Get in Touch: 0115 794 0445   09.00 - 17.00 GMT

3D Printing Infills – Stronger & Lighter Parts in Rapid Prototyping

In this article, we’ll explain how to apply infill in 3D printing, how to set the correct percentage to optimise strength-to-weight ratios. We’ll also cover most troubleshooting issues surrounding rapid prototyping with infills.

What Are Infills in 3D Printing?

Infill is one of the most important variables when 3D printing a part, this term refers to the internal structure printed inside of an object. Its density, patterns & orientation are all factors comprising how a part is made up effecting its strength and functionality. It determines how reliable & efficient it is to print flat, horizontal faces over an empty space.

diagram of top and bottom layers, shell side walls and the infill (dashed) in a 3d printed (rapid prototyped) part

Shells

This area of a 3D print is the outside wall or surface of a part that’s typically built up on the z-axis. The golden rule for defining shell thickness is to ensure that it is a multiple of the nozzle diameter, to prevent gaps / voids between the walls leading to weaker parts. 

Shells can be a useful variable when defining infills, strength can be added to parts by increasing this outside wall thickness and can help to reduce the infill density. However this is a balancing act and for smaller components can lead to increased material, print times & costs. 

This is a great tool to utilise for parts that are being post-processed (sanding, polishing or chemical smoothing). It is mandatory that this variable is increased to reduce the amount of surface penetration from these processes. 

Bottom Layers

Bottom section of a part, typically attached to the build plate. This variable won’t effect part strength or functionality too much, however its recommended to adjust this value so that the surface is fully filled in. 

Top Layers

Upward section of a part, typically the last section of a component to be printed. This variable is important to ensure the infill is bridged and filled in and sometimes is a higher value than the bottom layers for certain materials. 

Patterns

rectangular / rectlinear pattern showing the different infill patterns available in 3d printing

Rectangular

The standard go-to infill type for 3D printer, as it provides a reasonable amount of rigidity in all directions without compromising print times. Biggest advantage of this infill type is that it requires minimal bridging. 

triangular pattern showing the different infill patterns available in 3d printing

Triangular

Appropriate when strength is required in the direction of the outside wall / shell. This infill type takes longer to print, however is better suited for printing taller parts such a pillars or lithopanes. 

zig zag or wave pattern showing the different infill patterns available in 3d printing

Wave or Ripple

Waveform or ripple style pattern, that’s well suited for parts that need to twist or compress, This infill type is best suited for flexible materials and is slower to print than rectangular & triangular patterns. 

honeycomb pattern showing the different infill patterns available in 3d printing

Honeycomb

This is the most popular infill pattern in 3D printing, as is provides the greatest strength in all directions due to its out-of-plane shear properties. The only downside to this infill type is the increased print times. 

Percentage Density

slightly dense rectangular / rectlinear pattern showing the different infill patterns available in 3d printing
rectangular / rectlinear pattern showing the different infill patterns available in 3d printing

The density of an infill refers to the percentage of the inside void space of a part that will be occupied by material. Typically the higher the density = more strength. However the gains may not be as much as you think.

  • Increasing your density from 25% to 50%, you’ll see an increase your part strength by 25%.
  • Increasing your density from 50% to 75%, you’ll see an increase your part strength by only 10%.

Screwing, Tapping or Bolting

For parts that are being screwed, tapped or bolted in anyway we recommend a base infill of 50% for maximum strength. Increase in shell thickness & infill density will result in better compressible strength which provides for better anchoring.

3D Printed Screw Holes

Rules of Thumb

  • Understand the application of the part, especially when in the initial design stages it’s important to consider Design For Manufacture (DFM).
  • Shells should be multiples of the nozzle diameter. 
  • When screwing into a part, consider increasing either (or both) the shell thickness or infill density to improve anchoring. Use of clearance holes & bolting with washers practices should always be implemented. 
Share on facebook
Facebook
Share on google
Google+
Share on twitter
Twitter
Share on linkedin
LinkedIn
Share on pinterest
Pinterest
Sam Gribben

Sam Gribben

Managing Director at SGD 3D Limited

0 Comments

Leave a Reply

Your email address will not be published. Required fields are marked *

Save & Share Cart
Your Shopping Cart will be saved and you'll be given a link. You, or anyone with the link, can use it to retrieve your Cart at any time.
Back Save & Share Cart
Your Shopping Cart will be saved with Product pictures and information, and Cart Totals. Then send it to yourself, or a friend, with a link to retrieve it at any time.
Your cart email sent successfully :)

SGD is rated 4.97 stars by reviews.com based on 267 merchant reviews

FREE STANDARD SHIPPING

uSUALLY £4.99 (OR MIN £30 SPEND)

coupon code: FREESHIP19