3Design ABS and PLA guide lines

ABS

ABS is short for Acrylonitrile Butadiene Styrene. I’ve you’ve payed attention in chemistry class, you’ll probably sense that the last two words sound very chemical. The last word indeed sounds like polystyrene which is used in packaging – and chances are that you’ve hold a flame against it as a child and discovered that it would melt and smell pretty bad. The melting part is what makes ABS a thermoplastic polymer suitable for FFF 3D Printing.

ABS has been used in industrial 3D printing a lot and has been a very popular plastic in the development of prosumer 3D printing: it melts consistently at around 225 degrees Celsius, which can easily be achieved with small and home-safe electronics. It is relatively strong, a little flexible and has a relatively high “glass transition temperature” of around 100 degrees. That’s the temperature above which a plastic goes from it’s solid state to a pliable state where it can loose it’s shape. These characteristics mean ABS is very suitable to 3D Print functional parts, like spare parts for machines or objects that are exposed to high temperatures like sunlight or hot water.

ABS is dissolvable in acetone. This is a widely available and relatively save chemical that most woman know as nail polish remover (be aware that not all nail polish removers contain 100% acetone though). This characteristic is used to smooth the surface of a 3D Print. Sanding an ABS print and then wiping it with acetone will dissolve the outer layer, essentially smoothing it by reducing the visibility of layers in the print. To fully take advantage of this you smooth prints with acetone vapor. I will go into the details of this in a later post, but I would like to say in advance that this technique deserves the “don’t try this at home” warning. While acetone vapor can also remove small intended details, it will give ABS prints – that otherwise have a matte finish – a high glossy look.

The downsides of ABS are the smell it produces while being heated – which is neither nice nor healthy to live or work around – and the fact that it expands and shrinks in the process of being heated and cooled down again. The shrinkage in particular is a problem for 3D printing, because it causes 3D prints to curl up while cooling too quickly, which is called warping. To counter this, ABS has to be printed on a heated build plate – and preferably in an enclosed, heated build chamber – so it stays warm during printing and can cool down slowly when printing is done. A heated build plate and chamber usually increase the price of a 3D printer and it uses considerably more electricity. So while ABS also comes in green, it’s far from it in terms of health and climate awareness. A third downside of ABS is that the bonding between layers isn’t always perfect.

This image by Boots Industries clearly shows the problems with ABS warping.

PLA

PLA – or Polylactic Acid – is a completely different kind of thermoplastic. It’s being made from corn starch or sugar cane and is biodegradable, so it’s greener than ABS. It melts can melt at a lower temperature between 190 and 210 degrees and doesn’t smell bad when it does. In fact many people like the smell of hot PLA. I’ve even read that people refer to it as the smell of waffles, but they probably have never been to Belgium.

Because PLA flows a little better than ABS, you can print more detailed objects with it at higher speeds. It’s especially good at producing sharp corners. It also is a lot less prune to warping, so you won’t necessarily need a heated print bed to print PLA. However, if you want to print objects with a large flat bottom surface without the edges warping a bit, a little bit of heat (around 60 degrees) from the bed can counter this. PLA prints have a relatively glossy surface compared to ABS, but the amount of gloss depends on the vendor, color and print temperature. Advanced users could vary the glossiness of different parts of a single print by varying the temperature during the printing process.

Unlike ABS, PLA isn’t dissolvable in acetone. It can be dissolved in Sodium Hydroxide. That’s what’s in drain cleaner and if you’ve ever used that you know that’s dangerous stuff to say the least. Some people use PLA as dissolvable supports for ABS prints on dual extrusion printers, but I would advice to only use Sodium Hydroxide when you have a nozzle that’s clogged by PLA. And even then you should very carefully choose a container for this, since Sodium Hydroxide can also dissolve some types of glass. If that scares you: just buy a new nozzle!

The optional heated bed has to be set around 60 degrees, because this is the glass transition temperature of PLA. This means that it gets pliable above that, which means it’s not very suitable for objects that get exposed to high temperatures. It’s also fairly brittle, so you wouldn’t want to use it for functional parts that have to last a while. PLA is simply easier to print with than ABS, so the conclusion is that PLA is currently the best “standard” material voor home and office 3D Printing of decorative objects.

