5. First Print with the Simple

Now that the Simple is assembled and the software is configured, there’s only one thing left to do—let’s print something!

In this chapter you’ll be reading about the last few tasks required to print a 3D object model with the Simple using the Repetier software. Given that more than 100 different models of 3D printers are out there, this chapter can’t possibly cover every situation. But keep in mind—even if you’re not using Repetier, even if you’re not using a Printrbot Simple—there is a fairly standard list of tasks that you must do to print an object on all 3D printers:

• You’ll need to download or create an STL file on your computer.

• You’ll need to import an STL file for printing into the software.

• You’ll need to connect your 3D printer to your computer.

• You’ll need to get the Hot-end up to proper temperature.

• You’ll need to slice that object into layers.

• You’ll need to “home” the nozzle end of your 3D printer’s hot end (more on that in a moment).

• Print!


Note

STL file—this is a new term for you. STL stands for stereolithograpy, a form of 3D printing (that you’ll read about in Chapter 10, “Alternatives to the Printrbot Simple”) that used this special file format for storing data to print a 3D object. STL files are pretty common these days for all forms of 3D printing, including with the Printrbot Simple.


Not all of these tasks must be done in the order specified, but certain tasks (such as beginning the print job) won’t start unless others have already been completed (such as slicing the object into layers).

In this chapter I walk you through the steps I do each time I want to print an object with my Simple. If you’ve got a different model of 3D printer, not everything will match up. That’s when it’s time to consult the documentation for your own 3D printer and figure out the list of tasks that required for you to print something. Keep in mind that there are lots of folks who have gone before you, so reach out to them in the forums if you need help. The amazing thing about the 3D printing hobby is how friendly and helpful the community is with novices; we all want this hobby to grow and prosper, and that means lending a hand to those who have questions.

So, without further ado, let me print something for you.

Downloading an STL

Before I can print anything with my 3D printer, I need to decide on what I’d like to print. I have designed a number of objects with Tinkercad (see Chapter 7, “Creating a 3D Model with Tinkercad,” for a walkthrough of a 3D object being created from scratch), and I can certainly choose one of them for my first print job on the Simple. Lots of 3D printer owners choose to print what are called “calibration” objects—they allow users to print out an object and compare the accuracy of angles and widths and lengths to the actual 3D model to determine if the printer is working properly. But I want to jump right in and print something of mine. If I discover my printer needs some calibration, I’ll do that a bit later. Right now, however, I just want to print something fun.


Note

Printrbot’s “Simple Getting Started Guide” recommends a specific 3D model from Thingiverse called the 5mm Calibration Cube with Steps; you can view (and download) that model by visiting the following link: http://www.thingiverse.com/thing:24238. If you don’t have the STL file for a 3D object to print, grab this one and perform the same steps I do in this chapter for my medallion object.


Figure 5.1 shows the Hello World file that I created in Tinkercad (see Chapter 7) and saved to my computer.

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Figure 5.1 A 3D model’s STL file.

Notice that its icon is a copy of the Repetier software icon. If I double-click it, the Hello World STL file opens in Repetier, as shown in Figure 5.2.

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Figure 5.2 The STL file as viewed in Repetier.

This object is a small, thin, rectangular plate (with rounded ends) that has the words “Hello World” created via holes in the solid object’s body. Right now, I’m not concerned about all the buttons and values being displayed in Repetier. Instead, I want to open up the STL file and confirm that I can view it in the 3D Viewer. (Click the 3D View button if you don’t see your STL file after double-clicking it.)


Note

Before you begin printing, it is recommended that you put down a strip or two of blue painter’s tape onto the print bed. When the plastic cools, it will adhere quite strongly to the wooden print bed surface—the painter’s tape will allow you to more easily remove a cooled, printed object because the plastic doesn’t stick as securely to the tape’s surface as it does with wood.


