cat.farmer thanks for the idea to check out that hobbed bolt. I just did some touch ups to the hobbed bolt and re-aligning with some washers, and the problem totally went away. Thanks everyone here for your help!by bergerab - Reprappers
I just soldered a new stepper wire and it didn't change the behavior of the extruder. So then I disassembled the extruder to get to the hobbed bolt and I found a small (about 3mm) area where the screw was a bit beaten up. There were also some other areas that the ridges on the screw seemed a bit flat. Is there anyway I can "re-hob" this bolt? Or should I just rely on the one I bought from eBay? Tby bergerab - Reprappers
Thanks for the suggestion. I'll solder up a new bipolar stepper wire, then I'll take out the hobbed bolt and check for any flat areas. I'm a little curious.. how do you make your hobbed bolts? Is it as easy as using a dremel tool? Or does it require a special tool? I've just been ordering them online and I'm wondering if making them yourself is a better way than buying pre-made bolts. Thanks!by bergerab - Reprappers
Ok so after digging around I found a screw that was just long enough to work as a second idler screw. After having the extruder run about 50mm of PLA at 200C I found that I'm having the same problem as before. I double checked the voltage going to the extruder motor, and that all the gears were moving consistently, and they are. When I watched the extruder, I saw the bearing right below theby bergerab - Reprappers
I bought from this eBay listing: I chose that listing because it included not only the screws, springs and nuts but also a hobbed bolt. I'm a little skeptical about my hobbed bolt since I rebuilt this printer as an old Prusa i3 that was pretty damaged and I don't know what kind of damage could have been done that could possibly lessen the grip of the hobbed bolt. The $17 is kind of pricey for leby bergerab - Reprappers
Just as an update, I've ordered all new hardware for my Rework extruder. I should get it by Wednesday. I'll update this post once I test with the new hardware to see if this resolved my issue.by bergerab - Reprappers
Thanks for sharing your calibration values! I just started printing another die with your exact values (besides your steps_per_unit of course) and I can already see that this print is going to be better. I think the main factor was slowing down the XY jerk, and changing my extruder acceleration from 800 to 10000. I'm still experiencing a little bit of the inconsistent flow problem, but I'll pickby bergerab - Reprappers
Thanks for the tip Steve! I'll check that out this weekend. By the way I love your instructable on how to build a prusa i3. It helped me build this printer! I do a lot of project sharing on instructables too, its cool to run into people who do the same. Do you think you could take a look at my acceleration/jerk/feedrates and judge if they are a little too high/low? I couldn't find any good guideby bergerab - Reprappers
Yes I've always used one screw just because long M3 screws are hard to find around me. I'll order some online, but for now I just added a zip-tie keeping the other side tight. With the screw I do have on the idler, I keep it very tight to make sure there is enough tension. I have 8 rolls of 3mm filament that I have been using, all of them have the same results. Thanks for your response!by bergerab - Reprappers
Hello RepRap community! I've been working on a Prusa i3 Rework and have ran into problems with my extruder. The flow of PLA through the hot end is inconsistent. For several seconds the filament will flow properly, but soon after I can tell that the idler's bearing is not spinning (which indicates to me that the hobbed bolt is grinding). Finally the flow returns to its appropriate amount and contby bergerab - Reprappers