I had noticed a rough spot in my y axis. After I replaced the guide wheels, one of the older ones fell apart. The bearing just fell out of the wheel. I suspect this was my issue. It is now smooth as butter!
A friend sent me a drill block he wanted printed so I started setting up the printer. The old PTFE guide was stuck in the feed and hotend connections so new guide and connections.
I am using PETG. I was having issues using the existing settings so I replaced the nozzle and increased the temp 10 C. Amazing how a few degrees can cure a bad print!
I know this wouldn’t solve the disintegrating bearing problem but the V wheels just don’t jive with how my head works. The rubber being shed on wheels on my Ender3 proves this is a really bad design. A better wheel design would be like this where there’s mostly flat contact with the extrusion and the V part is only a simple guide.
In a previous post by @mcdanlj I mentioned that I was having some issues with my printer. After rebuilding the feed system with new parts with the exception of the hotend, I was not getting acceptable prints. These are prints in which in the base layer, the adjacent lines were not adhering to each other and not consistent. The latter layers delaminating. I replaced the hotend and still have the same issues.
This printer worked great from the get go so I am stumped but need to get a print off for a friend.
My old Prusa I3 clone was put away but working when I retired it for the new printer. Alas it did not want to start up without a fight! I had to replace the X bed linear bearings. Taking it apart, the belt connection which is polycarbonate like the rest of the printer, snapped! It took awhile to find the right glue that would work with this particular material. A gel cyanoacrylate did the trick after a couple of failures. Back together, I put it through its paces and find the filament stepper has gone bad. My wife had dinner ready and so it is put off until this weekend. ARGH!
generally, unless there is a mechanical problem, when adjacent lines are not adhering to each I look at the filament diameter, then the extruder gear(could be clogged) and run a single wall calibration to see if the widths are not coming out correctly. But the first layer should always be slightly over extruding so there’s plenty of pressure to push the plastic into the bed and this also makes for slightly wider lines/traces so horizontal adhesion isn’t an issue.
If you are telling it to over extrude on the first layer(150-200%) AND you are measuring the correct height yet it’s not putting tracks adjacent with a good amount of over extruded track-to-track contact then the bed level/zeroing is off or the slicer is screwing up. First layers should be thicker and wider than normal spec put down a fat wide track and such that it’s pushing plastic into the bed. If that’s not happening something is not right. FFF is based on that first layer and the whole thing falls apart(literally) if that first layer is not right.
I may have missed something, but in “All calibrations” did you test extrusion length? Marking 100mm of filament, extruding 100mm, checking that it’s correct?
My problem was ultimately temperature, and I wish I’d used the temperature probe on my multimeter to validate the hotend temperature; I could have put it between the sock and the heater block, for instance.
when I was building 3D printers(deltas) and teaching building the delta motion calibration/validation was the first step. ie make sure the machine moves the correct number of mm in the X, Y and Z axis and the 4th motion was the extruder motion which was as you stated, mark off 100mm from the extruder body, command it to move 100mm and see if it moves 100mm.
If the filament is 1.75mm in diameter at this point you can set your slicer to have a extuder multiplier of 1.0.
Next was setting a temperature and making sure the displayed temp looked like it was correct. At 180-185 I would push a bit of plastic through the extruder to see if it would show melted PLA and if it did then things were looking good to do bed leveling calibration followed by making real calibration objects and adjusting the slicer accordingly.
The rabbit hole started when I had a bad bearing on my x-axis. Prior to taking it apart to fix it, the printer worked flawlessly. The problem shows up regardless of what slicer I use. I have tried three of them with the same poor results. I have tried three different programs to send the file to the printer and each one produced the same for results. I calibrated the feed with the hot end at the temperature I normally print at for that filament. The new calibration value was less than a percent off the existing calibration. The new hot end with a new heater and thermocouple produced almost exactly the same results. The strangest thing is that it will print a few good lines and then it all goes bonkers. It will then maybe do a few more good passes. I have also attempted to print at other locations on the bed without any success.
I’ve actually tried six different spools of filament and two different types, PLA and PETG. One spool was brand new never used still in plastic.
Again nothing had changed other than me taking the y axis apart and replacing the bearings when things fell apart.