Connecting the Simple to Repetier

Now that I’ve imported my STL file into Repetier, it’s time to connect my 3D printer to my computer. I do this by first plugging in the USB cable to the Simple’s circuit board and the other end of the USB cable into my computer. I already configured Repetier back in Chapter 4, “Configuring the Software.” so that my computer knows which USB port to use. (Fortunately, my laptop has only one USB port, so Repetier has it easy. If you’ve got multiple USB ports, try to remember to always connect the 3D printer to the same USB port on your computer.)

Next, I need to apply power to the Simple using the AC adapter that came with the kit. I first plug the power cable into the wall and then insert the other end into the power port on the circuit board. A small green LED lights up on the circuit board to indicate the Simple is receiving power, as shown in Figure 5.3.

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Figure 5.3 The green LED indicates all systems are go!

Now it’s time to test to see if Repetier can communicate with the Simple; to do this, all I have to do is click the red Connect button in the upper-left corner of Repetier, as indicated in Figure 5.4.

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Figure 5.4 Click the Connect button.

If everything is connected properly, I should see the Connect button change from red to green. I also get a confirmation of the connection from the text that appears at the bottom of the screen, as shown in Figure 5.5.

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Figure 5.5 Confirm that your 3D printer is connected to Repetier.


Note

Consult the “Simple Getting Started Guide” at http://printrbot.com/support/instructions-and-guides/ for troubleshooting help with the Simple and Repetier software. You might also want to visit printrbottalk.com and post a question if you can’t find an answer to your technical issue.


Get the Hot End Up to Proper Temperature

The hot end must get up to the proper temperature for melting the filament. The Printrbot Simple “Getting Started Guide” will have you configure the temperature to 195 degrees Fahrenheit (refer back to Chapter 4), and that’s the temperature you will see used for this chapter’s print job.

To get the hot end heating up, change to the Print Panel in Repetier. On the right side of the screen in Repetier, I click the Print Panel button shown in Figure 5.6 and then click the Heat On button.

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Figure 5.6 Turn the heat up to get the hot end melting plastic.

To verify that the temperature is climbing, tap the Temperature Curve button indicated in Figure 5.7, and take a moment to watch as the line climbs upward toward 195.

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Figure 5.7 The hot end temperature increases.

While the hot end’s temperature is increasing, be very careful not to touch it. You also want to make certain that nothing is touching the hot end, such as paper, wires, and so on.

Slice Your Object into Layers

Now it’s time to slice up the object you’ve selected to print into layers. Click the Object Placement button indicated in Figure 5.8 and then click the Slice with Slic3r button.

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Figure 5.8 Use Slic3r to cut up your 3D object for printing.

After clicking the Slice with Slic3r button, you’ll see some text appear in the window below the Object Placement button, as shown in Figure 5.9. This is the g-code that will be used to control the motors and Extruder, telling the motors how to rotate and in what direction.

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Figure 5.9 G-code for the 3D object.


Note

I mentioned g-code earlier in the book, but now you can see what it actually looks like. It’s very cryptic stuff, but it’s basically just code that tells the various motors how to operate. X10, for example, tells the X motor to spin in such a way that the print bed moves 10mm. The g-code Z-15 would tell the Z motor to spin the lead screw so that the hot end moves down (toward) to the print bed. You’ll also see the various settings you configured for Repetier back in Chapter 4 submitted via g-code. If you’d like to see just how substantial the list of commands/codes for g-code really is, visit http://en.wikipedia.org/wiki/G-code.


Home the Hot End

Look at your Simple (or whatever 3D printer you are currently using) and take note of where the end of the hot end’s nozzle is located. Figure 5.10 shows where my Simple’s nozzle is located. It’s about 5cm above the print bed and slightly to the left of dead center. It’s also more toward the rear of the print bed.

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Figure 5.10 Treat the tip of the nozzle like a point in space.

