PLA and ABS are the most widely used FDM 3d printing materials in the World. Designers and hobbyists are all interested in knowing which material is better than the other. Which material do you think is better among the two? The answer of course is not so black and white. It depends on the application. We’ll cover all the differentiating aspects of ABS vs PLA in great detail throughout this article.
What are ABS and PLA?
ABS stands for acrylonitrile butadiene styrene. It is an oil-based strong thermoplastic. ABS is well-known in the injection molding industry and is used for applications such as LEGO, automotive bumper parts and musical instruments. It is one of the more economical materials used in injection molding.
PLA is polylactic acid and it is a biodegradable thermoplastic obtained from organic resources such as corn starch or sugarcane. PLA gives a shinier and smoother finish to the final products. Products made with PLA are aesthetically more pleasing. PLA is both strong and extremely rigid. It will not bend or elongate as much as ABS before breaking.
Properties of ABS vs PLA
Let us compare some of the properties of these two materials to get a better understanding of their strengths and weaknesses…
| Properties | ABS | PLA |
| Tensile Strength | 27 MPA | 43 MPA |
| Elongation at break (XY axis) | 3.5% | 2.1% |
| Density | 1.07 g/cm3 | 1.3 g/cm3 |
| Biodegradable | No | Yes |
| Glass Transition Temperature | 105C | 60C |
| Price (per kg) | $USD 20 | $USD 19 |
More material properties can and differentiating factors can be found using the Optimatter 3D printing material optimization software.
Strength
As seen from the table above, the tensile strengths of both materials are relatively high. Due to this, both are good for manufacturing prototypes and other applications. But when it comes to prototyping, PLA is preferred over ABS due to its higher accuracy and better aesthetics. It is also chosen for end use parts when rigidity is required over impact resistance.
ABS is preferred when the actual functionality of the part requires better flexibility, elasticity and impact resistance. This is a major factor in why ABS is used for many end-use parts in the automotive field.
Melting Point
The melting point of PLA is around 180C and it can be printed without using a heated bed. However, using a heated bed at 55C will provide better results. Its glass transition temperature is only 60C. This makes it a bad material for functional and end-use parts directly off the printer.
On the other hand, ABS being an amorphous material has no fixed melting point. Although, its glass transition temperature is much higher at 105C when compared to PLA and it is recommended to use a heating bed at around 80C during printing.
PLA vs ABS Print Accuracy
Both ABS and PLA have excellent accuracy and can be used to create dimensionally correct parts. Printing details down to 0.2mm and minimum features down to 1.2mm are possible using ABS and PLA filaments.
However, PLA is preferred over ABS when it comes to the sharpness of corners and features. This is mainly due to the fact that PLA has a lower printing temperature and is less prone to warp during printing.
Surface Finish and Post-Processing
As both the materials are used with FDM printing, hence print layers are visible on parts obtained from either material. However, ABS gives a matte finish while PLA usually gives a glossy look to the final parts.
Acetone is used during post-processing to give a glossier finish to ABS printed parts. This method of “vapor finishing” chemically smooths the layer lines with a solvent. This creates an extremely smooth and shiny part which can be compared to the aesthetics of injection molding.
As mentioned previously, PLA has a relatively low glass transition temperature directly off the printer. However, unlike ABS, PLA can be annealed to reach a higher glass transition temperature. This high temperature annealing process allows PLA to reach operational temperatures up to 130C.
ABS vs PLA: Which filament to go with?
As you see, there is no definite answer as to which among the two 3d printing materials is a clear winner. It mainly depends on the user requirements and part application.
For instance, if you’re looking for mass prototyping then PLA is likely a better choice owing to its ease of printing, aesthetically appealing parts, and high accuracy. If you need to create a small FDM part with high glass transition temperature, annealed PLA is a great choice.
Similarly, if the requirement is to produce fast functional end-products with high impact and temperature resistance, then ABS is the obvious choice. Or if you need the best aesthetic quality that FDM printing can offer, vapor finished ABS would be your choice.
One thing to keep in mind is that PLA is an obvious choice for users who are only 3d printing for fun. This would be the case if you just want to print out multiple parts to evaluate different designs. ABS is more suitable for professional users. This is mainly due to the fact that great care is required during 3d printing of ABS parts. The fumes need to be properly ventilated and a heated bed is a must in the process.
Now, let us ask you again… Which of the two materials is best suited according to your requirements? Contact us about your project and let us know!
