FEATURE MATERIALS IN DESIGN & PROTOTYPING
3D printing – where you turn a computer-based model into a physical object by ‘printing’ it layer by layer – is becoming increasingly popular for product designers, design engineers, manufacturers, hobbyists and more. Rüdiger Theobald, marketing director, Verbatim EMEA, explains why and looks into the importance of choosing the right materials for the task
feed of material. Good quality filaments guarantee the diameter of the product is within tight limits and the make-up of the material is consistent. Without this, the strength and appearance of the end result will suffer. The key thing to look for is the
Material matters: The importance of selecting the right filament
Above: A Verbatim 3D printer. For design engineers, 3D-printed prototyping has the power to
transform and accelerate their working processes, better understand their designs and produce superior end products
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D printing enables us to create complex shapes and structures;
to combine raw materials in new ways; and, because there’s no need for large upfront tooling investment, it can make one-off and small-scale production runs commercially viable. There is also less waste than with traditional manufacturing. For design engineers, 3D-printed
prototyping has the power to transform and accelerate their working processes, better understand their designs and produce superior end products. It is, however, important to pick the
Right:
3D printing can be used to create a wide range of products, like this piston, for example
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right 3D printing material – known as ‘filament’ – for the product being created. There’s no one-size-fits-all solution: each material has distinct benefits, and understanding them is key to getting good results. Verbatim, part of the Mitsubishi Chemical Holdings Group, has therefore put together a guide covering the filament materials it currently offers – including established options such as ABS and PLA, as well as emerging offerings such as TPE, PET, PP and BVOH.
FILAMENT QUALITY To print accurately and consistently, the printer needs to pull through a consistent
NOVEMBER 2016 | DESIGN SOLUTIONS
filament’s diameter accuracy. With 1.75mm diameter ABS or PLA, high- quality filament would offer variances of no more than 0.02mm, while with 2.85mm diameter ABS/PLA filament this figure would be at most 0.03mm. In addition, filament materials’ properties alter when exposed to moisture. The material must therefore be purchased in sealed containers with desiccant included, and stored correctly.
ABS (ACRYLONITRILE BUTADIENE STYRENE) ABS, a petroleum-based plastic, has long been a popular choice for 3D printers, thanks to its low cost, toughness, durability and ability to withstand higher temperatures. Once cooled, it can easily be sanded and painted, and is soluble in acetone, enabling you to modify your creations after printing. ABS contracts when it cools, meaning the printed product must be kept warm while printing is in progress. ABS therefore requires the printbed (the surface onto which the material is laid) to be heated to around 90˚C. As a petroleum-based product, it is
less environmentally friendly than certain other filament types and doesn’t biodegrade, although it can be recycled.
PLA (POLYLACTIC ACID) PLA is easier to work with and is made from plant material. It doesn’t require a heated printbed, though in some cases printing onto a bed at around 60˚C can improve results. It enables higher print speeds than ABS, but has a lower melting point – so it is therefore less suitable for objects that will be exposed to heat, such as engine parts. Once it cools, PLA is relatively strong but more brittle than ABS and can warp. The new high performance PLA material from Verbatim, however, includes special additives from Mitsubishi Chemical that virtually eradicates these issues and offers longer life. In addition, the mix is soft enough to allow 3D printed objects made from Verbatim’s high performance PLA to be sandpapered for a smooth finish.
TPE (THERMOPLASTIC ELASTOMER) Where both ABS and PLA are rigid, TPE filaments are soft and elastic. An interesting product is Verbatim’s PRIMALLOY, which offers flexibility and rubber-like elasticity. This is strong, highly oil-, chemical- and heat-resistant, and can withstand repeated flexing. It therefore makes 3D printing a viable production technique for products such as tool grips, seals, gaskets, tubing, electrical connection sheaths and medical bags. A heated print bed of around 50˚C is recommended, but TPE can be trickier to work with than ABS and PLA.
PET (POLYETHYLENE TEREPHTHALATE) PET is relatively easy to work with as it has good layer adhesion and is solvent-resistant, meaning it can (in most cases) be used for food and other types of packaging. Verbatim’s PET filament is easy to
use, has a tensile strength of 70Mpa, and offers a high level of transparency. Printed objects will therefore be relatively smooth and provide an attractive transparent, sparkly appearance.
PP (POLYPROPYLENE) Using PP 3D print filament it is possible to create durable, flexible, transparent, heat- and chemical-resistant containers for food packaging, medical equipment, IT kit and other appliances. This requires a heated print bed of around 100˚C and is ideal for objects that require softness, transparency and heat resistance.
BVOH (BUTENEDIOL VINYL ALCOHOL CO-POLYMER) Unlike the other filament materials, BVOH is water-soluble. As it offers great adhesion to both ABS and PLA, it can be used to support these materials during printing, before dissolving it later. This means complex structures can be created that wouldn’t be possible with ABS or PLA alone. It is also highly durable against general moisture.
Verbatim
www.verbatim-europe.co.uk/3D
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