When Repetier takes the g-code and begins to issue instructions to the motors, it is assuming that the nozzle tip is in the front-left corner of the print bed and almost touching the print bed. I can manually adjust the X and Y axes on my Simple by carefully pushing or pulling them so that the nozzle is as far forward and to the left as possible (without breaking anything). I can also manually adjust the Z axis by turning the vertical lead screw by hand. If I turn it enough times, I can get the nozzle to the proper starting location, as shown in Figure 5.11.

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Figure 5.11 Nozzle now in proper starting location.

Manually moving the nozzle isn’t difficult, but there is a better solution that doesn’t require you to adjust the three axes by hand. Change back to the Print Panel shown in Figure 5.12 and note that X, Y, and Z axes each have a collection of strange buttons with values on them: –100, –10, –1, –0.1, 0.1, 1, 10, and 100. These values are in mm, and a single click on one of the axis buttons will cause that motor to move either the print bed or the nozzle that distance.

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Figure 5.12 You can move the hot end nozzle in small or large increments.

To use these controls correctly, you need to determine the direction that a motor will move the print bed or nozzle when each button is clicked. You can do that easily enough using the 0.1 or –0.1 buttons for each axis (or maybe the 1 or –1 buttons). For example, if you click the –1 button for the X axis, the print bed moves 1mm to the right. If you click the –10 button for the X axis, the print bed moves 10mm to the right. If you click the 10 button for the X axis, the print bed moves to the left.

Similar experimenting with the Y axis tells me that the negative buttons (–0.1, –1, –10, –100) move the nozzle forward, toward the front of the print bed. The positive buttons move the nozzle back, away from the front of the print bed. For the Z axis, the negative buttons move the nozzle closer to the print bed, and the positive buttons move the nozzle up and away from the print bed.

As you can see, by properly using these buttons, you can move the print bed and nozzle in such a way that the nozzle’s tip is placed in the correct starting position at the front-left corner of the print bed.

One of the secrets to a good print job is getting the nozzle as close to the print bed surface as possible so that it lays down a flat bead of molten plastic during the initial movements. To do this, Printrbot recommends cutting a small square from a sheet of 8.5” x 11” paper. Place this slip of paper under the nozzle tip and lower the nozzle until it requires a slight tug or two to pull the slip of paper out from underneath the nozzle tip. You’ll have to experiment a few times until you get the right distance figured out, but as a rule, I lower the nozzle as far as I can get it without it digging into the print bed’s surface. Figure 5.13 shows how I’ve placed this slip of paper underneath the nozzle to get the proper distance from the print bed surface.

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Figure 5.13 Slip of paper underneath nozzle.

If you find that the slip of paper is too tight and can’t be pulled away easily, use the 0.1 button for the Z axis to move it up a tenth of a millimeter, and try again.

When you’ve got the nozzle in the proper X, Y axis location and the right distance from the print bed surface, tap the Set Home button shown in Figure 5.14.

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Figure 5.14 Press the Set Home button when the hot end is in the right location for starting a print job.

After clicking the Set Home button, you should see that the values for X, Y, and Z on the Print Table change to 0.

Now it’s time to print.

Print!

Before clicking the Run button, perform a last-minute check. Switch to the Temperature Curve image and verify that the temperature is where it needs to be. Click the g-code button (to the left of the Print Panel button) and verify there is actual g-code there from the object slicing tasks. Finally, verify that you’ve homed the nozzle. It should be in the front-left corner and almost touching the print bed surface, and all three axes should have values of 0 on the Print Panel.

Take the end of your filament, clip it off at an angle to provide a sharp point, and feed it down through the extruder and into the hot end. When the filament is inserted properly into the hot end, lock down the extruder to put pressure on the filament so the extruder motor can feed it in on its own.

Now switch back to the 3D View button shown in Figure 5.15 and click the Run button.

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Figure 5.15 Watch the progress in 3D view as the path of the hot end is traced.

