Hi all, have had my Taz now for probably close to a year. Basically i am very happy, when it prints properley its awesome.
But…
I am not sure if I am doing something wrong. Quite often, when printing, at some point during the print, sometimes early on, sometimes later the filament “stalls” for want of a better word in the drive head, and basically the drive shaft eats a notch in the filament stopping it printing.
I have had this happen on PLA and ABS. I have thought the issue is the tension on the drive roller, I basically screw it down until the threads slightly protrude out of the back of the head.
When it happens, i remove the filament, and carefully clean out any material trapped in the grooves of the drive roller and start again.
So has anyone else had this problem, and any suggestions on what i may be doing wrong, or what to try?
There’s a couple solutions I’ve seen floating around for this. The first is, as you said, to tighten the hobbed bolt further. How hard is it to compress/load the filament? Another has to do with “heat creep” from the hotend up to the hobbed bolt. The solution is more cooling above the hotend. However, I’ve only heard this problem with PLA, so I doubt it’s the issue here.
Usually when this happens for me I have the tension wrong on the idler springs. There is a jig to help adjust this posted somewhere.(extruder latch jig)
There is another way this happens. Assuming your idler clamp is set correctly, this also can happen from back pressure caused from your nozzle being not set to the correct height + incorrect flow rate %
Here’s how you confirm that you have this correct:
Print a test cube with a skirt of maybe 3-4 skirt diameters. Peel off the skirt and use calipers and measure the skirt thickness. If you’re using cura standard profiles, your initial layer thickness should be set for 0.425mm. When you measure your skirt thickness with calipers, does your skirt measure 0.425 exactly? If not, you need you adjust your Z-height until Cura matches what you’re getting in real life
Post a picture of the bottom of one of your parts. That’s an easy way to tell if your flow rate/nozzle height is correct. If you can confirm your first layer thickness matches your initial layer thickness in cura, print a cube and look at the bottom of the print. Are all the print lines mashed together there it is hard to discern individual passes of the nozzle? If so, your flow rate is too high. Reduce your flow % and try again (This assumes you’ve already measured your filament diameter with calipers and entered that actual diameter into cura).
I had this exact failure printing with XT (ABS-like material) I had another person who had this failure using PLA. Both were caused by nozzle height problems and overextrusion.
What happens is Cura thinks your nozzle is at a height of 0.425 and is using a specific filament diameter. It’s going to push out a volume of dilament to fill that calculated area. If your flow rate is high and your nozzle is closer to the bed than it expects, it’s going to try its hardest to push the same amount of material out. This causes back pressure in the tool head and the hobbed bolt shears the material because it physically can’t push any more material out because the nozzle is effectively blocked because too much material is being requested to be pushed out of the print head vs. how much space is actually available.
Since this is happening with ABS and PLA. I’m 99% sure this is your issue. Please report back with what your skirt thickness measures on the test print and send a picture or two of the bottom surface of your last few prints that failed.
Looking at that photo posted, the first thing to check will be the tension. Tighten those springs down until they are compressed to 5mm. (That is distance from inside washer to inside washer.)
Second will be to double check the specific type of filament you are using. This includes Type, Color, Diameter and Manufacturer. Each different manufacturer has a different formulation and therefore different ideal settings. If you are using a different manufacturer you may need to adjust items such as temp, speed, cooling, infill, etc. in order to find what works best with that specific manufacturer.
Thanks for the replies so far people. Well the company that sold me the printer suggested i was using too much tension. I tried backing it off, I undid it until the screws were only flush through the main body not protruding through and it did a print perfectly last night. Of course before it was intermittent so i am not totally sure that was the issue until i do more prints.
I tried before to find info on how much tension to apply to the idler, without any joy. Has anyone got a link to the 5mm distance quoted above or whatever it should be set too? I must have missed that somehow.
Thanks so much all. OK, so since backing off the tension, it seems to work perfectly. Cant quite believe such a simple change can solve something that was so annoying!!
So now i have a second issue, and I thought i might as well keep it in the same thread. The part I am printing is approximately 225, or 9" tall. Whats happening is the print is not bonding fully between layers as you can see. At first I had the wall thickness set to 3mm with 20% infill (ABS btw). The problem was worse that these pics.
So last night I tried making the part wall thickness 4mm and it is significantly better.
I was printing at 240 deg C, bed 110. I am in Australia so the room temperature where the printer is is reasonably warm, say around 25 deg C.
That’s ABS delamination and the way I fight it is upping the hotend temp a bit (I go as far as 250) and turn off the part fan, especially with thin walls. If you must have the fan on, sometimes reorienting the part (turning clockwise, so the fan blows at a different angle on the walls) helps, I noticed but you probably will move the problem around, looking at the design.
Thanks for that, just trying exactly that by upping the extruder temp to 255. Lets see how that goes, sounds like the fan off is another thing to try, cheers
If you plan on printing ABS a lot it’s worth building a heated chamber. It’s basically a box all around your printer that keeps the heat inside and you can even add extra heat.
You do need to make a hole for the electronics fan or move the electronic enclosure outside the box. Do a search on this for for heated chamber and you will find plenty of info.
Yea thanks and agreed an enclosure is something i have been thinking about for a while. The Taz is a big unit though so it would have to be pretty big. But if anyone has any pics of one done for a Taz would love to see it or even a link?
Btw the reason i am tying to stick with ABS is most of my parts are custom parts for performance cars, so its the temperature range and strength I am after This below is a picture of the CAD model I have done for this, which is a Cold Air Induction for my 454 ci Senator, and this is a pic of the engine as it is now. The plan is to make two open top plenums, and modify the bonnet with two cut outs to enable cold air to be drawn into the engine.
Thought I would post up a follow up to this. I decided to make my own enclosure, i managed to score an old TV cabinet pretty cheap. I deepened it at the rear to fir the Taz and added a pair of acrylic doors. I have to say the difference in printing success with ABS is like night and day. Basically every print so far since moving to the cabinet is perfect, couldn’t be happier.
So anyone printing large thin walled ABS parts, i would highly recommend some sort of sealed enclosure.
That’s a sweet conversion of an old cabinet. Please tell me the large black cube next to the controller box is a vent box that vents to the outside of the cabinet. If not, DO THAT!
You don’t want the box to fry the electronics inside, especially if you’re going to be doing long print times.
