We already used 3D printers for PC modding, taking you through the basics of using TinkerCad to design your objects. There’s far more to TinkerCad than making 2D fan grilles and modding components, though, and in this post we’re going to use it to create a case.
Tools You’ll need:
1. TinkerCard
2. 3D printer or 3D printing service
3. Digital vernier caliper
4. Finger files
How to…
1. DOWNLOAD RASPBERRY PI STL
To create your Pi 2 case, you first need a 3D model of the PCB. Thankfully the Pi B+ PCB is physically identical to the Pi 2 in terms of case layout, and is available to download for free from [www.thingiverse.com]. Search for the Raspberry Pi B+ board by jayftee and grab the 9MB STL file.
2. IMPORT MODEL INTO TINKERCAD
Importing the STL file into TinkerCad [www.tinkercad.com] is easy, and you can then start to build your case around it. In the right-hand menu, under Import, simply point TinkerCad at your downloaded STL file and upload it.
3. START WITH A CUBE
Now you can start building the case, starting by dropping a cube shape into the workplane from the same menu. You can, of course, choose any shape but we’ll be making a rectangular case so we’re starting with a cube.
4. ENLARGE CUBE TO FORM BASE
Modify the cube so it’s the right size for the base of your case. You can either use the measurements provided by TinkerCad to guide you, or simply make the base a little larger than the PCB. The total PCB model size is 58.5x 86.89 mm, so your base needs to accommodate that area measurement.
5. CREATE SCREW HOLE INSERTS
With the PCB lined up on your base, create some cylinders for inserting holes into the case to mount the PCB. You can use standard PC screws – just make a cylinder that’s slightly smaller than the screw thread (a digital vernier caliper will come in handy), so the screw can bite into the plastic.
6. PLACE INSERTS INTO BASE
Move the inserts on to the case and position them in the PCB mounting holes, in order to ensure they line up once the case is printed – another good reason to have a 3D model of the PCB to hand.
7. CHECK BASE FOR CLEARANCE
You now need to raise the inserts, so they don’t go all the way through the base when you convert them in to holes. Lift them by 3-4mm so the screws can pass a little way into the base – you can check they’re clear by looking underneath the case.
8. CREATE CUT-OUT INSERT
As we saw in last month’s 3D printing feature, it’s best to create holes in as many parts of your project as possible to cut printing time and costs. We started by laying down a large object in the base to create an opening – we’re also moving the PCB model out of the way for now.
9. SWITCH TO HOLE MODE
Now convert the object into a hole by selecting it, then clicking on Hole in the Inspector box, which converts it from a colored object into a hole. It should now appear translucent, which indicates that it’s acting as a hole and not a solid object.
10. GROUP OBJECTS
To finish creating the hole, select the base and hole only (leave the mounting holes separate for now), and select Group from the top tool bar. This process will delete the area of the base with which the hole is merged.
11. CREATE CUT-OUT DESIGN
You can then create a vent using individual pieces or, as we did, drop some letters and numbers into place. You can simply enlarge or reduce them to size as needed, depending on your chosen vent design, or you could lay them on top.
12. INSERT SUPPORTS
To hold the characters in place, we created small supports that connect them to the case at the edges. They’ll still look like they’re suspended, but this reinforcement will help them to survive any knocks. We also reversed the lettering, so it will read the right way when you pick up the box.
13. GROUPOBJECTS
Merge your vent design objects into one group by selecting them and clicking the Group icon again, being careful to avoid any objects that you don’t want to group yet.
14. CLONE BASE
We want to apply the same design to the lid of the case, and the easiest way to do this job is to clone the entire base, then remove the PCB support holes as shown. You can move the lid to one side for now.
15. ADD PCB STANDOFFS
You don’t want to screw the PCB directly into the base, so create some small standoffs into which you can insert screws. These bits are just like the standoffs in a PC case, except you only need them to be 5mm or so high. Place these standoffs over the mounting holes.
16. CREATE HOLES
You can now convert the mounting holes from solid objects into holes. Check if they’re aligned with the standoffs, then click on each one and convert it into a hole using the same method employed in step 9.
17. GROUPOBJECTS
In the same way you grouped the vent objects together, you can now group all the base objects together so you can move on. Hold down the left mouse button down, as you would to select an area in Photoshop, or characters in Word, then click the Group button in the top menu.
18. CREATE SIDES
Now put the PCB model back in place and create some side sections. Only two sides of the Raspberry Pi 2 have ports, so the other two can be solid objects. We dropped in a couple of cube shapes and manipulated them to form 3mm-thick walls that run from end to end as shown.
19. CREATE LID MOUNTS
You’ll need away to mount the lid too. You could have a sliding lid, but we preferred the idea of securely screwing it into place. We created two mounts that could sit inside the case, level with the side sections.
20. INSTALL LID MOUNTS
These mounts sit diagonally from each other, and only two are needed so save space – most of the lid will rest on the base’s side sections anyway. We’ve placed the mounts so that there’s still enough clearance between the PCB and the side sections – at least 2-3mm.
21. ADD LID MOUNT SUPPORTS
We went through to the end and printed a test base at this point, but found the supports were too weak, breaking when screwing the lid into them. We went back and added these corner braces to strengthen them. You can also add vents in the sides – we opted for a hexagonal pattern.
22. PLACE LID
Now you can move the lid into position, lining it up with the base and side sections. You can then move onto finishing the side sections and creating holes for the mounting screws.
23. SURROUND PORTS
You don’t really need to create a sealed case with the Raspberry Pi 2, but a sealed case definitely looks neater, so we went some of the way, and surrounded the end ports at the side and the bottom by extending the lid.
24. CREATE PORT SIDE SECTION
We then added a further surround in the lid section, as well as a long side section as the final piece –we’ll cut holes into this part through which the ports can protrude. The idea will be to delete the PCB model, leaving a 3D-printable and two-part case.
25. CONVERT TO HOLE
By converting the side section to a hole, it becomes translucent so you can see the ports you need to cut out to provide access. There are just three – the HDMI port, micro-USB connector and audio output.
26. ADD PORT AND LID HOLES
You then need to recreate the ports from appropriately shaped objects, and then resize them to provide plenty of clearance around them. For the HDMI port, we opted for a rectangular hole, rather than a larger-sized hole shaped like an HDMI port, to ensure there was enough clearance.
27. PRINT YOUR DESIGN
Click on Design, then Download for 3D printing to get the STL file for your design, and either print it on your own 3D printer or use a third-party service, then enlarge any trouble some holes and file the edges. Here’s our design, printed on 3D Systems Cube 3, with a Pi 2 installed.
