As enclosure specialists, we are often asked, which is better metal or plastic for custom enclosures? Each material has its strengths and weaknesses, and which material you use for your next enclosure project will depend largely on what you need it for and how many you are looking to produce.
Pros for plastic enclosures:
The term “plastic” is a blanket term that typically covers many different materials, including ABS, HIPS, PC, PVC and acrylics.
- Plastic enclosures can be more cost-effective and lighter than metal.
- Custom plastic housings generally weight less than their metal counterparts.
- Plastic cases are electrically insulated whereas metals are good conductors so plastic boxes, unlike a metal box, would not need to be grounded. Grounding a metal box takes more time and expense.
- Also, often plastic enclosures have PCB slots integrated into them which can make the assembly of the components easier and quicker than screws and studs associated with metal units.
- Plastics have a clean surface with no sharp edges or corners. They look professional and work well where aesthetics are important.
- Flame retardant plastics can be used where necessary, and if a metallised coating is needed for EMC purposes, then plastic housings can be sprayed with Nickel, copper or silver coatings.
Cons of plastic enclosures:
- Some plastics are not suitable for long term outdoor use.
- Plastics have limited chemical resistance relative to metal.
- When absolute strength is needed then metal will be harder to damage or vandalise than plastic.
Pros for metal enclosures:
- Metal is fire resistant and in some simple designs can be cheaper than plastic.
- A metal housing is also stronger over a plastic case.
Cons of metal enclosures:
- They tend to be more expensive and heavier than plastic enclosures. Metal enclosures also have sharp edges and have to be painted, which adds to the cost of the enclosure.
- Metal can also be difficult to work with and shape. Shaping a metal part can require die work, welding, grinding, rework, or bending to achieve design specifications and desired look, which can be limiting. Metal also needs to be earthed, given its conductivity which can present safety issues.
- Metal can get hot to the touch, which may be dangerous.
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Plastic v Metal for custom enclosures conclusion
It seems that it is entirely dependent on the application and your budget as in reality, both are possible solutions. Questions around the application, quantity and the environment that it will be used in will all influence the decision made.
If you would like to discuss any aspect raised in this article, please contact CDT, the UK’s leading plastic enclosure experts on 01280 845530.