I am sure it will be very interesting when I find the true culprit!
I’ve only ever had to calibrate Bowden based machines(long PTFE tubes to the hotend) and for these you simply extract an end of the PTFE and send 100mm through while very carefully and accurately measuring the distance to the mm. It must be excruciatingly slow pushing 100mm through a heated nozzle and even then it’s not ideal since there will be a bit of pressure on the extruder gearing. It’s a big deal keeping the teeth of the extruder clean of plastic particles so it can dig into the filament and not skip.
What make/model of 3D printer are we talking about? It sounds like an i3 based design since I saw you were using rubber wheels on the Y carriage. on the i3 this is the part which moves the entire print bed forwards and backwards( Y directions ).
So let’s get this laid out, you had an Y axis bearing go out so I’m guessing you were missing steps and prints were failing because of a positional errors.
Replacing the bearing which required the Y axis carriage to be disassembled then readjusted for proper wheel pressure on the extruded rails.
At the same time you replaced your hotend nozzle and the PTFE tubing and connectors.
At this point it would not print well at all with adjacent lines on the first layer not adhering to the previous line and ALSO upper layers were not sticking to lower layers.
If this is correct and you are darn sure the extruder gear is clean and with adequate pressure so it does not lose any steps… I would look at the hotend and hotend nozzle to see if it is perfectly perpendicular to the bed. BEEN THERE DONE THAT… I had a 3D printed effector crushed on one side because the jackass who sent me the part wanted to save plastic and printed 2 top/bottoms/walls and 10% infill and this jackass(me) knew it was way too light to be a solid part but I used it anyway. A slight angle on the hotend pushed plastic to one side so lots of lines were not sticking because the lines were not centered under the nozzle and the layer top was not flat.
if not that then maybe a wheel is oblong(not round). Tough to guess without some eyes on what’s happening and what it looks like. I had to look at my stuff with calipers and magnifying glasses to see the top of the lines were not parallel to the bed.
The feeder was disassembled and the gear cleaned with a wire brush.
There’s a great site which I don’t have on hand at the moment but you put in all your measurements and it tells you exactly what your calibration number should be. You measure 200 mm of filament going into your drive. You set your feed for 180 mm and then measure what is left and it should be 20 mm if everything is calibrated correctly. If you have too much or too little left over then it tells you what you need to make your calibration numbers be. Rinse and repeat.
My next step is to tear it apart and re-square everything. I was thinking the same thing.
I took the printer apart and squared all the axis. The Y axis was off by a little more than a 1/16. Not sure how this happened during the Y axis bearing replacement. The rail was never touched and was very secure when I loosened the screws. The X bearings were rough even though I had checked them prior to putting everything back together. I replaced them. The Z axis appeared to slightly cock when driven due to the far bearings being slightly loose. Tightened the bearings to the rail. Reassembled the printer and tried to print the part that started giving me problems. Printed like a charm! I am not sure how the average person is able to keep these printers running when they start to act up.
Well I spoke too soon! I was still having extruder problems but found the problem. I documented the solution in this thread;
I did replace other items and I am surprised at how much better it does print. The most surprising is the extruder motor. In trying to trouble shoot my extruder problems, I ordered some stepper motors but in my haste, I ordered the wrong type. Instead of a 42-40 style, I had ordered a 42-23 which is smaller and lighter stepper but still has the same mounting and shaft as the 42-40. I thought I would give it a shot due to being lighter on the Z axis. So far so good. I also purchased an all metal extruder. It also appears to be performing well.
Now on to repairing my Sunhokey Prusa I3 that I tried to set aflame!
ya the hotends vary for sure. I upgraded the PTFE on the Ender 3 and the way it went into that hotend it was compressed between the heatblock and a spacer placed below the PTFE fitting. This prevents the fitting from being a problem and lets you remove the bowden tube from the fitting without opening up your hotend.
I once had a guy in Germany custom make a hotend for my MiniKossel where the PTFE tube went down to the top of the heat break. The idea was it was not going be subject to heat creap into the cold end but was still in the cold end so was able to handle higher temperatures. Worked really well but I’ve not seen anyone do something similar as they usually put it further back in the cold end.