How To Maintain a Lulzbot Taz 5 3D Printer

For 3D printing, I have been amazed at the difference between my first 3D printer from hell and the Lulzbot Taz 5.

I have been 3D printing with the Taz 5 on a daily basis for over 8 months. Just recently I noticed a lot of stringing, and the hobbed gear was grinding filament more often. Given all the PLA and exotic filaments that I have put through the Wade extruder of the printer, I figured now would be a good time to reward my Taz 5 for all its hard work.

Idler arm, nozzle, hobbled bolt, and extruder body.

Tools and parts

Lulzbot does not make replacement 0.5 mm nozzel, so I ordered similar ones online. The hobbed bolt is available from Lulzbot. I had printed a replacement idler arm and extruder body when I first started printing. A great part of Lulzbot is their commitment to open source parts, which come in handy when you decide to overhaul your printer

For tools, I needed the following.

2 mm, 2.5 mm Allen Keys. Old tooth brush. Hobby knife. 2 adjustable / slip joint wrenches. Torque wrench. Dental pick. Spare washers for spacers.

---

TAKE PICTURES OF EVERYTHING! IT IS EASIER TO PUT THE EXTRUDER TOGETHER WRONG THAN IT IS TO RIGHT!!

---

Wade Extruder

1. Turn off the power, disconnect the pins from the extruder.
2. Use the 2 mm Allen key to un screw the extruder from the carriage. Lift the unit up, and replace the screw in the carriage to prevent loss.
3. Use the dental pick to clean out the teeth of the hobbled bolt.
4. Use the old tooth brush to clean the filament bits out of the extruder.
5. Use the old brush to clean the herringbone gears on the extruder.
6. Use the hobby knife to chip off old burnt on plastic from the hot end.
7. Use the old brush to clean out all the fan intakes and blades.
8. Brush off the dust from the hex hot end.

---

Hobbed Bolt

The hobbed bolt is the gear that grabs and feeds filament into the hot end of the printer. After serious use, especially with abrasive exotic filament it does wear down. The replacement from Lulzbot is not an exact fit to the Taz 5, so you will need some extra washers (from your endless supply in the coffee can) to space the teeth of the hobbled bolt correctly.

Original hobbled bolt. The teeth in the middle had ground down, grinding filament.

Take pictures and notes on how the washers and bearings are arranged, so you can remember how to correctly put it all back together.

1. Unscrew the extruder from the hot end with a 2.5 mm Allen key.
2. Remove the idler latch and carefully put it aside.
3. Use the 2 mm Allen key to unscrew the 3 screws that hold the motor. One of the screws is hidden below the main herring bone gear.
4. Use the adjustable wrench to unscrew the silk-lock nut from the extruder.
5. Carefully pull the main gear with the hobbed bolt out. Keep track of all the washers and bearings that come along. Check or take pictures as you go along.
6. At this point you can clean out the extruder body with a brush and rag, or you can replace the extruder body.
7. Press the old hobbed bolt out of the main gear, and press in a new one so the head lies flush to the center of the main gear.
8. Use the washers and bearings to space the teeth of the hobbed bolt so they align with the feed hole of the extruder.
9. Screw the silk-lock nut back on, making sure the main gear turns freely. Check against your pictures to see how you did.

---

Nozzle

Lulzbot does not sell a direct replacement for their 0.5 mm nozzle, which I think they are losing business on. Their nozzle is fairly short (6 mm) from the base to tip compared to other commercial nozzles. All 3D printer companies are guilty of making exclusive nozzles and hot ends. The short nozzle does like to collect burnt plastic, so future nozzles should be taller or have a narrower profile.

0.5 mm nozzle with burnt on plastic.

1. Make sure the nozzle is cool. Burn fingers are no fun.
2. Use the adjustable wrench to hold the heat block.
3. Use the other wrench to unscrew the nozzle.
4. Use a torque wrench to tighten the nozzle to 30 ft / lbs of torque.

---

Idler Arm

This part holds the filament against the hobbled bolt and provides the tension needed to smoothly feed filament into the hot end. This part tends to wear the most, especially around the top.

The U shaped channel on top of the idler arm wears the most.

Abrasive filaments like Proto Pasta Stainless Steel  and 3Dom USA glass fill will also chew away at the idler arm.

I printed a batch of these in clear ColorFabb XT with 100% infill to have a solid part.

Check the pictures you should have taken at the start.

1. Use a 2 mm Allen key to unscrew it from the extruder.
2. Hold onto the nut that is seated in the idler arm. You will need it for your new one.
3. Use a screwdriver to pry out the bearing.’
4. Press fit the bearing into the new idler arm. You may have to stand on it to fit it into the arm.
5. Hold the nut in the slot of your new idler arm, and use the screw and Allen key to seat the nut into the slot.
6. Screw the cap screw through the idler arm and extruder body. Check that the arm is loose enough to swing open freely to feed filament.

---

Final Assembly

1. Use a 2.5 mm Allen key to seat the nuts back into the extruder body. IF YOU DON’T, be prepared to play “find that one dark nut on a dark floor”.
2. Screw the motor back onto the extruder body. Make sure the small and main hearing bone gear turn freely, than tighten the cap screws.
3. Screw the hot end back into place with a 2.5 mm Allen key. This part may take a while to get right. Hopefully you took some pictures before you started.
4. Check your assembly against the pictures you took. Curse and fume when you realize you have some parts back-asswords.
5. Use a 2 mm Allen key to secure the extruder back into the carriage.
6. Connect the pins from the extruder to the printer.
7. Turn on printer and spend more quality time re calibrating it.