Metals and thermoplastic materials: 5 characteristics in comparison
10 September 2020
The comparison between metal and plastic has always been a much debated topic. In fact, until some time ago, plastic products were considered to be of lower quality than their metal analogues. Nowadays, however, advances in the production and industrial processing of plastic materials can increasingly better satisfy the demands of many sectors.
In fact, thermoplastic materials are gradually replacing metal in a large number of items destined for the land, maritime and aerospace transport, medical devices, food and many other industries.
The aspects to be considered for a comparison between plastic and metal concern mainly their physical-mechanical characteristics, and the economic convenience in large-scale production.
1. Weight
The first difference between plastic and metal is easily detectable: articles made of plastic materials are much lighter than their metal analogues. For example, the weight of a 500-litre polyethylene tank is 25 kg, aluminum is about 70 kg, and steel over 200 kg.
This is a great advantage of plastics on metal because reducing the weight of the raw material means saving on maintenance, logistics, installation and transportation costs.
2. Resistance
Until recently, the main downside of plastic compared to metal was the lower mechanical strength.
Currently, the development of new technologies in the production of plastic composites, such as the addition of carbon fiber, graphite, or other elements, guarantees many thermoplastic materials similar or even superior performance to metal.
3.Elasticity
Most thermoplastic materials have the ability to react to external mechanical forces such as compression, traction and others, slightly deforming, to return to the original form as soon as the stress ceases.
This feature makes them suitable for a much wider range in terms of usability and design complexity than metal.
4. Construction time
Industrial plastic manufacturing processes, especially thermoforming, are much faster than metal ones.
In fact, the realization of a metal article requires various manual or automated steps of production such as cutting, bending, drilling, welding and machining such as embossing, knurling, and others. In many cases, it should also be finished and painted.
Instead, the plastic thermoforming process consists in the electronic programming of a machine that, starting from the raw material, is able to produce the ready-made piece, finished and of the desired color.
This allows you to easily meet deadlines or increase production without affecting too much delivery time.
5. Production costs
Even with today’s technology, some intrinsic characteristics of metals make it impractical to make parts such as composite curves or complex surfaces.
In fact, meeting the design specifications and getting the desired look means greatly increasing design, production and delivery times. And this inevitably results in a considerable increase in costs.
Instead, in the case of plastic thermoforming, the complexity of the project is almost negligible. In fact, any additional shapes, decorations and patterns of the surfaces are incorporated into the molds. In this way no secondary processing is required to obtain a finished and ready for delivery product.
