Tinkercad For 3d Printing

[Wynellewe Gr]

Ifyou have been wanting to design your own 3D printed object, Tinkercad is a great starting point. Advanced modelers may prefer programs like Fusion 360, SolidWorks, and Blender, but these can have a steep learning curve. If you are looking to design your own 3D printed object in a modeling software, Tinkercad can get you there in no time.

This tutorial will walk you through designing a simple project box. It has been designed to hold an Arduino Pro Mini. While this may seem fairly useless, you are encouraged to change the dimensions to meet the needs of your own project.

You will not need any components to follow along with the modeling part of this tutorial. Should you wish to print and build the box, you will need access to a 3D printer. This tutorial shows you how to use the Cura (LulzBot Edition) slicer program and print on a LulzBot.

Depending on your 3D printer, you will want to be familiar with its basic operation. This guide shows you how to operate the LulzBot TAZ 5, but many printers have a similar operation. These documents might be helpful:

The advantage of 3D printing your project enclosure is that you get to make it the exact size of your project! You're also able to add any features, such as mounting holes and side ports to access USB, power, etc.

To start, lay your parts (electronics, motors, switches, etc.) on a flat surface, and orient them in a way that you think is the most space efficient. For this tutorial, we'll create a box that fits the Arduino Pro Mini, but you can modify the dimensions to fit your own project. Use a ruler or set of calipers to measure the outer dimensions of your project (also known as the "footprint"). This is the minimum amount of area we'll need in the base of the box.

The electronics portion of the project (just the Pro Mini in this example) has a footprint of 1.326 x 0.723 inches. This guide shows things in inches, as most of the SparkFun boards were created with the Imperial system. Feel free to change to Metric. Next, we want to measure the maximum height of the pieces to be enclosed.

There are several ways to attach screws to a 3D printed object. One of the most robust methods is to use heat-set inserts. You can use use a soldering iron to push these into an opening, which melts the plastic. Once it cools, the insert will be firmly embedded in the plastic, and you can use them as screw taps.

For our quick-and-easy enclosure, we'll just make holes slightly smaller than the screw size so that the thread bites into the plastic. It won't hold as well as a heat-set insert, but it should be good enough for prototyping purposes. Ideally, you will want self-tapping screws intended for plastic, but machine screws will work in a pinch.

We'll be using #4-40 screws to affix the lid to the enclosure. As a result, we'll want to look up the sizes of the holes we'll need. Take a look at this tap and drill size chart from Michigan Tech. You can see that for a #4-40 screw, we'll need to drill a hole with a diameter of 0.0890 inches (tap drill size) for the screw's threads to bite into the material. These holes will be put into the base of the enclosure. For the lid, we'll want the screws to be able to freely spin, so we'll use the free fit drill size, which is 0.1285 inches.

Most fused filament fabrication (FFF) 3D printers, like our LulzBot, do not have great tolerances or resolution (e.g. down to the 0.001 inch). The molten plastic that comes out of the extruder also has a habit of "melting" a bit around the edges, which can cause holes to shrink. In addition, using self-tapping screws forces some of the material to move out of the way, which can cause stress and fractures in the plastic. As a result, we'll need to oversize the drill holes by 0.01 to 0.02 inches.

From here, it can help to sketch out what we want the enclosure and lid to look like. Adding dimensions will help us when we go to model it in the next section. Just to give us even more room, let's round up the required cavity space to the nearest 0.5 inches. Because the posts in the corners (that hold the screws) are each 0.25 x 0.25 inches, this will make our entire enclosure's footprint come out nicely to 2.0 x 1.5 inches.

You'll be presented with a blank workplane and a number of shapes on the right side. The basics of Tinkercad are simple: you drag a shape onto the workplane, modify it, and combine it with other shapes. If you right-click and drag on the workplane, it will rotate. If you middle-click and drag on the workplane, it will pan. Try playing around with rotating and panning your workplane to get a feel for how it works.

We'll want to work in inches for this project, so click Edit Grid in the bottom right of the Tinkercad window. You should get a pop-up with some options. Change Units to Inches.

