3D Printer: What Should Be the Design for Printing?

We have compiled the design options and details for printing for you in this article.

Although Thingiverse and similar sites provide ready-made and free 3D models, we may need to design from scratch when complex geometries are needed. This guide will tell you the basics of design requirements for FDM 3D printers and details on how to better produce models.

Melt Stack Modeling (FDM) is an affordable 3D printing technology of choice for fast and cost-effective prototyping. However, like other layered production methods, FDM has some limitations on the production of a 3D printable part.

On the one hand, the harder it is to design a model with a complex design, on the other hand, it can be a nightmare for you that this 3D printed part does not fit during assembly with other parts.

The manifiability of a model in the FDM 3D printer must be checked. We've compiled the experiences of 3D printer manufacturers and 3D printing companies for you.

Supports Hyperlink

design for printing

Bridge Supports is a type of support that is created between two ports, added depending on the design. It is very useful and efficient to use over short distances, but as the bridge length increases, the long layers that make up the bridge begin to sag, thus preventing the upper layers from forming and sticking.

With a well-cooled mechanism during filament spillage, bridge lengths can be as much as 25mm on average, but this depends on the temperature of the environment, the settings of the 3D printer used and the operator.

Reducing the Length of a Bridge

Reducing bridge length may be your first choice to prevent the bridge from being fully damaged or sagging during printing. The advancing layers of a bridge whose first layers are dangling will fall molten, so it cannot provide a healthy support environment. Although the easiest solution seems to be to reduce the length of the bridge, this may be directly related to the design of the part.

Reducing bridge length will make it easier for two support points to be printed by a 3D printer without the need for another medium support.

Using Other Support Builds

In addition to bridge support, support structures act as a kind of foot to the bridge when bridge printing is carried out. After the bridge and design are printed, these support and bridge structures can be easily removed, but may leave slight marks on the removal sections, in which case it may be necessary to sand the model or clean the residi.

Holes

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In 3D printers, there will always be a difference between the dimensions and diameter of the holes of the designed model and the 3D printed model. With the example, horizontal holes are not round without errors, and vertical holes are often smaller than desired.

In a hole pressed horizontally, it is considered normal to form sagging from the surface to the inner and outer part. Therefore, the hole parts of the model may not come out exactly as desired.

The reason why a vertical hole is smaller than desired is that the nozzle passes over the perimeter lines next to the hole, melting and crushing it. If these lines are wider than desired, the hole will be narrower than expected. The smaller the hole, the more likely it is to cause problems during printing.

Changing the Shape of a Hole

Choosing a tear-shaped hole that the 3D printer can easily print, rather than designing a fully relational hole, will affect the quality of the print in a very good way.

The tear-shaped hole provides a margin of error for hanging in horizontal holes. Sagging limits reach up to 45 degrees and make large holes printable.

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This practical solution works especially well with functional and prototype parts where the appearance of the hole does not matter. However, if you are not in a position to do this, that is, if there is no possibility to change the design, you can try putting a thin layer of support at the top of the hole.

Small Pressing Holes and Then Drilling Them

If the problem still persists after you find the best settings for the model and printer, you can shrink the holes in the model and expand the hole with a physical intervention after the print is finished. For example, hand drill, drill, caviar.

Designing a Larger Hole

In order to get a successful hole pressure, the diameter of the hole must be greater than 1mm. In vertical holes, if you know the angular reduction of these diameters, in short, you can measure them after the trial pressure and enlarge and reduce the diameter of the hole accordingly in the design.

Support Structures

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FDM 3D printers produce layer by layer stacking. This means that each layer is supported (upgraded) by the layer before it. However, if the design has a ledge of more than 45 degrees, you will surely need support structures to make a successful print.

However, if you're trying your support settings for the first time, you may see unsuccessful pressure or support that doesn't come out. To get around this, you need to try many settings one by one and choose what is best for you.

Redesigning and Reducing Supports

Positioning the model correctly is a very important issue for printing. As seen in the model below, repositioning the model in a ranked way will give quite good results in terms of the amount of support and time to be used. Therefore, when designing your model, it is important to pay attention to such details and resort to the support part little.

You can also use programs such as Ultimaker Cura and Meshmixer to change the positioning of an existing model. Thanks to meshmixer's automatic operating plane positioning tool, it can adjust the optimum setting for you.

