What is PLA?
Poly Lactic Acid or PLA is a plastic manufactured from organic materials like cornstarch, tapioca and sugarcane. PLA is a biodegradable plastic and classified as a bioplastic. Like most plastics it can be processed into a fibre which allows it to be extruded in a 3D Printer to form a solid layered plastic object. Also being a bioplastic the fumes when melted are not harmful or noxious and being made from a sugar or starch like raw material are quite sweet smelling.
What is ABS?
ABS or Acylonitrile Butadiene Styrene is an oil-based manufactured plastic. It has a long history in manufacturing and industry being used to make everything from Lego blocks to car parts. ABS, being an oil-based plastic, produces noxious fumes when melted and ventilation is required when printing or a 3D printer with a HEPA filter is required to remove the fumes. ABS has a much higher melting point than typical PLA and greater strength, flexion before failure and durability.
PLA vs ABS
PLA being made from natural materials is much safer to work with than ABS. PLA also has a lower glass melting point of around 60-65 degrees which results in a shinier finish and faster print. This makes it excellent for use as a 3D Printing plastic however the obvious downside is the relatively low melting point makes it unsuitable for high heat environments. The tensile strength of PLA can also vary widely depending on the quality of its manufacture.
ABS has a higher melting point and typically a more impact resistant and durable end result. Due to its higher melting point, however ABS can be more difficult to work with. It can warp when cooling if a heated printing base is not used and can produce less accurate or rougher surfaces and less sharp corners. This means it will often requires some post-print finishing, but can be sanded and machined more easily than PLA. Some printer manufactures like UP 3D Printers have developed methods to improve the accuracy of ABS by printing at slightly higher temperatures than when printing with PLA filament.
The more earth friendly and safer to operate PLA filament makes it a much better choice for home hobbyist, schools and education institutions. It is often also used for prototyping as it has a smoother finish and is easier to print and work with. ABS is typically required when creating any plastic part or product for industrial or commercial use which requires a higher melting point, impact resistance, ductile strength and generally better durability.
Not All Plastics are Created Equal
This is where the lines get slightly more blurred. The PLA vs ABS discussion so far has focused on generalities. PLA and ABS are manufactured via a chemical process and with all processes the final product may vary in terms of pureness and structure depending on both the quality of the raw materials and the process itself. This results in often significant differences in the quality and ease of extrusion. Further different processes, additives and blends can result in vastly different properties of the plastic.
The first problem can be in the consistency of the shape of the filament itself. Filament that is not consistently round along it's length can cause the printer extruder head to block or worse be damaged. The second problem is in the quality of the 3D printer plastic. Poor quality filament results in poor quality 3D prints. It is not the same as a regular ink printer where the finished results between genuine and generic ink are often indistinguishable to the untrained eye. The differences in the finished product can vary to the point of being unrecognisable when using cheap filament. Given the price of filament this is one case where sticking to genuine or reputable branded 3D printing materials will save a lot of frustration and wasted prints.
A Different Kind of PLA
Not all PLA behaves like PLA! Currently the biggest improvements in 3D printing systems are coming from advancements in filament composition. Innovative filament manufactures like PolyMaker have developed new types of filaments with vastly different properties than the traditional composition. For example PolyMaker's PolyMax PLA filament is 9 times stronger than regular PLA and is 20% stronger than ABS while offering the same printing benefits of PLA - a smoother finish, easier printing and less pollution. PolyMax also offers similar ductile properties as ABS meaning it achieves similar flexion and so can be used in place of ABS for many applications.
The Future of 3D Printer Filament
PLA and ABS filament are just the beginning for 3D printers. A whole range of new special blend plastics and different materials are powering the 3D printing revolution. Super-strong polycarbonate filament is pushing 3D printing into areas of manufacture where lightweight strength and hardness are required. Wood blend filaments are giving hobbyist the chance to experiment with different finishes and flexible printer filaments are opening doors into fashion and accessories.
While many have questioned the commercial usefulness of 3D printing with current technologies it is new filament advances that are opening up whole new worlds to existing printers owners. The promise of on-demand manufacturing and eliminating previously prohibitive tooling costs allowing innovative plastic products to be produced quickly has put the power back into the hands small-scale manufacturers, inventors and enthusiasts and the maturing 3D printer filament industry is powering that promise.