STL Files in Additive Manufacturing – Optimization and Generating

Additive manufacturing is a very different and very advancing and improving technology in our lives. And also, STL files are the most common types of files to use in the production of parts in these systems. Additive manufacturing systems are very automated systems that generally work with software in them. So, to set up this software, we need to use special files and systems. Here, we explain what is STL file and how to use them in 3D printing applications.

You will have very good knowledge about these topics which may be a very good start in the additive manufacturing sector. Because this is the most common file format in this sector that you will probably deal with.

What is the STL File Format?

STL file format is the general file format that we use in additive manufacturing machines. It is the acronym of Standard Tessellation Language or STereoLithropghy according to some sources. It is a different kind of file format that we use in additive manufacturing machines. So, we need to apply some different things to obtain them.

In these formats, tessellation is one o the most important feature that we will talk about in the preceding topics. You can use this format in the slicing applications.

CAD Modeling

Before obtaining the STL format, we generally obtain the 3D model of our part that we manufacture with an additive manufacturing machine. We need to consider all the important parameters in the design phase.

There are different kinds of CAD tools such as Solidworks, Autocad, Siemens NX, and CATIA. All of this software has great 3D modeling abilities and tools. And most companies are using this software in general.

This software have also STL format generation tools. So, they are easily integrated with 3D printers or other types of additive manufacturing techniques.

And because this file format become very popular and the most supported one, nearly all the CAD software supporting these file types to become compatible with rapid prototyping.

Converting the CAD to STL File Format

Here is the genuine answer to what is STL file format. In this step, we produce our STL file format that we will use in manufacturing. Because the machine will perceive the STL format of that geometry. You can not directly use CAD formats in the machines.

Also, most CAD software produces their STL formats automatically. So, you can use these automatic STL files in additive manufacturing machines. But, you need to control the possible errors on STL files.

STL files are the files that divide the geometry into small triangles. And the number of triangles is a definitive factor in the manufacturing accuracy. So, you need to check the triangle structures at the critical sections of your parts. All the sections must be shown with the required amount of triangles.

As we stated above, it is very easy to convert the different types of CAD extensions to STL formats. Some of them give the advantage of optimization of these formats while you are converting them. Also, some of them do not give any optimization right. You need to use additional software packages to make optimizations.

How to Obtain STL Files in Different CAD Software?

There are different kinds of CAD software and they are very easy to use in additive manufacturing applications. So, obtaining STL files in this CAD software today is very easy and basic. You can check here the general CAD software STL generations.

Here, you will see that the general CAD software that you can obtain this file format with optimization features or without optimization features.

AutoCAD

AutoCAD is a very common software that you can use easily in the STL file generation. After creating geometry, you need to follow these steps;

• Firstly, your model must be 3D. Because you can also have 2D geometries in AutoCAD in a very effective way. But, there is no use of 2D geometries in additive manufacturing applications.
• Adjust the geometry to be in the positive space of the coordinate systems.
• There is an option that you need to adjust the Facetres to 10.
• With the STLOUT command, you can start the STL file conversion of the 3D shape.
• After that, select the important objects to obtain STL formats.
• For the binary option, select the Y coordinate.
• And enter your name of the STL file then save it.

So, AutoCAD provides some optimization features for these file formats while you are saving them.

Solidworks

Solidworks is also very common software that we use to produce STL file formats. After obtaining your 3D geometry, you can follow these steps;

• Click on the File menu and ‘Save As.
• You need to select the file type as “STL”.
• In the Options section, select the Output As option as Binary. And select the units as inches.
• Make the resolution adjustments like this; Custom, Deviation Tolerance = Minimum (Slide bar to the right), Angle Tolerance = 5 degrees.
• Click on the OK button.
• And you’ve successfully saved the file in STL format.

Also, you can adjust the optimization features while you are saving your files in Solidworks.

