good afternoon.
I have a problem with the cb3.
the hotend is stuck, it is indifferent on 1 that the 2, in an impression of 4 hours, between the two have been stuck 28 times. It is exasperating.
I have printed at different temperatures and proving different pressures of the pushing gear.

1 week with this new machine and I'm tired of it.

sorry for my English. I am Spanish

January 15, 2019

Roger24 Roger24
Beginner
9 posts

14 replies


Hi Roger,

Not Spanish, but I can try to help.

Can you push the filament in with your hand?

Regards,
Norbert

January 16, 2019

NorbertF NorbertF
Admin
151 posts

Thanks for your help.
Yes, I can push the filament with my hand.
And the gear also pushes it, but it gets stuck often.
(excuse my English)

Gracias por tu ayuda.
Si, puedo empujar el filamento con mi mano.
Y el engranaje también lo empuja, pero se atasca a menudo.

January 16, 2019

Roger24 Roger24
Beginner
9 posts

can help me???

January 18, 2019

Roger24 Roger24
Beginner
9 posts

I wanted to do a video about what you can check and do, but had no time at work to do it. And I don't have a CB3 at home.

I will try explaining some things you can check:
- on the right side loosen the screw. This makes the grip tighter
- remove the extruder drive gear and see if it is clean. Easier to remove if you remove the bearing first.
- reinsert the extruder drive gear, make sure the screw holding it is at the back and is tightened.
- redo the FMS calibration
- update firmware. (Sometimes after update the XY calibration is needed to be done again)
- and some questions: What filament do you use, and on what temperature? Which slicer software, and what settings?

Regards,
Norbert

January 18, 2019

NorbertF NorbertF
Admin
151 posts


NorbertF wrote:I wanted to do a video about what you can check and do, but had no time at work to do it. And I don't have a CB3 at home.

I will try explaining some things you can check:
- on the right side loosen the screw. This makes the grip tighter
- remove the extruder drive gear and see if it is clean. Easier to remove if you remove the bearing first.
- reinsert the extruder drive gear, make sure the screw holding it is at the back and is tightened.
- redo the FMS calibration
- update firmware. (Sometimes after update the XY calibration is needed to be done again)
- and some questions: What filament do you use, and on what temperature? Which slicer software, and what settings?

Regards,
Norbert



thank you very much for your help.
everything you mention, I've done it several times, I've even put 0.4 new nozzles.
use PLA, according to manufacturer at 220 degrees Celsius. I tested from 195 to 225.

I continue with the problem.

excuse my English

January 18, 2019

Roger24 Roger24
Beginner
9 posts

The CB3 extruders clog and stick a lot. A whole lot. Sorry to hear this is happening to you Roger, but this happens to me too.

If the gears aren't pushing the filament but you're able to push it with your hand, then I would focus on this particular suggestion from Norbert:

- on the right side loosen the screw. This makes the grip tighter


I also wish they would, you know, put these basic tips in their instruction manual. But yes, the extruders are the worst part of the CB3 - difficult to maintain and rebuild, and unreliable. I have spent several entire weekends attempting to get some sort of consistency out of them.

January 20, 2019

ruggie ruggie
Friendly
124 posts

ruggie wrote:The CB3 extruders clog and stick a lot. A whole lot. Sorry to hear this is happening to you Roger, but this happens to me too.

If the gears aren't pushing the filament but you're able to push it with your hand, then I would focus on this particular suggestion from Norbert:

- on the right side loosen the screw. This makes the grip tighter


I also wish they would, you know, put these basic tips in their instruction manual. But yes, the extruders are the worst part of the CB3 - difficult to maintain and rebuild, and unreliable. I have spent several entire weekends attempting to get some sort of consistency out of them.


It is very sad to read that the same thing happens to you.

When the filament is stuck, I can not get it to flow, or push with the fingers. I have to remove the filament, cut and put it back, so the whole impression.
you have not got a solution?
It can not be that a machine that is worth so much money has these failures.
It is a deception.

January 20, 2019

Roger24 Roger24
Beginner
9 posts

Hey Roger -

Well, I'm not certain it's "deception", I think it's just a lack of testing and quality assurance. That's my take. I also want to point out that you tend to get a quicker response on the Craftbot Users Facebook page if you also want to ask for help there.

So, this filament tensioner is one of those features-turned-bugs things. It's a good idea that didn't carry out well in practice. There's no visual indicator of how tight or loose it is. The spring makes it difficult to carry out a cold atomic pull (instead of trying to hold the spring open with one hand and pull with the other, unscrew the idler gear instead - would be better to have a lever like on CB+/2). It's also a bear to reassemble the extruder and get that spring in place!!!

