Introduction
From design to testing and function, the concept of creating consumer electronic products definitely takes considerable effort. With 3D printing, product development teams can simplify their approach, design faster and land the perfect product. In this article, we take a look at how 3D printing can be harnessed for making part enclosures in a matter of hours as well as all the information you need to create functional and befitting enclosures with lower risk of defects. 

 

Technology 
3D printing can be performed under an array of solutions. When dealing with 3D printed enclosure assemblies, the preferred solutions include FDM, Material jetting, SLS and SLA. 
FDM is suitable for rapid prototyping while material jetting is used in heat-sensitive, transparent and high quality surface finish applications. SLS and SLA can be also used for transparent, high quality and high accuracy applications. 

 

How to design for 3D Printed Enclosures
It is important to follow a flow when designing electronic components and assembly. For instance, it is expected that you will design the components to be contained before modelling the enclosure. This is because doing the latter before the former opens up the risk of incorrect placements, improper fittings and wrong calculations of clearance holes in the enclosure design. Designing the ideal enclosure typically entails planning and measurement. It also considers on how the enclosure is to be secured after the parts have been placed within. 

 

Enclosure positioning and measurement 
Before designing the enclosure, ensure that you have modelled the internal components and used a 3D software to determine the optimal positioning of the inside parts.

 

Access to components 
Factor how the design allows for seamless access to the internal components in its everyday application. Also, consider the type of fastening or adhesive to secure the enclosures. The ideal design will have free access to plug and play components, power outlets, USB/HDMI hubs and more. 

 

Securing Enclosures 
After your assembly’s enclosure has been successfully 3D printed, you may consider the use of interlocking joints, living hinges, threaded screws, push-fits and snap-fits to connect the enclosure parts. 
Your selection here will greatly depend on whether or not you want to have access to the internal components, the frequency of use of the part and how often the part may need to be disassembled or re-assembled.
Glues and adhesives may be more appropriate for quick and rapid prototypes while snap and push-fits are better suited for designs that will not see a lot of repeated openings in its day-to-day use.


Design Guidelines for 3D Printed Enclosures 
The following will serve as design guidelines when working with 3D printed enclosures to secure your part. It is important to note that the following guidelines, tolerance and clearance recommendations may vary ever so slightly depending on the printing technology.


Wall Thickness

When designing 3D printed enclosures, we recommend working with a wall thickness of greater or equal to 2mm for all enclosure walls. This helps with the structural integrity of the part and provides an allowance for any type of shrinkage that may occur.

Also, ensure that the wall thickness is uniform throughout the design of the part.



Fillets

Fillets and radii help in 3D enclosure designing by aiding the printer to avoid sharp corners and reduce stress concentrations around the edges of the part. Adding even a small fillet/radii can be significant in ensuring that the part is accurately printed. 


Bosses

Bosses can help to deliver additional strength around corners, holes and locations where threaded screws will be used to secure the enclosure. Bosses help by reducing the likelihood of fracture, distortion and bulging in these areas. 

As a guideline, do not go less than 1 hole diameter for the thickness of the walls around the holes.



Port Clearance

Keep at least 2mm (each side of 1mm) of clearance between the 3D printed enclosure ports and the components I/O plugs to be placed in the part.


Lips, Lugs and Cut-outs 

Lugs, lips and cut-outs all assist with part alignment, assembly and disassembly. They are relatively easy to incorporate into your design and alignment of the enclosure with multiple parts and structures in the design.

When using lugs, ensure that they are at least 5mm in width.



Self-taping holes

Reduce the diameter of self-taping holes by 0.25mm to allow the screws or fasteners bite into the case and secure the part firmer


Clearance holes

Add 0.25mm to expand the diameter of your fastener and screw clearance holes to obtain improved results. Also, ensure that you drill the holes after printing to obtain better clearance holes.


Ribs and Gussets

Although not essential for 3D printing as much as it is for injection molding, these structures help to improve structural performance by reducing the stress throughout the part. As Ribs and gussets are not mandatory in 3D printing design, they can be made to 75% of the part’s wall thickness to save material and lower cost.


Other Rules and Guidelines


•    SLS nylon is ideal for 3D printed enclosures that will see a significant number of repeated open and close action 

•    FDM is ideal in instances where rapid prototyping is required for low-cost production

•    Maintain, at a minimum, a wall thickness of 2mm and tolerance of 0.5mm for internal design components 


Step by Step Guide for 3D Printed Enclosures
2020-07-17