VCUQ FabLab 3D Printing Certification

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Introduction

3D printers, are a very useful tool for prototyping, and fabricating your projects. In the Fablab, Our Ultimaker printers heat PLA plastic and extrude it in thin 2 dimensional layers on on top of the other, to create a 3D form.

To make a 3D print, you will need a 3D model. This could be constructed in 3D modelling software, or taken from a 3D scan.

We have many Ultimaker’s, they are reliable and easy to use. Therefore this certification will focus on Ultimakers. We also have a Dimension Elite, a Zprinter 650 and a Lulzbot Taz 5 that can be used for more advanced, experimental print applications. If you would like to use these printers, take this certification and print a prototype of your part on the Ultimaker. The FabLab staff will then take you through the process of working with our more advanced printers.

If used properly, the 3D printing is safe and easy to use. Take this certification and make a booking! Make sure you read everything because you need to correctly answer all of the quiz questions to get certified. The certification will last for your entire tenure at VCUQ.

If you need to refresh your memory on any of the details in this lesson, you can refer back to this page at any time.

3D printer Safety, Bookings, and Expectations.

Safety

If operated properly, with PLA plastic provided by the shop, 3D printers are perfectly safe to use, however there are some hazards, please observe the following steps :

The FabLab provides free White colored PLA filament for you to use on the Ultimaker. Polylactic acid (PLA) is a Biodegradable thermoplastic made from plant matter, it 3D prints very well, it is safe to use, and free of harmful odours. Although technically it is food safe by making contact with the Ultimakers heated print head, it may contain harmful metallics. Furthermore the porous texture of 3D printed parts make them susceptible to contamination, and make them impossible to clean. For these reasons prints made on the ultimaker should not be used for consuming food.

Bookings Fab Lab Expectations

The Fab Lab Staff and Lab Monitors are available to assist you with:

It is up to you (with the assistance of your instructor) to do the following:

3D printer Misuse

Misuse of the 3D printers will result in a 1 week suspension from booking. After 3 suspensions, you will be barred for the remainder of semester and required to re-take this certification. Examples of 3D printers misuse include:

If you have any concerns with any aspects of this, please talk to Fab Lab Staff or student Lab monitors.

Quiz: From the options below, check all of the statements that are TRUE based on what is stated above:
All Use of the 3D printers requires a booking.
If you are not certified you can have a friend make a booking for you.
Fab Lab Staff and Lab monitors can assist you with the use of Cura Software
Fab Lab Staff and Fab Lab monitors can help you design your 3D model
You need to monitor your print job for the entire duration of its printing time.
You need to monitor your print job for the first 30 minutes of the print.
Although PLA is technically food safe, prints made on the Ultimaker should not be used for consuming food.


Getting Ready to make 3D Print

This Certification assumes that you have already designed your 3D model for printing and that you have exported it as an STL file. With that in mind, this section covers some of those basics.

Although the Fablab can assist you with sending your 3D model to the printer and using the Cura Software, we cannot help you to design your 3D model. If you are using 3D printing in a class project ask your instructor for assistance. Here are some other resources which you can use to learn more about 3D modelling :

STL files and Creating a ‘watertight’ mesh.

Not only do 3D printers require and STL file to make a 3D print, it is also essential that your STL file is a ‘watertight’ mesh. A ‘watertight’ mesh is a singular, manifold surface of polygons which describes your shape. Put simply, you need to ensure that your 3D model is made of a single surface (shell) that doesn't have holes, gaps or overlaps in it. If the mesh where a bag, you could fill it with water without any leaks. This vital in 3D printing because without it, the software cannot distinguish the Solid (inside) part of the print from the outside of the print.

Even if your design is intended to include thin ‘walls’, the surface covering the inside and outside of those walls needs to be water tight.

Solid Modeling software like 123d Design, Solidworks, Autodesk Fusion 360 and Autodesk inventor are good to use to design your Models because they work in such a way that they only produce water tight meshes, because they only allow you to create solid models.

