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Manually cleaning and refurbishing the extruder head - with the extruder head removed from the Zeus

This section will explain the process of manually cleaning the Zeus extruder head, in the event that alternative clog-recovery or filament breakage recovery methods haven't proven effective.

If you've navigated to this section and haven't yet attempted to restore filament flow as described in the section entitled, “Clearing a Filament Clog or Breakage - without removing the extruder head”, then please explore those options first, by clicking on this link:

Clearing a Filament Clog or Breakage - Without Removing the Extruder Head

However, if you've already explored those options, then you're in the right place, and we welcome you.

Before You Proceed - you have the option of sending the extruder head back to us...

Please be aware that AIO Robotics provides you with the option of sending a clogged extruder head back to any of our branch offices, where trained technicians who do this pretty much every day, will clean, refurbish and test the extruder head(s) and then return it (them) to you. If this is the option you'd prefer, please contact us and we will make the arrangements; turnaround time (not including return shipping) is usually just a day or two once we receive your items.

But if you would prefer to know how to clean the extruder head yourself - then please read this section thoroughly:

If you have chosen NOT to send a clogged extruder head back to AIO Robotics, and to clean it yourself then we are assuming that you have read and understood the statements below:

A. I consider myself to be quite technically capable, and would prefer to do this work myself, to save the time and return shipping expense involved with sending a clogged extruder head back to AIO Robotics.

B. I understand that this process is far from difficult, but that it requires that I have some AWG 13 PTFE sleeving (available from AIO Robotics), as well as a few standard, and some specialized tools and parts (also available from AIO Robotics).

C. I understand that I my attempts to clean the extruder head myself may result in further damage to my extruder head if I am not careful, as the process for disassembling the extruder head includes handling a few delicate parts that can be damaged if not handled correctly. I understand and accept that AIO Robotics is under no obligation to provide free replacement parts to me under these conditions, but that will sell me replacement parts.

D. I understand that AIO Robotics has provided the information, associated procedures as well as the ability to acquire the requisite parts and tools to execute these procedures to allow me to clean/service/refurbish a clogged extruder head (without having to return it to AIO Robotics), not because AIO Robotics is attempting to externalize costs that they would normally absorb under warranty terms, but because they are aware that a significant portion of Zeus users/owners are in possession of more advanced technical understanding and skills. AIO Robotics wishes to provide the greatest possible utility and system uptime to all Zeus users, including those sophisticated/professional technology enthusiasts who may be capable of executing the cleaning procedure themselves.

E. I understand that the process of cleaning the Zeus extruder head requires that I safely remove the extruder head from the Zeus, and requires that I use the recommended tools, and execute the recommended procedures in a safe manner at all times, and that it is incumbent upon me to use the appropriate PPE (personal Protection Equipment).

F. I understand that I execute the recommended procedures “at my own risk”, and as such, AIO Robotics assumes no responsibility for any injury I might sustain using small hand tools, or handling the Zeus extruder head during the recommended procedures.

Whew!! Sorry about that, but our lawyers told us that we needed to do that in order to provide this information to you…

Just to recap some of that in plainer english:

The procedures outlined and described in this section are far from “rocket-surgery”, but they do require that you have a few very specific tools and supplies on hand, some of which are quite specialized, and not available in every hardware store, or hobby shop.

In addition, it's important that you are comfortable, and preferably somewhat experienced doing very basic maintenance on electro-mechanical equipment, and generally “tinkering”, as that is the level of insight and experience these procedures require. The Zeus is, a rather sophisticated electro-mechanical-computer system, which is designed and built to be as intuitive and straight forward to use as possible. However, in the same way that surfing the net on your computer requires far less technical ability than opening up your computer and swapping out RAM, adding an additional hard drive, or even changing out the power supply, using the Zeus requires far less technical ability and understanding than it does to effectively clean a clogged extruder head.

Okay then, let's get started !

Advanced Troubleshooting 2.1 - Tools that you'll need to successfully perform this task:

A Phillips head screwdriver - preferably size #1:

Once you've safely removed the extruder head from the Zeus, the first thing you'll need is Phillips head screwdriver, so that you can remove the single coarse-thread m3 screw that holds the two plastic shells together.

You'll need one of these:

So that you can remove this screw: A high-quality 1.5 millimeter hex driver or allen key:

There are three m3 grub screws that will need to be removed/loosened, and it is important to use a quality tool to remove/loosen them, so that these grub screws do not become “rounded out”. If these grub screws become stripped, rounded or damaged, then the chances you'll be able to properly clean and refurbish the extruder head are greatly diminished.

