3D printing is a great way to turn your creative ideas into tangible objects. Whether it is to make a quick prototype of a novel clothes peg, some funky new earrings or to replace a broken part of your favourite fishing rod, 3D printing provides you with the technology to easily do this.

To print something out in 3D, you will need to take a couple of steps before you can hit the print button. First you will need to create a 3D model and save it as an STL file – a file that contains all the information about the object’s shape. Then you will need to use some software to turn that model into a format that the 3D printer can read. This format is called GCODE and you use a slicing software package to produce. This file can then be printed out. Sometimes the objects comes out of the printer looking a little bit rough on the surface and you can sand the surface to give it have a smoother finish. Each of these steps will be discussed in more detail below.

Create a 3D model

Before you can start, you will need to create a digital model of the 3D object you want to print. Models can be created using a 3D modelling software package. There is a very large selection of software to choose from, but to start of with we recommend TinkerCad. Head over to the tutorials page on their website to learn about the basics of designing 3D objects with ThinkerCad.

The Internet is another great resource for finding 3D models. Sites like thingiverse, yeggi, pinshape or youmagine have large libraries of designs that other people have created and shared. These sites are a great place to find inspiration, to find existing designs for projects that you are working on, or for people who are just starting out and are a little apprehensive about using 3D modelling software. Most of the models on these sites can be reused under a creative commons license, or can be bought for a small fee.

If you want to print a copy of an existing object, and have access to a 3D scanner you can create a digital model of that object.

With your 3D model saved as an STL file, you are now ready for the next step.

Prepare model for printing

Next you will need turn the STL file into a format that the 3D printer can use for printing. This process is called slicing and it defines the path that the print head will follow, what speed it should travel at, what temperatures to use for melting the plastic correctly and much more. The slicing software saves all this information in a GCODE file.

Printers like the UP mini2 that we have in our Makerspace use their own dedicated slicing software (youtube tutorial). Other printers rely on third party software packages like Slic3r or Cura to create the GCODE.

Some printers can print directly from your computer, whereas with other models you will have to transfer the GCODE to the printer using an SD card.

Tip & tricks for slicing

  • Infill
    • For smaller objects generally no infill is necessary, just make sure to use sufficient perimeter layers (see below for more details)
    • If the object will be loadbearing during use, then generally a good idea to have infill
  • Perimeter layers
    • Sides – 2 layers
    • Top and Bottom – 4 layers
  • Supports
    • Printers have issues with printing parts that have an overhang of more than 45 degrees. Make sure you add supports under these parts. Some slicing software even does this automatically for you.
    • It is a good idea to use a layer by layer preview in the slicing software, to check if there are elements that have little or no support underneath. If this is the case, make sure to add support under this
  • Rafts/brims
    • The less surface area the bottom of your object has, the more important it becomes to add a raft/brim. This will prevent your object from detaching from the print bed during the print. When an object detaches from the bed, it generally causes the object to deform.
  • Object orientation
    • There are a couple of things to pay attention to when you orient your object relative to the print bed:
  • Use a large flat area on you object as the base during printing makes the object more stable and more likely to stick to the print bed during the printing process
  • Orient the model in such a way that you minimise the number of overhangs in your object during printing. This will the number of necessary supports and reduce printing time and cost
  • Nozzle and bed temperatures
    • Make sure to set the correct nozzle and print bed temperatures for the material you are using. Check the manufacturing specs of the filament and printer for exact details. Check out this guide for some general advise on temperature settings.
  • Layer thickness
    • Setting the layer thickness is a trade off between print speed and the finish quality of the print. When you half the layer thickness (e.g. from 0.1mm to 0.05mm), the print time will double. If you are just making a quick prototype and do not really care about how smooth the surface looks, then go for thicker layers. If however you want to print a nicely finished product that has lots of intricate details, then use thinner print layers.
  • Print speed
    • Like layer thickness, print speed is also a trade off between quality and print speed. Objects printed at lower speeds (around 50 mm/s) generally have a better quality. However, if you are printing a quick prototype to see what a product will look like, then by all means use a higher speed.

With the GCODE ready it is now finally time to see your design come to life. The 3D printers available in our Makerspace are FDM (Fused Deposition Modelling) printers. These printers heat up a plastic filament and build up the 3D objects layer by layer.

In the Makerspace we have the following printers available for use. If you are going to use one of these, familiarise yourself with the specifics of that machine by reading the manual.

You can choose between PLA or ABS plastic filament for your prints. For more details about which of these materials best suits your print project, check out this materials guide by Tierney Brothers.

Tips &Tricks for using the 3D printer

  • Clean the bed of the printer before a new print, to make sure that the
    • Use some rubbing alcohol (isopropyl alcohol) on a bit of cotton wool to rub the bed clean. The cotton wool does not have to be drenched in rubbing alcohol, just a small splash is enough. The alcohol will clean off any grease and will also loosen any plastic remaining from previous prints. If these do not come off straight away, then use a plastic spatula to scrape these off the print bed.

Finishing

After the print is done, you will have to remove any rafts/brims and supports that were added during the slicing of the 3D model. The best way to do this is to use needle nose pliers or small sharp cutters. You can use a small file or a sanding block to remove any last little burs.

If you need a high quality finish on your printed object, the most straightforward way to smooth the surface is to sand it. Check out this youtube video on advice on how to best do this .

If you want a smooth spray painted finish, then check out this youtube video on how to achieve this.

Safety

Working with 3D printers requires some caution, as parts of the printer, such as the nozzle and print bed can reach temperatures well above 200°C and can take a while to cool down. Printed objects can also have very sharp edges. For this reason it always a good idea to wear gloves when removing the print from the print bed. When you remove the finished print from the printer bed and while removing rafts and support materials it is advised that you wear safety goggles, as small parts of filament break off easily and can cause a threat to your eyes.