Models made from 3D scans, or made in Rhino, Sketchup, Maya, blender or 3Ds max, will often produce STLs that are not watertight. This will require careful work in the software to ensure your model is water tight. Here are some resources to help describe this concept and troubleshoot your model.

Furthermore, Software like NetFabb, MeshMixer and Meshlabs (all available on Fab Lab computers) can be used to inspect and ‘repair’ your mesh.

Although we cannot help you design your 3D model, Use these resources to help you resolve issues with your model yourself or with the aid of your instructor.

Making your Model the correct Scale

If you want to print something at an exact size, it is important to set the scale before you export your STL file. If you are making a prototype you may want to reduce the size of your model in Cura Software to shorten the print time. In either case, Make sure your model is set to the correct scale, and that the scale is set in millimeters (mm).

Quiz: From the options below, check all of the statements that are TRUE based on what is stated above:
FabLab Staff and Lab Monitors Cannot help you Design your 3D model
If you need help with Rhino you should ask your instructor.
Fab Lab Staff and Fab Lab monitors can help you design your 3D model
STL files made in Rhino are always ‘Watertight’ and are ready to print.
STL Files should be set to the correct scale, in Centimeters(cm)
STL Files should be set to the correct scale, in Millimeters(mm)


Materials for Ultimakers

The FabLab provides free White colored 3mm PLA filament for you to use on the Ultimaker If you would like to print in another color, you could purchase a spool of a different color from the VCUQ Bookstore. Each spool will create many prints, so this is only recommended if you plan on sharing the spool among the entire class or a group of students. Experimental Materials on the Taz5 If you choose to, you can purchase other appropriate materials externally, and we can attempt to print them on our experimental Taz5 3D printer. providing they meet the following specifications:

Printing in alternate colours or experimental materials is time consuming and can be fraught with issues.. We require you to print your design first on the ultimaker before electing to purchase or experiment with other materials.

If you need to make a colored part on the 3D printer, we suggest painting, or coloring the white PLA after it has been printed.

Quiz: What Plastic does the Ultimaker User?
1.75mm PLA filament
3mm (or 2.85mm) PLA filament
1.75mm ABS filament
3mm (or 2.85mm) ABS filament


Planning your 3D print

Once you have prepared your STL file, you are ready to think about your 3D print. Consider the following factors:

1. Need for Support Structure

Ultimakers print by extruding plastic layers one at a time, from the bottom to the top. In other words, the layers build upon each other. If your model has any large overhangs, it will most likely need an additional support structure that will be generated by the 3D printer. Remember that the more support structure that your model needs, the longer it will take to print. Supports can later be broken off, once 3D printing is complete, to reveal the original model. However, the separation of supports from the model can be a difficult and time consuming process, and can thus degrade the quality of the 3D print.

2. Position

As a general rule of thumb, the model should be positioned in the center of the printing bed. The way you position your model in Cura can also reduce the need for additional support structure. Try to rotate your model such that the largest possible surface area of your model is in contact with the bed of the 3D printer. This is likely to reduce the need for additional support structure. Optimal positioning of the model will also reduce the 3D printing time.

If the model is complex, think of separating the model into fragments or chunks to increase efficiency and likelihood of success of 3D printing. A minimum distance of 6 mm should be kept between each element.

Note: that it is possible to import more than one STL file in the same Cura window.

3. Scale

The Ultimaker can theoretically print objects up to the dimensions of 35.7 cm x 34.2 cm x 38.8 cm. However, print jobs are more successful if the model is smaller. If your model exceeds these dimensions, it is possible to scale it down in the Cura software. However, it is best that you make sure your file is the right dimensions in the modelling software itself (rhino etc.).

4. Fill Density

Fill density refers to the internal structure of a print. It therefore relates directly to the strength of the model. The lighter and less dense the infill is, the weaker the 3D print will be.

5. Brim

Brims are generally 1-2 layers of filament that are produced around your 3D model. If generated, they touch the model, having a 0.00 mm offset from it. Brims can be used to stabilize small model elements, by securing them to the print bed. It should be used every time a model does not have its own flat base.

