How To Load Filament in Prusa i3: A Complete Guide

Manufactured by Czech company Prusa Research, Prusa i3 is one of the most popular 3D printers around. The first model was released in 2012, and since then, the machine has gained incredible popularity. Prusa i3 is more affordable compared to other 3D printers and intuitive to use for beginners. Whether you’re a seasoned enthusiast or a 3D printing novice, this guide will show you how to load filament and troubleshoot other common issues.

Loading new filament in Prusa i3 is as easy as it gets. All you have to do is pre-heat the nozzle and remove the old filament, then load the new filament using the auto-load option. The printer will check if preheating is required, then you can insert the filament tip.

How To Load Filament In Prusa i3 

Loading filament in Prusa i3 is very easy. However, if you’ve never used this 3D printer before and don’t feel like searching information through the machine’s instructions, this guide is for you. Simply follow the steps below to load filament with the Prusa autoload filament option.

1. Prepare the filament 

If you want to load a new filament, there is nothing to prepare. However, if you’ve used the spool before, then stored it in open-air for a week or more, you may have to dry the filament before loading it.

Whether or not drying is necessary depends on the type of filament you use. As a rule of thumb, nylon, ABS, TPU, PLA, and PETG need drying

The drying temperature and time vary from one filament to another, so you should check the material’s specifications. If you don’t have a filament dryer, use your oven or food dehydrator.

Top tip: You can prevent the filament from getting wet by storing it in a dry box, sealed container, or airtight bag.

2. Unload old filament

Whether the filament spool is empty or you want to switch from one filament type to another, the first thing to do before a filament change is to unload the old filament from the printer.

To do that, click the printer’s knob and open the main menu. Go to Unload Filament, then select the filament type loaded into the printer.

Wait for the extruder to heat; the Prusa i3 will heat the extruder to a preset heat automatically, based on the filament you selected. An acoustic signal will let you know when the extruder has reached the temperature.

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Starting out with 3D printing and want to AVOID rookie MISTAKES?

Once the extruder is hot, follow the prompts on the printer’s screen to pull out the filament

If you’re replacing the filament because you want to print with another material, but the spool is still full, cut the filament end with a pair of scissors (make a clean cut with no burrs) and wind the filament on the spool holder. Store the spool in a dry box or another cool, dry place.

3. Load the filament 

Once the filament is dry and the old filament is removed, place the new spool in the spool resting area. Unwind a length of the filament and straighten it as much as possible

Cut the filament tip, then open the printer’s main menu and go to Preheat. Set the filament type you want to load and wait for the extruder to heat up.

When the extruder is hot, go to Autoload from the main menu. Once you’ve selected this option, push the cut end through the extruder. Follow the screen prompts to make sure the filament is loaded correctly.

Filament Not Feeding Properly On Prusa i3

Sometimes, you may notice that the filament is not coming out even though you loaded it correctly. There are a number of reasons why there is no extrusion. The most common is an incorrect temperature point. The filament may behave differently, or the nozzle could be clogged.

In addition to these common reasons, there are several other things to check. Let’s find out all you need to know about Prusa i3 filament not feeding troubleshooting.

Incorrect Temperature Point

While Prusa i3 does an excellent job adjusting the printing parameters to the type of filament you use, technology could sometimes fail. If the printer fails to adjust the temperature setpoint for the new filament, it could be that it won’t feed it because the extruder is too cold

You can check the temperature setpoint in the printing settings and adjust it if needed.

Stock Heatbreak

Stock heatbreak happens when the heat spreads irregularly through your printer’s hot end. Irregular heating may disrupt the way filament melts, causing extrusion jamming. The only way to fix this issue is to replace the Prusa heatbreak with a standard E3D one.

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Swapping From Different Filament Types

Filament swaps take minutes to make on Prusa i3, but many users rely on the Autoload function alone and fail to check the temperature setpoints for different filament types. 

In addition to adjusting the temperature, you should also understand that each filament behaves differently. Thus, extrusion might happen, just not as fast as you’d expect it. 

Mechanical Related Problems

Mechanical problems aren’t common on Prusa i3, but they can happen. Luckily, there are four major culprits, and the issues are generally easy to fix: 

  • Misaligned extruder gear: Three-dimensional printing has one simple rule when it comes to proper extruding – the filament must travel in a straight line. Deviations will create friction, causing the extruder to feed the filament improperly or direct it in the wrong way. To check for misalignments, look at the extruder gear groove and make sure it passes directly in line with the PTFE’s tube hot end. Realign if needed, following the manufacturer’s instructions.
  • Gummed up teeth: To feed the filament, the extruder gear has teeth that bite into the material. If these teeth are dirty, they might not bite properly and prevent feeding.
  • Loose pulley: Alongside the extruder gear, the printer’s pulley helps feed the filament through the extruder. If the pulley comes loose, it will loosen the gear’s grip on the filament. Check the set screw and tighten it if needed.
  • Loose or overtightened idler spring: Lastly, you should check the idler’s spring and make sure it has the right tension. Adjust as needed.

Clog In The Hot End

When referring to a 3D printer’s hot end, most people talk about the nozzle. This tiny hole feeds the filament and creates the object on the printer bed. The nozzle can sometimes clog, but you can clean it easily with the cold pull method. 

To do that, you have to heat the hot end to the printing temperature, then feed the cold pull filament through the nozzle until it starts oozing out. Wait for the hot end to cool down to about 140°F (60°C), then release the pressure and heat the hot end again.

When the extruder is hot, grab the cold pull filament with a pair of pliers or tweezers and pull it out. Hopefully, all the dirt and grime are stuck to it.

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What nozzle does the Prusa MK3 use?

Prusa MK3 uses an original Prusa nozzle which has a diameter of 0.4 mm. This nozzle is preferred because it ensures optimal material flow, thicker layer heights, and reduced printing times. If you want to print thinner layers, you can replace the nozzle with a compatible 0.25 mm one.

Is the Prusa i3 MK3S worth it?

Prusa i3 MK3S is more affordable than other 3D printers on the market, but that doesn’t mean it’s cheap. However, it offers the best value for money at the moment.

This printer is an excellent choice for professional 3D printers and beginners alike. It is easy to use and incredibly versatile, allowing newbies to scale up their knowledge and try new printing techniques without upgrading their hardware.

The MK3S is available in a full-size and mini version, the mini being a more appropriate choice for beginners who don’t want to break the bank.

What filament does Prusa i3 use?

Prusa generally uses 1.75 mm PETG filament, but you can use other filament types with the Prusa i3. PETG is the brand’s choice because it is suitable for printing objects designed for indoor and outdoor use alike. PETG also has good thermal resistance and is generally easier to work with compared to other filament types.

PLA is another common choice. Unlike PETG, PLA is biodegradable, very strong, and easy to print. It has low thermal expansion but also a low melting point, which makes it an ideal choice for printing tiny parts. 

In addition to PLA and PETG, you can also use other filament types, including nylon, ABS, and TPU.

Wrapping It Up

Prusa i3 is one of the best 3D printers for enthusiasts and beginners alike. Whether you opt for the full-size or a mini version, unloading and loading filament is a cinch, thanks to the automatic options. Troubleshooting the unit if the filament doesn’t come out is also straightforward. 

We hope this guide has helped you gain insights on the filament loading and replacement procedures, as well as taught you how to unclog the nozzle and fix other filament feed issues.

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