How Do You Design a SOLIDWORKS Model for 3D Printing?
Before your 3D model can be printed, you have to consider a couple of things: the version of SOLIDWORKS you are using (student or professional), and the year of its release. For example, SOLIDWORKS 2015 has a built-in 3D printing command (which only works with Windows 8.1) that previous versions do not. Also, only SOLIDWORKS 2015 users will need the SP5 version to be compatible with Windows 10.
Another thing to keep in mind is what 3D printer you will be using, and what material with which you want to print. Doing your own printing can save you money if you expect to print a large number of objects. There are industrial 3D printers (expensive) and desktop printers (relatively cheap), and a wide range of materials available overall.
But let’s step back. If you are modeling in any SOLIDWORKS edition for the specific purpose of 3D printing, there are some things you should keep in mind and know before you start.
1.) Know your 3D printer. You will need to know whether or not to create support structures.
Whether you are 3D printing from home or using a service, it is crucial to understand if the 3D printer that will be fabricating your object requires support structures in order to optimize the likelihood of a successful print. You will have to have a basic understanding of which type of 3D printer you will be using to print your part.
If you have a 3D printer at home, chances are it’s either a fused deposition modeling (FDM) printer such as a MakerBot, Ultimaker, UP, DaVinci, or Cube printer; a stereolithography (SLA) printer such as a Form1 or Form2; a MoonRay printer; or a digital light projection (DLP) printer, and you are going to need to know how to create support structures. If you are using SOLIDWORKS 2015 with Windows 8.1, the default 3D print settings automatically create support structures.
If you are sending it away to a third-party service such as Shapeways, Sculpteo or i.materialise, it is important to know what material and type of 3D printing process they will be using to complete your print. Most of these services have and use selective laser sintering (SLS) machines that print in a wide variety of materials including nylon, glass, ceramic and different types of metal.
SLS printers do not require support structures. The reason they do not require support structures is because they are surrounded by print material (from which each layer is sintered) throughout the duration of the print, which acts as a perpetual supporting structure.
There are a few other types of 3D printing which are used by third-party printing services, some machine shops, universities and manufacturers that are important to keep in mind when it comes to the necessity of support structures. Selective laser melting (SLM), direct metal laser sintering (DMLS), and electron beam melting (EBM) all require varying degrees of support structures, but high speed sintering (HSS) prints do not.
All of these 3D printers work in the same basic way—by fabricating one layer or slice of a 3D model. FDM printers deposit one layer of a print in hot molded plastic from an extruder, SLA printers use a UV laser to cure one layer of a photopolymer at a time, and SLS printers heat up a giant pile of particulate and sinter one layer at a time. The same is true with every 3D printing process available today, no matter what material is being used.
These printers operate by depositing layer after layer of your model, which is sliced either by SOLIDWORKS 2015, or by a third-party software. (If you are not using SOLIDWORKS 2015, you will have to export your file as an .STL file.)
2.) Incorporate these 3D modeling practices when using SOLIDWORKS specifically for 3D printing
Each part has to have a thickness. Each printer has different capabilities when it comes to thickness, but this is just a reminder that making 3D models for show is different than making one to be produced, in this case by 3D printing it.
The different bodies that make up your model should not intersect. This will create a confusing situation for slicing operations (when software cuts your 3D model into printable layer instructions for your printer). You should create a model in solid modeling mode for ease of design, but you can transfer a surface model into a solid one. The reason it’s easier is that surface bodies do not have a translatable digital weight, so your computer won’t be able to equivocate it physically. However, you can make sure a surface model is watertight and then convert the skin into a solid model, or you can use the thickening tool to expand your surface model into a solid model.
Build in solid modeling mode:
To start with building a model in solid modeling mode, create a new file, check off the “Merge Result” option and then check “Selected Bodies.” If you want to start with separate bodies, you can use a Boolean tool later on the software. To combine separate bodies, click “Insertion,” then “Functions,” hit “Combine,” then hit the “Add” option until you have a single solid model. In “Cut” view, you can verify that your models have merged if you see a bright blue flash between the two models with no spaces. If there is a space in the blue, then use the “Combine” function to merge them fully.
Merging two separate bodies in SOLIDWORKS is vital when designing for 3D printing. Image courtesy of Dassault Systémes.
