Benefit of 3d printing in abs

In Geen categorie by CoenLauwerijssen

Benefit of 3D printing in ABS versus PLA

There are a number of benefits of 3D printing in ABS over PLA. Hereby 3D Prontoprint will first give an fact based overview of the differences between ABS and PLA.

Some Common Ground

There are many materials that are being explored for 3D Printing, however you will find that the two dominant plastics are ABS and PLA. Both ABS and PLA are known as thermoplastics; that is they become soft and moldable when heated and return to a solid when cooled. This process can be repeated again and again. Their ability to melt and be processed again is what has made them so prevalent in society and is why most of the polymers you interact with on a daily basis are thermoplastics.

Now while there are many thermoplastics, very few of them are currently used for 3D Printing. For a material to prove viable for 3D Printing, it has to pass three different tests:

  • initial extrusion into plastic filament
  • extrusion and trace-binding during the 3D Printing process
  • then finally end use application.

The first test, that of production from base plastic resin into top-notch plastic filament is a strict and carefully monitored process. It is the engineering process that takes the plastic from a pile of pellets to a uniformly dense, bubble free, consistently sized, round rod. Here there is little difference between ABS and PLA; most thermoplastics can pass this test, it is mainly just a question of the time and costs required to do so while still producing plastic filament that runs smoothly and consistently during the 3D Printing stage.

Here is where the two plastics divide and will help to explain why different groups prefer one over the other.

 

Storage

Both ABS and PLA do best if, before use or when stored long term, they are sealed off from the atmosphere to prevent the absorption of moisture from the air. This does not mean your plastic will be ruined by a week of sitting on a bench in the shop, but long term exposure to a humid environment can have detrimental effects, both to the printing process and to the quality of finished parts.

 

3D printing in ABS

Moisture laden ABS will tend to bubble and spurt from the tip of the nozzle when printing; reducing the visual quality of the part, part accuracy, strength and introducing the risk of a stripping or clogging in the nozzle. ABS can be easily dried using a source of hot (preferably dry) air such as a food dehydrator.

 

3D printing in PLA

PLA responds somewhat differently to moisture, in addition to bubbles or spurting at the nozzle, you may see discoloration and a reduction in 3D printed part properties as PLA can react with water at high temperatures and undergo de-polymerization. While PLA can also be dried using something as simple as a food dehydrator, it is important to note that this can alter the crystallinity ratio in the PLA and will possibly lead to changes in extrusion temperature and other extrusion characteristics.

 

Smell

The smell of 3D Printer filament while printing will vary largely from manufacturer to manufacturer based in large part on how much degradation occurred during production. Of course, plastics are tricky things and you’ll find that the biggest influence on smell regardless of plastic type or source is printing temperature.

3D printing in ABS

While printing ABS, there is often a notable smell of hot plastic. While some complain of the smell, there are many who either do not notice it or do not find it to be particularly unbearable. Ensuring proper ventilation in small rooms, that the ABS used is pure and free of contaminants and heated to the proper temperature in a reliable extruder can go a long way in reducing the smell.

 

3D printing in PLA

PLA on the other hand, being derived from sugar gives off a smell similar to a semi-sweet cooking oil. While it certainly won’t bring back fond memories of home-cooked meals, it is considered by many an improvement over hot plastic.

 

Part Accuracy

Both ABS and PLA are capable of creating dimensionally accurate parts. However, there are a few points worthy of mention regarding the two in this regard.

 

3D printing in ABS

For most, the single greatest hurdle for accurate parts in ABS will be a curling upwards of the surface in direct contact with the 3D Printer’s print bed. A combination of heating the print surface and ensuring it is smooth, flat and clean goes a long way in eliminating this issue.

For fine features on parts involving sharp corners, such as gears, there will often be a slight rounding of the corner. A fan to provide a small amount of active cooling around the nozzle can improve corners but one does also run the risk of introducing too much cooling and reducing adhesion between layers, eventually leading to cracks in the finished part.

 

3D printing in PLA

Compared to ABS, PLA demonstrates much less part warping. For this reason it is possible to successfully print without a heated bed.

PLA undergoes more of a phase-change when heated and becomes much more liquid. If actively cooled, much sharper details can be seen on printed corners without the risk of cracking or warp. The increased flow can also lead to stronger binding between layers, improving the strength of the printed part.

 

ABS and PLA General Material Properties

In addition to a part being accurately made, it must also perform in its intended purpose.

 

3D printing in ABS

ABS as a polymer can take many forms and can be engineered to have many properties. In general, it is a strong plastic with mild flexibility (compared to PLA). The flexibility of ABS makes creating interlocking pieces or pin connected pieces easier to work with. It is easily sanded and machined. Notably, ABS is soluble in Acetone allowing one to weld parts together with a drop or two, or smooth and create high gloss by brushing or dipping full pieces in Acetone. Compared to PLA, it is much easier to recycle ABS.

 

Its strength, flexibility, machinability, and higher temperature resistance make it often a preferred plastic by engineers and those with mechanical uses in mind.

 

3D printing in PLA

Created from processing any number of plant products including corn, potatoes or sugar-beets, PLA is considered a more ‘earth friendly’ plastic compared to petroleum based ABS. Used primarily in food packaging and containers, PLA can be composted at commercial compost facilities. It won’t bio-degrade in your backyard or home compost pile however. It is naturally transparent and can be colored to various degrees of translucency and opacity. Also strong, and more rigid than ABS, it is occasionally more difficult to work with in complicated interlocking assemblies and pin-joints. Printed objects will generally have a glossier look and feel than ABS. With a little more work, PLA can also be sanded and machined. The lower melting temperature of PLA makes it unsuitable for many applications as even parts spending the day in a hot car can droop and deform.

 

In Summary

Simplifying the myriad of factors that influence the use of one material over the other, broad strokes draw this comparison.

 

3D printing in ABS

Its strength, flexibility, machinability, and higher temperature resistance make it often a preferred plastic for engineers, and professional applications. The hot plastic smell deter some as does the plastics petroleum based origin. The additional requirement of a heated print bed means there are some printers simply incapable of printing ABS with any reliability.

 

3D printing in PLA

The wide range of available colors and translucencies and glossy feel often attract those who print for display or small household uses. Many appreciate the plant based origins and prefer the semi-sweet smell over ABS. When properly cooled, PLA seems to have higher maximum printing speeds, lower layer heights, and sharper printed corners. Combining this with low warping on parts make it a popular plastic for home printers, hobbyists, and schools.

Benefit of 3d printing in abs was last modified: March 17th, 2015 by CoenLauwerijssen