Issues on TAZ Workhorse

General LulzBot TAZ
1

Hi there, I’m a new user of the TAZ Workhorse, it’s my first Lulzbot product along with my first 3D printer. I’m having many issues with the test prints I’ve been trying out. I’m using Inland’s PLA White filament for the test prints.

  1. Stringing - I’ve had pretty bad stringing on all my prints. I’m using Lulzbot Cura 3.6.21, I believe I’m also running the latest firmware on the printer. I run the printing temperature at 205 degrees celsius, build plate at 65 degrees celsius, retraction distance at 7 mm, retraction speed at 25 mm/s, and Outer Wall Wipe Distance at 0, at the suggestion of one of the forum posts.

  2. Jamming, No Extrusion when printing - This comes up at relatively random times, but I think it could be due to heat creep. Almost every jam I’ve cleared, the filament had been chewed away by the hobb. With the most recent jam, re-inserting the filament allowed some filament to ooze out, but when I tried to make another print by itself, it wouldn’t extrude anything out. I’ve periodically checked to make sure that the filament wasn’t being too difficult to pull into the feeder, but sometimes it’ll still not extrude anything even if the filament can move freely.

  3. Print doesn’t bond and parts break near the end of the print. This has been happening specifically to the Benchy test. The initial octo gear test hasn’t broken apart yet, and other prints have had extrusion issues before it gets completed. What usually happens is when the Benchy prints out the cabin, suddenly part of the top of the cabin breaks off and the rest of the print turns into a spaghetti mess. I’m thinking it could possibly be the filament not being hot enough to bond to the rest of the print, bit I’m also worried that the heat from the hotend is creeping to the hobb. Filament is already sometimes leaking out of the hotend slowly whenever the hotend gets hot/ I purge some filament anyways. I’m not sure of that’s normal.

Overall, I’m deeply disappointed with the Workhorse so far. I was hoping it would be a simple plug and use situation, but I’ve been trying to figure out issues with the printer for about a week now. Any help would be appreciated.

2

On issue 1 –

Have you printed a temperature tower? I use PolyMaker PolyLite PLA and found that 205°C was much too cool… and got the best prints at 230°C. Every material is different, but a temperature tower will help you find good printing temperature. I’ve posted previously on how these work but basically it’s a model you download (you can find many of them on sites such as Thingiverse, etc.). The “tower” has several levels each labeled for the temperature the want you to use at that height. You vary the temp for each level and watch it print … then determine which level got the best quality. There is a Cura “Extension” (from the main menu navigate to Extensions -> Post Processing -> Modify G-Code. Then in that window add the script called “Tweak at Z or Layer”. Pick either the layer number or the heigh in millimeters and tell it to change the temperature to the next temp meant for that level of the tower. Repeat this (do another ‘Add a Script’ and add another Tweak-at-Z for each temp change.

The hardened steel extruder nozzle doesn’t conduct heat as efficiently as a brass extrusion nozzle. You’ll need to run the print-head just a little hotter to compensate (e.g. maybe +5°C)

I heat my build plate to 55°C for PLA. I used to do 55 for first layer only and let it cool to 45 after it gets the first layer down. But that amount of cooling caused some parts to break free. So now I leave it at 55 for the entire print.

7mm sounds like a LOT of retraction. It is possible to over-retract. When you pull back the filament, it is possible to pull air into the hot-end. That air heats up and expands. When it re-primes the nozzle to continue printing, the air-bubble can pop out and create problems with prints.

Usually my retractions are around 1 to 1.5mm. You can print a “retraction tower” … to determine what amount of retraction works best for that filament. It will probably be a low number for PLA.

Item 2 –

This can be related to the part but could also be related to the temp. I’ve had parts that called for a lot of retractions in a short amount of filament and this causes the hob to grind on the filament a bit more. There’s a setting in cura to limit the max number of retractions in a given length of filament.

Item 3 –

If you’re not getting good bond then what are your layer heights? The layers need a little “squish” to get them to bond the layer below. You have a 0.5mm nozzle. So a layer height of just 0.5mm would result in the next layer barely resting on the previous layer with no “squish”. You should probably make sure the layer height is not more than about 75% of the nozzle diameter. So a .35mm layer height could be used when you’re printing “fast”. Use shorter layer heights for more detail.

