illuminarti

It might be that the head is catching on the print, if part of it is curling up at the edges... but most likely it's just a loose pulley. The shift is towards the front of the printer? If so, you need to tighten the pulleys for the y-axis - especially the ones on the short belt. The one in the back left top corner is the easiest to get to - tighten the set screw in that one first. The pulley at the bottom is harder to get to - you'll have to remove the two screws holding on the corner cable cover, and will probably need to loosen or remove the stepper motor to get good access to the pulley.

Really need to see pictures.

What type of printer is this? Most likely you have a slipping pulley, or possibly some additional source of friction that is causing the motor to skip steps.

See: http://umforum.ultimaker.com/index.php?/topic/4525-how-to-upload-an-image-to-the-forum/

The wires for the side fans are usually yellow and green, connecting to two red-black pairs. There is one totally unused wire pair in their as well, that isn't plugged in on either end. The long belts should not be super tight, but also not visibly sagging, either. They may have slipped a little bit. If you push the head all the way to one end of the belt, is one half really lose, and the other much tighter? If so, loosen the set screw in the pulley at the end away from the head, and allow the tension to equalize itself, and then retighten the pulley hard.

It's one thing to calibrate the total distances moved - especially for the extruder as that's not an exact number as it depends on the pressure applied to the filament, how far the teeth penetrate into the material (and hence the effective diameter of the drive gear) and also the effects of http://www.extrudable.me/2013/04/18/exploring-extrusion-variability-and-limits/, if you really want to go there. However, measuring the size of finished parts is futile looking for a generally applicable magic number is futile.

The shrinkage amount not only varies with the color, brand and even production run of the plastic (since all can introduce different additives), but more importantly with the geometry of the object being printed and the rate of cooling (which depends on fan settings, ambient temperature, humidity, etc). It's not in any way a simple linear factor.

Welcome, Sconet! Glad to see that the lead times are getting better.

It looks like you're skipping steps on the y motor. Have you tried lubricating the rods with a little light oil? Also try turning off the power, and moving the head around by hand, and feel for any tight spots. It may also be that you have a slipping pulley - most likely one of the two short-belt pulleys for whichever axis is slipping - it looks like its the y-axis?

When you start printing, are you allowing some time for the filament to start flowing? Usually things are printed with a 'skirt' of several loops around the object that gives some time for the filament to properly pressurize the print head. It's also quite possible that the firmware issues are causing problems for you, as Steve noted. We have tested some fixes lately that affect how the head is primed. These have not all made it into the released firmware yet, as far as I know. You can find it here: http://umforum.ultimaker.com/index.php?/topic/5935-z-axis-homing-inconsistent-on-um2-workaround-and-patch/?p=57095 That fixes some problems with bed leveling, and also makes the initial priming extrusion less strong so that the extruder doesn't chew up the filament. Download the hex file listed on that post, and then install it using the 'Machine -> Install Custom Firmware' menu option in Cura.

See my PM...

What exactly did you change, firmware-wise?

Regarding the test file, just change the extension from .txt to .gcode. You should definitely get better performance than 5mm³/s. And even 5mm³/s is a lot faster than 30mm/s at typical layer heights. What sort of layer heights are you using? Are you just printing PLA?

You can also lose the skirt/brim if the first layer height is less than the normal layer height, I think.

I've never had one, and don't really see the need for them. Generally you're better off putting the filament somewhere other than on the back of the printer anyway.

Firstly, are you sure that you're printing with PLA? Secondly, is your printer set to use PLA as the material? And what temps are preset for that? As a starting point for diagnosing, I would unload the filament, and then do a factory reset (Maintenance -> Advanced -> Factory Reset) It's possible that it could be absorbing some moisture and that could cause steaming etc, but it sounds more likely that the temperature readings are off somehow. Do you have any way to validate the temperature readings for the nozzle - e.g., using an external thermocouple thermometer?

Do you have the pullup resistor attached where indicated?

Welcome, Dag! We look forward to seeing what you make!

Jordan - that crack probably won't make much difference either. But you should loosen all of the four long vertical thumbscrews before it gets any worse. Loosen them off (you may need pliers) and then re-tighten by hand until they're just finger tight.

I'm not disagreeing at all - I wish it was more consistent too. Especially as the 'every other layer' infill tends not to print well a lot of the time, due to the fact that it's always bridging. But it is what it is....

Below 25%, it prints the grid in both directions on each layer. Whereas, above 25%, it only prints the grid in one direction per layer. So, you only get half as much plastic on each layer, compared to the behavior at 24%. To make up for this, it puts the lines twice as close together.

I didn't see if you'd checked the end caps over the axis rods? If those are screwed too tightly, they can stop the rods rotating as they need to. You might also need to square up the cross-rods through the head. To do that, undo diagonally opposite pulleys on one of the axes. E.g., front-left and back right, on the x axes. This allows the two long belts around those axes to move independently of one another. Move the head all the way to the back, making sure both sides of the cross rods are an equal distance from the pulleys. Then tighten the front pulley back up. Move the head all the way to the front, making sure its still square, and tighten the back pulley. Then repeat for the other pair of axes. You might also need to loosen the tensioner/screw in the sliding blocks, to make sure that the cross rods are fully seated - if they aren't you can end up with the exposed part of the cross rod being too long - and that can also push things out of square.

I generally print at 230 for utility prints, yes. I might go cooler if a particular print needs it to get the best possible surface finish, but 230 generally works fine for me. The extrusion test is designed just to test the throughput of the nozzle; to see whether you can force 10mm³/s through the nozzle without the motor stalling. Raising the temperature makes the PLA more liquid, making it easier to extrude, so the extruder motor has less pressure to overcome. The flow setting changes the amount of plastic extruded compared to what it specified in the gcode; so it defeats the point of the test to adjust it. You can get some pressure-related underextrusion when printing at higher speeds, which increasing the flow might help to offset - but that's not the point of this test. (See my analysis ofhttp://www.extrudable.me/2013/04/18/exploring-extrusion-variability-and-limits/ for more details on that - the general principles still apply for the Ultimaker²).

Raising the flow rate isn't compensating. It's making the test even harder: by raising the flow rate you're increasing the volume per second even higher. By setting the flow to 120%, you're actually printing at 12mm^3/s by the end of the test.

Welcome! It's good to see that delivery times are getting better.