Cheap allen keys are just that, “cheap” and they tend not to be made of good quality steel. Below is a picture of a 1.5mm hex driver that we use. It is a pretty common item from hobby shops that cater to RC enthusiast, and can easily be acquired online or as part of the Zeus field service kit.

A 5.5mm miniature open-end wrench and/or a good quality needlenose pliers:

A crucially important step in the disassembly process requires that the hexagonal thermocouple is removed/unscrewed (very carefully, so that the wires that connect it to the PCB are not compromised) from the extruder tube assembly. This requires that it is first loosened, so that the extruder tube can be rotated against it. You can do this with a small pliers, or else if you wish, you can use a miniature 5.5mm open end wrench. Examples of both of these items are pictured below:

A pair of 10mm socket drivers, wrenches or similar:

To separate the brass extruder nozzle from the stainless steel extruder tube (to unscrew one from the other), you'll really want a pair of 10mm wrenches Just about any 10mm wrenches will work, and even two pairs of pliers will work if you don't have 10mm wrenches or sockets, but it's always better to use the correct tools for a particular task.

Below are examples of a pair of 10mm socket drivers (available as part of the Zeus field service and spares kit), and pair of ratcheting wrenches fitted with 10mm sockets:

2.0mm and 2.5mm drill bits, pin vices and some 2.0mm carbon fiber rod sections

There are certain clogs that will require that you ream out the stainless steel extruder tube, and others that can be cleared by merely pushing the PTFE/Teflon sleeve out of the stainless steel extruder tube and replacing it with a new PTFE/Teflon sleeve. Below is a picture of a pair of pin vice drill bit holders, one fitted with a 2.0mm drill bit and the other fitted with a 2.5mm drill bit, as well as four sections of 2.0mm carbon fiber rod (you only need one section of carbon fiber rod, but four seemed to make for a better photograph):

Hang in there, we're almost done showing you what tools you'll want to be familiar with…

X-ACTO/hobby knives and/or single edge razor blades

Why would you need blades like the ones in the picture above? Two reasons; first to cut and trim the new PTFE/Teflon sleeve (more on this crucially important step to come…), and second, in case you need to scrape melted filament adhered to the outside of the brass extruder nozzle, which looks like this:

The severity of the molten filament on the extruder tube/nozzle assembly pictured above is extreme (and fortunately not all that common) such that it needed to be soaked in acetone prior to scraping, but you get the picture.

Almost done, one more and then we'll get to the “how to” portion…

A 0.013“ steel guitar string

No, we're not kidding. This is actually a very handy thing to have around, but it's not mandatory. A 0.13” guitar string is an inexpensive, flexible piece of steel that is 0.0332mm, so it's the perfect size to allow you to clear the 0.35mm aperture in the brass extruder nozzle. Most of the time this won't be necessary, as the heat of the extruder nozzle will allow the old filament remnants in the aperture to be cleared by the new filament, but with some stubborn clogs, it's not a bad idea to clear the aperture so that you know you have a completely cleared filament flow path.

Advanced Troubleshooting 2.2 - supplies/parts you'll need to successfully execute this task:

PTFE/Teflon tubing - size AWG 13:

Probably the most important item you'll need to successfully clean and refurbish the extruder head is a modest supply of the PTFE/Teflon sleeves. Six pre-cut sections are pictured below, alongside the extruder tube to show where the sleeve is inserted:

Some M3 x 4mm grub screws, and possibly spare brass extruder nozzles:

Where to acquire the AWG-13 PTFE/Teflon sleeving, grub screws and spare brass extruder nozzles:

PTFE sleeving:

If you're in North America, then sourcing the AWG-13 (as in “American Wire Gauge”) PTFE sleeving is pretty easy, but you'll still need to buy a significant quantity. An AIO Robotics branch office can sell you smaller quantities, and in many cases the lengths will be pre-cut to size. Outside of the US and Canada you're almost certainly best off getting the PTFE sleeving from AIO. The PTFE Sleeving can also be purchased here via McMaster-Carr

M3 x 4mm grub screws:

These are plentiful from suppliers on ebay and can be sourced from any fastener supply house that deals with metric products (which most of them do these days). You can also get them from AIO if you'd prefer.

Brass extruder nozzles:

These you will need to source through AIO Robotics, but it's important to remember that you probably won't need spares of these unless you encounter a pretty severe clog (in which case you'll want to soak the extruder head in acetone overnight anyway…). Chances are that you'll be able to reuse the exact same brass nozzle many times without ever needing to swap it for a spares, but they're nice to have if you're operating in a production environment. Contact AIO for further information regarding pricing and availability.

