Carabiner - Setting Up and Printing - Idiot's Guides: 3D Printing (2015)

Idiot's Guides: 3D Printing (2015)


Setting Up and Printing



Project Time: 30 minutes

In this project, you’ll be getting hands on and printing your very first part. For your first print, let’s start with something quick and easy: a one-piece carabiner. This model should print quickly, and most printers will have it finished in under 20 minutes.

Before you begin, make sure you’ve downloaded the model pack from the Idiot’s Guides website ( and have unzipped the folder so you can access the files. For this project and the subsequent projects, I’ll be using Repetier Host and Slic3r, because both are free and popular programs. However, if you’d prefer to use other software (or your printer requires it), the steps should still be pretty similar.

Preheat the Extruder and Heated Bed

Start by opening Repetier (or whatever host software you’re using) and connecting to your 3D printer. Once the connection has been made between your host software and your printer, click on the Manual Control tab to get to the temperature settings for the extruder and heated bed, which you’ll now begin preheating. If you’re printing in ABS, the extruder should be set at about 230°C and the heated bed should be somewhere between 80°C to 100°C. For PLA, the extruder should be 200°C and the heated bed (if you have one) should be between 50°C to 70°C.

Preheat the extruder and heated bed to the appropriate temperature for the material you’ll be using.

Load the .STL File

While the extruder and heated bed are heating up, go ahead and load the .STL file for the carabiner and slice it (found at To do this, look for a button in your host software that says Load or Open. Push that button, and then find and select the carabiner.stl file. Slic3r, which runs within Repetier, will display the 3D model in the Object Placement window.

The Object Placement tab will display the loaded 3D model.

The gray box in the viewer window corresponds to your 3D printer’s print area and is based on the settings you entered when you set up the host software. The carabiner is a small part that is only a few inches long, so it should be printable on virtually every 3D printer on the market.


If the model shows up very large (compared to the gray box), either your printer settings for the print area are wrong or you have your units set to inches (it should be in millimeters).

Slice the Model

With the model loaded, you can go ahead and slice it. With a simple part like this, the particular settings you use won’t be crucial. However, make sure you have at least two or three perimeters (including top and bottom) and at least a 50 percent infill. This can be modified by going to the Slicer tab and clicking on Configuration. Once there, click the Print Settings tab and fill in the information if necessary under the Layers and Perimeters and Infillsubsections. Your print temperature settings should be the same as what you preheated the extruder and heated bed to.

Check to be sure you have at least two or three perimeters (including top and bottom) and at least a 50 percent infill.

With your settings entered, you can start slicing the model by clicking Slice with Slic3r. How long it takes to slice depends on your computer and the slicer you’re using, but it shouldn’t take more than a few minutes.

Slicing a small model like this should only take a few minutes.

Load the Filament

A lot of people keep the filament loaded all the time and only change it when they run out of filament or switch to a different material or color. But if you haven’t loaded any filament yet, load it into the extruder now, while the slicer is running.

How you load the filament depends on the specific extruder your printer is equipped with. Some of them, like the Greg’s Wade Reloaded I’m using, have thumb screws and a latch that needs to be opened up. Others have a lever that needs to be pushed to release tension on the bearing. Or it could be a completely different mechanism altogether.

However, no matter what kind of mechanism it is, the process is about the same once you have it open:

1. Trim the end of your filament with scissors at an angle, so there is a point (this helps it slide into the hot end).

2. Push the filament into the hole below the hobbled bolt or drive gear. With the hot end heated up, you should be able to push it in until melted filament starts coming out of the nozzle.

Load the filament by opening the mechanism and sliding the filament into the hot end.

Extrude Some Filament

Once you’ve closed the mechanism, switch back over to the Manual Control tab in your host software. There should be a button to extrude a specified amount of filament, which you can see in the following figure. Extrude 10mm or 50mm of filament in order to verify the filament has been loaded properly and to build up some pressure in the hot end (which helps improve flow while you’re printing). This isn’t absolutely necessary to do, but it helps to make sure everything is working.

Extrude a small amount of filament to make sure it’s loaded properly and to build pressure in the hot end.

When you extrude, you should have filament come out of the nozzle steadily in a consistent size. If it’s erratic or comes out at an angle, something may be wrong. (If you run into this or any other problems, be sure to check Chapter 15, which covers troubleshooting.) Once you’ve determined that the filament is extruding correctly, you can pull off the pile of filament with a pair of pliers, being careful not to burn yourself on the hot end.

Make sure that the filament extrudes consistently, and then remove the plastic.

Start the Print

Now it’s time to go ahead and start the print! Go over to the Preview tab, which gives you estimates on the print time and how much filament is needed (in millimeters). The viewer window shows you the G-code paths the slicer generated, so you can get an idea of what the printer will actually be doing from layer to layer.

Check the Preview tab to make sure everything looks right, and then start printing.

If everything appears to be correct, push Start Print. Depending on the software and settings, the printer may not do anything immediately. Sometimes it will wait to make sure the temperature is steady before it begins. Once that’s done, though, it should home each of the axes and start printing.

Watch the First Layer

Pay very close attention to the first layer being printed. The first layer is the most important one, because it’s the foundation for the rest of the part. If the first layer is right, the chances are good the part will turn out right. You’re looking to make sure you have good adhesion, without squishing the filament too much. You also want to make sure the flow of the extrusion is steady and consistent.

Pay close attention to the first layer, because it’s the most important one.


I have my slicer set up to do a couple of loops around the part before it actually starts printing the first layer of the part. The purpose of this is to get the hot end flowing before it actually gets to the part, so I can see that the filament is adhering nicely all the way around (meaning the bed is level) and that the part actually fits on the bed. I recommend doing this for your prints as well.

After you’ve ensured the first layer is good, you can sit back and relax. However, it’s still a good idea to check on the print every now and then to make sure there are no problems.

Let the Part Cool

Ten to 20 minutes later, your carabiner should be done! I know it’s tempting, but resist the urge to immediately yank off the part. You want to give it five minutes or so to finish cooling off to make sure the plastic has finished hardening.

Your first print is done. Take a minute to admire your work!

Remove the Part

Once you’ve tested your patience by letting the part cool off, it’s time to remove it. If you can’t get a grip on the part, you can use a flat tool to pry it up from the bottom. Be careful, though; it’s easy to break the part if the adhesion is good. You may need to work at it from different sides to get it off the bed.

A flat tool can be used gently to remove the part if it’s stuck on the bed.

If you’re having a really hard time getting it off, give it some more time to cool down. Once the bed and the part have cooled down to room temperature, it should be a lot easier to remove.

Enjoy your first print, and spend some time contemplating the fact you just had a robot do your bidding to create a physical object from scratch!

Congratulations on your first part! The future is now!