back to crap

hi all.,
have been printing great stuff (for me) during the week at night (seee photo).
but today have gone back to my prev morse code yucky crap.
the only thing i have changed is that it is day time (a hot day 31C).
will wait to tonight and see if anything is better again.
can the day temp make such a difference? doesn't seem to get much comment if it does?
roger.

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Prusa 'Explorer' (3dStuffMaker), GEN6, J-head Mk III-B, Bowden Extruder, Marlin 1.0.0 RC2, Repitier-Host V0.84 and Slic3r 0.9.8, PLA. Live at Victoria, Australia.

is it humid?

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- akhlut

Just remember - Iterate, Iterate, Iterate!

[myhomelessmind.blogspot.com]

Roger, did your extruder end up jamming up, or did you stop the print? Do you have a fan on your cold end?

I have a makergear prusa, and I would get similar results on hot days before I added a fan on the top part of the extruder. At least in my case, heat was climbing up the extruder, making the plastic rubbery higher up. That made it harder to push, so it would slow down, come out in bits and blobs, and then fail entirely.

Instead of a fan, maybe you could drop your extruder temp down a bit for hot days, or blow a little mor eair across the hot end while printing.

10 past 11 at night and finally printing again. have spent all night try to get this going. i have a bowden setup.
the extruder just didn't seem to be pushing thru the plastic ie. marked a spot and said send thru 30mm/min and would only send thru 5-10mm.
i took the tube off the hotend and said to send thru another 30mm and it would - even when i had a lot of pressure on the filamnet from my thumb.
i then just manually pushed filament thru the hotend and was realitively easy to do (210-220 degrees pla) sometimes and then other time really hard to do.
and when i joined them back together they wouldn't work.
so have just been manually extruding mile after mile of filament. just focused on the flow coming out in the end and just kept pushing it thru.
started a print of an easy part. first couple of layers look a bit sus - like the speckle stuff would start any moment and then this big bold line of plastic came out and everything was back to normal.
i dont't know ....
ps. no is a dry heat here this part of OZ this time of year. same thing happened last weekend was printing good sat night then went to show off to my brother on sunday and coulded get a line down.
i just have a big portable fan (like from in your house) a pedistal fan which blows out lots.
tinyenormous yeah at some points during the evening was really hard to push the pastic thru manully and then would be quite easy - not sure whats going on.
has anyone ever compared this to golf. just about to throw the clubs in the lake and then you cream a shot and your hooked for another week.
thanks guys.

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Prusa 'Explorer' (3dStuffMaker), GEN6, J-head Mk III-B, Bowden Extruder, Marlin 1.0.0 RC2, Repitier-Host V0.84 and Slic3r 0.9.8, PLA. Live at Victoria, Australia.

Sounds like a hot end or feed issue. I'm not sure if you've described or posted a photo of your hot end before. That would help.

all seems well - see photo from overnight print.
brnrd have attached a picture of my hot and extruder.
i'm not sure what sort of hotend it is. (does anyone have a sectional drawing of a hotend so i can understand what it does).
am i allowed to just pull the filament out of the hotend willy nilly. have been doing this to make sure the extruder was working and then'
manually pushing filament thru the hotend. (think i read a post where he was saying you had to do this when it was cold ???? which didn't make any sense to me).
also a strange thing that did happen that i now remember was that at some point in the morning of the hot day i got a puff of smoke from the hotend and an extra wiff of the nice smelling melting pla. not sure if this was before or after things started to go wrong. to recap I printed one part early on yesterday morning which took an hour or so and then by 10 aclockish i started printed some more parts and it started going astray.
also during last night i got the puff of smoke too but it was still a while later before i go it running again.
yes i find it hard to know which one is playing up - the extruder or the hotend - thats why i was trying to test each one seperately - they seem ok seperately and then when i connected them back together they wouldn't work. finally after many hours it seemed to come together. i'm not sure what i did. and i'm not going to print today !!!! (another hot day)

Edited 1 time(s). Last edit at 11/24/2012 04:30PM by rogerw.

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Prusa 'Explorer' (3dStuffMaker), GEN6, J-head Mk III-B, Bowden Extruder, Marlin 1.0.0 RC2, Repitier-Host V0.84 and Slic3r 0.9.8, PLA. Live at Victoria, Australia.

tiny - i stopped the print

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Prusa 'Explorer' (3dStuffMaker), GEN6, J-head Mk III-B, Bowden Extruder, Marlin 1.0.0 RC2, Repitier-Host V0.84 and Slic3r 0.9.8, PLA. Live at Victoria, Australia.

There doesn't seem to be any info about your hotend in their website. 3dstuffmaker doesn't seem to be open source. It might be best to contact them for help in figuring out what's wrong with your hotend.

thanks brnrd - will do. have a few other little test i want to do as well.