When this is first happening, you can save yourself some time by being a little careful - if the filament is not forwarding, it could be because the tension is too loose or because it got too tight and so eats away at the filament. This can happen to me on the first layer especially because it's so difficult to accurately level both print heads - Extruder #2 always calibrates too low, so I find if I level the bed on Extruder 1, Extruder 2 can dig into the print bed enough to prevent enough filament from extruding, which can cause this "digging" into the filament from the hobbed gear and then failure.

Check out the filament - if it rubs away just a little bit of material, it's enough to decrease friction and stall filament. Here's some close-ups from my testing:

Caftbot 3 hotends that get stuck
Caftbot 3 hotends that get stuck

Another issue is that if you need to adjust the tensioner springs during a print because of FMS detection, you would have access to the left extruder's spring but not the right extruder. I've had to just stop prints because there was no way to adjust the tension on the right without canceling:
Caftbot 3 hotends that get stuck

January 21, 2019

ruggie ruggie
Friendly
124 posts

Again, can happen more easily on first layer.

Caftbot 3 hotends that get stuck
Caftbot 3 hotends that get stuck

January 21, 2019

ruggie ruggie
Friendly
124 posts


ruggie wrote:The CB3 extruders clog and stick a lot. A whole lot. Sorry to hear this is happening to you Roger, but this happens to me too.

If the gears aren't pushing the filament but you're able to push it with your hand, then I would focus on this particular suggestion from Norbert:

- on the right side loosen the screw. This makes the grip tighter


I also wish they would, you know, put these basic tips in their instruction manual. But yes, the extruders are the worst part of the CB3 - difficult to maintain and rebuild, and unreliable. I have spent several entire weekends attempting to get some sort of consistency out of them.


Has anyone replaced the CB3 extruder? I agree. Just horrible. I'm thinking about going with a Bondtech extruder.

I'm definitely rethinking if my CB3 purchase was just a waste of money? The extruders are poor, the case fan doesn't work due to a firmware bug, I had to replace the aluminum bed to glass to get good results. On Craftware Mac, if you change the Skirt Min. Count, it just crashes. Seems like the quality control department was all laid-off.

May 20, 2019

Allen67 Allen67
Beginner
36 posts

Stop that! I claim to be the one to get CraftUnique on their nerves! It's the only joy left in life for me...

Nevertheless... The first batch CB3's (I have one and 6 sold) had some flaws, but they are all solved IMO (loud power supply replaced, better wipers, smooth heatbreak for the extruders).

But with the second batch all those problems were solved. There were some new ones though: as not well mounted assembly of the XY movement (so it was not planar to the bed) and some bad fan sets / bad soldering so they were always turning or not at all.

But I beg to differ about the extruder and hotend assembly mostly: the second batch worked very well. Surely the cold-end, although for some soft filaments you had to adjust the tension of the filament clamping. But flexible filament feeds well.
As for the hot-end: the second batch has a smooth heatbreak and generally works well. But you have to be sure the nozzle is at least half a turn loose to get it pressed to the heatbreak, Otherwise it leaks.
But what is annoying is that after some printing the little grub screw is covered with melted filament, and the thermistor and heater can't be loosened to get the hotend out in case of clogging.
As the connectors are sticking in the the mini PCB under the motor way to hard, you indeed have to disassemble the extruder. I solve it by cutting the connectors clean. After that you can get them easily out of the connectors. But even when you have to remove the motor, IMO disassemble the extruder is a minute job.

Nevertheless, my customers and I haven't to unclog the hotend that often. That happens maybe once in three months, and when trying some exotic filament.

What is important to investigate, is where the hotend clogs. If it's near the nozzle, than maybe dust is a problem, or cheap filament with hard particles. But that you can solve with small 0.4mm drills or the new flexible uncloggers.
But if the hotend is clogged higher, so at the top of the heatbreak, than it's surely a cooling problem. Not good, but happens often. As by printing PLA at 240 degrees. Than it's to be expected the Glass Transistion Temperature of 45 degrees is already reached at unwanted places in the heatbreak. So for that, just test your filament ans set the slicer temp at minimum tested temp plus 10 or 15 degrees C.
Another clog possibility is filled filament. As woodfill can clog in a 0.4mm nozzle.

As for quality: I exchanged the standard CB3 hotend by an (adapted) E3d hotend. I assure you there was no difference in quality of the print or clogging.
So I and others don't have sticky CB3 hotends at all after the first batch.

Regarding glass: the 5m alu bed is actually not bad. But I change all to glass as well. Just because I can't get Kapton bubble free on a bed....
The back fan not spinning brecause of a firmware problem? Are you sure? As I tested a couple of CB3's recently with the latest firmware and it was responding well manually and during print.

As for the use of a Mac I laugh! Ha! Mac users should buy am Ultimaker! Also a lot of money to pay for just their marketing sluts!
But if you want to try a platform indifferent slicer that works great with the CB3, try KISSlicer! I have tweaked profiles available for it. Worked great on my Mac Pro as well... ssshhh.

