3D Printing

3D Printing Project

Introduction

The latest and final addition to our repertoire of manufacturing skills we need for making our product, 3D printing is otherwise known as additive manufacturing, whereby a three-dimensional object is made using a Computer-Aided Design or digital three-dimensional model. This method is especially useful when the geometries of the objects needed are complex and intricate. For the first 3D printing assignment that we embarked on over the holidays, we were tasked to design an object in Fusion360 that can be 3D printed in less than an hour.

Designing The Product in Fusion360

Before the product can be 3D printed, the 3D model needs to be made and I did so using Fusion360. The product I had in mind was a small, cube box with a sliding lid. This box cannot be easily made by subtractive manufacturing due to the design of the divots on the box to make the lid able to slide in and out. We would not be able to laser-cut such a piece as it is differing in thickness at the slope. The small scale of the box would also make it difficult to make precise cuts at an angle using a drill bit. 

I started the sketch by first defining the parameters of the product I wanted to make, doing so by clicking on Modify on the ribbon and selecting Change Parameters.

I set the following parameters for the box:

I then proceeded with the modelling, starting off by making a box by selecting Create and then Box, defining the box's dimensions to all be the parameter I made earlier, CubeEdge.

To make the box hollow, I used the Shell tool by selecting it in the Modify section of the ribbon on top. I defined the shell's outer walls to be the parameter I had set, Thickness.

To make the divot where the lid can slide into and out of, I started by projecting the corners of the face of the cube where the lid will be, as well as those of the inner walls. I did so by using the shortcut key P for project, and selecting first the middle of the outer face of the cube where the lid will slide out of to project all four corners, then the two lines perpendicular to the inner face where the corners will be. This makes sketching the divot easier as it gives me reference points for the sketch.

To sketch the divot itself, I started by clicking create sketch on the Create section of the ribbon and clicking on the face of the cube where the lid will slide out from. The first part of the sketch is the diagonal line that is the overhang for the divot. I made the line length to be the same as the thickness of the box and at a 55 degree angle, which is a viable angle for the overhang as the printer would have sufficient support to handle the print.

To make the divot symmetrical, I sketched a vertical line at the midpoint of the edge of the cube.

Using the keyboard shortcut by pressing the X key, I changed the line I just sketched into a construction line.

To make the horizontal edge of the divot, I made the end of the newly-sketched construction line and the diagonal line I drew earlier to be coincident on the same horizontal line using the Horizontal constraint. Clicking on the Vertical/Horizontal constraint and shift-clicking the two endpoints achieved this, and I finished off the line by clicking on Line in the Create section and clicking on the two points I want to connect.

I mirrored the sketch using the construction line as the mirror to make the sketch symmetrical.

To turn the divot from a sketch into the actual divot on the box, I extruded the sketch. I selected To Object for the extent type and clicked on the back inner wall of the box so that the divot extends all the way to the back of the box.

To make the lid, I started by clicking on New Component in the ribbon above. In the popup, I renamed the component to lid and deselected the box as it would make the lid appear under the box.

The box will then be inactive but still visible, so I started by projecting the four points of the trapezium that will make the lid.

I then offset the trapezium by a distance of the parameter I defined, Gap, to make the lid not snug to the divot and hence able to slide in and out. Using the Line tool, I connected the two intersections of the offset diagonal lines and the top line of the trapezium we projected from earlier.

To form the lid into a three-dimensional object, I extruded the sketch in a similar manner as the divot from earlier.

Seeing that the gap might be too large for a box of such a small scale, I adjusted the parameter by reducing it from 0.25mm to 0.1 mm. This resulted in a smaller gap, yet the lid still remained not completely in contact with the divot.

At last, the box was done! They say all's well that ends well, but this was not the case. Importing the STL file of the box into Ultimaker Cura, the print times totalled less than 10 minutes, which is great as it is within target, but I feel like the box would be too small. Hence, I increased the cube edges to be 25mm instead of 10mm.

Again importing the STL file into Ultimaker Cura, I tweaked the settings as follows to make the box have good print quality, and sturdy at the same time. Though not seen in the screenshots, the print speed was at the default setting.

The box is ready to be 3D printed! Here is the final product:

The lid had turned out to be quite a nice fit, though it was a little tighter of a fit than I had expected. Perhaps I should have scaled up the Thickness parameter as well to compensate for having a larger box, and that is one thing I could improve on in future projects. You can click here to view and download the .stl and .f3d files for the project.

And here's a 360-degree view of the box:

Reflection on 3D Printing

Overall, this simple 3D printing project has made me realise how easy it actually is to 3D print an object. Truly, the only limit would be our imagination with what we can come up with in our computer-aided designs. In this assignment, I was able to utilise the skills I had learnt earlier in the semester that I have acquired that I talked about in my post on Computer-Aided Design. CAD and 3D printing really go hand-in-hand, and we simply cannot print anything without making use of CAD. I feel like I could have definitely explored more and made a more intricate design rather than do something very rudimentary. In terms of the use of Ultimaker Cura, I only found after the design process that we could actually scale the product up and down as a percentage of the actual scale, instead of doing so manually for the parameters of the product. This could have made my final product more refined, especially after fine-tuning the software parameters even further, and hence this is something I could take note of in the future. After the assignment, I definitely feel a lot more enthusiastic about 3D printing and I am looking forward to making good use of it in our project.