There will be a slight delay before the nozzle begins to move. When the print job is first executed, the nozzle increases slightly in temperature (up to about 5 degrees or more of the temperature you’ve set) to get the filament melted and ready to flow.

When the print job begins, the nozzle starts to move. If you’ve configured Repetier as recommended in Printrbot’s “Simple Getting Started Guide,” you’ll notice that a few loops around your object will first be put down; this is both to get the melted filament flowing through the nozzle and to allow you to visually verify that a bead of plastic is being put down on the print bed, as shown in Figure 5.16.

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Figure 5.16 An initial bead of plastic is put down around your object.

If you don’t see a bead of filament on the print bed, it’s possible the extruder is gripping the filament too tightly or too loosely and is not feeding it into the hot end. Loosen or tighten the extruder mechanism on your 3D printer slightly and see if the bead begins. If not, click the Kill Job button and check a couple of things:

• It’s possible your hot end might need a slightly higher temperature to get things flowing. Use the Print Panel to raise the nozzle 3cm (30mm) or so away from the print bed. Release the mechanism on the extruder that applies pressure and manually push the filament down into the hot end. You should see a wormy bead of plastic come out of the nozzle, as shown in Figure 5.17. If the bead appears, you’ve got the temperature set properly and need to adjust the tightness of the feeding mechanism on the extruder.

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Figure 5.17 Testing filament extrusion.

• If manually pushing the filament down into the hot end doesn’t produce a wormy bit of filament coming out of the nozzle, you might need to increase the temperature. Raise the temperature manually by 5 degrees. Manually push in the filament. If it comes out too fast (almost like liquid), pull the temperature back in one-degree increments until you see the filament coming out and immediately cooling and curling up on itself.

After you’ve got the plastic extruding properly, you’ll have to home the nozzle again and start the print process over (including possibly turning on the heat). You won’t have to slice the object again, but click on the G-code button to verify the code is still there.

Your first few (or first few dozen) print jobs aren’t going to be perfect, so be aware of that fact to avoid frustration. It took over a dozen adjustments in the nozzle height (above the print bed) and the tightness of the extruder feeding mechanism to get it “just right” before the Hello World medallion began to take shape, as shown in Figure 5.18.

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Figure 5.18 The Hello World medallion printing properly.

Notice in the photos that I’ve put down a wide strip of blue painter’s tape on the print bed as I wrote about at the beginning of the chapter. I did this before the print job began (and before I turned on the heat). Don’t forget the painter’s tape—it will help you remove the finished print job—you don’t want the hot plastic stuck to the wooden print bed! Just peel the tape off the print bed when the print job is done, and your printed object should pop off the tape easily. You can see the finished medallion (before removing from tape) in Figure 5.19.

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Figure 5.19 The finished medallion.

Upgrades!

Homing the nozzle for every print job can get annoying fast, but there’s an upgrade that now ships with every Printrbot Simple. It’s a set of end stops that automatically do the homing for you—cool! The end stops were released too close to the finishing of this book, so I was unable to include their installation in Chapter 3, “Assembly Assistance for the Printrbot Simple.” But Printrbot has added the steps to install the end stops, and I highly encourage you to use them. After installation, instead of using the axes buttons to move the nozzle tip to the proper starting location and distance from the print bed, you click the Home All button on the Print Panel and this task is done automatically. The motors spin and the print bed and nozzle move on their own, and no fine-tuning by you is needed.

As for the painter’s tape, there’s also an upgrade coming soon (but not ready at the time of this writing) that will eliminate the need for the tape. It’s called a heated bed, and it’s a tool used to let the plastic cool gradually so that it doesn’t warp or curve. If you’re a painter’s tape user, you may notice that the plastic sometimes has a tendency to warp slightly as the plastic cools. The heated bed helps prevent his. Be sure to check with your 3D printer manufacturer to see if a heated bed is available; if you’re the owner of a Simple, the heated bed should be available by the time you’re reading this.