Prusa i3 prints only decent when very slow

I have a homemade prisa i3 from complete scratch (no kit) and i am having trouble with the print speed.

I can't seem to print anything at a reasonable speed without it turning out terrible or just nesting.

It has produced some good prints but only when the printer is running very slow, e.g. 10mm/s print speed

It's very frustrating and I am considering changing my extruder to a direct drive extruder with an all metal hotend instead of the j-head with a wades extruder.
Would this help?

I have printed with my homemade prusa i3 with a wades and used to have a j head. I was able to get 80mm/so with that setup. Most likely somewhere in the motion platform, belts, frame, bolts, etc. Check that everything is tight and that you have slower accelerations and jerk. See Thomas sanladerer guides on tuning speed.

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Prusa i3 Rework - Ramps 1.4 - E3d Lite6 - Full Graphic LCD Controller

Does the print fail at the first layer when you try faster settings?
I'd start investigating the cause for the failure before I spent money.
-Olaf

thanks gmckee, ill try all that as soon as i finish my final year exams

No, it doesn't fail, everything just becomes messy

If i try a print ill always have the first few layers slower than the rest of the print, when i do this, they start just fine but as soon as the speed increases it just gets messy like the infill keeps constantly getting caught on the previous layers and building up blobs in the middle of the prints and the outer layers are all shaky

I think my extruder is wobbling a bit :/

Also check that your extrusions are the actual nozzle size. Extrude some plastic and see that actual width. My E3D nozzle was said to be .4mm but was actually extruding .5mm. That's a 25%increase in size causing over extrusions and insufficient movement. Also see Tom's Guide on extruder calibration.

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Prusa i3 Rework - Ramps 1.4 - E3d Lite6 - Full Graphic LCD Controller

That's a failed print in my book

You'll need to calibrate the printer some more. Find the right balance for the extrusion multiplier, z offset/z endstop, hot end temperature etc. Tune acceleration, Vxy-jerk, retraction acceleration, speed and length.

The extruder should be rock solid. It should not move during retraction for example. If it does, reprint the hotend holder part, preferably in abs. Use 30% infill for extra strength. If you use the greg wades extruder, try finding one with a better hot end clamping design. The two screws jamming against the hot end peek or aluminium damages the hot end. Especially if you need to remove the hot end for maintainance the repeately screwing in the bolts will wear the top part of the hot end making it loose and wobbly.

When starting out I could get prints at 30mm/s with reaonable quality, with a jhead and greg wades extruder and pla. One year on and I'm now able to print at 45-80mm/s with good quality using a custom dual extruder holder with two bowden e3d v6. It's a steep learning curve but if you keep working on it, eventually it will make much more sense and trouble shooting will get easier and prinspeed faster with better quality.

Is this a real J-Head hot-end or a chinese knock-off?

Yes, you're right, my nozzle was supposed to be .35mm but when i measured the extrusion, it ended up being .4

Yeah, i definitely need to secure my extruder better, it gets a bit shaky especially when changing direction. yeah i think i will start off with just printing off a new extruder and just using my j-head with it before i buy an E3D one.

Yes it's a real J-head

Edited 1 time(s). Last edit at 11/07/2015 11:04AM by monkeychan18.