In 3D printing, a shell is a printed object’s outer wall or perimeter. It is typically composed of multiple layers, each slightly offset from the one below. The thickness of the shell walls can vary, but they are usually thin to save on material costs.
The shell plays a vital role in determining the strength and durability of a 3D-printed object, so it is essential to choose the right shell thickness for the desired application.
In general, thicker shells are stronger and more durable, but they add weight and cost to the final product. Thinner shells may be lighter and less expensive but they may not withstand the same stress level as thicker shells.
As such, it is essential to carefully consider the trade-offs before choosing a shell thickness for a 3D printing project. So, lets dive right in.
Shells in 3D Printing: What They Are and How to Use Them
3D printing creates a three-dimensional object from a digital model layer by layer. The 3D printer reads the data from the computer-aided design (CAD) software and prints successive thin layers of material until the entire object is created.
After the desired print times, the printed object may have sharp edges, or some support structures, as they are part of the 3D printing process.
However, Shells support overhanging features or parts of an object that would otherwise be too delicate to print without them and also play a role in the strength, durability, and polishing of printed objects.
In addition, the walls created by a shell must be the correct thickness for the desired application and material properties.
How to Use Shells in 3D Printing
The following factors should be considered to derive premium value and satisfaction while using shells in 3D printing:
Slicer Settings
Choosing the correct settings for your slicer software and material is essential to use shells effectively. Different materials may require different shell thicknesses or perimeters due to their properties, such as flexibility or strength.
Infill and Infill Percentage
It is also important to adjust the infill percentage of the object to match the shell size. Infills are generally dense for thicker shells, reinforcing the object’s strength.
Infills are the raw material used to fill the spaces between the shells of a 3D-printed object. It helps to support the shells and prevent them from collapsing. It also holds the shells in place when slicing software generates the g-code for 3D printing operations.
The infill percentage is the amount of infill material relative to the shell thickness. A higher infill percentage will provide more strength and durability, while a lower infill percentage may save time and cost.
Shell Settings
Also, it is vital to consider the shell settings to other print parameters, such as infill settings, layer height, speed, and temperature. These should all be considered when optimizing a particular object’s print settings.
Finally, remember that shells are part of the 3D printing process and should be used with other parameters to get the desired results.
Settings of 3D Printing Shell
Shell settings can be adjusted in many slicer programs, including Simplify3D and Cura. These settings include;
Shell Numbers
The number of shells depends on the strength and durability required by a particular object. A higher number of shells may be needed for parts that require more rigidity or are exposed to higher stresses.
Shell Distance
The distance between shells should be set depending on the printed material, as some materials may require a more significant gap for proper adhesion between layers. A gap of 0.2mm to 1mm for most materials will suffice.
Shell Thickness
The shell thickness is a significant component in the setting that must be adjusted according to the printed material and the object’s intended use.
It usually is in multiples of a nozzle diameter; for example, a nozzle diameter of 0.4mm requires a shell thickness of 0.8mm above. Thicker shells are generally stronger but add weight and cost to a 3D-printed object.
Thinner shells may be lighter and less expensive, but they may have a different level of strength. Ultimately, it is up to the user to decide which shell thickness is best for their 3D printing project.
The rule of thumb here’s that the shell thickness should be between 0.4mm and 1.2mm for most materials and applications with 2-3 nozzle diameters. However, this may vary depending on the type of printed material and the desired strength and durability of a 3D-printed object.
Effect of Settings on 3D Printing Shell
The settings you choose for your 3D printer can have a significant effect on the shells that are produced. For example, increasing the infill percentage will result in a stronger shell, but it will also make the printing process slower and use more material.
Conversely, decreasing the infill percentage will weaken the shell but print faster and use less material. The choice of filament can also affect the properties of the shell.
Filaments made from PLA plastic tend to be strong and temperature-resistant, while filaments made from ABS plastic are more flexible and resistant to chemicals.
Ultimately, the best filament for your needs will depend on the intended use of the shell. By understanding how the various settings can affect 3D-printed shells, you can ensure that your shells meet your specific needs.
The post-processing of your 3D-printed shell greatly affects the final strength of your product, adding support structures or increasing the infill density. In terms of cost and time, it is often more expensive and time-consuming to post-process your 3d printed shell.