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Support Options

If you have not found any solution and need to use support, you need to choose supports that are in easy-to-remove places, which are prone to removing patterns. You should change the overhang threshold by trying options such as density, pattern, and so on.

Designing Custom Supports

Many CAD design programs have the ability to automatically create support for the model you are designing. However, sometimes these tools cannot be successful due to design reasons. Sometimes the model is not fully used, sometimes it can cause the problem of putting the supports in places where it is not easy to get out.

You can use the Meshmixer program, which we often use, to add support to the design later. Once you know the program, you can create support and support structures that aren't design-dependent. In addition, you can save time and filament compared to the support created by the slice programs.

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Groping

In some printed models, the protrusion has corners and sections. Most often the reason for the protrusion is the design points that exceed 45 degrees. Support must be used in model parts with more angles than this degree.

Reducing Protruding Structures

Reducing protrusions in the model will help eliminate groping. By referencing these groped parts, it can make things easier to change the model and perfect the print.

Hyperlink Support Instead of Protrusion

If you need to use a protruding design, you can use hyperlinks instead of upright supports. Although it is an alternative to the use of upright supports, it can lead to filament and time loss. It can even leave damage to the print area on the surface of the model in a bis printing that is not adjusted correctly.

YHT Rule

YHT rule, does the model to be printed need support? It is a method used to answer questions such as can it be printed.

design for printing
YHT Rule
  1. Anything "Y" can be printed because the protrusions are not long enough to require support. For example, a print in the form of a vertical triangle can be printed without problems, as long as it is wide enough and has a solid base.
  2. Printing a model similar to the shape "H" largely depends on the length of the bridge, filament and print settings.
  3. The shape "T" has sections that protrude without any support. Models similar to this design cause scattered or unsuccessful prints, repositioning the design surface in such models can change the whole event.

Gear Structures

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Like screws, bolts, wheels, teeth are often small and detailed, they are challenging and difficult to print.

Rounding The Tops and Bottoms

Reducing sharp and precise edges when making gear designs will improve print quality and help keep printing successful. Instead of sharp parts, you should use rounded tops and bottoms.

Adding Cylinder Head

Adding a cylinder head has a straight, untreated tip that extends from one end of the screw. This tip is useful for finding the groove on the shaft and holding the pressure. If you do not have such a cylinder head in your design, it can be difficult to produce gear screws. Incorporating this cylinder head part into the model will facilitate printing, it is also recommended that the recommended cylinder height be at least 0.8mm long.

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Alternatives for Smaller Teeth

With FDM 3D writings, gear parts under 1.6mm are difficult and not recommended. For prints that require smaller gears, it is necessary to turn to a different alternative, for example, to use molds. Teeth can be opened to the printed model using the guide and pad.

Using Fillet

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Fillets are used to soften the corners of the 3D model. Because FDM 3D printers are mass-produced, whether or not you use fillets on these printers may not change the result much, but in some models and cases, using fillets may be useful.

The purpose of fillet softening is to strengthen fragile structures. It is used as an additional support for a thin vertical structure to hold well to the base, reducing the likelihood of rupture and breakage.

Embossing and Carving In

design for printing

With the embossing and carving method, you can add different things to the model, such as writing, logo. This image can be obtained by lifting a two-dimensional object up or down from the surface. Filament thickness, text size machine settings are the settings that stand out in these subjects. You can print this type seamlessly with FDM machines, as long as there are no small fonts and objects.

Making Accurate Measurements

Text operations with embossing or in-carving technique are directly linked to the width and depth of the text and these measurements should be at least 1 mm, printing or appearing texts of lower sizes may be problematic.

Choosing a Text Font Correctly

Choosing large and simple fonts has a higher success rate than small, mixed fonts and can provide a seamless printing experience.

Filament Selection

Knowing the properties of the filament you will use when designing the model can help you figure out how to proceed with the design. It will be quite difficult to get the print with ABS filament compared to PLA and PETG filaments. ABS filaments are suitable for bending due to the high pressure temperature.

design for printing

Expanding the Print Area for ABS Filament

Expanding the area of the print base to solve problems such as lifting and curling while printing with ABS filament will often solve the problem.

Small Details and Flexible Filaments

Flexible filaments do not work well in detailed and small size designs due to their structure. In such models, you may need to change the design or filament.

In order to recognize the filament you use in addition to these issues, you should always carry out temperature tests with models such as temperature towers.