Consider minimum thickness and hollow out your object where possible:
When your model is fully merged and designed, you’ll want to hollow your model to use less 3D printing material, which can be quite expensive if you’re printing in metal, for example. To hollow your model, use the “Shell” function, but be sure to leave fragile parts and thin parts (available thickness depends on the limitation of the 3D printer being used). If you want to play it safe, make sure your minimum thickness is at least 1mm. Another important thing to remember when hollowing out a structure is to select a face to allow your object to be hollow. If you don’t select a face, you have to add a hole for the material to drain out, otherwise SOLIDWORKS will interpret the model as solid and not hollow. This will add unnecessary material expense to your print.
Consider material cost:
It’s true, most 3D printing material is expensive. FDM printers have the cheapest materials in general and they come in spools of filament. Most spools are interchangeable. However, some FDM 3D printers like the CubePro have proprietary filament cartridges. Photopolymer resins in SLA and DLP 3D printers are more expensive than FDM material, and SLS materials rise in price from nylon plastics to ceramics, porcelain and metals like aluminum, stainless steel (the cheapest), gold, silver, and brass (the most expensive). If you are unsure about thickness requirements, most 3D printing services like Shapeways and Sculpteo have helpful design guides based on the materials they offer and they include minimum thickness.
Measure your object:
If you haven’t been measuring your file for some reason, be sure to use the “Measure” tool to measure the exact volume, angle, length, width, height and so on. You can also click on the “Information” tab to get more data on your model (weight estimations, global size, etc). One thing you should definitely measure is the distance between parts of a moving part or assembly. Be sure that the distance between parts is .5mm between surfaces. Any closer and there’s a good chance that the 3D printer will fuse them together.
Using the measuring tool to determine an angle of a 3D model in SOLIDWORKS. Image courtesy of Dassault Systèmes.
Now that you have your part or component completed in SOLIDWORKS, you are almost ready to 3D print.
3D Printing in SOLIDWORKS
Change the file format to an .STL file:
Depending on which edition of SOLIDWORKS you are using, the instructions vary for preparing a model for the best 3D printed version possible. In the last few editions, you can simply click “Save As” and select an .STL file.
Student version: Open eDrawing, which comes with every SOLIDWORKS edition. Open your .SLDPRT file by clicking “File,” then “Open” and then select your design. Finally, save your file as an .STL file by clicking “File,” “Save as,” select “Save as type” and then hit “.STL.”
Be sure to enable “Export STL in eDrawings” in the student version. Image courtesy of Dassault Systèmes.
You can then take this .STL file and upload it to a home printer’s proprietary or open-source software, where you will add support structures, infill, layer resolution and so on. There will be an option for you to print, and it will send your SOLIDWORKS .STL to your printing destination, and then you’re all set.
Creating a mesh and exporting:
SOLIDWORKS does not have the ability to create a mesh before exporting. However, when you export an .STL file, SOLIDWORKS automatically creates a mesh during the export. SOLIDWORKS will render your meshed .STL and give you an estimated file size as well as the number of faces on your object. If you are using a third-party 3D printing service, the file size is extremely important because of upload limits. Check the upload maximum on a third-party service to make sure your model is below it before finishing the export. You may need to reduce the size of your model if it is too large.
To 3D print in SOLIDWORKS 2015:
Open your STL file, click “File,” then “3DPrint.” This will open the Print3D property manager dialog box and show you a list of 3D printer drivers available through Windows. If you are printing from home, this dialog box allows you to select your printer (if it’s supported by windows 8), set your print resolution settings (higher equals more detail but takes longer), infill percentage (sets the amount of material inside a solid model, i.e. a higher percentage will yield a stronger model but take more time), and allow you to add or remove support structures (the default settings add them automatically). Then all you have to do is press “Print” and watch your digital model slowly become a physical object.
If you are using a third-party service like i.materialise, Shapeways or Sculpteo, you will need to export your model file first and then upload it to the service of your choosing.
To 3D print in other SOLIDWORKS versions:
If you are not using Windows 8.1, or are using a SOLIDWORKS version that does not have the newer built-in 3D printing capability, you can always save your 3D model as an .STL file. You can also download and use a free analyzing and mesh repair software like MeshLab or send it to a cloud repairing service like netfabb.
Performing a standard analysis of a 3D model to ensure quality that will fix damaged parts of the mesh and optimize it for 3D printing. Image courtesy of netfabb.
These applications and others will ensure that your model is fit and optimized for printing. You can either upload it to a third-party printing service or open it from open-source or proprietary printing software for your printer at home. Either way, if you are a SOLIDWORKS user, these guidelines may help improve your 3D printing experience no matter what material or 3D printer you use.
About the Author
Andrew Wheeler is an optimistic skeptic whose lifelong passion for computer hardware has led him to 3D printing and his latest technological passion, Reality Computing.