General design guidelines for 3D printing
The sixth chapter of the Complete 3D Printing Guide is for those interested in printing 3D printed model.
This chapter will explain the basic principles to consider when modeling the file for printing.
Preface
Each printing technology has unique limitations and conditions in the design of the computer model, but there are certain principles that apply to all printing technologies.
This chapter will address basic concepts that are necessary to understand before designing a model for printing.
When designing a 3D model for printing, keep in mind that the computer model will become a physical model.
In the digital environment there are no physical laws and it allows the creation of almost anything, but, the laws of physics apply for the physical model and therefore: not everything designed in computer software will be printable.
Familiarity with basic concepts and restrictions
WATERTIGHTNESS
A printable model must be closed.
A closed model can be compared to balloons in various shapes that trap air inside them.
A model that contains a hole of a certain type is not printable. In term that describes a closed model is WATERTIGHT, similar to a balloon that traps air without being able to come out, the description “waterproof” refers to a product in which water cannot penetrate, and hence, it is closed, without holes or spaces between surfaces. There is a wide range of software in which you can make sure the model is free of holes before sending for printing.
For an article on the reasons for the formation of holes and how to close them, click here.
Thickness
CAD software enables the production of 3D elements even if their existence in reality is not possible.
One example of such elements is all types of surfaces. A surface is a system of points with length and width but no thickness. Or in other words you can imagine a surface as a cloth blanket that is spread out on different rails and produces varied shapes but its thickness is 0.
Although surfaces can look quite 3D on a computer screen, they are not manufacturable in reality as they have no thickness.
Therefore the desired wall thickness must be produced for the surfaces.
The wall thickness can be produced using two methods.
One is the closure of the surface. For example, when there is a concave surface, the open part can be closed with the help of another surface and thus produce a model that is WATERTIGHT since it captures a space inside it.
This method causes the most material use, when it is not the required form, the other method should be used.
The second method is to create a wall thickness using an offset operation (the set). Offset is the displacement of all the points that make up the model, a uniform distance in a certain direction.
After performing the offset operation, connect the two parts created and close the hole between them.
In addition, since 3D printers allow production in a variety of materials and technologies, each material has different wall thickness restrictions.
There are technologies where printing too thin a model will cause distortions in the model, and in other technologies creating too thin a model can cause the model to break.
Therefore, the limitations of the technology used should be examined.
In addition there is a large impact on the geometry of the model.
Two models produced with the same wall thickness in the same technology, but with different geometries, will respond differently to distortions and fractures.
For example: Usually large, thin-walled surfaces will be more likely to warp.
