GHS CAD Keychain Tutorial

This Instructable was created for CAD Mechanical Design students at Grantsville High. In it, we'll be going through how to design a basic keychain in SolidWorks. We'll also learn how to save that file as an STL, and import it into the slicing program MakerBot. Where we'll then slice it, and print it on a MakerBot Replicator +.

To begin, open up SolidWorks 2017, press the page icon to create a new file, and select part.

First, locate the toolbar that says features, sketch, evaluate, etc. This is where most of our operations will take place. Select the Sketch tab, and select sketch within it to create one. Select the top plane. Next, select a rectangle from the sketch tab. Move the cursor so that it finds the origin, it should light up with a little icon when you do so. Click once, and move the cursor in a diagonal away from that point. Click again to create the rectangle, the size doesn't matter too much right now.

Because now, you smart dimension it. Before doing this, verify that the units in the bottom right corner of the screen say IPS. If not, click the little arrow, and change it accordingly.

Click on Smart Dimension under the Sketch tab, and click on the bottom line of the rectangle. Move the cursor away from the rectangle, and click again to start dimensioning. For this line, put a dimension of 2 inches. Once that dimension is complete, click on one of the vertical lines of the rectangle, and dimension it the same way to a length of 1 inch.

Exit Sketch.

Select extrude boss/bass from the Features tab, and it should bring up a dialogue box on the left side of the screen. Set thickness to 0.375". Click the green checkmark to complete the sketch. Next, select Fillet from the Features tab. Select all 6 faces of the rectangle. (Navigation tip: Press in the scroll wheel of the mouse and drag it to rotate the part around an imaginary axis.) Set Fillet radius to 0.1".

Press the checkmark.

Under the Sketch tab, press the little arrow next to sketch and select 3D Sketch. Then, select one of the end faces of the rectangle. Select the circle icon under sketch, and click in the middle of the face. Drag it out to the edge of the piece, and click again to create it. Smart dimension the circle with a diameter of 0.375". Dimension between the edge of the rectangle and the center of the circle with a length of 0.5". And smart dimension between the middle of the rectangle and the top face of the piece with a length of 0.1875". All this is to center the circle on the end of one of the faces.

Exit Sketch. Verify that the last sketch you made is highlighted in the menu to the left, then, under features, select extruded boss/base. Click on the opposite face to select a direction. Check the box for direction 2. Make sure that both directions are dimensioned to be 0.25", and click the check mark.

Under features, select fillet and select the top face of the cylinder you just created. Specify radius as 0.1", then click the check.

You should now have a somewhat rounded top.

Start a new 3D sketch, and start a new circle. The center for this circle is in the middle of the dome you just made. Reference the picture to find it, the mouse pointer should highlight it if you're positioned just right. Start the circle, and finish it, and make sure that it's created vertically. Again, reference the picture. Smart dimension it to a diameter of 0.15". Exit Sketch.

Make sure the sketch is selected on the left hand side, and create an Extruded Cut, under the features tab. Select Direction 2, and make both of them Through All instead of Blind. Click the check, and you should have a cylinder protruding from a rounded rectangle, with a hole through the center of it.

Create 3D sketch On Plane. Select one of the big faces of the rectangle. Click the little A icon in the sketch tab, and type whatever message you want. Keep in mind, Goodsell approves all prints. Also, the larger the text, the more likely it will be readable when printed. Select the bottom of the rectangle as the bounding curve, and dimension the text how you want it. Exit sketch when ready.

Make sure it's selected on the left, and do another extruded cut. Click the opposite face to specify direction, then set the depth to 0.0625". Click the check to create, and your keychain is done!

Save the part, first as a solidworks file. .SLDPRT.

Then, save it as a .STL. This format is what the printer can read.

Goodsell will assist with this step. Turn on the printer, a small switch is located on the back.

Save your .STL to a thumbdrive, the printer is only connected to one computer that the teacher has to sign into. Open MakerBot on said computer. Add your model with the little file icon.

Press the orient button, then select the bottom plane. Press the bottom button to orient the keychain properly on the build plate. Press the settings button. Verify the following settings: Rafts on, Layer height = 0.1mm, Number of shells = 2, infill density = 10%.

If you want to know what these settings do, Google it. There's a lot to learn as far as 3D printing settings.

Press the estimates and time preview button, and the program will slice the file and create a print file. Select 3D Two as the printer unless otherwise told, then press print.

The computer will now send the print file over, and you need to press the dial on the printer to verify it. After the printer heats up, you may notice a small string of plastic dangling. Try to grab it quickly with your fingers; this will make it offset more accurately. Be careful though, the metal head is approximately 410 degrees F. The printer will lay down a string of plastic in the front, and begin your print.

With something this small, no warping should happen. Cancel the print if anything doesn't look right. Enjoy watching it work, and your new customized keychain.

-Peter Porter

12.13.17