vibration. However, the electrical integrity of the earth connection is governed less by the insert material and more by the metal-to-metal interface between the insert and the aluminium substrate. Aluminium oxide, anodising and powder coating are electrically resistive so the PE insert must be installed into bare aluminium, with the bonding area masked during finishing. The self-clinching process is advantageous here, as it cold-flows the aluminium into the serrations of the insert, creating a gas-tight interface that is stable over time and far superior to a tapped hole or loose nut from both electrical and mechanical perspectives.

All incoming protective conductors should terminate using a crimped ring terminal, secured to the PE stud with a stainless nut and serrated or star washer on the conductor side to maintain contact pressure and break any residual oxide film. The same philosophy applies to the bonding of removable panels and subassemblies: where self-clinch nuts or studs are used to secure panels, at least one fixing per panel should be designated as a bonding fixing, again installed into uncoated aluminium and paired with a serrated washer to ensure a reliable earth path independent of cosmetic finishes.

View the full range of fixings and inserts >>

Are ventilated rack enclosures enough for heat dissipation?

Yes, sometimes – but it depends on the electronics within the enclosure. A ventilated rack enclosure can be perfectly adequate for heat dissipation but only if the thermal problem has been properly quantified and the enclosure is matched to it. In low-power or convection-friendly designs, a well-ventilated enclosure can be entirely sufficient, quieter and more reliable than an actively cooled one. But relying on ventilation by default – without analysis – is one of the most common mistakes in rack equipment design.

From a thermal engineering perspective, ventilation slots or perforations enable natural convection: heat generated by internal components warms the air, reducing its density and allowing it to rise and escape, drawing cooler air in from below. This mechanism is effective only when three conditions are met:

• the total heat load is modest
• there is a clear vertical airflow path
• the pressure drop across the vents is low.

In practice, a folded/fabricated aluminium enclosure with a small ventilation area can typically dissipate only a few tens of watts by natural convection without an excessive internal temperature rise. Above this, temperature rises will be rapid and non-linear.

Ventilated enclosures also suffer from diminishing returns if the apertures have been poorly executed. Small slot areas, cosmetic perforations or vents placed on a single face often look reassuring but contribute little to real airflow. Moreover, internal obstructions – PCBs, wiring looms, subchassis – can severely disrupt convection paths.

Where power dissipation is higher, or ambient conditions are poorly controlled, forced convection (fans, blowers or fan trays) becomes unavoidable. At that point, the enclosure’s role is to support controlled airflow rather than merely letting heat out.

Are custom 19 inch aluminium enclosures expensive?

Not as expensive as you might think. Hi-tech machinery and optimised processes help to reduce customisation costs. Smart design and advances in CNC machining and digital printing have made customisation viable even for many low-volume orders. This is particularly important for electronic instrumentation destined for niche applications.

Advanced 19" rack cases such as COMBIMET have been designed to make customisation faster, easier and more cost-effective. COMBIMET has a flat front with no bezel. This helps to reduce manufacturing costs and makes this model easier to customise. This has led to the development of many variations of COMBIMET including open top, smooth/solid top and super-deep (24" (610 mm)) versions – all of which are now available as standard, further helping to reduce the cost of modifications. For this reason, COMBIMET is METCASE’s most cost-effective 19" rack case model – despite being its most versatile.

Which finish is best for aluminium electronic enclosures?

Fine-textured powder-paint finishes are strongly recommended. METCASE has a large range of these paints in stock, with no extra charge for special colours that are from the stocked paint list. The benefit of fine textures is that they are hard wearing, they do not scratch as easily as a glossy surface and they look very professional. If need be, extra-hard-wearing fine-textured powder-paint can be specified for an even more durable finish.

Are aluminium enclosures suitable for display-mounted electronics?

Yes, they are ideally suited. METCASE has produced many 19", desktop/portable, wall-mount and VESA-mount aluminium enclosures with different types of display mounting solutions. They include integrated metal brackets behind the display for flush mounting. Threaded standoffs and mounting plates are also popular.

Aluminium enclosures are generally very well suited to display-mount electronics – they are often the default engineering choice. Success depends on treating the enclosure as part of the mechanical mount, thermal solution and EMC strategy from the outset, rather than as a cosmetic shell around the electronics.

Mechanically, folded aluminium sheet provides a strong stiffness-to-weight advantage. The folds do most of the structural work – even relatively thin material can be very rigid if the geometry is correct.

Thermally, aluminium can be advantageous for devices with displays but it needs to be part of the thermal path; heat sources need a deliberate conduction route into the chassis via thermal pads, spreaders or bonded interfaces. When done correctly, the enclosure becomes a passive heat spreader and radiator, enabling fanless designs. Surface temperature still needs checking under worst-case conditions but this is generally manageable for behind-display products.

From an EMC perspective, aluminium enclosures are usually preferable to plastics in this application. A metal enclosure provides inherent shielding in an environment that can be crowded with switching supplies, display cables and wireless technology. Seam design, aperture control and electrical continuity matter as much as material choice. Anodising and powder coating are insulating, so grounding and bonding points must be designed in, rather than assumed.

How can I reduce the cost of a fabricated enclosure?

Specifying a standard electronic enclosure and having it customised is almost always quicker and more cost-effective than opting for a fully bespoke housing. As an enclosure specialist, METCASE always assesses designs and suggests small changes which can significantly improve manufacture speed. Cost is driven far more by design decisions than by the aluminium itself. You can usually achieve meaningful savings without compromising function by simplifying geometry and standardising features.

Early engagement with a manufacturer like METCASE often yields direct cost savings. METCASE designs around its own press tools, hardware insertion equipment and finishing lines. Small changes to bend orientation, seam design or part split can eliminate entire operations. Designs that look equivalent on a drawing can differ materially in cost once translated into a real production workflow.

The single largest lever is to reduce fabrication complexity. Every additional bend, return flange, jog, or folded detail adds time, setup effort and cumulative tolerance risk. Enclosures that can be formed from one or two simple folded parts are consistently more cost-effective than designs that require multiple interlocking panels. Avoiding tight bend radii, back-to-back folds and small flange heights reduces scrap risk and enables faster, more repeatable forming. Designing bends to align with standard tooling rather than forcing special punches also lowers cost, particularly at low to medium volumes.

Material choice and thickness should be justified structurally rather than chosen conservatively. Aluminium sheet cost increases rapidly with thickness, and unnecessary thickness also increases bending force and handling time. In many cases stiffness can be recovered through fold geometry rather than added material. Selecting a commonly stocked alloy and temper in standard gauges avoids the extra costs and long lead times associated with non-standard material. Simplifying cut-outs, avoiding unnecessary internal profiles, and keeping aperture sizes sensible relative to sheet thickness all reduce cutting time.

Tolerances should be no tighter than function demands. Sheet-metal processes have inherent variability, and over-tight tolerances increase scrap, inspection time and rework. This is particularly relevant at mounting interfaces such as VESA patterns: the hole location tolerance should reflect what the mating bracket actually requires – not a generic machined-part assumption.

Hardware strategy has a disproportionate effect on enclosure cost. Each unique fastener type adds assembly overhead. Using a single screw size throughout the enclosure and minimising the total fastener count pays dividends. Captive fasteners can reduce assembly labour and prevent lost parts in the field.

Surface finish is often an underestimated cost driver. Anodising and powder coating are not interchangeable in cost or performance. It is important to get expert advice to see how costs can be minimised without compromising enclosure quality.

Get expert technical advice

Contact METCASE for specialist technical advice on specifying the best aluminium enclosures for your electronics. Engaging with METCASE early in the design process can result in cost savings and reduce time to market.