Creating a 3D model is the initial step in the process of 3D printing. This model is typically designed using CAD software and then converted into instructions that are compatible with the 3D printer. The instructions are known as “slices,” and they allow the printer to build up layers until it has created a tangible, physical object that accurately reflects the digital 3D model.
Having knowledge of how to craft a 3D model for printing is absolutely essential, as it is the only method available for producing printed objects. Creating these models involves intricate techniques which must be mastered in order to produce a successful result. Without this expertise, it would simply not be possible to fabricate physical objects from digital designs.
Compared to other manufacturing processes, such as machining, 3D printing solely relies on digital instructions. Machining can often be done with either computer numerical control or manually without any digital foundation whatsoever. Nevertheless, 3D printers do not allow for manual operation and are only able to function with the use of a digital blueprint.
CAD (Computer-Aided Design) software is an essential tool for creating 3D models that can be printed. This powerful software offers a range of features, allowing users to create truly intricate and sophisticated designs. Many CAD applications allow users to draw and customize geometric shapes on their computer screens in order to create their own unique 3D models. Alternatively, some programs enable the algorithmic generation of 3D designs with just a few clicks.
Typically, users have the ability to select between two-dimensional (2D) or three-dimensional (3D) design views when utilizing modern design software. This type of software provides users with an abundance of features that enable them to produce highly sophisticated and visually striking 3D models.
In order to ensure that a 3D model can be printed, it is essential for the designer to understand both how to create a digital model and the capabilities of the 3D printing process. As extruding molten plastic does not always allow for intricate details like ultra-fine propeller blades or protruding wings, designers must be able to adjust their models accordingly. Additionally, those who plan on using a 3D printer should have an understanding of G-code and slicing software in order to convert their designs into machine-readable instructions.
This article provides an in-depth exploration of the process of creating a 3D model suitable for printing. It covers which CAD software is most beneficial for 3D printing, offers advice on basic design principles that should be taken into account when constructing a 3D model, and presents the optimal slicers to convert your 3D creation into printable code.
However, it should be noted that this article is only concerned with the printability of 3D modeling; those who are new to CAD and wish to gain extensive knowledge of 3D design must look towards the documentation and tutorials provided by their chosen software. It is these resources which will provide them with an in-depth understanding of the complexities involved in 3D design.
3D Printing Using CAD Software
CAD (Computer-Aided Design) software is the foundation for any 3D printing model. This powerful software enables users to create highly intricate 3D models composed of a variety of geometric shapes and forms. With CAD, it’s possible to unlock the potential of 3D printing, allowing users to manufacture objects with complex geometries that would otherwise be impossible to produce using traditional manufacturing techniques.
CAD (Computer-Aided Design) software is an essential tool for engineers and designers in a variety of industries, from aerospace to healthcare, consumer products, and beyond. This specialized software allows users to create virtual representations of parts and products, which can then be used for digital manufacturing processes like 3D printing or CNC machining. Additionally, CAD software has become increasingly popular for creating 3D models solely for digital applications such as animation or video games.
Most 3D modeling tools can be divided into two distinct paradigms: direct modeling and parametric modeling. Even though many applications support both of these approaches, direct modeling is often the go-to for early-stage design as it enables users to quickly and easily adjust 3D geometry with greater speed and simplicity compared to parametric modeling.
Parametric modeling is an approach to design that encompasses both a mathematical and “history-based” perspective. It involves the creation of parts by defining features and establishing certain constraints; modifications are made incrementally in a manner that adheres to the pre-existing restrictions. This process enables designers to quickly generate different variants of components while simultaneously retaining control over their desired shape throughout the design cycle.
Although the majority of professional-grade CAD software is rather costly, with yearly licenses now being more popular than those with perpetual rights, there are many free programs which can be used for 3D printing that are just as reliable and of high quality. Examples of these include some of the following options:
For 3D Printing, FREE CAD Software
- TinkerCAD
- Blender
- SketchUp Free
- FreeCAD
- Onshape
- Fusion 360
- 3D Printing Design
Mastering the use of CAD software for creating complex 3D shapes requires dedication and patience. Every application has its own particular way of operating, and each one is full of intricate features that can take time to explore and understand fully. Learning how to make the most out of this powerful toolset is an incredibly rewarding process that can open up a world of possibilities.