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Prusa 'Explorer' (3dStuffMaker), GEN6, J-head Mk III-B, Bowden Extruder, Marlin 1.0.0 RC2, Repitier-Host V0.84 and Slic3r 0.9.8, PLA. Live at Victoria, Australia.

the other thing ive noticed is that my bed is not flat - is higher at the edges thna in the middle (both directions) is this normal??
as you can see from the photo i can easily slip a folder piece of paper thru the gap.

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Prusa 'Explorer' (3dStuffMaker), GEN6, J-head Mk III-B, Bowden Extruder, Marlin 1.0.0 RC2, Repitier-Host V0.84 and Slic3r 0.9.8, PLA. Live at Victoria, Australia.

as for the bed - that should be as close to dead flat as possible. Most people use glass because it is one of the best cheap flat surfaces available. Yours looks really thick to be glass. Is it plexi? That probably isn't causing your blobbing though.

One cause on my machine of blobbing is if my fan is up too high and it cools down my tip too much. The auto temp shutdown will sometimes kick in. Do you have any errors in your log?

tiny, which program would generate the error - repitier? slic3r?
i don't think anything is physically broken - i seem to be able to print 1 layer wide dia 60 rings ok.
starting to suspect that is siomething to do with the first layer.
my first layer on rings is quite round, where as for parts with fill or whatever it really flattens the first layer out.
i have been using a 15 loop skirt (wide brim) as well. so if it is too low then this is making it really worst.
maybe all that plastic cant get out and it backs up in the nozzle.
what happens if plastic can't get out of the nozzle (and the extrude keeps pushing)? does the plastic back up in the nozzle some where???
roger

Edited 1 time(s). Last edit at 11/25/2012 06:11PM by rogerw.

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Prusa 'Explorer' (3dStuffMaker), GEN6, J-head Mk III-B, Bowden Extruder, Marlin 1.0.0 RC2, Repitier-Host V0.84 and Slic3r 0.9.8, PLA. Live at Victoria, Australia.

that would be the wrong photo.
anyway further to what i said. i think my first layer instead of coming out as a bead is coming out just as smear (because i have the height wrong or something expanded on the hot day). think maybe the plastic has nowhere to go when it is not coming out properly.
doing 15 loops of smear can't be good (thought it would be ok when it got to the 2nd layer). the
print i did on the hot day was the first where i had two parts on the bed so the skirt would have been even bigger.
so thats the plan i'm following. wrong height causing block up of plastic.
will clean everthing up, redo levels and start form scratch printing parts i have printed before.
roger.

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Prusa 'Explorer' (3dStuffMaker), GEN6, J-head Mk III-B, Bowden Extruder, Marlin 1.0.0 RC2, Repitier-Host V0.84 and Slic3r 0.9.8, PLA. Live at Victoria, Australia.

Quote
rogerw
what happens if plastic can't get out of the nozzle (and the extrude keeps pushing)? does the plastic back up in the nozzle some where???

The pinch gear eventually digs into the feed until it can't push it anymore. Then the feed is stuck and nothing will come out of the nozzle. If your hot end is too hot and it stays hot for along time, then this can result in your nozzle clogging due to the decomposition of the plastic feed.

If you build plate (bed) is not flat, then you should get one that is flat. As tinyenormous pointed out, glass is a good choice.

thanks brnrd. i'm not sure why they would give me a bed that is not flat (obviously isn't made of glass)- sound like a given to me that it should be flat.
it was only when i printed in the middle at the start of last week that i started getting great results. (ie. was level)
had been avoiding the middle as it had some tears. but printing at the side i get half the skirt coming out good and half a smear.
how long to you think it would take for a nozzle to clog ie. 10mm of too low printing, 50mm?
thank you
roger.
ps. i have a bowden extruder

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Prusa 'Explorer' (3dStuffMaker), GEN6, J-head Mk III-B, Bowden Extruder, Marlin 1.0.0 RC2, Repitier-Host V0.84 and Slic3r 0.9.8, PLA. Live at Victoria, Australia.

ps. the other thing i might have changed (seem to be recalling a few things now*) is that seeing i was printing so well that i sped
up the first layer speed . instead of 30% of 30mm/min i just set it to 30mm/min as well.
was not having any trouble with sticking to the bed so i thought i would let it rip.
i was using a 15 rings wide brim (2 layer high) to hold it down which worked really well.
but when i am too close maybe these 15 quick rings of too close is clogging it up.

is there a set way to unclog it????

