Calibrating

Hi guys, need your help !

Created an account for that, cannot manage to calibrate my Prusa i3, I built this one from a kit, so keep in mond that problems could be material.

So I'm still trying to print the 0.5mm thin wall, managed to have something great two times, but now it doesn't work, almost each time it failed it hapenned like that:

• Everything start well, and first layers looks great
• After a random amount of time (sometime at first layer sometime at tenth), it starts failing

Looks to me like theire not enought plastic flowing anymore, it starts making small dots instread of a line, then everything fails cause their is no more support for layers (it usually starts flowing great after a while, but without support it doesn't stick).

The prusa is equiped with a 0.35mm hotend and using 1.75mm plastic. I use Repetier Host with Marlin, slicing with Slic3r. Disabled cooling and Retraction for now.

This is a photo of the last piece: [i.imgur.com]


Any clue on what could be the problem ?

What extruder and hot end are you using? Pictures will help if you don't know what type they are. Have you adjusted the current to the extruder motor?

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Thanks for your answer !

Haven't realy adjusted the voltage, did not find any clear instructions on how to find the right voltage :s

Here is a picture of my (messy) extruder: [imgur.com]

What happens when it stops extruding enough plastic? Is the extruder motor skipping, or is the hobbed bolt grinding into the filament? What kind of plastic are you using (ABS or PLA)? It looks like you have a knock-off Chinese made J-Head hot end. Those a notorious for not working reliably, especially with PLA.

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I don't see anything anormal when it stops working, the weel still turns and the filament seem to be going down normaly. I use PLA, and the hotend is the one from reprapit:
[www.reprapit.com] (but doesn't look like I got the aluminium heatsink as advertised).

Do you think it comes from the hotend ? Will make a video of the problem when I get home.

Hmm, the hot end in your picture is definitely not the same as the one you linked to. The hot end you have in your picture looks like one of these: [www.ebay.com] (without all the Kapton wrapped around it). That is definitely a J-Head, and a clone at that. See: [jheadnozzle.blogspot.com] (that blog is run by the original designer and manufacturer of the J-Head type hot ends).

Are you getting any plastic grindings or dust by or in the hobbed bolt groove?

Can you release the idler on the extruder and push the filament through the heated hot end by hand, and does it give much resistance? Does it get harder to push as you go, and does pulling back slightly then pushing again result in increased force required?

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Yeah definitelly looks like a copy (can't see your ebay link, looks like it is blocked in Canada), the one I actually purchase should be this one: [www.reprapit.com] (But ours is aluminium, will take a look closer tonight).

Definitely got plastic dust on the bolt, but might be from the previous times it got stuck, will try to clean it and see if it makes dust again.

Will try what you say by and tonight.

Well, I now have the opinion that reprapit.com is a shady business, if in fact that is the hot end you ordered and the one pictured on your printer is what you received. They took the image and description of the J-Head directly from the RepRap wiki (here), but are selling a cheap clone that does not match the image or description, and even worse, are selling it for the same price as an original J-Head. Brian Reifsnyder is the original designer and manufacturer of the J-Head design, and that image and description are his. Here is where he sells his hot ends: [www.hotends.com]

Anyways, you may still be able to get what you have working. If you did order that hot end, but received the one in your picture, I would recommend filing a complaint to reprapit.com and see what they say.

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