Are 3D Printed Parts Strong? PLA, ABS & PETG


Companies worldwide have recently turned to 3D printing to create technical parts quickly while saving some money in the process. But, developing 3D versions of pieces involves using new materials that might not be as durable.

So, are 3D printed parts strong? Most 3D printed materials will not be as durable as traditional methods, but they can be up to 80% as strong. Adding infill is a great way to make 3D printed parts much denser and stronger. You also have the option to increase the number of walls and wall thickness to increase the overall strength.

There’s a lot that goes into the strength of a 3D part. So, we’re going to be reviewing the materials used during 3D printing, how strong they really are, and what you can do to increase the strength of your 3D printed parts.

The Strength of Materials Used to Create 3D Parts

3D printed parts can only be as strong as the material that they’re made of. With that said, some materials are a lot stronger and more durable than others. That’s exactly why the strength of 3D printed parts varies so greatly. 

Three of the more common materials used to create 3D parts include PLA, ABS, and PETG. So, let’s discuss what each of these materials is, how they can be used, and how strong they really are.

PLA (Polylactic Acid)

PLA, also known as polylactic acid, is perhaps the most popular material used in 3D printing. Not only is it quite cost-effective, but it’s also very easy to use to print parts. That’s why it’s often used to print plastic containers, medical implants, and packaging materials. In most circumstances, PLA is the strongest material used in 3D printing.

Even though PLA has an impressive tensile strength of about 7,250 psi, the material does tend to be a little brittle in special circumstances. That means it’s a little more likely to break or shatter when placed under a powerful impact. It’s also important to note that PLA has a relatively low melting point. When exposed to high temperatures, the durability and strength of PLA will severely weaken.

ABS (Acrylonitrile Butadiene Styrene)

ABS, also known as acrylonitrile butadiene styrene, isn’t quite as strong as PLA, but that doesn’t at all mean that it’s a weak 3D printing material. In fact, this material is much more capable of withstanding heavy impact, often flexing and bending rather than shattering completely. That’s all thanks to the tensile strength of about 4,700 PSI. Given the lightweight construction yet impressive durability, ABS is one of the best 3D printing materials out there.

That’s why ABS is used to make just about any type of product in the world. It’s quite a popular material when it comes to printing children’s toys like Legos, computer parts, and even piping segments. The incredibly high melting point of ABS also makes it able to withstand just about any amount of heat.

PETG (Polyethylene Terephthalate Glycol-Modified)

PETG, also known as polyethylene terephthalate, is usually used to develop more complex designs and objects when it comes to 3D printing. That’s because PETG tends to be much denser, more durable, and more rigid than some of the other 3D printing materials. For that exact reason, PETG is used to make plenty of products like food containers and signage.

Why Use 3D Printing at All?

If 3D printed parts weren’t at all strong, then they wouldn’t be used as an alternative production method for many supplies and materials. 

But, are they as strong as metals like steel and aluminum? Definitely not!

However, they are quite useful when it comes to designing new pieces, printing them at a lower cost, and getting a good amount of durable use out of them. They’re also great for small parts and have a generally decent tensile strength given their size and thickness.

What’s even better is that these 3D printed parts can be manipulated to increase their strength and overall durability.

How 3D Printed Parts Are Made Stronger

Most 3D printing materials are rather durable on their own, but there are some things that can be done to increase their overall strength. This mostly comes down to the minor details in the design process. 

Most important would have to be manipulating the infill, wall thickness, and the number of walls. So, let’s take a look at how each of these factors can impact the strength of a 3D printed structure.

Infill

Infill is what’s used to fill in the walls of a 3D printed part. This is essentially the pattern within the wall that adds to the density of the piece overall. Without any infill, the walls of a 3D part would be completely hollow and rather weak to outside forces. Infill is a great way to increase the weight of a 3D part, also improving the strength of the part at the same time.

There are plenty of different infill patterns that can be used to improve the strength of a 3D printed piece, including a grid infill or a honeycomb infill. But, just how much infill there is will determine the strength. For regular 3D parts, up to 25% is likely more than enough. For pieces designed to support weight and impact, closer to 100% is always better.

Number of Walls

Think of the walls of a 3D printed part as the support beams in a house. If a house only has four exterior walls and no support beams or interior walls, just about anything can cause the house to collapse or give under any amount of weight.

In the same way, the strength of a 3D printed piece will only exist where there are walls to support weight and impact. That’s exactly why increasing the number of walls inside a 3D printed piece can increase the strength of the structure. This is an especially useful strategy when it comes to larger 3D printed parts with a greater surface area. 

Wall Thickness

The actual thickness of the walls used in a 3D printed piece will determine how much impact and weight a part can withstand. For the most part, thicker walls will mean a more durable and sturdy piece overall. But, there does seem to be a point at which it’s difficult to print 3D printed parts when the walls are too thick.

The best part about adjusting the wall thickness is that the thickness can vary based on the area of the part. That means the outside world probably won’t know that you’ve thickened the walls unless they cut your piece in half to dissect it. Generally speaking, extremely thin walls will be quite flimsy and won’t be able to support any exterior weight without collapsing.

For the most part, walls that are at least 1.2mm thick are durable and strong for most materials. And, as the length and size of the walls increase, so should the thickness of the walls.

Conclusion

3D printed parts are definitely strong enough to be used to make common plastic items that can withstand great amounts of impact and even heat. For the most part, ABS tends to be much more durable, though it does have a much lower tensile strength than PLA. 

But, you also need to take into consideration what’s being done to make these printed parts even stronger. When you bump up the infill density, increase the number of walls, and improve the wall thickness, you’re adding to the strength and durability of a 3D printed piece.

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