3D Printing & Modeling + Ed3DP

3. 3D Modelling- TinkerCAD

3.2. Design Project Tips

It is presumed that you are combining the 3D modelling in Tinkercad with 3D Printing, so most of these tips relate to easy, fast, successful 3D printing for classes with multiple prototypes for an introductory mainstream class (not a specialist design or extension class).

Project Design Tips:

  1. Small and Simple Designs
    • Its possible to not do any lessons using the TinkerCAD tutorials and just use Project Based Learning (PBL)- so keeping the design projects to about 1-2 hours of class time allows for repetition to consolidate TinkerCAD techniques.
    • Simple basic shapes with vertical faces- for example making a ring for your finger is just two cylinders (hole + solid)
  2. Limit "overhangs": 
    • "overhangs" are parts of the model or print job that do not have anything directly beneath and are defined as degrees from the vertical i.e. straight up is a zero degree overhang while a horizontal protrusion is a 90 degree overhang
    • Limit overhangs to 30 degrees or 45 at most- this means that you don't need any "support" material when 3D printing and makes printing faster and simpler for beginners- so a pyramid has no overhangs while human with outstretched arms has lots of overhangs and is not suitable for beginners to 3D print
    • Consider simple model rotation:  for example a table standing upright would be horrendous to print but if you flip it so that the table top is on the bottom plane and legs sticking up then it would be simple to print with no overhangs
  3. Avoid projects with large surface area to volume ratios:
    • such projects, for example a thin tall wall has a large surface area and a small volume so it dissipates heat quickly and unevenly which will cause "warping" and lifting of the print job from the print bed.
    • "Squat" and "Chunky" models have low surface area to volume ratios and are thus less prone to warping and lifting issues.
  4. Use a minimum of 3mm wall thickness
  5. Avoid fine features with lots of detail- stick with simple coarse designs- for example a key ring with your name and phone number that's about 40 by 70mm in total would be easy to print,simple to design and look good- however putting an embossed photograph of your loved one on that same keyring is an advanced project and would look amazing but takes considerable design and 3D printing experience.
  6. Set specific design guidelines: it is unwise to set the task as "make a key ring of your choice" as this leads to dubious learning outcomes and is not suited to Project Based Learning in mainstream classes- Rather the task should be "design a key ring that has 70mm x 40mm base of 3mm with your choice of end shapes and your name perfectly centred with a 5mm border with the text either embossed or cut through
  7. Do not allow students to "drag" and redimension objects- insist they use the ruler and directly enter dimensions with the keyboard or they will find it extremely difficult to progress to complex designs and it is poor design and engineering practice.