If your model has too long a protrusion, it is likely to fall or even break during a press. Having support structures underneath will help prevent this from happening. Although support structures are often considered a necessary evil in 3D printing, they can also cause problems with the model surface. In this article we will talk about the various factors that affect the design and operation of support structures.

When do you need it?

If your model has a bridge that is too long or an overhang that is not supported by anything underneath, you may need to use support structures to prevent it from falling.

Not all protrusions require supports: 45 degrees rule

The general rule is that if the model overhang tilts at an angle of less than 45 degrees, it can be printed without support structures. 3D printers use a small horizontal offset between layers to allow them to print models that don’t have excessively long bridges or overhanging overhangs. If the vertical portion of the model doesn’t skew too much, previous layers can still support it.

The vertical portion of a model can also be supported without support structures if its protrusions have an angle of less than 45 degrees. This rule applies to letters such as Y and T. However, if the vertical portion of the model has too long a bridge or overhanging overhang, support structures must be used to prevent it from falling.

Not all bridges require support: the 5mm rule

Although there are not always bridges and arched overhangs in 3D printing, if a model has a print length on the gap between two points of less than 5 millimeters, it can be printed without support structures. To do this, a 3D printer uses a technique known as bridging, which involves stretching the hot material. However, if the model bridge is longer than 5mm, support structures must be added to prevent it from falling.

Test unsupported printing

As we have seen, the general rule is that if the vertical portion of the model has an angle of less than 45 ° or a bridge of less than 5mm, it can be printed without support structures. However, before you start printing 3D models with protrusions larger than indicated without supports, it is important to test the capabilities of your 3D printer to support them. You can understand this easily by printing a Massive Overhang Test pattern. This pattern has multiple arched sections ranging from 20 to 70 degrees. This step is very important in identifying the maximum angle at which you can print without supports with your machine.

Disadvantages

Like many things in life, 3D printing support structures can have their drawbacks. In this article we will talk about some of them.

Increase in material cost

Since 3D printing comes at a cost, it’s important to consider not just the cost of a model when it comes to choosing what to print. The support structures that consume a lot of material, which in the end is then discarded, also increase the cost of the model. This adds to the overall cost of the 3D printing process.

Extended print life

Support structures also increase the duration of the 3D printing process. Depending on the number of supports needed and the height of the structures, the final printing time will vary.

Added post-processing work

Although support structures are not included in the model, they are used to support various parts of the model during the printing process. This means that once the process is finished, the supports must be removed before the model is ready for use. In a production environment, added work means additional costs for the model.

Risk of damage to the model

Although there are numerous advantages in using support structures, it is important to minimize their use and add them only where necessary. In this article we will talk about how to minimize the use of support structures in 3D printing. Since 3D printing support structures are designed to adhere to model walls, they can easily damage the surface if not removed properly.

Structure geometry

There are two common types of support structures for 3D printing: tree support and linear / accordion support.

Tree

A tree support structure is a type of 3D printing support that develops from the print bed in a branched fashion. Although tree support structures are generally easier to remove, they cannot support flat patterns. They can only be used for over-arch models.

Linear or accordion

The most common type of support structure used in 3D printing is the vertical column support. This type of support is commonly used for bridges and arch sections. However, it is also more difficult to remove and can cause damage to the model’s surface.

Media types for ease of removal

Detachable

Printers with an extruder use separable 3D printing support structures by default.
So if you no longer have extruders, you have to use the same material for the support structures and for the press. This means that even if it is possible to adjust the density of the support structure, it is not possible to change its appearance.

The only way to separate the model and the support structure is to remove them by hand or by carefully cutting them with a knife. Unfortunately, these methods can introduce many risks to the model. It is important to follow proper technique and avoid damaging the model surface during the removal process.

Soluble

If you have a multi-extruder machine or one that allows you to change the material automatically, it is possible to print the support structures in a soluble material. After printing the model, simply remove the support structure using even just plain water. This method of removing the support structure and model eliminates the risk of damage to the model and simplifies the post-processing process.

How to remove structures from 3D printing

In this article we will talk about some of the proven techniques that can be used to remove detachable support structures.

1. Posizionare il modello così da avere completamente esposta la struttura di supporto e rimuoverla delicatamente con le dita.
2. After removing most of the support, use a tool to remove the hard-to-reach parts. There are various types of knives and tools that can be used to remove these parts.
   1. Before using a knife or scraper to remove the support structure, make sure it is well heated. Also, be sure not to damage the model with the heat source.
   2. Be very careful with the knives as they are very sharp.
3. Sandpaper is another great tool for removing media contact points. You can wet sand with high quality abrasive papers to remove support structures and polish the model.
4. Models made with PLA materials can also develop stress marks due to the detachable support structures. To prevent these marks from remaining, apply nail polish to the model.

Reduction of supports in 3D printing

Integrate 3D printing supports into the model

One of the most common mistakes people make when it comes to support structures for 3D printing is not adding elements that can perform the same function. For example, in Antonio Canova’s Venus Vitrix sculpture, the support structure was added to the model’s body. The supporting structure attached to the body of Venus Vitrix is ​​composed of elements that self-support the sculpture.