* am going to keep a diary of every setting i change from now on

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Prusa 'Explorer' (3dStuffMaker), GEN6, J-head Mk III-B, Bowden Extruder, Marlin 1.0.0 RC2, Repitier-Host V0.84 and Slic3r 0.9.8, PLA. Live at Victoria, Australia.

tiny wrote " At least in my case, heat was climbing up the extruder, making the plastic rubbery higher up."

tiny - how much further up ??? i will post the bits of filament that i pulled out of the hotend (3 of them) all where solid for a cm or so - then strectched (where i had pulled it out) and then went back to the solid filament again.
seems strange that there is a solid bit at the tip of the filament and softer in the middle.
will compare this to pulling it out when I am just extruding into air.
(when i get home),
Roger
PS. i am trying to bring my temps down - not sure why i got up to 220 (think it was when i was having trouble getting it to stick - one problem leads to another !!)

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Prusa 'Explorer' (3dStuffMaker), GEN6, J-head Mk III-B, Bowden Extruder, Marlin 1.0.0 RC2, Repitier-Host V0.84 and Slic3r 0.9.8, PLA. Live at Victoria, Australia.

If your nozzle is clogged the. You won't be able to extrude in free air.

The fact you have issues at the higher side of the bed probably implies you are printing too close to the bed for you're first layer.
I'd also say from the earlier images that you are over extruding.
The failed prints obviously have varying extrusion rates, is the extruder skipping steps or is it chewing filament, you can usually tell just by feeling the filament going into the extruder.

i suppose another thing i have changed is i had a little fan sitting on the bed blowing air and now am using a big indoor pedistal fan (about 1/2m away).
maybe the smaller fan was doing a better job of cooling the nozzle too.


wow i didn;t think i had changed anything but seems i have
- hot day
- bigger foot print for the print (maybe going into non flat part of bed, maybe too much smeared platic)
- fast 1st layer
- different fan setup

Edited 3 time(s). Last edit at 11/25/2012 09:59PM by rogerw.

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Prusa 'Explorer' (3dStuffMaker), GEN6, J-head Mk III-B, Bowden Extruder, Marlin 1.0.0 RC2, Repitier-Host V0.84 and Slic3r 0.9.8, PLA. Live at Victoria, Australia.

polygonhell,
once it has happen i usually stop and then .. can't remmeber have done it too many times... i try to extrude and most time it will not work ... yes i think it has stripped (not skipping steps by the way) then i give it a push manually which sometimes is really really hard to do (maybe blocked) so then i disconnect the ptfe tube at the hotend (bowden setup) and push it from there .. sometines its is really easiy to push thru some times a bit harded... then reconnect the ptfe tube ... push again manually from the cold end past the ground in hole and then re-engage the extruder drive .... and then extrude to air for minutes and minutes (its the only thing i am any good at !!!) at a time until i am happy ... run again and i really think this is where i am going wrong - it is too close to the bed - ie. smear the first layer - is probably made worst when i have a part that has a bottom and so smears the hole thing with infill (*) ... seems to struggle thru smearing the first layer ... then normally comes good for a while but the lines are really skinny ... i know this is going to bugger up ... then a couple of good lines and then will start to blob and fart away .

* I seem to be able to print 1 loop wide rings ok. ie. no smearing of fill on the first layer.

have teed up to get some glass cut tomorrow - just need to measure up - will get a couple of bits and put kapton on one, blue tape the other, etc.

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Prusa 'Explorer' (3dStuffMaker), GEN6, J-head Mk III-B, Bowden Extruder, Marlin 1.0.0 RC2, Repitier-Host V0.84 and Slic3r 0.9.8, PLA. Live at Victoria, Australia.

>roger - then a couple of good lines and then will start to blob and fart away

Roger, Is there any air trapping in the hot end. may be because PLA has absorbed some moisture. As it heats up the moisture builds up the pressure and as some stage it just blow out.

The other thing could be inconsistent extrusion pressure. If the PLA is pushed into the hot end with different pressures then it could result in blobs. The sudden changes in the pressure will try to push the already molten PLA in the hot end to form blob. Also air trapped in between can cause this.

How is your extrusion from the extruder end and at the hot end of the tube. Disconnect the tube from the hot end and test it.

Also another check. Remove the PLA from the PTFE. normally the hobbed bolt leaves some marking. have a close look around the path of the hobbed bolt on the PLA. You should notice - one of the following:

1. Consistant gripping marks (everything is well)
2. some erratic marking with irregular intervels or Constant repeated pressure points along the path (may be missed gripping or feed rate is high)

ta 3 - will do tonight - am getting some glass for flat bed - yippee

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Prusa 'Explorer' (3dStuffMaker), GEN6, J-head Mk III-B, Bowden Extruder, Marlin 1.0.0 RC2, Repitier-Host V0.84 and Slic3r 0.9.8, PLA. Live at Victoria, Australia.