Siemens NX or Unigraphics

Also, Siemens NX is a very common software that we use to convert the CAD files into STL file formats. You can follow these steps to make this conversion.

• Click on the File menu and Export button. Then select Rapid Prototyping.
• After selecting it, set the Output type as Binary.
• Adjust the triangle tolerance to 0.00025.
• Also, adjust the adjacency tolerance to 0.12.
• After that adjust the Auto Normal Gen as On.
• Adjust the Normal Display option Off.
• And adjust the triangle display On to show the triangles.

This is very simple to obtain these formats in Siemens NX like above. So, it is possible to optimize the files in Siemens NX while you are making conversions.

Geomagic Design or Alibre

Between the 3D printing and rapid prototyping communities, this software is also very common. Because obtaining STL files are very easy with this.

• In the interface, click on the ‘File’ and select the ‘Export’ option.
• Select the Save As and choose the file type as STL.
• After that, enter the file name.
• Then click on the Save button to save the STL file.

As you see above, obtaining STL files with Alibre is very simple as that. So, Geomagic does not provide any tool for optimizing these files after the conversion. You need to use other programs or optimizers to adjust the file according to the ideal condition.

Inventor

Inventor is also a very common CAD software among designers. And also, if you are using this CAD software, you can use the STL file conversion of it like this;

• Firstly, click on the Save Copy As option.
• And then, select the file type as STL.
• In the Choose Options section, select the Set to High adjustment.
• And enter the name of the file.
• Click on the Save button to obtain the STL file of your 3D geometry.

In Inventor, there are no optimization tools while you are converting the CAD extensions into this file format.

IronCAD

IronCAD is also a very common mechanical design software which is very common in the US. You can use IronCAD to obtain these files. Check the steps below to learn how to do it.

• After you obtain the 3D geometry, right-click on the part.
• Hover your mouse on the Part Properties in the pop-up menu and click on Rendering.
• After that, adjust the facet surface smoothing to 150.
• Click on the File and click on the Export button.
• And then, choose the STL format and click on the Save button.

IronCAD provides a primary optimization of geometries easily while you are transferring the CAD file into the STL format.

I-DEAS

This is also a very common software package in the automotive industry. Especially, Ford Motor Company and General Motors are using I-DEAS CAD software. So, after obtaining a 3D CAD design model on your computer, you can follow these steps to obtain your STL files.

• Firstly, click on the Export and choose the Rapid Prototype File and click on OK.
• After that, you need to select the part from the interface to obtain the file.
• And then, you need to select the rapid prototyping device which is SLA500.dat then click on OK.
• After that, select the absolute face definition as 0.000395.
• Finally, select the Binary method then click OK to save it.

So, it is very easy to convert the CAD files into this file format by making the required optimizations. Maybe this is because that is the most used type of file that most of the biggest companies are using this software.

ProEngineer

Creo Elements or PTC Pro Engineer is another important common CAD software that designers generally use. Around the most bran-new CAD software, ProEngineer also provides very good STL conversion for its users.

• After obtaining your 3D geometry in ProEngineer, click on the File tab and click on the Save a Copy.
• Select the type of the file as STL.
• After this point, select the chord height to 0. And this field will be replaced with a minimum value.
• And you need to adjust the Angle Control to 1.
• And enter the file name then click Ok to save the STL file.

You can make angle controls and optimizations while you are saving your file in the ProEngineer CAD software. This is a very important feature to do not use any extra software.

SolidEdge

SolidEdge is another important common CAD software that is released by Siemens. So, most of the additive manufacturers are using SolidEdge. You can follow these steps to obtain STL files after creating your 3D geometries.

• Firstly, click on the Save As button to obtain the file.
• Adjust the file type as STL.
• Click on the Options button.
• You need to set the conversion tolerance as 0.001 inches or 0.0254 millimeters.
• After that set the Surface Plane Angle as 45 degrees.
• Click on the Save button to obtain the STL file in SolidEdge.

