When talking about additive manufacturing, they are five elements to consider when designing for 3D printing. Those five aspects are necessary to build a perfect balance in creating a 3D part. Balance between size, resolution, thickness, orientation and choice of material will contribute to the esthetics and success of your creation.
First aspect to consider when designing is the size of the part created. Every technology has an optimal build format, some larger than others. Our FDM machines will accomplish the largest size possible at 16" x 14 " x 16 ".
Parts that are too big for this type of technology can be cut before manufacturing to then be fixed together. Size of parts will have an impact on build time. The larger the part, the longer it takes to build and more material is required, resulting in additional costs.
Resolution is actually the thickness of each layers applied when building a 3D part. Depending on the technology, a thinner layer can reduce imperfections or ridges that can appear on the surface of the part. A higher resolution will give a better quality to the surface and definition of the part before post-processing. The thinner the layers, the better the details, but the longer the build time.
For a small object with intricate details, choose the SLA (Stereolitography) technology, which has a resolution of 25 microns at its most precise. The SLS technology also offer a great resolution at 100 microns (0.1mm). The standard thickness of a FDM print is 250 microns (0.25mm), and we also offer a high resolution (0.175mm). If your part is very big and you need less precision, you may use the low resolution on the FDM machines (330 microns, 0.330mm).
After choosing appropriate resolution, the wall thickness is another aspect to consider. This characteristic is fundamental in your design, ensuring stability, precision and tolerance for a 3D printed part. Thinner walls can shorten build time, but a wall too thin can result in a more fragile part with less definition.
Thin parts built with SLS are more prone to warping because of the way the technology works. The SLS built parts are subject to high temperatures as well as the weight of the powder during fabrication, and the plastic material can warp when cooling if it is too thin. With a thickness between 1mm and 3mm, the geometric stability of your features will be much more achievable.
When using the FDM technology, you should have a minimum thickness of 1.6mm.
Another important aspect to obtain a optimal stability is orientation. In 3D printing, orientation refers to how the part is placed on a 3D printing platform. The part can be oriented at a certain angle, lying flat or standing vertically. Orientation during fabrication is a crucial step affecting quality, particularly geometric dimension and tolerance errors on the part, and thesize of the support structures needed, all contributing to the overall cost of the part.
Orientation may change depending on technology. With FDM, the parts are stronger along the X-Y plane and have a lower strength in the Z-direction because of the technology's way of building the part. Some orientations are better for curved or square objects. Others may reveal layer lines affecting the aesthetics of the part. Some orientations will be more effective if over-hanged, needing more support.
That said, we will always choose the right orientation for your parts, unless specified.
The choice of material
Many materials are available when 3D printing, depending on the technology used. Your choice will be guided by the contraints that your part will take. if your parts need special caracteristics, it is important to choose the right material. Let's say your part has to go through high temperatures, or chemical solvents. In that case you should look into the ULTEM of the PPSF material, in the FDM technology. If it has to resist to shocks and impacts, the polycarbonate would be a better choice.
The SLA technology also offer interesting printing materials. If you need to produce a part that has to replicate how a rubber material would react, it is possible to use the flexible resin. If you want to do a lost wax casting, the castable resin would let you do the work, instead of using wax.
When the material caracteristics are not important, the acrylic resin (SLA), the ABS (FDM), and the Nylon 12(SLS) will do good work for a cheaper price.
L'équilibre du design
Size, resolution, thickness, orientation and material choice are the important elements to consider when creating a part destined to 3D printing. When all of those aspects are in balance, you are ready to build your part!