You may need to slow down the printing speed.

You may need to increase the nozzle temp (and I’m guessing you do… 205°C strikes me as a bit cool for PLA based on the results from several temperature towers that i’ve printed).

From time to time I encounter filaments or parts of models where I need to reduce the part cooling fan speed (or sometimes even turn it off completely). This allows the filament to stay hotter longer to help it bond before it cools off.

I really like my Workhorse and I’m very happy with it. 3D printing isn’t really a “plug and use” thing … there’s often a bit of tweaking (this is gadget for those who love to tinker and tweak).

The sample filament that came with your TAZ (the LulzBot green filament) was PolyMaker “PolyLite PLA” and it’s pretty easy to work with (most PLA is). But even when I use that, I set the nozzle to 230°C (I think the profile was for 215 but I got much better results at 230).

3

Hi, I’m still using use Inland’s PLA, but I switched to blue filament after hearing about issues with the white filament. I’m still getting issues.

I’ve been trying to get the temperature tower to print, but without success. The tower starts at 215 degrees and goes up in 3 degree increments up to 230 degrees. It’s only gotten up to layer 2 before it falls apart, so I haven’t been able to see how it does at higher temperatures. I’ve also lowered the retraction to 1.35 mm, and it seems to have lowered the amount of jams, but stringing is still an issue.

I’m also still getting terrible bond. My layer height is set to 0.15 mm, and the initial layer height is set to 0.35 mm. Like I said before, the temperature tower falls apart before the third temperature story gets printed out. The print in general comes out pretty bad. I’ve also had to set my hotbed temperature up to 70 degrees to get a good bond, anything lower than 65 and the print doesn’t stick to the bed.

I’m going to try to reverse the order of the temperatures of the tower, starting from 230 degrees. I’ll see what happens.

4

I usually run mine from hottest to coolest… e.g. my bottom floor might be 230 and my top floor would be 190. But for my PLA, 230 prints best.

The layer height doesn’t need to be 0.15mm unless you are trying to check out how your printer does on ‘fine’ detail. For the 0.5mm nozzle, you can print 0.35mm layers if you’re in a hurry and don’t need fine detail. You can print .25 as a common every-day layer height. You can print 0.15mm if you want finer detail on the layers (or even 0.1mm) But those prints will take longer (e.g. if printing 0.1mm layer height then it would require 100 layers to get just 1 centimeter high. A .25mm layer height would require 40.

When testing a temperature tower for stringing and bridging, etc. the amount of filament being extruded will vary based on the desired layer height and that means the ability to “bridge” over openings in your print will be affected.

5

I have noticed a substantial performance issue with Inland white filament also. Disappointing because it was a great value product until they switched suppliers and raise the price $2 a roll. I have a Taz 6 at my restaurant working at all hours that we are open. Raising the temperature to 230 has helped but it doesn’t keep filament from flaking and building up in the Extrusion gear. It fills it up after about 8-10 hours printing so the feeder is unable to grip it. By the time you realize it’s too late you have to trash the prints. The heat Tower is a good idea I haven’t printed anything with this newer filament at a substantial height but will try today.
Haven’t tried any of the other colors yet still using old stock guessing it’ll all be the same but will update.

1 Like
6

I have use Inland’s filaments (Microcenter’s brand). They tend to be wet when delivered. I dry all filament now, no matter the brand. All of the issues you listed are many times related to wet plastic.

Also, no 3D printer is “plug and use.” You purchased a torture machine with parameters within parameters that have hidden parameters. Worse yet those parameters will change day to day because the temperature that water boils is determined by the pressure altitude (which changes with the weather). Water vapor escaping from the melted plastics produce weird and unpredictable artifacts.

All printable filaments are hydroscopic (they suck up water from the air rather rapidly). Dry, baby, dry!

You will tweak more than you print at first until you stop using low quality filament and settle into a range you are comfortable in.

I tell people NOT to buy 3D printers unless they are ready to spend months, wait, no years goofing with settings.

So sit down, suck it up and start tweaking!

:slight_smile: