Constant Problems and some seized bearings!
The 3D Touch has been pretty much a pain in the ass since day one. Filament will not consistantly feed though the extruder and put material down on the print bed. After at least 10 failed attemps to make a part, I thought I was having some success after the part had made it 7 hours into a 20 hour print and was still going. It would ussually fail after about 2 hours. I left it running and went home. From the looks of the part, the feed screw striped the filament shortly after I left and stopped feeding. Of course, the heater kept cooking the PLA in the head for another 10 hours or so and made it impossible to remove the PLA. After failing all attempts to get it out, I decided to tear extruders down to clear the jam.
Did I mention that the third head had over heated months ago and has been useless ever since. I thought I would try to fix that too while I was at it.
So after I get it apart, I notice that the lead screws on two of the heads do not turn freely. After further tear down I find the two small needle bearings at the bottom of the lead screw to be seized up. It seems maybe from the excessive dust or maybe from the heat, I don't know.
Has anybody else had these bearings sieze? And does anybody know a part number?
First picture is of the bearings, second is showing the melting that occured from the third head overheating.
I plan on replacing the bearings. Might find some that are better quality and will last longer. The detailed pictures from that thread will be helpful if I forget how to get everything back together. Thanks.
Here is a part number and description of the bearings that seized.
MR128ZZ Miniature Ball Bearing 8x12x3.5 Shielded
I would reccomend to anybody that has had this problem to replace them and not jut loosen them up and put them back in. I found some for under $3 apiece.
Cool. Thanks. Ordering some ahead will be a first priority. That and getting some replacement Gilmer belts for them and the transport. Having spares on-hand can turn downtime from days/weeks into a couple of hours.
Got the bearings in today and am rebuilding the extruder heads. When I removed the Z sensor, I didn't measure it and now I am not sure at what height to tighen it down at. Does anybody have a measurement from the bottom of the nozzle or somewhere else?
Thanks
Looks like 10mm in the attached picture... But a also seem to remember 15mm being mentioned somewhere on the forum.
of course this is only a starting point as you can adjust the z height in the settings on the screen.
I'll check later. Misplaced my inspection mirror. :-\
It controls Z-height, so you can temporarily set it to be way too low and do a Home or Z-height to see where it stops, then adjust to taste, then set your Z-height. Z-height on my machine always stops early, about .25" lower than touching the bed to the nozzles, so that is probably the better bet when you are determining the gross adjustment.
Thanks, where did you get that picture? There is nothing like that in my manual. A more detailed manual could come in handy!
It was from the bfb3000 "maintenance operations" section .... "How to replace a hot end" http://3dpedia.3dsystems.com/display/BFBCustTechRes/BFB-3000+Maintenance+operations
there is also a manual "changing a z limit switch" http://3dpedia.3dsystems.com/download/attachments/40534366/D100260+Changing+a+Z+limit+switch.pdf?version=1&modificationDate=1301571018407
..... And others!
Top tip..... Work through all the manuals etc and download them for offline reading.... As a PDF file you can do a search for keywords etc much more easily than online.... I prefer to have local copies of manuals just incase I have problems getting online, etc.
dave
There's at least this thread:
http://www.bitsfrombytes.com/usd/forum/post/stuck-extruder-syndrome-bfb3000
Might be another as well but this is the one I remember off the top of my head.