As you see above, you have the right to optimize adjustments on these files before installing them on the rapid prototyping machines.

Rhinoceros 3D

In additive manufacturing applications, people also commonly use Rhinoceros 3D CAD programs. You can follow these steps on how to make STL conversions in this CAD software.

• After creating a 3D part that you will manufacture with additive manufacturing, click on the ‘File’ and select the ‘Save As’.
• After that, select the file type as STL.
• And enter the name of the STL.
• To save this file, select the Binary option.

As you see above, there are no angle and smoothness optimizations for STL files in Rhino CAD software. Maybe you need to use additional software to optimize the files.

CadKey

CadKey is also a very common mechanical design CAD software we generally obtain the 2D and 3D designs. So, the use of the CadKey is very common. Also, you can obtain the STL files easily with CadKey software. These are the general steps that you need to follow.

• After obtaining the 3D model, click to select the Strereolitrography from the Export options.
• And enter the name of the file.
• Click on the OK to save the file.

Also, CadKey does not have any extra optimization tools for the STL files.

As you see above, there is a wide variety of CAD software available in the market that you can use in additive manufacturing applications.

STL Viewer Software

Also, you can use the different kinds of STL viewer software. This software ar every compact software that you can easily update and adjust the STL files inside it. Maybe you can not create objects in this software. But you can easily and instantly view the different kinds of STL files.

They can be very efficient to show the different features of these files with this additional viewer software. Because general CAD software does not provide any viewers or STL editors with themselves. You will probably need basic viewer software to use.

STL Converter Tools

For example, you have a CAD file but you do not have CAD software to convert this specific file into STL formats. You can use the STL converter tools to do it. You just need to open the STL converter tool and convert the CAD file into an STL file.

This software is also very basic software to use. Because they provide various kinds of abilities for the users. Furthermore, these converter tools are very simple programs that you can easily run on your computer.

Also, these tools can provide extra optimization tools that some CAD software does not have.

STL Repairining and Optimization Tools

You may have STL files that are corrupt or do not work efficiently şin your additive manufacturing machine. There are also STL repairing software and optimization tools that you can easily use. You can easily repair the STL files with these optimization tools.

They are also very basic software that you can use. Also, you can find online software that you can easily optimize the files for 3D printing activations.

You need to have one of these tools. Because you may need extra optimization on these files before uploading them to the rapid prototyping machines.

Optimizing the STL Files

After creating the STL files, optimization of them is also very important. We need to take special care about these optimizations.

We state that the STL files are the tessellation of the geometries where the triangles are created to show the complete part. If the triangles are too big, the part will be very coarse. And we can not obtain the shape that we want.

And also, if we overoptimize the STL files, we obtain very fine structures. So, we need to make the triangles smaller. With the decreasing sizes of triangles, the total accurateness, and fineness of the part increase. But after a level, it is not possible to increase the fineness. Also, with the very small triangles, the files will be very huge. And it is very hard for a siling software to adjust the part.

So, the optimization is every time good. You need to optimize the parts. In general, you can optimize the STL files in CAD software in two ways;

• Chord Height Tolerance
• Angular Tolerance

In most CAD and optimization software, you can make optimizations regarding these values.

Adjusting Chord Height Tolerance

The chord height tolerance has a direct effect on the smoothness of your model. So, you can easily adjust it for your STL file.

Chord height tolerance is the average distance between the triangle edge and the actual surface of the part. So, it is very important to decide on this tolerance well.

In most cases, define the chord height tolerance between 0.01 to 0.001 to obtain the most optimized results. So, your parts will be well optimized for additive manufacturing.

Adjusting the Angular Tolerance

This is a second tolerance that you can adjust. This is the angular deviation from the actual surface of the part. In general, you can adjust it from 0 to 1 degree to obtain smooth results. It is very important to have correct angular tolerances.