Without question, 3D design is much more intricate than 2D design. Apart from having an additional dimension to take into account, designs must always be composed of a variety of geometries; they need to be true 3D shapes with completely connected edges, faces, and vertices. Thus, the whole process requires far greater complexity and detail in order for it to be successful.
Many 3D printing mistakes and blunders can be attributed to non-manifold CAD models, which are essentially not suitable for 3D printing due to the fact that they do not present objects that are able to exist in our real physical world. These CAD models lack the necessary features for them to be 3D printed accurately and efficiently.
3D printer users should take into account that the 3D models they create won’t just remain as a computerized image but will be transformed into tangible 3D objects. Thus, designers must make sure to design their 3D models with the Fused Deposition Modeling (FDM) printing process in mind so that the end product is accurate and of high quality.
In the professional world, this approach to design with an emphasis on 3D printing is known as Design for Additive Manufacturing (DfAM). However, the principles of 3D printing design are just as relevant to industrial designers and those pursuing it purely as a hobby. As such, anyone looking to create objects using 3D printing can benefit from understanding these guidelines in order to maximize the potential of their pieces.
Corners
When making your own model with CAD software, it is simple to make blocky shapes with crisp corners and edges. However, 3D printer nozzles are circular, meaning that the lines of material they put out cannot make perfectly right-angled corners; this should be taken into consideration when designing parts meant to fit together snugly. A similar restriction applies when constructing for CNC machining where the cutting tool is round.
Fortunately, rounded corners can greatly benefit the structural integrity of a 3D model. The strength of the model will be increased, and any stress brought on by overhangs or bridges can be significantly reduced, by the addition of fileted (rounded) internal or exterior corners. This is an invaluable advantage that should not be overlooked when designing complex structures with limited space or weight constraints.
Bridging
Bridging, a process used in 3D modeling consisting of a horizontal section suspended between two vertical sections similar to an elevated bridge supported by abutments, can cause significant issues when it comes to 3D printing. This is because the horizontal section cannot be supported from beneath and so has a tendency to droop or even fail entirely if not constructed properly. Therefore, special care must be taken when incorporating bridging into 3D models intended for printing.
A solution to the issue can involve keeping the bridge less than 5 mm in order to stop it from sagging. If not, a support structure must be established beneath it. The slicing software can generate this structure automatically; therefore, it is unnecessary to be incorporated into the CAD model. It will be printed with the other components and should then be cut or broken away by hand.
Overhangs
Overhangs can be thought of as similar to bridges in that they are horizontal sections that protrude outward. However, unlike a bridge, overhangs are connected on only one side to a vertical section. An example of this would be the two horizontal ‘wings’ of an upright letter ‘T’. Such overhangs extend away from the vertical part and give the structure a unique aesthetic quality.
Similar to bridges, if not adequately supported from beneath by the appropriate support structures, overhangs can suffer from sagging or even a catastrophic collapse. Typically, an overhang will be able to sustain itself at angles up to 45° without requiring additional support. However, beyond this limit, additional structure may be needed in order for it to remain stable and secure.
The two “wings” of an upright “Y” shape, for instance, can be held up by the vertical stem. However, if the angle between the wings is greater than 45°, additional supports should be provided in order to ensure stability and prevent any potential collapse.
Holes
3D printing offers a myriad of advantages, one of which is the capability to produce components with holes integrated directly into them, thereby eliminating the need for drilling at a later stage. Designers should be aware though, that Fused Deposition Modeling (FDM) printers may not always be able to accurately reproduce the details from the Computer-Aided Design (CAD) model.
Problems may be encountered when using vertical axis holes (such as a hole in the top face of a part). This is because when the nozzle applies pressure to material around the perimeter of the hole, it pushes it towards the opening and decreases its diameter. If a fastener has been designed to fit inside this hole, it could cause issues. As such, these holes must usually be made slightly larger than necessary, with trial and error sometimes needed to get them right.