Large First Layer

It is normal for the first layers to be wide, as the nozzle crushes the filament with its warm surface when switching layers. However, if this width is greater than it should be, it is absolutely necessary to fix layer problems.

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Using Raft

While printing with raft often seems a hassle and a waste of time, it is a very useful option to prevent the prevalence of the first layer of the printed model. It collects the prevalence caused by heat and nozzle on the shelf itself and prevents errors in the layers of the model that comes on top of it.

design for printing

Using Chamfer and Fillet

The problems of getting up and not sticking are usually spread throughout the printed model, starting at the corners. To minimize this problem, it can help to "chamfer" the runes of the model or add "fillet"

To avoid this classic problem, you can add a chamfer or fillet to the lower edges of its design. This minimizes the effect and prevents the material from extending beyond the limits of the model.

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Complex and Large Models

Large models sometimes may not fit on the printing table. Mixed designs can require difficult support structures.

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Disassembly the Model

The most logical and healthy way to print complex and large models is to divide the model into multiple parts. In addition, this method is very useful in cases where there is a bug or interruption of large model prints.

Blanks

If you want to print mechanical parts that need to be placed in a system or gears, you must first pay attention to the dimensions between the parts, the margins of error. FDM 3D printers are not 100% sensitive, so parts are likely to come out in unexpected sizes, and continuous and healthy calibrations must be made to increase this sensitivity.

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Increasing the Gap of Transition Zones

Designing nested partitions slightly more than the measured value can solve potential problems. To find the right distances and measurements, it is to make trial prints and as a result update the measurements.

Detail Level

When dealing with a design with complex detail and subtleties, it's important to know the minimum sizes and scales that the 3D printer you use supports.

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Knowing the Scales Supported by the Machine

Knowing the resolution of the 3D printer you're using directly affects your designs and prints. Before printing, you should always know the X-Y-Z (layer height) resolutions to achieve the highest efficiency during design.

For example, if the lowest layer elevation your printer supports is 0.2 mm, using measurements less than 0.2 mm on the Z-axis will not produce proper results. It is very important to know the characteristics of your machine before moving on to design.

Wall Thickness

If you can't get proper prints of what you've done with your models, maybe it's because you're using a very thin wall thickness. The printers we use can build thin walls up to a certain size.

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Adding Thickness

Wall thicknesses must be made during design and should not be left to the program with a slice. Although some models may vary in wall thickness with the slice program, some models may not be compatible with this change.

The wall thickness should be at least twice the width of the nozzle. For example, the wall thickness of the model to be printed by a 3d printer with a widely used diameter of 0.4 mm should be at least 0.8 mm.

Beam(ribs)-Add Support

In cases where it is not enough or cannot be done to increase the thickness, you can add beams to the walls, which are weak and thin. Beam support distributes the pressure on the pressed wall and strengthens the wall.

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When adding beams, the important thing to note is that the added beam is suitable for wall thickness tolerance. The recommended minimum beam thickness is 1.5 mm.

Hole-Free Design (Manifold)

The model you are designing is already a manifold in a closed format. That is, it has a monolithic hole-free structure. For this reason, non-manifold designs may seem flawless in design programs, but those holes visible to 3D printers are not successfully printed.

design for printing

Therefore, you should make sure that the structure of the 3D design has edges, corners and remaining surfaces as a whole and without holes. Your design must be hole-free for it to be printable.

The easiest way to manifold a non-manifold design, that is, to repair it, is to fix it with programs such as Meshmixer, Netfabb, Meshlab, rather than designing from scratch.

Print Direction

In accordance with the principle of operation of FDM 3D printers, the stack model is used, in short, the model is printed by stacking the layer on top of each other. The direction of placement of the parts to be printed is a very important factor in terms of robustness and visual aspects.

design for printing

Layered models are durable when physically upright relative to their layers, but weak when in parallel direction. For example, if you want to print an L-shaped model, make sure that the model is tilted horizontally on the table and pressed. In short, the longer the layers have an environment, the more durable the pressures.

Objects produced in layers are naturally strong when they are perpendicular to their layers, but weak when in parallel direction. For example, if you want to print a bar that will be subject to bending, make sure that it prints flat against the print area. In this way, you can make the layers move the length of the part.

Changing the Print Direction

Knowing in advance what kind of printing the model will be in and in which directions when designing solves many problems without creating them. In this way, it will be good to optimize the pressure direction in advance.