Congratulations!! You made it through the tools and parts section, and now we're finally ready to get into the section on how to use these tools and parts to clean the extruder head.

Advanced Troubleshooting 2.3 - How to manually clean the clogged extruder head:

2.3.1 - STEP 1: You've allowed the Extruder head to cool down, and It has been safely removed

Dealing with a filament clog or breakage is never a pleasant experience, and it's important to remember to allow the extruder head to cool off completely prior to removing it.

Once you've done this, you should be looking at something very similar to the photo below:

Video clip of step 2.3.1 (coming soon!)

2.3.2 - STEP 2: Remove the single M3 coarse-thread screw

Using a phillips head screwdriver, remove the screw that secures the two halves of the molded plastic “clamshell” housing together. Now would be a good time to find a cup or a small container to keep the parts you remove in a safe place, otherwise they might get lost.Note: You still need to gently shift the position of the four plastic tabs before you separate the two halves, which is discussed in the next step.

Video clip of step 2.3.2 (coming soon!)

2.3.3 - STEP 3: Lifting the four plastic retainer tabs

This step is actually a little tricky, especially if the extruder head is from an early production run and has been through many cycles of heating/cooling, as these tabs can break off when you try to lift them “just enough”. Not to worry if you snap any off though (though try not to, okay?) as the two halves of the housing will still lock together with just the single screw you removed in the previous step.

You can use a small flat blade (micro size) screwdriver, fingernail, or other slim blade to lift the outside tabs a little bit first, and they tend to stay up pretty well at that point so that you can then do the same for the tabs on the top. After you've done it a few times it becomes easier, but if you break one/some, don't worry about it, as everything will still work just fine, and the most important thing is that you can get back to being productive. (AIO can provide you with these replacement parts as well, if a broken tab bothers you enough. Contact us for pricing and availability).

And once you have separated the two halves of the housing, you'll see the extruder tube assembly, snugly seated in its locked position in the rear half of the housing:

Video clip of step 2.3.3 (coming soon!)

2.3.4 - STEP 4: Releasing the extruder tube assembly from its locked position

Once you've separated the two halves of the housing, you'll need to get the extruder tube assembly (the brass extruder nozzle, the stainless steel extruder tube and the heat sink) out so that you can do further disassembly.

Assuming that you've allowed the extruder to cool off completely to room temperature prior to attempting any of this, it should be relatively simple to wiggle/rock the assembly out of its locked position with your hands. Note: You need to pay very careful attention to the conductors (wires) that connect the heating element and the hexagonal thermocouple to the brass extruder nozzle. These wires need to be treated with care so that they are not damaged

Video clip of step 2.3.4 (coming soon!)

2.3.5 - STEP 5: Properly handling and understanding the parts of the extruder tube sub-assembly

In the photo below, you'll see what the extruder tube sub-assembly looks like once it has been released from the rear half of the extruder housing:

Video clip of step 2.3.5 (coming soon!)

2.3.6 - STEP 6: Remove the M3 X 4mm grub screw that retains the heater element

Now you'll need to remove the M3 x 4mm grub crew that retains the heater element, which is pictured below. This is the first of the two grub screws that you'll need to remove. The second grub screw is the one on the opposite side of the brass extruder nozzle that locks the nozzle into position against the threaded shaft of the stainless steel extruder tube. For now though, let's stay focused on this grub screw so that we can carefully dislodge the heater element, paying very careful attention not to stress or otherwise damage the wires that connect to it.

Video clip of step 2.3.6 (coming soon!)

2.3.7 - STEP 7: Dislodge the heater element

Once the grub screw has been removed (remember to put it somewhere safe and not to lose it…), then the heater element should slide out without too much difficulty. DO NOT TRY TO PULL THE HEATER ELEMENT OUT BY ITS WIRES, AS THAT WILL ALMOST CERTAINLY DAMAGE IT.

Using a wooden dowel, a pencil or (as long as you're careful) the tip of a screwdriver, you can usually dislodge the heater element pretty easily.

However, under certain circumstances where a clog is particularly bad, and excess filament dripped out and solidified around the grub screws and heater element, then you may need to do one or more of the following:

- Take a deep breath - Soak the lower portion of the extruder tube sub-assembly in acetone for a few hours (try not let the acetone get on your skin) - Use a hairdryer or heat shrink gun on a modest setting to heat the molten filament up enough to get the heater element to slide out. - While securing the extruder tube sub-assembly (a small hobby vise will work great) so that the wires are not stressed, gently tap a hammer onto a dowel, pencil or other appropriately sized cylindrical object. You shouldn't have to use much force at all.

Video clip of step 2.3.7 (coming soon!)