Round surfaces
Due to the layered printing process of FDM, it is common to observe “layer lines” at the junction of each layer. These lines are often quite visible and can even be overly pronounced on 3D-printed objects with round surfaces, such as a ball. This issue can be particularly problematic when trying to achieve a desired result.
When creating a 3D model with curved surfaces, designers should be aware that the actual printed surface can look considerably more rough and uneven than its digital counterpart. It is important to note that this difference in texture will become increasingly apparent as the curves become more exaggerated.
One viable solution to reduce the visibility of steps in a 3D-printed model is to slice the model with a very low layer height. This will ensure that each individual layer is smaller, thus reducing the number of visible steps between layers. Alternatively, using a 3D printing service that uses Stereolithography may be beneficial, as this process produces parts with smoother surfaces. Also, post-processing techniques such as sanding and smoothing can further improve an already smooth surface and reduce residual signs of steppage.
First layers
The first layer of a print is the most significant, as proper bed adhesion prevents the part from sliding during printing. To guarantee optimal bed adhesion, it is advisable to design a 3D model with a wide and flat base: the more points of contact with the build surface, the greater its adherence and stability will be.
Unfortunately, this can sometimes mean that one has to concede the terms of the part’s design. Printing a ball is notoriously difficult because it only touches the build surface at just one small point. To print more successfully, an alternative option could be to fabricate a half-ball or dome shape with a flat base instead.
It is possible to divide components into distinct sections, such as two individual domes, and reassemble them by using adhesives or fasteners to create the finished product. This technique can be particularly advantageous for complex objects which may be more difficult to construct in a single piece.
Layer orientation
One of the most significant considerations to bear in mind when it comes to 3D printing is that the parts produced are anisotropic, meaning they are more robust and durable in certain directions than others. Consequently, when constructing components for a functional purpose that necessitates a certain level of strength, it is essential to take into account both the printing process as well as the layer orientation.
In brief, printed parts are not as robust along the Z-axis, making them more prone to breakage when pulled from top to bottom rather than side to side. This is due to a weakened area in the layers where they meet, resulting in a lower tensile strength. Conversely, parts created through printing are strongest in planes parallel to the build surface.
An illustrative example that is pertinent here is a thin printed shelf crafted to withstand significant loads. Its structural integrity will be maximised when it is printed in a flat or parallel orientation on the build surface; however, should it be produced perpendicular to the build plane, its strength shall be significantly reduced.
Slicing software
Once a 3D model is finished, it can be exported as an STL file using CAD software. However, G-code instructions must be provided for the 3D printer to interpret and use this file. Therefore, knowing slicing software is necessary to create a model suitable for 3D printing.
A slicer is a piece of software used in 3D printing that is essential for the successful execution of a print job. It performs the important task of converting a 3D model into machine-readable instructions, transforming the digital object into something tangible. To do this, it takes the 3D model and breaks it down into a series of flat layers, calculating the linear movements required by the 3D printer to create them. This process enables physical objects to be created from their digital representations.
The slicing software also referred to as a slicer, is responsible for taking a 3D model and turning it into instructions that the 3D printer can understand. It does this by converting the design into G-code consisting of individual commands for each object layer. The slicer sets a range of printing parameters, such as infill pattern, printing temperature, support structures, and much more, before writing them into the G-code. Several free slicing applications are available to do this task, making it possible to easily turn 3D models into 3D printer instructions.
Free 3D printing slicers
- OctoPrint
- Cura
- Slic3r
Creating A 3D Model For Printing
Figuring out how to create a 3D model for printing necessitates comprehension in three major areas: being familiar with your preferred CAD software, having knowledge of the 3D printing design requirements and specifications, and possessing an understanding of the slicing process. To be successful, it is essential to have a good grasp of each of these topics so you can ensure that your 3D model will be ready for printing.
Once these crucial foundations have been laid and established, the process of creating your own models will become an efficient and effortless procedure that yields practical, mistake-free printed components.