How Strong Are 3D Printed Parts? Determining Factors & How to Make It Stronger!


3D printed parts are very robust, especially when specialized filaments like Polycarbonate or PEEK are used. You can adjust wall thickness, print orientation, and infill density to enhance the strength of the printed part.

We cannot conclusively say how strong 3D printed parts are but, we can say that the strength of 3D printed parts will vary. The strength depends on certain factors especially the type of plastic printing material used. This means that the strength of 3D-printed parts can only be strong if the material used to produce them are strong.

Three of the most common material used in 3D printing include ABS (Acrylonitrile Butadiene Styrene), PLA (Polylactic Acid), PC (Polycarbonate), and PETG (Polyethylene Terephthalate Glycol-Modified)

However, we can look at it from the perspective of what is the strongest plastic/ filament for 3D printing and compare other options with it

3D Printing Is Here To Stay

So, How strong are 3d Printed parts? The strongest plastic/filament in the market is polycarbonate filament. Its mechanical structure is much stronger than other filaments, having shown excellent strength and resilience. It is widely used in engineering processes and has a tensile strength of 9,800 PSI compared to PLA’s 7,250 PSI, nylon’s 7,000 PSI, and ABS 4,700 PSI  .  (Source)

Note that this does not take into consideration deterioration from environmental factors such as PLA which degrades when exposed to light

Most people used to think 3D printed models are weak and fragile. However, serious strides have since then been made to enhance the strength and durability of these models. Today, 3D models are being processed that can stand very hash conditions.

There is much that goes with the strength of a 3D-printed part. Therefore, we will review the factors that determine the strength of the 3D printed parts, what can enhance the strength of 3D printed parts, the plastic materials used in 3D printing, their strength, and so much more.

What determines the strength of the 3D-printed item?

Whether you consider using 3D printing technology for end-user applications or prototypes, there are many factors you need to put into consideration to ensure the printed parts are strong enough. Here are some of the key factors that influence the strength of the 3D printed item: (Source)

  • Orientation of the part

Positioning of your part on the 3D printer is an important unique strength consideration to 3D printing. You need to understand how 3D printed parts are produced on an FDM 3D printer if you want to understand why the orientation of the part is such an important impact.  

Even though each layer’s plastic bonds to a previous layer, There still exist weak points which are the boundaries between the layers. If your 3D printed parts break or crack, it is basically between layer lines. Factoring out this aspect in 3D printed parts is vital when the parts are subjected to forces in a specific direction. 

For external forces acting across the layers that cannot be avoided, A good printing material/plastic you can consider is PETG because it has the best performance when it comes to layer bonding.

  • Material choice

The material used to make your 3D part has a substantial impact on the strength of the 3D printed part. Usually, the materials used in 3D printing include ABS (Acrylonitrile Butadiene Styrene), PLA (Polylactic Acid), PC (Polycarbonate), and PETG (Polyethylene Terephthalate Glycol-Modified). Before making a decision on the most appropriate material to use, you should first evaluate what type of force your 3D printed parts will go through.

Polycarbonate is best for parts that require tensile strength to help resist forces pulling on your 3D printed object. Although the polycarbonate material has high tensile strength, it is not cost-effective. This is why the PETG is a good alternative because it offers 70% of the tensile strength of polycarbonate. (Source)

PETG is a common choice of material for 3D printing both for general purpose and commercial applications. Apart from the two printing materials mentioned above, the PLA material is also a good one to use with ABS being the least effective choice of material for resisting this intense kind of force.

PETG material has strong bonding layers, making it stronger compared to other options. This is another reason why it is considered the best choice for parts that require high strength.  

In case you subject your printed part to bending forces, ABS is the strongest material option available for you due to its ductility nature. This is followed by PETG material. PLA is not the best bet for applications that require flexural resistance because it is stiffer and more fragile than the other two options.

In case your 3D part is to be subjected to fall, PETG or ABS are the best bet. But, PLA is not recommended for this use because it is rigid. 

  • 3D printer settings

3D printer settings such as the infill Percentage is required when placing an order for a 3D printed part. This represents the density of your model interior. The infill percentage ranges from 0% (a complete hollow model) to 100% (a complete solid model).

