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need print problem diagnosis please [SOLVED]

Posted by Anthong Redbeard 
need print problem diagnosis please [SOLVED]
February 21, 2011 10:12PM
Hi all, I'm happy to be printing on my new printer, it can be fast, it's quiet, has no leaks, and extrudes all day long. However, I'm having ome real print quality issues. I'd appreciate any suggestions on skeinforge settings etc to try... I've been through several iterations but as the picture shows I'm still a long way off.

I'm printing PLA on a Prusa Mendel, with Ramps, Repsnapper, Arcol V3 hot end .35mm. Please dont take this post as any hit against these items, everything seems to be working perfectly besides my skeinforge settings = user error.

My first print today, the furthest back was the smoothest but it's too short, my setps per unit for Z were off and I corrected that.

since then I've been struggling with everything after the first few layers being really messy, brittle, and the edges wont stay put where they are laid.

I've tried many variations on layer height, speed, flow rate, temp from 175-190, and several other settings.

If I could get the whole part to be as good as the first few layers it should be great, so I matched the print speed of the first few layers to the whole thing, which is the latest print, but it still didn't turn out very good.

Any help is appreciated. thanks... giant picture of the prints

Edited 2 time(s). Last edit at 02/23/2011 09:46AM by Anthong Redbeard.
Re: need print problem diagnosis please
February 21, 2011 10:39PM
What kind of PLA are you using? Does it come out smoothly in air? I'm guessing that you're tip is not high enough. You might have the kind (4043D) that extrudes at higher temperature (220-240C).

Also, when printing on 3M blue tape, I found I had to have the tip closer than one layer to the bed. So, if it looks good on the first layer, your flow rate is probably too low for the rest of the layers. There's a setting in Skeinforge under rafts to adjust the feed rate and flow rate of the first layer relative to the rest of the layers. You can turn the flow rate down here and then increase the flow ratre in the Speed settings.
Re: need print problem diagnosis please
February 21, 2011 10:52PM
thanks, I'm using pla from ultimachine and it seems to extrude very nicely in air, no hissing or pops. clear smooth and consistent.
Re: need print problem diagnosis please
February 21, 2011 11:16PM
Your prints look similar to some that I've printed with low temperature in the past. smiling smiley It shouldn't hurt anything to go even higher. What is your feed rate? When you watch the extruder while printing, you should see the filament come out smoothly and lay down a nice even track. Your nozzle (0.35) is much smaller than mine (0.5). What is your layer thickness? Perhaps it's too high. I don't have experience with this size, but you probably don't want it more than 0.28 mm.
Re: need print problem diagnosis please
February 21, 2011 11:28PM
I'm printing with RAMPS, a 0.35 mm nozzle, and PLA. I use a layer height of 0.20 mm and can print quite well. I print at 175 C at the nozzle, but I likely have a different PLA than you do. Try using a higher temperature, it may be that your layers aren't bonding together properly. Your flow rate might be too low as well, causing the extruder to pull on the filament as it's laying down. Try increasing the flow rate to higher than the feed rate, and if that helps you can increase your e_steps_per_mm in firmware and put the flow rate back equal to feed rate.

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Re: need print problem diagnosis please
February 21, 2011 11:38PM
thanks, I'll try all options mentioned so far. I haven't tried layer height less than .25 because it looked like it was sloshing it around too much, like it was spitting out a lot more than it was accounting for. I'll also try higher and lower temps than previous runs.
Re: need print problem diagnosis please
February 22, 2011 01:45PM
I figured out a significant variable I was missing in tuning... e_steps_per_unit in the firmware. Adjusting this makes a big difference in what I can work with.. I slowed it down and it seems like I can match extrusion with feed speed now.
Re: need print problem diagnosis please [SOLVED]
February 23, 2011 09:48AM
Just as a quick follow up... I got someone elses skeinforge settings and it helped a lot. I was missing some settings in mine that controlled the extruder speed. The other significant thing was my Y belt needed to be tightened. I have a few other things I found I can tighten and keep from jiggling during a print but that was the main stuff.
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