Page 1 of 1

Under extruding? Too far from the bed?

Posted: Fri Jun 06, 2014 6:22 pm
by mlapaglia
[img]http://imgur.com/xDYyvjj[/img]
[img]http://imgur.com/lJrEhvZ[/img]

Trying to figure out what is causing this. Is my print head too far from the bed? I have slic3r configured for 1.71 filament and I went through the calibration process successfully (i think). Any thoughts?

Re: Under extruding? Too far from the bed?

Posted: Fri Jun 06, 2014 7:52 pm
by Captain Starfish
Those photos look horribly familiar to what I was seeing yesterday here.

The fact that the filament is pressed down with a flat bottom face suggests to me that your z height is correct.

But not enough filament's coming through. I would check your filament diameter with a micrometer or even a dial caliper and also check your nozzle temperature with a thermocouple and another look at your print speeds.

I say this because it looks quite a lot like mine did after I corrected an overtemperature issue on my unit this week. All the settings which worked fine for a nozzle at 260º (ouch!) generated similar results to your photo at 230º. I ended up backing the speed down to 120mm/s for the fill, switching the layer fan off, and upping the temp to 235º to get much better results.

The big one was nozzle temp though - if your thermistor is telling you 230º when it's 220º these photos would be about what I'd expect.

Re: Under extruding? Too far from the bed?

Posted: Sat Jun 07, 2014 8:25 am
by mlapaglia
lol 120mm/s infill? I'm sitting around 60, i've been bumping things up slowly, apparently too slowly.

I'll get a thermocouple and check out my temps

Re: Under extruding? Too far from the bed?

Posted: Sat Jun 07, 2014 8:36 am
by Captain Starfish
Don't rush your speed up, get everything settled first.

Re: Under extruding? Too far from the bed?

Posted: Sat Jun 07, 2014 12:33 pm
by Polygonhell
Don't get distracted by other peoples reported speeds.
You need to take speed out of the equation when dialing things in then increase them later.
I personally would dial things in at 30mm/s or less for everything, and I'd go as low as 10mm/s if trying to track down a specific issue.
Ramping up speeds later is easy.
I can't see the images in the first post so I can't comment on the issue at hand.

Re: Under extruding? Too far from the bed?

Posted: Sat Jun 07, 2014 5:07 pm
by mlapaglia
Hm not sure what happened with that image.

Anyways, been messing around with settings. Here's the hollow pyramid, looks like I need to dial in my retraction settings a bit more. I upped the temperature to 210 in order to get things to stick without breaking off.

Retraction is at 7mm at 55mm/s (anything less than that distance wasn't retracting all the way), and z lift at 1mm. 2mm brim. Retract on layer change and wipe while retracting are enabled:

[img]http://i.imgur.com/oUyZkn7.jpg[/img]

[img]http://i.imgur.com/shYpTam.jpg[/img]

[img]http://i.imgur.com/Uqn6Zy5.jpg[/img]

Re: Under extruding? Too far from the bed?

Posted: Sat Jun 07, 2014 10:18 pm
by Captain Starfish
Puddle on the top is usually from the setting in filament cooling which slows the head down for small layers - either it's too low meaning you're piling one hot squishy layer on top of another layer that's still too hot, or it's too low in which case you have a nozzle just pouring heat into the part.

Spiderweb I'm guessing is a need to up your retraction speed and maybe distance. That might also fix up the shonky edges on the corners, too.

Re: Under extruding? Too far from the bed?

Posted: Sun Jun 08, 2014 12:27 pm
by Polygonhell
The spider web will go away if you drop the temperature some, for PLA you really want to print as close the the minimum temperature you can reliably extrude it at as you dare. The hotter it gets the more liquid and the harder it is to control strings.
What surface are you printing on?
Although you can print directly on glass with PLA, how well it works seems to be very dependent on the filament you use.

Re: Under extruding? Too far from the bed?

Posted: Sun Jun 08, 2014 2:52 pm
by mlapaglia
I am printing directly on glass cleaned with soap and water. The prints are coming out fine now, I tried something larger but the print broke off the bed. I've noticed it doesn't take much force to separate the print from the bed at 60 degrees. I'm going to try a PVA glue mix, any thoughts on using the Elmer's glue stick for pla?

Re: Under extruding? Too far from the bed?

Posted: Sun Jun 08, 2014 4:22 pm
by Polygonhell
If you're printing directly onto glass, print the first layer hotter, as I said it can be a complete crap shoot, I had one roll of filament I could not get to reliably adhere to clean glass and others that were fine.
PVA works, glue sticks work, hairspray works, I use UHU glue sticks which I believe aren't PVA but work, and if you can stomach the cost and messing around to cut the sheet PEI is utterly awesome for PLA.

Re: Under extruding? Too far from the bed?

Posted: Sun Jun 08, 2014 5:27 pm
by mlapaglia
Yes I suppose this reel doesn't want to stick well. I'm interested in getting a sheet of PEI, would the .03" 12"x12" suffice?

Re: Under extruding? Too far from the bed?

Posted: Sun Jun 08, 2014 7:04 pm
by Polygonhell
That's way at I bought, along with a roll of Scotch 468MP which I used to a fix it to the glass.
I think the PEI cost me $18 and the tape $8, both from amazon.
Cutting the sheet into a circle turned out to be a pain in the ass, but mostly because I cut the sheet after it was attached to the glass.

Re: Under extruding? Too far from the bed?

Posted: Mon Jun 09, 2014 9:21 pm
by mlapaglia
Picked up a few sticks of disappearing purple glue today. Put a few layers down on the glass and started my print. Came back and it was next to impossible to get the print off the bed! The opposite problem haha!

If I print farther away from the bed for the first layer would I get less sticking? Or is there a better approach to getting parts to come off the glass?

Re: Under extruding? Too far from the bed?

Posted: Tue Jun 10, 2014 10:08 am
by geneb
Once the bed cools the parts should come off easily.

g.