This can happen to me on the first layer especially because it's so difficult to accurately level both print heads - Extruder #2 always calibrates too low,

Que? I know nothing...

Just heat, push the vertical callibrate that only steers the extruders to the same place) and loosen the two tiny grub screws. If gravity isn't enough, just push the heaterblock down to the bed. Than they are always completely even.

As for the initial pst: do you have the newest hotends assembled? That ones are completely covered with silicone and using vulcano nozzles in stead of the standard E3d nozzles. if so: I haven't experience with the new CB3 hotend, so maybe that's causing an issue.

Bart

May 21, 2019

Bart ter Haar Bart ter Haar
Service partner
1648 posts

Thanks Bart:

Wow that was a long list of problems. Luckily I haven't experienced many of these, but there are some.

So as background, I have been 3D printing several years now, so I am not a novice. Most printers have problems initially. The Original PRUSA i3 MK2 was a terrible printer at first. The pinda sensor was not consistent with different bed temps, but eventually Joseph fixed that.

This is my first Craftbot, so it is an experiment of one. I will say the main problem I have, has been experienced by many here. There aren't many CB3 reviews, but you may want to read this one, The Supervisor Needs Supervision

I spoke to the author, and he had the same problems I did, so these are NOT isolated. In general its my goal to get 3D printers to work better. All of mine work great now, but the CB3 still has problems. But anyway, let me start at the beginning, the bed. The aluminum bed is workable, but not the best. Bart you know that as you sell glass replacements. Aluminum warps with heat. I bought a 6.5mm Borosilicate glass cut to size for $55. Same thickness as the aluminum and just slightly heavier. Not much.
Caftbot 3 hotends that get stuck
It works great. Craftbot sells their aluminum beds for $90 so why pay that and live with it when you can get a better professional bed for half the price. I will say I like Buildtak Flexbeds the best, but glass works well with a big bed printer like this.

Next, the PTFE tubes. Why aren't there connectors to hod them? Maybe without the dome you could live with that, but with a fastened on dome, the tubes NEED to be fastened as well. I also switched to a shorter Capricorn tubing.
Caftbot 3 hotends that get stuck
I will say this wasn't required, but is nice. I DO have a dome, so this is helpful.

Next problem. The dome fan does NOT turn on when printing when it should. It does operate manually with the fan control, but you can only turn it on for 60 seconds this way. I will be fixing this by adding a cheap ($6) manual fan control. Craftbot could fix the firmware, but I don't see it happening soon.

Now the BIG problem. So what is happening is this. Usually maybe an hour into the print, I get this message that the nozzle is suddenly "clogged." It goes to the side, extrudes a bunch, then starts again. Usually a few minutes later this repeats. It may reoccur 10-20 times in a print. This occurs with ABS and PLA. It also occurs with the NEW hotend and the long nozzle, and it occurs with the old hotend. I have switched the nozzles to Olsson Ruby nozzles and it STILL occurs. I use these nozzles on all my printers, and I have had maybe three clogged nozzles in several years on hundreds of prints.

So WHAT is the problem? First, since the dome fan doesn't run, maybe its getting too hot and the extruder is clogging. I've removed the dome and this helps, but doesn't solve the problem. Second, maybe the filament encoders are seeing a "clog" that doesn't really exist. I need to turn OFF the filament monitors to see if that fixes it. Finally, maybe the extruder is not the best. Its NOT the best design, and I have seen it slip ALOT. Yes have played with the adjustment tension. I'm going to see if I can change the extruder. At this point I'm not sure how.

I can say, the new "Volcano" hotend seems to have the problem the same amount as the old E3D nozzles. Yes I know about the silicon, but really, from experience, that isn't causing the "clogging."

Also one more WIERD thing. Look at these pictures.
Front right corner: Caftbot 3 hotends that get stuck

Front left corner: Caftbot 3 hotends that get stuck

For some unknown reason, the extruder seems to underextrude in the front left corner but works fine otherwise. This was printed with nozzle #1.

Any ideas???




May 25, 2019

Allen67 Allen67
Beginner
36 posts

Hello there, I am having the same problems with my craftbot+, everything was fine, but I update the firmware and now I have problems with the extruder, first was a layer or part of it, but now just stop extruding, the extruder gear is clean and tight, and the step motor is heating more than usual, I think the motor is overworking.

Does anyone is having the same problem?

May 26, 2019

Rodrigo34 Rodrigo34
Beginner
1 posts

I suspect the extruder is not up to the task. I can't speak for other Craftbots, but on the CB3, the extrider uses spring tension with limited force. Its only as strong as the spring. You can make it weaker, which maybe you would for flexible materials, but you can't make it stronger. I have always been a fan of Bondtech extruders, and I ordered two to replace the stock extruders. We'll see how it goes.

June 6, 2019

Allen67 Allen67
Beginner
36 posts
To start a discussion or reply to a post please Login or Create an account.