Click Update Grid. At the top left, you should see the name of your project, which should have been given some random sequence of words (for example, mine was named "Fantic Wluff-Gaaris"). You can click on the name and change it to anything you'd like. I'll keep mine as Fantic Wluff-Gaaris because it's awesome (albeit not terribly descriptive).

Click on the red box (from the list of shapes on the right side), and drag it to somewhere near the middle of the workplane. Note that everything we do is relative to the workplane, and we can move the workplane to make things easier (which we'll do in a future step).

Zoom in on the box using the buttons on the left side (or your mouse wheel). Rotate and pan the workplane as necessary to get a good view of your box. With the box selected, click on the red color swatch above the word Solid on the object properties window. From there, you can select the color of your box. No, it won't affect the color of the print (that comes from the color of the filament that we'll choose), but it might make your 3D model easier to see in Tinkercad. I'll leave mine as red; it's a good color.

Click on the dimension (1 in this case) and change it to 0.1. In my experience, 0.1 inches is a good thickness for walls for an enclosure like this. Any thinner, and they become quite flimsy.

This box will act as the base of our enclosure. We will build the screw posts and walls up around it. However, the lid for our enclosure looks exactly like this base (but with screw holes). To make life easier, let's just copy this base. Click on the box, and then click the Duplicate button on the top left.

Let's make screw holes in the lid next. Above the red box and orange cylinder objects on the right pane, you should see a box and cylinder with gray stripes. These are "hole" objects that are useful for cutting, notching, and drilling into other objects. It's helpful to think of them as negative objects that subtract parts from other objects.

Drag one of the gray striped cylinders to the workplane and change the width and height dimensions to 0.14 inches (remember from the drawing: the screw holes in the lid need to have a diameter of 0.14 inches). The height doesn't matter, as we'll be using these to "drill" into the lid (so long as it's at least as tall as the lid).

Because everything is relative in Tinkercad (there is no 0,0 origin, unless you create an arbitrary one with the ruler--but we won't need to do that for this tutorial), we will need to align the cylinder with the corner of our lid and move it from there to precisely place it. Select both the cylinder and the second box we created (left-click and drag a selection around them, or hold shift and click on both the cylinder and box).

In the upper-right corner, select the Align button. You should see several black dots appear around both of your selected objects. If you hover your mouse over one of these dots, you should see an outline of where the objects will move to should you click it. But don't click!

We don't want both objects to move! We just want the cylinder to move in relation to the box. To accomplish this, click on the box (the one that we have selected). You should see the set of black dots disappear and another set appear around the box. This indicates that the box will stay still and the cylinder will align with the box (instead of both objects moving). Hover your mouse over the bottom black dot on the left side. You should see an outline of where the cylinder will move.

If we were to subtract the cylinder from the box to get our hole right now, we'd end up with some edges of the walls with 0 thickness, which doesn't make for a very strong mounting hole. To fix this, we need to move the cylinder in toward the center of the box by a small amount.

We want the screw holes to line up in the center of the posts, which have a footprint of 0.25 x 0.25 inches. This means that the center of each post is 0.125 in from each side of the corner. Right now, the center of the cylinder is 0.07 inches away from each side of the corner. This means that we need to move the post 0.055 inches in from each side in order to line up with the center of the post (0.125 - 0.07 = 0.055). Here is a diagram of how we came to that measurement:

Click on the cylinder and begin to drag it toward the center of the box. You should see a couple of numbers appear showing how much you're moving the object in the X and Y directions (along the plane--note that we can't move objects in the Z direction by dragging them).

In the top right corner, click the Group button. This will combine any selected objects into one object. Solid shapes (like our boxes) will be added together. Negative shapes (like our "hole" cylinders) will be subtracted from solid shapes. This has the effect of "drilling" or "carving" out shapes. You should see our lid with 4 holes drilled in the corners.

We need to make the posts on the main enclosure body next, but first, we need to move the workplane. The workplane is the 2-dimensional area that provides an area for objects to be created on, and we can move it to be parallel with any surface of an object we've already created. By moving it up to be in line with the top of the enclosure's foundation, we can make the posts directly on the top of the foundation. That way, we don't have to move the posts up (in the Z direction) later.

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