JohnFox

I used this one:- http://www.thingiverse.com/thing:177794 then made a modified one which is bigger and wider arms. You need some 40mm M3 bolts.

I got some new ones from Ulitmaker, ( under warranty ). Very obvious that they slid up and down cleanly. JohnFox - After some more investigation, I have found that this is exactly the problem. They move freely for the first 10mm then lock up as you say, when the balls reach the end of the race. Did you change to a different bearing from what Ultimaker provides or the same bearing without that fault? I'm very keen to find out. Thanks.

I use Faberdashery as well, it's a bit awkward but avoids the very tight coils and high friction that come with a normal spool. They supplied me with a .stl file for a folding spool holder, works very well, holds 100m of filament.

Looks like a bearing problem to me. That guide that |Robert| refers to is VERY useful. Try the idea of unscrewing a bearing and running it up and down the pillar, maybe the balls have got out of alignment .

I would suspect the Z bearings if you saw the bed drop. I think the balls locked up in the raceway, then suddenly released again. It's a bit involved but if you can undo the bearings, try sliding them up and down the pillars. They should move smoothly but mine had frequent lockups. Changing the bearings solved the problem.

Does this problem only occur after 10mm? It sounds like a problem I had, caused by a problem with the Z axis bearings. Have you ever put any oil onto the Z axis pillars? If you have, then possibly the balls in the bearings are trying to slide rather than roll. This causes the bearing race to lock up and jam, resulting in the Z axis error. Try and clean the pillars so there is no oil at all. Then with the power off, raise and lower the print head a few times, trying to feel if there is any sudden friction. I eventually bought some new bearings, cleaned everything and it fixed the problem.

Not used PET but had some success with PLA, the key thing was to make the objects solid. Normal walls up to 3 layers thick with conventional 20% infill always leaked, once I moved to solid objects - no leakage. Be aware though that some fluid could seep into the Z axis layers.

Not a lot wrong with that one. How long did you leave the die in place?

I agree with the others, bed height too low. Extrusion looks good. You should just be able to slide 90g/m2 paper under the nozzle without feeling friction.

Is there anything coming out of the nozzle at all, just wondering if it is blocked? Is the nozzle getting hot, you could touch it with a piece of filament to check? A heater problem would prevent any extrusion and cause the results you are seeing. The extruder may not be perfect but it's not that bad. Are you running default settings? At this stage, I would really keep to machine defaults. A brand new machine should be able to run the supplied PLA perfectly well without any need for changes. Again, may not be perfect but not far off.

'Pritt stick' or any PVA type of glue will be fine. A few strokes of the glue followed by a wet cloth to spread it evenly over the plate.

Depends on wether the hole is horizontal or vertical. I suspect that your hole, if printed vertically would come come out about 7.8mm, ( at least on my printer ). I have a lot of holes to take 3mm bolts and routinely print them with 3.2mm diameter to get a perfect fit. Horizontal holes are more accurate but the tops of them are a bit distorted when the gap is being bridged.

Text can do strange things, especially when small font. If the font is smaller than the nozzle, then you can get 'Braille'. I found that text on the front of an object is fine, yet on the back can be illegible, the two sides are equal In quality. A close inspection of the Cura file is vital with text.

It also could be the ball races on the Z pillars, I had a suspect one. Do you hear anything odd when you do a Buildplate up/down?

Stepper motors do run hot. I would avoid dropping the current, there is a danger of them missing steps. I was surprised that UM2 allows changes to the currents, you could easily get very unexpected results.

I sometime get that, I can see the bed flexing a bit as the head moves along - not sure about its significance. No need to recalibrate the bed, that is only for the 1st layer, after that the bed moves down the correct amount each time and is not affected by the initial bed height. If the robot comes out OK, then you are all set to go.

Only use PLA filament, ( quality grade ). Use the glue stick provided to stick the object to the glass. You will probably need a 'brim' round the objects to keep them in place. 0.1mm layer height gives the best quality in a reasonable time. Use Cura in X-ray and layer mode to see if your design is sound. Start small. Use this forum - there are some really helpful and knowledgable people on it.

Just done a test print at 0.3mm - it's quick! Quality and strength as expected - poor, starting to see gaps between the layers. Not possible with ABS, it would warp and delaminate. Worth doing with PLA if speed is the only issue. Certainly explains the original posting about lack of strength.

The amount of heat is going to be the same assuming constant extrusion but the area of contact between the upper and lower layers is going to be minimal at large layer height. The top layer is going to be a series of cylinders rather than 'squished' on the lower, the only points of contact being the top and bottom of the cylinder. The top layer of a raft works in a similar way so it is easy to peel off. How do I get images a bit smaller? Does anyone know the nozzle diameter of the Replicator 2x that jjl is using?

The problem has just gone away.!!!!! It cleared after I did the screenshot of the browser - crazy. I guess something with my Safari and Mac Sorry.

Not sure if it is odd on my Mac only but in the last couple of days the 'Log In' icon, ( top right ) has been obscured by language and country text. I can see my name but it is underneath 'language'

If you have a gearbox between the motor and the plastic, that will act as a thermal break. I was using stepper motors which can get quite hot. If you are using bearings, then stick to PLA, it's quite tough material, print 0.1mm for strength. ABS is stronger and easier to smooth but I have had so many print failures due to warping that I have abandoned it. So this exactly http://colorfabb.com/xt-black ? Or did you mean something else? What about Easyfil ABS? Ball bearings will be used. I have thought about nylon or PTFE spacers, also thought about a cooling fan Motor will be https://www.servocity.com/html/10_rpm_precision_gear_motor.html

No wonder the object is weak, at 0.3mm layer thickness on the UM2 with a 0.4mm nozzle, the layers will hardly bond. It's just like a raft, peals apart easily. For any strength at all you must get each layer to weld to the one below. It won't matter what infill you choose, if you don't get the layers to bond in the first place it will be weak. Try 0.1mm on the UM2 or use a larger nozzle. Also 240C may not be hot enough for ABS on the UM2. The machine default temperature is 260C.

At 10rpm, PLA should be fine, the rollers won't be moving that quickly. You must use grease on the moving parts as the friction between PLA surfaces tends to be quite high. Silicone grease would be good for this, ( or the green grease that Ulitmaker uses ). What motor will you be using, make sure that doesn't get hot? I use nylon washers between the motor and mount on my pumps, acting as thermal breaks. ABS would be a better material but it can be a sod to print.

Any ideas as to what could have caused this? The box is standing on its end, base towards you and the square holes were at the rear of the printer. Both sides were the same, sloping inwards towards the rear of the print. The front is reasonably OK but with a slight overhang at the top. PLA, 0.1mm layer, 210C, printed quite slow. An 11 hour print. It's certainly not in the original model or is it seen in Cura. The top of the object, ( the part that sticks out ) is the correct size, the sides are sloping inwards. Not seen the effect before and the current print looks fine.