ABS, PLA or coPET. what to choose?
ABS, PLA or coPET. WHAT TO CHOOSE?
ABS, PLA, coPET
- thermoplastic (material that becomes soft when heated and harden when cooled again, and this process can be repeated many times). All of them are used in FDM 3D printing. The price range in Ukraine - the cheapest ABS, than coPET, and the most expensive - PLA.
So which of these plastics is better? ... None of them is not worse than the other. The right question - which one is best to use for a specific purpose?
Each material has its advantages and disadvantages, features of printing, storage, operating conditions. So let's look at all the nuances of the order.
General properties of the material.
ABS plastic is synthesized on the basis of refined-petroleum products. ABS has a high toughness, good strength. Plastic is used for prototyping accessories for motor vehicles, musical instruments, the Lego blocks, case of the phones. Operating temperature ABS plastic products does not exceed 70°C. The ABS plastic is readily soluble in common organic solvents - acetone, ethyl acetate, methylene chloride. This fact allows us to carry out post-processing printed products from ABS plastic with solvent. It gives them a glossy surface and a monolithic structure. When it's heated, there is an unpleasant smell of styrene, so it is recommended to work with the material in a well ventilated room and closed frame of the printer.
PLA (Polylactide) is produced from organic annually renewable resources (corn starch and sugar cane), but it is rather complicated and expensive technology. PLA is brittle material, and well-suited for printing of prototypes, models, toys and disposable products. Products of PLA have a glossy appearance. Operating temperature of PLA products do not exceed 60°C. Another feature of the PLA - the opportunity to print products with improved detailing and bunch of small components. When printing with PLA sometimes appears sweet herbal smell, the smell of steamed corn. It happens if the material is poorly cleared of impurities in the preparation.
All three plastics - ABS, PLA, coPET - tend to absorb moisture from the air. So in case of long term storage, they must be isolated from the open air to prevent moisture absorption. Skeins of yarn should be stored in dry sealed packaging - bags with a lock or zip-lock sealable containers.
Moisture, adsorbed by plastic, have destructive process under their heating. With 3D-printing with wet plastic, material is foamed at the nozzle exit of 3D-printer. It adversely affects the appearance, physical, mechanical and geometrical characteristics of the printed product. In some cases it can lead to clogging of the printer nozzles. coPET and PLA intensively absorb moisture.
In order to return the plastic for 3D-printing suitability it sufficiently driers at 60°C for 3-4 hours in a stream of hot dry air in special dryers.
Features of FDM 3D-printing.
For high-quality 3D-printing with ABS plastic you need heated platform of 3D-printer with the ability to heat up to 105-120°C. In the case of the glass platform - the best solution is frosted glass, which increases the adhesion between the working surface and printing product. Another way to improve adhesion to ABS products with platform of 3D-printer is a glue, based on ABS (solution ABS plastic with ethyl acetate).
In order to create high-quality products made of ABS plastic, it is necessary to use a closed printer. This will allow to print products without delamination or cracks.
Absolutely new solution for solving this problem is using a plastic ABS +.
ABS + - new development of a company, plastic with high adhesion both to the working platform of 3D-printer and between the layers in the product. It is very comfortable to print large dimensional product, using this plastic, because plastic has minimal shrinkage. The temperature of the working platform for 3D-Printer with ABS + is 75-80°C.
Unlike ABS PLA, coPET can be printed on unheated platform of 3D-printer. In the case of 3D printing of large articles you can heat platform of 3D-printer at 60-65°C for the first 20-30 layers of the article.
coPET is also recommended to print on blue adhesive tape, because after printing, the product adheres very strongly to the platform of 3D-printer and its difficult to remove it from the table.
The quality of printed products.
ABS, PLA and coPET are perfect for FDM 3D-printing products with high detailed, lots of sharp edges, protrusions (for example - gears, sprockets, etc.), but in each case they have their own nuances.
A greater degree of shrinkage ABS leads to warping of the printed part of the product, which contacts with the work platform of 3D-printer. Printing on the platform with a temperature of 105-120 ° C in a closed field of printing and slow cooling of the printed products helps to cope with this problem. The using of ventilator in the process of 3D-printing helps to eliminate the phenomenon of smoothed corners. A ventilator provides rapid curing of plastic and prevent it from settling. On the other hand, intensive cooling can lead the cracking of the product between the layers - the so-called delamination (the solution of this problem is using ABS +).
During printing with coPET and PLA, cooling of the models does not lead to its deformation, but decreases the adhesion between the layers. When printing with ABS plastic, cooling leads to a deformation model and delamination between the layers.
The smell of ABS plastic depends on the initial quality of plastic. In the production process it passes through the stage of evacuation of organic compounds. The smell of raw materials depends on the completeness of the passage of this process.
When heated ABS there is unpleasant smell, it is recommended to print in a well ventilated room and closed frame of printer. When printing with PLA, coPET, smell is less sharp. The smell of ABS will appear when you print more than 220-230°C as a consequence of the partial thermal decomposition. ABS plastic containing moisture makes a great smell and loses mechanical properties. There is no smell during printing with PLA and coPET, which contain moisture, only deteriorate the physic-mechanical properties.
If the printer does not print, you need to extract material from it, because after 10-15 minutes staying on it, ABS as a consequence of thermal decomposition turns into a solid infusible product which smells bad and the further printing can clog the nozzle of the extruder.