2.3.8 - STEP 8: Loosen the hexagonal thermistor

After dislodging the heater element (it will happily dangle by its wires which will still be connected to the PCB on the rear of the extruder housing), you'll need to loosen the hexagonal thermistor. All you need to do at first is to loosen it with a pliers or 5.5mm open end wrench, so that you can then rotate the extruder sub-assembly while holding the hexagonal thermistor stationary.

Video clip of step 2.3.8 (coming soon!)

2.3.9 - STEP 9: Rotate the extruder tube sub-assembly while holding the hexagonal thermistor stationary

Once you've loosened the hexagonal thermistor, you'll need to rotate the extruder sub-assembly against the thermocouple, being careful to hold the thermocouple stationary so its wires do not get twisted or stressed. This technique will allow you to safely separate the two components, and then place the rear plastic housing (still containing the heater, thermistor, PCB, and mini fan) aside for a bit.

Video clip of step 2.3.9 (coming soon!)

2.3.10 - STEP 10: Remove the second grub screw

After you have unscrewed the hexagonal thermistor, you'll need to remove the second of the three grub screws, so that you can unscrew the brass extruder nozzle. PLEASE DON'T FORGET TO REMOVE THIS GRUB SCREW, OTHERWISE YOU'LL MANGLE THE STAINLESS STEEL EXTRUDER TUBE WHEN YOU TRY TO UNSCREW THE BRASS EXTRUDER NOZZLE AND YOU WON'T BE ABLE TO REASSEMBLE YOUR EXTRUDER HEAD

Video clip of step 2.3.10 (coming soon!)

2.3.11 - STEP 11: Unscrew the brass extruder nozzle from the stainless steel extruder tube

Do not proceed with this step until you are absolutely certain that you have removed the second grub screw that locks the brass nozzle to the extruder tube!!

Using a pair of 10mm wrenches, loosen and then unscrew the brass extruder nozzle from the stainless steel extruder tube:

Video clip of step 2.3.11 (coming soon!)

2.3.12 - STEP 12: Evaluate and remove the clog

Once you have unscrewed the brass extruder nozzle, you'll be able to see how simple or ugly/difficult the clog is or how tricky it will be to remove the remnants from a filament breakage condition. In this first example that we used for these photographs, it turns out that the filament was stuck to the inside of the brass extruder nozzle at the 0.35mm aperture, so it stayed adhered to the brass nozzle when we separated the nozzle from the stainless steel extruder tube:

Clog example #1:

And without too much difficulty, everything came out, and the PTFE/Teflon sleeve is in good enough shape to be re-used (though it's always better to use a new sleeve if you have one).

Okay, now let's explore a slightly different clog condition…

In the previous example, the filament stayed connected to the brass extruder nozzle such that when we separated the brass nozzle from the extruder tube, the filament and the PTFE/Teflon sleeve came out right away.

The photos below demonstrate a slightly different clog condition, and the method for remedying it.

The photo below shows an example of a more common condition you'll encounter, whereby the length of stuck/clogged filament and the PTFE/Teflon tube are lodged in the lower portion of the stainless steel extruder tube, and need to be removed.

In certain cases you may need to use the 2.0mm and 2.5mm drill bits referenced in the tools and spares section (see the third example), but in this next example all we need to do is push the PTFE/Teflon sleeve and captive piece of filament out with a length of 2.0mm carbon fiber rod:

Clog example #2:

The carbon fiber rod pushes the filament and PTFE/Teflon sleeve out pretty easily:

Here is a shot of the carbon fiber rod protruding from the other end:

And a third example of a clog, this one requiring a bit more effort…

The third example of a filament clog that we need to cover is the type that would be stubbornly lodged in the stainless steel extruder tube, and requires the use of the 2.0mm and 2.5mm diameter drill bits, as pictured below:

Clog example #3:

And then you'll want to use the larger, 2.5mm diameter drill bit to ream out the PTFE/Teflon sleeve and the filament that is stuck inside it.NOTE - This will destroy the PTFE, requiring that it be replaced with a new one. Once the stainless steel extruder tube has been properly reamed out, you'll be able to hold it up to your eye, and peer through it to clearly see light at the opposite end. If that's not the case, then you'll need to clean it out a bit more. Video clip of step 2.3.12 - Examples #1 #2 and #3 of removing stuck/clogged filament (coming soon!) Okay, you've made it this far, now we're ready to reassemble the extruder head, so click on the link below to go to the instructions for that procedure **

Reassembling the extruder head after manually cleaning

filament_clog_recovery_2.txt · Last modified: 2016/07/22 20:40 by navigating21