However, post-processing may be optional if you look for a quick and easy way to produce a shell. Ultimately, the decision of whether or not to post-process your 3D-printed shell depends on the intended use of your product.
Importance of Shells in 3D Printing
- Shells are an essential component of 3D printing. They provide support for the object being printed and help to distribute heat evenly by trapping air between their walls.
- Without shells, objects would be more likely to warp or deform during the printing process due to the uneven cooling of the layers.
- Shells help to protect the print head from debris and other contaminants, ensuring that objects are printed accurately and with a high degree of quality.
- Shells are used to create complex shapes and patterns, molds for casting metals, and lightweight objects for any 3D model.
- Shells give 3D-printed objects a smooth, polished finish, which can be further enhanced with post-processing techniques.
By understanding the importance of shells in 3D printing, users can make sure that their printed objects are of the highest quality.
Factors To Consider When Using Shells in 3D Printing
When using shells in 3D printing, there are several factors to consider, which includes
Types of Material
Different materials require different shell thicknesses, as well as specific infill percentages. The compatibility of the shell material as a major component is essential when using shells in 3D printing.
Depending on the type of 3D printer, certain materials may be better suited for use as a casing or outer shell. For example, materials such as ABS plastic or polycarbonate are often used to create durable and lightweight shells that are ideal for FDM 3D printing.
Other materials like metal alloys and composites can create more advanced shells that enable stronger parts with higher accuracy and precision.
Printer Speed
The speed at which the printer is running also influences how thick or thin the shells should be. Faster speeds will require thicker shells as they provide more support and stability. Slower speeds can usually get away with thinner shells as the objects take longer to print and have more time to cool down and harden.
Layer Height
The layer height of the printed object should also be considered when using shells. Thinner layers will require thicker shells for increased strength and durability.
Design
The design of the shell you choose will ultimately determine how well it functions in your application. It is always advisable to design with multiple nozzles.
When designing a custom-fitted shell for a particular project, you must consider factors such as wall thickness, part geometry, and structural integrity to ensure optimal performance and safety when 3D printing with shells.
Manufacturing Cost
In addition to design considerations, the manufacturing cost is important when deciding which type of shell material you should use for your project. Different types of shells can have varying costs depending on the complexity of their construction and the manufacturing techniques required for production.
Thermal Conductivity
Thermal conductivity properties affect how well heat generated by the 3D printed component can dissipate away from it during operation. Shells with good thermal conductivity can help protect sensitive components from overheating due to prolonged exposure to high temperatures during operation.
This could result in component damage or failure over time due to poor heat dissipation rates.
Durability
When selecting a suitable shell material for your project, durability is paramount since this will affect its long-term performance and reliability over time regardless of its initial cost or ease of fabrication during setup stages.
Harder materials such as metals offer superior durability compared to softer plastics. Still, they may only sometimes perform as well under extreme temperatures or harsh environmental conditions where flexibility may be desired.
Considering all these factors, you can ensure that your 3D prints come out with the highest quality possible.
Frequently Asked Questions
Shells in printing are components created with a 3D printer that are used to produce components for manufacturing. They can be used to create parts that require fine details, such as medical device parts or custom parts.
Digital manufacturing is an approach to production that uses advanced technology, such as 3D printing and computer-controlled manufacturing processes, to create custom parts or components.
Shells are important in 3D printing because they provide a structure and form for the model components. The shell acts as a mold, holding the model components in place while the 3D printer creates them.
The main difference between shells and infill is in the material properties. Also, Infill is usually used to reduce the weight and cost of a model component, while shells provide the necessary strength and rigidity for printing larger, more complex shapes.
Extrusion consistency is essential when 3D printing models with shell or infill components. It refers to how well and consistently the material is extruded from the nozzle of the 3D printer.
Conclusion
Shells are the first layer of protection for a 3D-printed object and can make all the difference between a successful print job and a failed one. It significantly affects the strength and durability of a printed object by protecting the inner layers of an object from warping and deformation.
When setting shells, you should consider the thickness of the shell and the impact it will have on other print settings, as also the trade-offs between thickness, weight, cost, and other factors before deciding on the correct shell settings for a particular application.
With the proper settings, 3D-printed objects can be made stronger and more durable than ever before.