How to choose the right Filament

After reading the above it becomes clear that there are is a list of characteristics to consider when choosing filament and that ABS and PLA offer quite the opposite. There are a few more things to mind when choosing filament, so here’s an overview:
The melting temperature of the plastic, so you know if your extruder can reach this temperature.
The glass temperature of the plastic, so you know if it’s suitable for the ambient temperature of your purpose.
The printing environment, so you can determine if the smell and chemical fumes are a problem.
The requirements for a heated bed to prevent warping.
The stiffness or flexibility of the plastic, so you know what forces it can withstand.
The advised print speed of the filament: some have to be printed extremely slow for good results.
The possibilities of finishing prints. Some materials can be sanded, polished, vapor-smoothed, painted or finished otherwise to get interesting results, some don’t.
The availability of the color you require: ABS and PLA are available in almost every color, but other plastics that I’ll cover next might have a more limited range. Some materials even offer special effects, like glitters, glow-in-the-dark or color changes by heat or light.
The compatibility between a material and your 3D Printer and Extruder Type. Read both your printer’s manual and warranty conditions before experimenting with materials. Some materials can seriously damage certain extruders and because of this printer manufacturers won’t even allow the use of different filament brands other then those they’re selling. What’s also important is to check which filament diameter your printer supports: most printers use 1.75 mm filament but some (like the Ultimakers) use 2.85 mm filament, which is sometimes referred to as “3 mm”.
The size of the spool. Every printer has it’s own way of suspending the filament spool while printing and can usually accommodate a wide range of spool sizes. However, some vendors design their printers so they can only hold their own filament. MakerBot has done this with it’s latest 5th generation line of printers (which I reviewed here) which can only hold their own very wide and flat spools. Some printers even use dedicated cartridges instead of spools, so you can only use their brand, comparable to 2D printers. There are also FFF 3D Printers in development that don’t use spooled filament altogether, but instead use pelletized filament, but at this moment most used spools.
The price. More on that in the next paragraph.
Filament Prices &
the Differences between Premium and “Non-Premium”

You can imagine that special kinds of filament are more expensive than regular ones. And even that filament with special colors or effects come at a higher price. But when exploring what and where to buy you’re filament, you’ll quickly discover that prices of standard-colored filament – let’s say Red PLA – can range between €10 and €50 per kg. Some part of that is pure marketing: they’re more expensive because you also pay for the brand, like you do with clothing. But another part is quality: really cheap filament is sometimes made from less quality source material and is usually less well checked for consistency.

“Premium filament” usually (not always!) costs between €25 and €50 per kilogram, but comes from better suppliers that offer better quality checking in the production process. The most important factor in this is the filament diameter. If a 3D printer is designed for 1.75 mm filament, it needs to be very close to that measurement: too wide filament could jam the extruder and too narrow filament could lead to extruder gears losing grip and extruding inconstantly, resulting in lower-quality prints.

In the current market it’s hard to say for sure which filaments are “premium”, but those that are usually have their own brand name – or are certified by 3D printer manufacturers – and are made by a traceable manufacturer that supplies all kind of characteristics of the plastic on their website.

I won’t go into the pricing of the filaments I’ll cover below, because they may vary over time and can depend on your currency and location. Just make sure that when you check the weight when you compare prices: spools usually contain either 0.75 kg or 1 kg of filament, but MakerBot’s “Large” Spools for instance, contain 0.9 kg. You might also find very big spools of 2+ kg, but keep in mind that they could be either to large for your spool holder, or too heavy for your extruder motor to unroll. Very big spools can best be put on a separate spool holder with some kind of bearing system. You can easily 3D print one yourself by downloading one of the many custom spool holder models on Thingiverse.

This information was provided by nick lievendag He has an amazing blog with lots of informative information. if your looking to purchase filament in New Zealand check our website here 

Contact Details

Technical Director email: design@3dinnovation.co.nz

Managing Director email: robert@3dinnovation.co.nz

Showroom hours: Monday to Friday 8.30am-5pm 

Open weekends by appointment only. 

Road front showroom:
74c Maleme Street
Greerton 
Tauranga 3112
New Zealand

Reference from nick lievendag