By Jason Morris
Let’s face it: anything can be designed in 3D on a digital sheet; however, not everything can be printed in 3D. While a drawing might look gorgeous in your CAD program, it could turn out messy when printed on paper.
This is every 3D designer’s nightmare.
Luckily, you can avoid this and create an easily printable 3D object by applying the following key design tips:
Overhangs and support
When it comes to making 3D designs for printing, one of the main procedures entails building parts layer-by-layer. What this means is that for your print to look neat, every layer must be printed on another supporting material.
Any area of your model that lacks support or is only partially supported by another layer is known as an overhang. Having many such parts deforms your design and makes your print look saggy.
Luckily, you can minimize the negative effect of overhangs by limiting angles to below 45 degrees: most printers can safely accommodate this range without the need to add support structures. And the best part? The fewer the support structures and overhangs, the lower the amount of time and materials you’ll need to print your 3D design.
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Issues arising from uneven wall thickness contribute the most common design problems that 3D makers grapple with when printing their wares. If the walls are too thick, your design is likely to suffer internal stresses, resulting in undesirable outcomes like cracking. On the other hand, thin walls produce fragile prints that easily get broken or damaged.
Usually, the appropriate thickness of a model depends on the materials used in printing and the overall design of your 3D object. However, a good practice is to add a wall thickness greater than 0.8mm which is adequate for most 3D printing processes.
Overheating and warping
For starters, 3D printing is quite vigorous and often involves quick and drastic temperature changes as the materials are sintered, melted, and finally solidified. Expectedly, this causes warping and shrinkage which in turn lead to deformation and even cracking of the models.
In particular, large and flat surfaces tend to warp easily as heat treatment causes lengthwise contraction. Other parts that are quite prone to shrinkage include sharp corners which act as stress concentration points.
To minimize these effects, use the correct machine calibration and also add adequate adhesion between your print bed and your part. You can also choose to go for a rounded brim instead of sharp corners.
When creating a 3D model with numerous intricate details, it’s important to take into consideration the minimum feature size that each printing process can produce. Naturally, this is determined by the material and the 3D technology used during printing. For example, most standard 3D printers are not able to produce models with extreme levels of detail. Additionally, the type of materials used will impact on the processing speed and ultimately the cost of your print.
STL export settings
Considering that most 3D designers use FDM printers, it’s important to touch a bit on .STLs which is the format you’re likely to use when exporting your models for printing. For best results, your model should have high poly counts but not too high for your slicing program and 3D printer to handle. File sizes can range from as small as 200kb to big ones of up to 10MB. The goal is to create the smallest possible file that your printer supports while still maintaining the detail in the design.
In 3D printing, orientation refers to the direction in which a part is placed on the printing platform. The three main options here are orientation at an angle, vertical, or flat positions (represented by letters X, Y, or Z respectively).
During fabrication, build orientation plays a critical role in determining the quality of the model particularly in areas such as tolerance errors on the part as well as geometric dimension.
Inappropriate orientations can cause undesirable outcomes like needless overhangs which require more supports. Others expose layer lines, and this interferes with the aesthetics of the part.
For an attractively composed design that is ready for 3D printing, it is essential to take into consideration the six key design units namely overhangs, wall thickness, warping, resolution, STL settings, and orientation. Once you’ve found the right balance for all of these, you can proceed to build your part.