Making sure that the support structure fits perfectly into the design of the model is an art that requires a lot of planning and creativity. It is important to realize that the addition of support structures should not be done haphazardly. Doing this correctly will improve the model and make the support structures printing process unnecessary.

Chamfers

Another method commonly used to remove the support structures of 3D printing is the use of bevels. This technique transforms corner structures into curved and inconspicuous objects. This serves to replace a bent or angular structure with a slightly inclined one. This technique can also be used with holes. If a hole in the model has a beveled surface, this can be transformed into a teardrop-like support structure. This will help reduce the number of support structures needed to make a great model.

Reorientation

Minimize the number of support structures needed to make a fantastic model by reorienting it on the print bed. An example is the model created by @fantasygraph, which has a horizontal arm pointing towards infinity. If the model is 3D printed as it is, the support structure must be attached to the left arm along its entire length. This support structure consists of a long cantilever at a 90 degree angle. Eliminating supports will most likely leave marks on the underside of the model arm. Instead by reorienting vertically, add a support structure to the base of the model to avoid this problem. This way you can print the model with fewer support structures.

Limit support structures in 3D printing

In the previous sections, we talked about the importance of minimizing the use of support structures in 3D printing. However, this doesn’t mean you should avoid doing this at all. Instead, follow these simple steps to minimize the risk of model instability.

1. Make sure your 3D printer is in top condition.
2. Before starting 3D printing, make sure the material is cooling down quickly. This will prevent it from deforming or breaking. Also, lower the temperatures of your 3D printer to prevent it from overheating.
3. Reducing the print speed also helps cool and especially helps print longer bridges and difficult overhangs.
4. Try to use the lowest possible layer thickness. This will cool the material faster and reduce the amount of mass deposited on the print head.

Media Setup with Cura

Sometimes, it is impossible to avoid using support structures in 3D printing. However, to minimize the risk of model instability, ensure that the support structures are stable and removable. You can also customize the support structures in your 3D printer through the various settings provided by the software you use. Most of the time, the software will automatically generate support structures for you. However, it can also take advantage of a manual mode that allows you to remove or add support structures.

In this article we have chosen to focus on Cura, because it is one of the most popular free slicers around.
In addition, the software has a support structure setup section that allows users to create them according to their needs. By following these simple steps, you can easily customize the support structures that will be used in your 3D printer.

Activate auto-generated 3D printing support structures

To avoid printing unstable parts, make sure auto-generated support structures are enabled. First we will need to check if the model needs further support. After importing your model into the program, look for the red colored sections. In these areas, where the program has detected instability (especially in the lower part of the model) Cura will automatically generate the supports between the print bed and the model. It will also manage bridges and other unstable areas that appear between the shapes of the object to be printed. Although the software automatically generates support structures for your 3D printer, it does not show them in the Solid view. To see them, go to Layer View and click on Support Material.

Select between shaft support or linear support

Normally cura has a large choice of standard media to draw from including the default linear one. Since version 3.2, the software has introduced a tree support structure option that allows users to create ramifications from the print bed for their support structures.

Check the positioning of the structures

The Support section of the program shows a setting called Positioning. This allows users to control the placement of the supported structure. When the setting Anywhere is selected, the program tries to build support structures in all places where they need to be placed. This means that the support structures can also be used in areas not directly suspended on the bed. However, if you do not want them to be placed on top of the model, simply change the setting on media only from the print bed.

The supporting roof

Since support structures for 3D printing are always positioned above the model overhang, they can affect the surface finish of parts.
The Enable support roof setting can help improve the surface finish of the parts by making the skin of the support structure denser. However, this feature can also make it more difficult to remove the support structures.

The X / Y support distance setting

Sometimes, support structures built too close to the exterior wall of the model can leave marks on the model surface. To avoid this, go to the Support section and set the X / Y Distance setting. The setting of the X / Y distance of the support in the program controls the distance between the vertical walls of the model and the support structure. If the support structure damages the walls of the model, the value should be slightly increased. However, before printing, avoid adding small protrusions on the outer walls to prevent them from being unsupported. This will prevent the program from printing correctly.

The Z Distance setting to simplify removal

The connection between the support structure and the model layers must be made weaker in order to break free from the model layers. This function is called Z-offset.
You can also simplify the removal of support structures by setting, for example, the height of the level to 0.1. If the support structure is too strong to detach from the model, increase the Z-offset setting to facilitate its removal. Unfortunately, there are no half levels of support available in the program.

Select the correct support structure for the right balance of strength and ease of removal

You can also change the support material model for 3D printing by going to the Support section and setting a new setting called Support Model. The program’s default template is Z-Zag, which is considered to be the most powerful available. There are also other models such as Triangles, Lines, Concentric and Cross. You can also experiment with the other models by going to the Support section.

Conclusion

Unfortunately, support structures are required in 3D printing to be able to create difficult bridges and overhangs. However, it is a good idea to try to minimize their use. In this tutorial we talked about some creative ways to avoid the use of support structures and minimize the amount of material you use. We have also talked about some tips and tricks that will help you successfully remove support structures.