This allows you to change filaments during print. This modification lets you see the filament enter the extruder gear and guide bearing area as it passes though to the heater nozzle sleeve. This takes all the guess work out of changing filaments, especially during printing. Another reason this is a great upgrade, this eliminates the need to pull filament out of the tube when its hot to change it. which, can gum up the tube. Over time you will them have to replace the tube or whole heater nozzle assembly.

The old extruder assembly does not have a way to see if the filament is being fed into the tube properly. Which cause frustration and in my case a breakage of parts do to trying to force it.

The fun color picture is what my printer looks like now, and the other is how it used to look. For me machines should have personalities, so i give mine personality! :)

Step 1: What You Need:


· Several small files or a Dremel tool with metal cutting wheel

· Drill w/small drill bits

· Small metal handsaw / if you have Dremel then you don’t need this

· Pliers

· Hot glue gun w/glue stick

· Clear plastic from a thick water bottle


· 3D printer

· Filament ( I prefer Hatchbox brand!) its clean and even, makes for great prints.

· 1 x fine thread machine screw / can get from ace hardware.

Step 2: Theory

All i needed to do was think of a way to direct the air to the heat-sink but allow a gap of space for me to view the hidden extruder area. The two videos are based off of the picture showing how the mechanism works.

Possible Concerns:

This is not really a concern but I would image is a question that will come up. The heat-sink does not get real hot so the one that currently comes with the Prusa I3 is overkill. I image it is just a stock piece that did the job so they used it. I have had no issue with the amount of heat-sink material I removed.

Step 3: Printing


the link above will take you to the download site to retrieve the STL file.

First before taking your printer apart, you will need to print the window pipe piece to be added. I suggest you print with clear filament but you can use any color you like. Once the print is done go ahead and get a clear piece of plastic that will conform to the shape of the pipe. I cut mine from a smart water bottle I had laying around. Now cut the plastic to fit and glue it in. I suggest using hot glue because it covers the gaps for any air leaks. But you can use any glue you would like. One day soon I will upgrade the pipe to just accept a slide in piece of plastic. But that for another time. Prototyping is never perfect the first hundred times lol.

Step 4: Heat-Sink Modification

Once you are sure you no longer need the printer for anything. Go ahead and dismantle the section pertaining to the heat-sink after everything has been turned off and cooled down. I had to modify the heat sink I marked the back of the heat sink with the rectangle hole I wanted to make. I then drilled out the corners and hand filed everything until I had the rectangular hole I wanted. You can get a much cleaner look, if you use a Dremel. My personal opinion, imperfect is better and adds personality, at least for my home use. If this was for someone else, then i would definitely be very detail and professionally oriented.

Step 5: Final Assembly

Once you have your hole cut and your printed pipe all ready.

Go ahead and start fitting things together. If you find your original bolts are to long you may need to add spacers or washers to make up the difference. Just make sure that there is nothing between the heat-sink and the extruder housing. The whole point of the heat sink is to not let the heat migrate beyond the nozzle. Now since the assembly is a tad heavy I found a machine screw with tiny threads and installed it in the top left hand corner of the pipe / heatsink mating surface. Once screwed in, I crimped the heat sink fins to clamp down on the screw. This is an old cpu cooling trick I learned a long time ago. This is more than enough to keep the whole assembly supported.

Finally attach the fan with glue or screws and you are ready to go!

Step 6: My Thoughts About Prusa Printers :)

The Prusa I3

Is such a great printer. It is a product that will produce as good as quality as you put into its build. If you take your time and make sure everything is perfect. It will produce amazing results. This basically means the difference between a bad, good or great print is your attention to detail and understanding of how the printer works. With all that said. The Prusa could use a few upgrades!

After printing for about a year and half and using the push down lever to change out filiments. One of the 3d printed pieces broke. Now I don’t blame prusa. It is impossible to make an unbreakable product. Also I wrenched on the lever pretty good from time to time trying to BLINDLY get the filament in during a print so I could have a multi color print. I am quiet surprised it lasted as long as it did!

Great Job Prusa!!!!

About This Instructable




Bio: The answer is 42!
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