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[Guide] Why do I print supports in 3D printing?

Printing supports in 3D printing is one of the most normal things we can do. Although in the first instance it may seem a strange if not useless practice. You have to start from the beginning, then examine the technique with which our FDM machine physically creates objects.
Those who have seen a 3D FDM printer working (similar prusa, various corexies, Hbot, delta, etc.) have immediately realized that the figure is created through the deposition of material. This material is deposited in layers, one layer on top of the other, until the completion of the project. And as long as it is a cube, there is no doubt about it. The printer will lay one layer on top of the other until the figure is complete.

But what if we have to print this figure?

supports in 3D printing

Up to one third of the model the printing would proceed smoothly, just like the printing of a cube. The problem arises when you get to print the hands. How could the machine deposit the filament in the air? That’s where the supports come in! With the use of 3D printing media, the slicer, the program that translates STLs into machine language (Gcode), automatically creates the media for all the parts it reads to be “printed in the air”.

The automatism of creating the supports has positive and negative sides.

The biggest positive side is that the creation of the supports is automatic. All we have to do is decide whether or not the model requires supports. In order not to make a mistake, we could also leave them always active, so that they will only be printed if necessary.

The downside of automation is that the program does not have a real intelligence, so to make it work at its best we are the ones who have to give it the right inputs.
But how do you adjust the supports in 3D printing? You may wonder! Keep reading and you’ll find out soon!

When to use the supports

We can start by saying that the best possible support is the one that isn’t there. I’m not crazy, don’t worry. Only the support material, however well adjusted it may be, is in contact with the model and there is a risk that it will damage the surface of the figure. Sometimes you just need to choose the right orientation during processing to minimize the supports. And minimizing if not completely excluding substrates ensures that the surface is not damaged. Of course is also a nice saving in terms of material!

Imagine that you have to print a letter, each letter will require several media. However, if we lay the letters down (by turning them 90°) we would go to zero. Zero supports needed. We will save time, material and we will not risk to have points damaged by contact with the supports.

So first we try to find the best orientation for our models. That is, the orientation that minimize the use of the supports!

Settings

There are many options to decide on the slicer when you want to intervene on the adjustment of the supports. Here we will deal only with the most important ones, which give a real result. Practice will perhaps lead you to change these values a little, as well as to want to set other values as well.

Let’s say that here I want to offer you a good basis from which to start, explaining the choices.

The same reasoning can be done by you to create a personal approach. The settings we will talk about in this article are Plot, Infill Percentage, Projection and Distance from the model. By adjusting these 4 values well you will already have a support that is easy to remove and provides good support.
By setting the texture, filling percentage, projection and distance from the model for all axes (even if the fundamental is Z) the program will create a support base for the suspended points of the model. In some slicers we can also indicate if we want these supports only inside, only outside or in the whole area of the model.

Supports in 3D printing: PATTERN 

The slicers offer different plots to choose from, below in the picture you can see the available plots of the slicer CURA. The choice of the texture may seem like a minor option and the change according to the model is not very common. But since we are talking about optimization I would like to give you my theory. I normally choose the type of filling to use, according to the print.
They may look very similar but they don’t. A very thick braided infill (the second from the left to understand) will have more support. However it is more likely to ruin more the surface of the model to which it is connected. As well as the fourth from the left albeit in a lesser way.

Similarly, the third and fifth are weaker, but less invasive. So if we need a strong support for a mechanical part or a tool we will use the 2nd from the left. And if there will be evident signs on the surface we can proceed with sanding by hand or with tools like Dremel (at low speed). On the contrary for a statue, or an artistic piece, ornaments etc. will be preferable to use a less invasive infill (n. 3 or 5). In this scale the first infill from the left is exactly in the middle and can be a good compromise.

supports in 3D printing

Supports in 3D printing: INFILL PERCENTAGE

Just as in the case of Pillowing, already discussed in this article, set a plot of support little dense may not support properly the press. And leave holes in the face that must be supported. It is always recommended to use support infill values higher than 20%/25%, so that the object really has a support. Depending on the case, these percentages may be increased or decreased to achieve the desired effect.

PROJECTION

For this value, you must follow the 50° rule . Up to this angle from the plate, there is no need for the substrates in 3D printing and the plastic supports itself. Then we can use a little trick to increase our chances! Reduce the height of the layers. A thinner layer means multiple layers forming the same object. So a more gradual ascent can ensure the seal even with more overhang.

As an indication we can say that if a layer 0,2 mm can be printed without supports up to 50°. With layer 0,1mm we can push ourselves to 55°. As well using the very thin 0,05mm we can dare even 60°. These values are valid for all filaments. Especially for non-coolable filaments, such as ABS. In the case of the PLA if all this is assisted by a layer fan at maximum speed we can consider 5° more projection.

Supports in 3D printing: DISTANCE FROM THE MODEL

An equally important step is to determine the number of layers to leave between support and model. This value will determine how easy it is to remove the support without ruining the model. In addition how much the model will be supported. Usually you use 1 or 2 layers of vacuum. This value provides good support along with the ability to easily remove supports. Not leaving a vacuum would create a too strong bond between supports and object and separation would become a difficult task.

Unfortunately, beyond the distance and the composition, the supports still leave a mark of their presence. To get rid of them, you must proceed with sanding, by hand with abrasive paper or with sanders or with Dremel or the like.

The importance of Experience

Then there are some features of the support in 3D printing that you will have to check each time. More than with specific data with experience and common sense, one of them is the relationship between base and height. A stand with a very small base and very high is very likely to detach from the plate at the slightest contact with the nozzle or with the sole movement of the plate before supporting the model. You should increase the base with the slicer program.

Some slicer do not allow this option and where it is not possible you can easily replace the software in use with another, always free.

Maybe to use only for this particular case. (There are many slicers on the market, even free, you can find in the appropriate section a review of the main ones and the links where to download them, knowing how to use 2/3 slicers according to your needs can be a good idea).

Supports in 3D printing: ADVANCED LEVEL

What if we’re not satisfied with the supports we’ve created?

If we gain some experience we face some specific problems and the work of the slicer does not satisfy us we can build our own supports. Through a 3D drawing program (HERE you can find the reviews of the most famous and the links where to download them) and just erect geometric figures, based on the needs of parallelepipeds, cylinders or cones, and go to support the points that in our opinion deserve special attention.

supports in 3D printing


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