General Questions

I recently got this kit from Amazon. As far as I can gather, it's a variant of the Prusa Mendel i3. It's been a pain, but I got it together and got it through a handful of prints before I started having problems. I've been able to troubleshoot and solve most of my them, but there are two that I keep coming back to:

1. My printer suddenly stopped being able to maintain/reach the 70/210 for the heated bed/nozzle simultaneously. In order to get the former up to temperature, I've had to lower the temperature on the latter. I figured this might have something to do with my power supply, since that did seem like a common point of complaint with this kit. I've run it through at least two new ones, and let it tune the PID settings with no real luck (it tunes just fine, the adjustments just don't solve my problem when entered). Does anyone know what sort of problem I could be running into here?
2. Even when I can manage to get a print running, the initial line height needs to be very thick, and I get poor adhesion to the bed even while it's at temperature. Usually, only the initial layers are problematic, and the rest of the design in question prints fine. I'd like to fix that, if possible. But, more often than not the designs will get stuck to the hot end and lift off the bed altogether ~30% into nearly anything. I've run Cura's bed leveling wizard several times with acceptable results, but I still have no idea what's going on.

Any help would be greatly appreciated. I'm at my wit's end on this thing.

On your second point, tell us what you are doing to get your prints to adhere to the print bed. Is the bed glass? Are you using blue painter's tape, or are you using one of the other popular methods (hairspray, glue stick, etc)?
Are you printing PLA?

I find when small items are printing on the first layer (say a small print, or the circles surrounding screw holes, etc), there is the danger it won't stick well. This is because when the nozzle returns to deposit a line adjacent to one it has already laid down, the first one can stick to the new line and be pulled away by the nozzle, because the first line has not yet set.
Some things you could do to combat this are:
Lower the nozzle temperature (I print PLA at 190-195),
Slow the print speed on the first layer (go nuts, drop it to 30% and see how it goes)
Install a print fan (something I plan to do... I find myself blowing on my prints in these cases).
Find a good method to get the print to stick. (Painter's tape, glue stick, etc).

Most of these things help the previous line to set before another one is laid down next to it, by giving it more time to set, or by getting it to set faster.

If you have a weak power supply you can use the reduced max_PWM options in Marlin.
It will take longer to get to the desired temps, but the PSU will survive. ABS is a nogo then.
If you are experienced with RC-LiPo batteries, you could put a 3s-pack parallel to the PSU. This would help against powershortages for sure!
When extruder and bed are both on, it will take ~130W, but the average wattage is lower, once the temps are right.
The PSU has then enough juice left to charge the 3s-pack for the next print.

Using blue paintertape is also a good idea, because I could reduce bed temp to 45°C and the parts stick like hell.
Finding the sweet spot for z-zero is a trial and error game. I have a M4 allen head screw to finetune the z-endstop.
But again, the paintertape helps with a rougher surface and a little cushion effect to get sticky parts with no warp.
-Olaf

+1 on blue painters tape. This stuff works well for me (3m brand only for me though) I use it on both hot and cold bed.

On my delta the nozzle is .4mm, first layer height is .35mm, and first layer width is 200%.

I normally print with bed at 40 and have 0 issues getting prints to stick, I think 70 might be a little high though I have never tried it with pla.

Be careful adding a fan, if you turn it on too early or too high it will warp the parts (even on pla), I had my fan coming on at layer 5 at 50% and parts would warp so hard they would peel the blue tape off the glass. I have since switched the fan to only come on with very short layers and overhangs, and that seems to be the be best for pla for my setup. I dont print much else besides pla so cannot help much on abs or others.

As far as power supplys, ditch the crummy one that comes with the kit, and you will have 0 regrets. I recently dismantled an old tower PC i no longer needed so I stuck the 850W monster from it on my printer, and i was suprised to see my print quality was improved in the form of less visible layers, better bed adhesion, more accurate corners, and less stringing/oozing (better retraction i think). I think it came down to the PSU not handling the load well and dropping voltage a little, I say this because I have some very bright LED's on it that I always thought got slightly dimmer when I turned heaters on. Back then I was never sure it was happening though, imagination maybe? Which would then lead me to question reality itself while I watch the printer do its thing because the deltas are hypnotizing see: [www.youtube.com].

Edited 1 time(s). Last edit at 06/17/2015 07:52AM by jculver09.

Hypnotizing? While I had my Prusa I3 on the PC desk to dial it in, my chameleon was all over me and stared at the printer doing testcubes. That never happend before or after...
-Olaf

That's pretty cool Olaf... None of my pets seem to care...