As you see above, adjusting the tolerances and optimizations of the STL file is very simple. Also, as you remember from creating STL files from the CAD software, you care to adjust some tolerance values above. These values are these values.

Installing STL Files on Additive Manufacturing Machines

This is also a very important step after obtaining STL files for additive manufacturing of the parts. You need to take special care about installing these files in machines. Also, you need to be aware about there are different types of rapid prototyping machines. So, installing and configuring the machines according to these files can be different.

Here we explain the general aspects of installing STL files to rapid prototyping machines. You can follow these steps to install them effectively without any problem. This is the only step that, operator attention is required in additive manufacturing applications.

Normally, one may think that we upload the STL file on the machine, then click on the Print button to print it. But it is not like this. We have some steps to consider while we are uploading them.

Checking the Part

Most additive manufacturing machines also have interfaces that you can easily check the correctness of the part. From this interface, you can easily adjust the orientation of the part. So, it is very easy to double-check the part.

Adjusting the Orientation of STL File

For proper manufacturing of the part in the STL file, we need a proper adjustment. Because the part is produced with the layer-by-layer method. So, the most advantageous orientation will require the minimum extra structural parts to hold the different portions of the part.

Already, you adjusted the structural extra sections on the part. So, you know which orientation you will produce. So, you can adjust the orientation of the part in the additive manufacturing machines.

Scaling the Part

Also, if you care considering the shrinkages that can occur in the manufacturing phase, you can easily give a part scale. With the proper linear scaling, you can consider obtaining the exact sizes of the parts. So, you can easily linearly scale the part in additive manufacturing machines.

Part Count

And also in the additive manufacturing machine interfaces, you can adjust how many parts you will produce. You can copy the part inside the STL file. If you will produce multiple parts, it is very easy to make them.

So, as you see above, you can do all of these geometrical manipulations that we state here.

Setting Up the Additive Manufacturing Machine

After we installed the STL file on the machine, it is ready to set the machine to start the manufacturing process.

In the setup processes of the most machine, material selection is very important. Because these machines have very different material characteristics that you can easily adjust.

Also, all these parameters can have in the STL file. You just need to start the machine after installing the STL file into the machine.

Build Phase

This is the phase that material building takes place. So, we obtain the general shape of the part in the building phase. The machine starts to adjust the platform height and layer-by-layer adjustments according to the STL file. Also, auditory management from the computer machine is still an important thing in this phase. This phase may be completely automatic. But we need to also give a special amount of attention to the build process.

Removal of Part from the Machine

At the end of the manufacturing phase, the completely same shape is produced with the STL file. So, you need to apply extra manual applications to the additive manufactured parts. It is a very important step.

In general, we use support structures to produce the parts. These support structures are very important to prevent warpages and collapses in the building process. Because the material is still soft to obtain the exact shapes. And the support structures hold the material in their position.

The removal of these support structures is also very important to obtain the general shape. So, it is very important to do it.

Also, these support structures are designed in the STL file. You need to consider the proper support structures in these systems.

Post Processes

For some parts, we can require some finishing applications such as polishing and grinding. Because some defects and surface characteristics can occur because of the layer-by-layer production method.

Also for some additive manufacturing methods, it is not required to have post processes. You can easily have the near-net shape of the STL file.

Tessellation in STL Files

This is a very important feature of STL files. Once you create geometry, it can be a very complex shape. But the additive manufacturing machines can not sense this CAD geometry directly. So, it can be a special form of these CAD files that the machine can perceive and create a 3D model from it. This is possible with the tessellation of the CAD file or 3D model.

Tessellation means dividing the part into small separate parts. So, these separate parts constitute the near net total shape. These small parts are triangles in STL files. And the additive manufacturing machines perceive the part from these triangles. Because of it, STL is the acronym for Standard Tessellation Language.

You can think that tessellated CAD files are the types of files that machines can understand mathematically.

