Many 3D printers can print directly from an SD card instead of being hooked up to a computer all the time. This presents a problem of transporting SD cards without tying up your hands. Or pockets. A ring that you can put an SD card in is just the thing.
While a ring you can put an SD card in is a slightly silly solution, it's an excellent example of modeling based on physical objects. Both a finger and an SD card will need to be measured, and the design will have to be modeled too:
This chapter will walk you through the process of making a cool 3D-printed project, going through the following steps:
- Taking measurements
- Modeling the ring
- Testing the ring
- Adding an SD card holder
- Putting it all together
- Extra credit
The challenges of matching real-life measurements to 3D-printed objects is made difficult by plastic shrinkage and inaccuracies in 3D printers' operations. I'll comment on that when it becomes important.
Some would claim that Blender isn't capable of CAD-like precision, but this project will put those naysayers to rest.
Before opening Blender, some measurements must be gathered. Careful measurements need to be taken of the ring finger and an SD card. A digital caliper is an excellent tool to take measurements with, as shown in the following figure:
My middle finger measures 19.3 mm at the widest point. If a digital caliper is not available, another way of measuring your finger is to wrap a piece of paper around the finger, mark where it overlaps, and use a ruler to find your finger's circumference, like this:
Then, consult the following table to find out the standard ring size and diameter:
|
Circumference (mm) |
Circumference (in) |
Diameter (mm) |
Radius (mm) |
US standard ring size |
|---|---|---|---|---|
|
1.94 |
49.3 |
15.7 |
7.85 |
5 |
|
2.04 |
51.9 |
16.51 |
8.25 |
6 |
|
2.14 |
54.4 |
17.32 |
8.66 |
7 |
|
2.24 |
57 |
18.14 |
9.07 |
8 |
|
2.34 |
59.5 |
18.95 |
9.47 |
9 |
|
2.44 |
62.1 |
19.76 |
9.88 |
10 |
|
2.54 |
64.6 |
20.57 |
10.28 |
11 |
|
2.65 |
67.2 |
21.39 |
10.69 |
12 |
|
2.75 |
69.7 |
22.2 |
11.1 |
13 |
|
2.85 |
72.3 |
23.01 |
11.50 |
14 |
|
2.95 |
74.8 |
23.83 |
11.91 |
15 |
|
3.05 |
77.4 |
24.64 |
12.32 |
16 |
An adult male is generally around a size 10 mm, an adult female is around a size 8 mm, and a child is around a size 5 mm.
The next thing to measure is a standard SD card. Fortunately, SD cards are all the same: 2.2 mm x 24 mm x 32 mm:
