InertialPrint

I'm currently using 3mm filament mostly because I was under the impression that "3mm" was industry speak for 2.85mm but I now know that is incorrect. The UM2 can handle 3mm fine you just have to tweak a few settings. Some things to note are: 1. DO NOT EVER use the "change filament" option if you have the stock UM2 bowden tube. The inner diameter of the bowden tube leaves next to no wiggle room for this larger filament, this combined with heat-deformed filament almost guarantees the business end of the filament is going to get stuck in the tube which will result in the knurled wheel to have its way with the filament. 2. Install roberts feeder. This is almost mandatory, to remove filament use the "move option", back up the filament slowly until it's clear of the head, then open up the feeder and manually pull the filament out with your hand(it helps if you remove the tube from the feeder end and straighten it out). I know this is a pain in the ass but if you're stuck with the stock tube and 3mm filament this is now your work-around. 3. Get a new bowden tube. This one is still in the testing phase as I've ordered the new tube but haven't received it yet so I'm still unsure of its working. I believe the inside diameter of the stock tube is 1/8" and I ordered one that is 5/32", make sure you get the same outside diameter of 1/4" and that it is semi-hard, flexible, and can handle the high temperatures. 4. Print slower. No wiggle room in the tube means that printing at high speeds will cause obvious jams, settle down speed racer 5. Lube the inside of the bowden tube. I'm not sure which kinds of lubes are best and which ones should be avoided but I'm currently printing with my tube lubed with high temperature, non-corrosive, silicone o-ring lubricant. It seems to be doing the job but I've only got about ~5 hours printing since I've lubed it so we will see.

This is rather late but I sort of ran into the same problem with 3mm filament. I was having lots of issues and never realized that it was the inside diameter of the stock bowden tube on my UM2. I have some high temperature o-ring lubricant that I put on the inside of the tube which helped, but my biggest problem is changing filament since once the filament hits the heated end it deforms and almost always makes it impossible to retract back through the tube. I've resorted to manually pulling it through (thank god I installed roberts feeder).

So another update: Turns out temperature was the main problem with all this. The PLA that came stock with the UM2 was being printed @225C and this new filament had a significantly lower temp of 200C. Looks like it wasn't the size of the print but rather the temperature I was running it at, the constant high temp would eventually clog the nozzle with burnt bits of plastic and I couldn't see it since I was using black PLA. I've attached a few photos of a piece I'm printing to prove this point. The above picture is the furthest I've gotten with this print and you can see that it starts to clog near the top where the print head is sitting in a small surface area for a long time. I aborted this print when I saw this, used the atomic method to clean it, and saw some darkened spots on the pulled filament. Here is a view of the bottom, you can see all of the charred bits in the first layer and brim.

Hey everyone I just thought I would give a little update. The above mentioned print, although having a beautifully printed first layer, failed yet again. This new material I got fails after a few hours, usually after I've left work. I printed something smaller that would take just as long and it failed too. I've narrowed the issue down to either: 1. I'm printing at too high of a temperature (225C) and the nozzle is slowly getting clogged with burnt plastic. I say this because I've noticed that it has a lower melting point and when it first extrudes to clean itself out I see some smoke. 2. My stock feeder is failing me. One of the first things I did with this printer once I had it calibrated was print roberts feeder. I installed it yesterday and ran it for a test drive when I got into work this morning. I noticed right away that I was able to print at higher speeds where the stock feeder would click. I will see if these solutions fix my overall problem with printing large objects, hopefully this doesn't stray from the topic too much.

Here is the new print after adjusting the initial layer to 0.3mm Looks a lot better! Although a few of the circles got snagged I just need to drop the total speed a little bit and I should be golden

I will adjust that and post some pictures of my new print Actually the one good thing about this soft filament is I've noticed next to no lifting what so ever, even on a print this big. That actually reminds me, before this filament I was using the filament that came with the printer which stuck nicely just on the glass, I've only just recently been forced to cover the bed with kapton tape to get this new filament to stick

When I did my initial search for 2.85mm I kept getting hits on google for 3mm, I then found a thread (not here) where someone called 2.85mm and 3mm the same thing, that mixed with my inability to find a candian supplier for 2.85mm for the color I needed I ended up just going with 3mm. It is irritating how soft it is but I'll just chalk it up to another lesson learned.

Hey everyone, I purchased an UM2 about 4 months ago and have usually been able to solve any issues by just searching the forums, that is until now. I'm attempting to print something that is rather large, almost the entire bed and wondered if there were any special 'tricks' I should know about. Although the print is only 3mm high is has a lot of surface area, but I start to see issues when it starts the infill on the first layer, like this: The lines rarely touch, most of the issues seem to happen towards the back so I have played with adjusting the bed screw but making it any looser gives me really, really, flat lines and I'm worried about causing a jam. Would it be possible that when the printhead reaches the back the tube is bent as such a sharp angle that underextrusion is happening? I've downloaded IrobertsI feeder but haven't installed it yet, I can't afford the downtime yet (this is a work printer). I switched filaments recently so here are the settings of my machine: printer filament is 3mm PLA from here:http://www.voxelfactory.com/ layer height: 0.1mm shell thickness: 0.8mm retraction enabled bottom/top thickness: 1mm fill density: 25% print speed: 60mm/s Initial layer thickness: 0.15mm Initial layer line width: 125% travel speed: 100mm/s bottom layer speed: 30mm/s infill speed: 60mm/s top/bottom speed: 40mm/s outer shell speed: 50mm/s inner shell speed: 50mm/s combing: OFF z hop: 0.15mm Infill overlap: 25% machine settings filament: 3mm black PLA, I measured with a calliper in 4 different places and got the average of 2.96mm print temp: 225C total print speed: 25% for first layer, 75% for rest fan:100% bed temp: 60C I've noticed that this filament is more powdery than the stuff that came with the printer, it's A LOT softer so the UM2 will not hesitate for a second to start grinding. Since it's so soft I've noticed that I can't get my printer to go faster than 60% total speed of the above settings without causing the knurled wheel to start chewing into the filament.