ASCII and Binary STL File Formats

The difference between the ASCII and Binary STL file formats comes from the coding structures of the triangles. So, additive manufacturing machines will create the parts according to these codes.

In ASCII codes, the vertices and the normal vectors of each triangle are directly represented by code lines. And in binary STL codes, twelve 32 numbers are representing each triangle.

We generally use Binary STL file formats because they are much easier to use. Abd also, the codes are very huge in ASCII formats that have lots of kinds of codes. And binary ones are too simple for machines.

If you noticed that, we select Binary as a type of STL file in the STL file creation in CAD software. Because nearly all the additive manufacturing machines are using STL files to generate the geometries.

Other Alternatives of STL Files in Additive Manufacturing

Also, there are other kinds of alternatives to STL files in additive manufacturing. The data storing types of these different types of file extensions are different. Also, there are around 30 different kinds of files in additive manufacturing. And these are the most common ones;

OBJ Format: This is a type of file format that uses the second most common file format in these applications. They are storing data on the color and textures of the CAD geometries.

PLY Format: This is the polygon type format that stores the data of 3D scanned objects with different kinds of devices.

3MF Format: Also, this format gets very common in 3D printing machines.

Advantages and Disadvantages of STL Files

STL files are very common in additive manufacturing. We need to have them and optimize them to obtain successful manufacturing of these parts. But, they have advantages and disadvantages that we need to consider. If we know the general merits and demerits of these files, it will be much easier to deal with the possible problems that we will face. Check the advantages and disadvantages below.

Advantages

• As you understand from the full text, this file format can be used in nearly all additive manufacturing machines. So, the users of these machines will not confuse themselves with different kinds of file formats. You can easily use the STL format of the CAD geometries in most of the machines.
• You can adjust and optimize nearly all types and materials of objects without any problem. This wide variety of choices gives very common use property to these file types.
• STL files do not have any information about color and texture. So, the total file sizes are much smaller than the other kinds of file extensions. And this makes it easy to install into the machines and perceived from the rapid prototyping machines.
• There is a very wide variety of software that you can create, edit and optimize the STL files. Because they become very common these days.

Disadvantages

• The most important drawback of the STL files, they do not contain the color and texture information inside them. So, machines are not generating final products. They are generally used in the production of prototypes.
• Another important disadvantage that STL files have they can not store any data about the copyrights or authorship. So it leads to the situation that they are the general public’s use.
• To obtain requires smooth surfaces and high-quality parts, we need to decrease the sizes of the triangles and adjust the tighter tolerances. This gives very big and complex files to perceive and adjust. Both in the slicer software and the additive manufacturing machines, it becomes a problematic and time-consuming issue to optimize and produce.

Free Online STL File Resources

In the online environment, you can find different kinds of shapes and parts in STL format which are created and optimized into intended structures. For example, you can find files of structural parts for a camera holder, you can easily find them from different forums and the internet. So, the internet community to obtain these kinds of things about additive manufacturing is very common.

Conclusion

As you see above, the topic of STL files that we use in the additive manufacturing methods is not an easy one. If you are aware of the general titles and topics about these files, you have made a very big start to the use of the machines. Because this is one of the most common file types that most additive manufacturing machines use.

You can obtain the STL files after you design the CAD geometry with the CAD software. But not all CAD software has STL conversion and optimization tools. You may require extra software packages to optimize your files before uploading them into the machines.

Also, it is very important to know the general aspects of optimizing these files. You can easily do that if yıu know which feature is for which parameter. If you know it, you can easily obtain the best 3D printed parts.

Furthermore, installing and running the machine is also a very important task. You need to take special care about importing the file into the machine. You need to make some adjustments to the interface of the rapid prototyping machine that you will use.

After setting up the machine, you can easily start the process to make the part from zero. In addition, it is also important to know the general code structures and advantages and disadvantages of STL files in additive manufacturing techniques. You need to be aware of the other types of files.

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