The infill percentage supports the interior part of your model as it has the biggest impact on compression strength. While it looks obvious that a complete solid model would be the strongest bet, a value above 60-70% won’t do much to the model strength and is not worth the print time and cost.

So, stick to an infill percentage of 60-70% and always consider whether the merits outweigh the shortfalls.

Another 3D printer setting you should pay attention to is the shell thickness. This factor also plays a critical role in determining the strength of a 3D-printed part. Shell thickness refers to the outer surface thickness. The standard thickness most 3D printing services use is about 1.0 to 1.5 mm.

However, unlike the infill percentage, increasing the shell thickness setting can enhance the tensile strength greatly and impact the strength of your 3D-printed parts.

Check out our article on Why a 3D Print Becomes Brittle and How To Fix It!

Are higher resolution 3D prints stronger?

To determine whether a 3D printer is of high resolution, you must consider the resolution in 3D printing. Resolution in 3D printing is an important factor because it helps to evaluate the print quality of a 3D printer. However, manufacturers use different methods such as layer height when defining the resolution of a 3D printer.

3D printer resolution is beyond the layer height. In fact, layer height is considered a poor representation of 3D printer resolution because it doesn’t pay attention to the XY plane and only considers the Z resolution.

XY Resolution

The XY resolution or horizontal resolution is the smallest movement made by the 3D print head within a particular layer. Hence, the lower the XY value, the higher the resolution, meaning the high print details.

The X/Y values are normally defined on the 3D printer’s specification sheets. However, this value is not always accurate. You can also measure resolution using the 3D printer nozzle diameter. A smaller nozzle diameter will result in a higher resolution.  

Z Resolution

The Z resolution or vertical resolution is the minimum thickness of a layer, which can also mean layer thickness or layer height. A small vertical layer height will result in a higher resolution, meaning you will have a more detailed and smooth 3D printed surface.

On the other hand, the Z resolution (vertical resolution) is the minimal thickness of a layer; sometimes called layer height or layer thickness. The smaller the layer height, the higher the resolution, which means the printed surface will be smoother and more detailed.

One key shortfall of a smaller layer thickness is that the 3D printing process will take a longer time because more layers will be required. Also, thinner layers will not always result in better prints.

It is also crucial to note that the size of the nozzle affects the maximum layer height. It is impossible to print a layer, thicker than your nozzle size. Furthermore, it is recommended that your maximum layer height never exceed 80 percent of your 3D printer nozzle diameter.

For instance, if your nozzle diameter measures 0.4 mm, then the print layers should not be thicker than 0.32 mm. If you exceed 0.32 mm, the plastic will not yield easily to pressure, and the bond between layers will not be strong. (Source)

How can you enhance the strength of a 3D printed part?

The following are ways in which you can increase the strength of your 3D printer: (Source)

  • Increase infill density at least by 20%
  • Increase wall thickness by maintaining at least 1.6 mm thickness
  • Changing the orientation (extrusion direction)
  • Adjust flow rate
  • Decreasing print speed
  • Use a Strong Infill Pattern
  • Adjust your line width to an even multiple of your layer height
  • Reducing your cooling fan rate to enable your parts to bond strongly during the 3D printing process.
  • Increase your printer’s nozzle size to 0.6 mm or 0.8 mm diameter
  • Increase layer height (Use thicker layers)

The best way to have a strong print is to pick the right material. Here is the top 5 strongest 3D printing filament Listed to choose from:

  • Polycarbonate Filament
  • Carbon Fiber Filaments
  • PEEK Filaments
  • ABS Filament
  • Nylon Filaments

Wrap Up

3D printing is useful in making common plastic items that will be subjected to huge amounts of heat and impact. Polycarbonate (PC) seems to be the strongest for most parts with high tensile strength compared to the others although it is not cost-effective.

However, we also need to consider factors that can enhance the strength of these 3D-printed parts.

Such factors include; increasing the number of layers, improving the wall thickness, increasing the infill density, etc. By doing this, you are enhancing the durability and strength of your 3D printed piece.

Do you have any queries about how strong is your 3D printing material? Worry not! At 3D Print Schooling, we shall help you learn more about 3D printing technology.

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