Quiz: Answer the following question correctly:
1. Why are supports needed?
Supports prevent warping of the 3D printed object.
Supports are always required to initiate the print job.
Supports are needed to bear the load of any overhangs that are not braced by the existing structure of the model.
Supports are essential to avoiding issues of under-extrusion.


2. True or False: Positioning the model laying flat on the print bed, and in its center, is optimal for good printing results.
True: Placing the object in the center, and flat on the print bed, increases the likelihood of a successful print job.
False: There is no such thing as optimal position for 3D printing. Objects can be positioned in any way on the print bed.


3. When/why are brims used?
To stabilize large flat objects onto the print bed.
For every print job
When the model does not have its own flat base, or when the model consists of small elements that need to secured to the print bed.
Never use a brim as it ruins the 3D print.


Tutorial: Using Cura

Cura is the sotware we use to send our 3D files to Ultimaker 3D printer. It is available on FabLab computers or can be downloaded here.



1. Placing Model in Cura: 2. Adjusting Model for 3D Printing: 3. Printer and Print Settings

The window pane to the right of the screen displays the printer job settings.

  • Print Job: Select the printer(ultimaker 2+ or Ultimaker 2), nozzle size and material. As a default the nozzle size is set at 0.4mm, while the material is set to be PLA.
  • Ensure that you are in the Simple Setup Mode
  • Profiles: These refer to preset settings for the quality of 3D print. Profiles vary from ‘Fast Print (more speed, less detail)’ to High Quality (less speed, more detail).’ For most objects, Fast Quality’ is sufficient for most prints.
  • Infill: The infill option allows you to choose the strength of the internal structure of the 3D print. The ‘hollow’ setting denotes that the 3D print will not have any internal structure; rather; it will simply consist of the shell itself. Using a ‘light infill’ (20% infill) is appropriate for most models. For more strength, select the dense infill. The solid infill option is recommended for objects that have very thin parts, such as a fork or a piece of jewellry.
  • Note: The more dense your infill is the longer your print time will be.

  • Generate Brim & Generate Support Structure: If you have concluded that your model requires a brim (a flat layer of PLA around object around the object to help build plate adhesion), select the ‘Generate Brim’ option. Likewise, click on the ‘Generate Support Structure’ if you deem that your 3D print requires so.

Hint: You can view how the object is going to print by clicking on the ‘layers’ option in the ‘View Mode.’ Drag the blue button up and down to view the process of printing.

Hint: in cura, the overhangs of your prints are indicated in red. Usually these areas will require supports! Try and rotate your object to minimize the red

4. Saving file File into 3D printer

When done adjusting settings, Cura should indicate that your file is ‘ready to save to file.’

Quiz: Based on the tutorial above, select the true statements below:
Before importing your 3D model to Cura, it first has to be converted into the STL format
Any kind of 3D file can be imported into curat
You should always use a ‘solid infill’ option when 3D printing to ensure maximum strength to the object.
For most print jobs, a ‘light’ infill is sufficient.
For most prints the ‘Fast print’ profile is sufficient.
If your model contains overhangs it will require supports.


Monitoring your print

It is important to monitor the first 30 minutes of your print to ensure that:

During the course of the print and afterwards, inspect it to ensure that some common issues are not occurring, such as ‘Under extrusion’, ‘Stringing’, and Pillowing

Quiz: What is stringing? Use the following website to help find the answer:
https://ultimaker.com/en/resources/troubleshooting/3d-prints
‘Stringing’ occurs when the printer is unable to supply the right amount of material. It is evident if the model has layers missing or very thin layers.
Stringing are small, unwanted strands of plastic that is seen where the ultimaker shouldn't be printing.
Stringing are 1 to 2 layers of filament produced around a 3D model, used tostabilize it.
Stringing are the loose and deformed corners of a 3D print that happens when the very hot plastic cools down fast.


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