Topic: Intermittent blobs on first layer with PLA
I recently switched to PLA and I have been having this issue on the first layer
What is causing this? Thanks in advance!
1 2013-11-02 00:00:51 (edited by FordGalaxie 2013-11-02 00:01:17)
Re: Intermittent blobs on first layer with PLA
My guess is that you're printing too hot, and that the moire effect is actually there with ABS too, but it's more pronounced with the hotter PLA. What temp are you printing at? You might try 20C colder.
You can reduce the moire by adjusting the VREF on your extruder stepper driver, and reduce it further by installing a microstepping driver, see http://www.soliforum.com/post/33357/#p33357
But for now, lowering the temp should help.
3 2013-11-02 00:41:17 (edited by FordGalaxie 2013-11-02 00:44:07)
Re: Intermittent blobs on first layer with PLA
Right now im printing at about 165 C. What, may I ask, is the moire effect?
Also, those stepper drivers are for a new brand of stepper. Would a driver for the STOCK steppers have an effect as such?
4 2013-11-02 03:12:44 (edited by adrian 2013-11-02 03:13:33)
Re: Intermittent blobs on first layer with PLA
pla is inherently more 'oozy' than ABS.. meaning you will need a higher retraction setting under slic3r->printer settings->extruder 1 ....
And PLA can vary in temp range from 155->185 (for natural) on the SD... so your temps sound ok - i'd tweak the retraction settings more first...
Re: Intermittent blobs on first layer with PLA
That link I posted before shows you an example of the moire effect caused by the stock 1/16 stepper drivers. If you have a newer SD then the steppers are not swappable, but you can still adjust the stepper voltage to minimize the impact. Wikipedia has more on the Moire Pattern (http://en.wikipedia.org/wiki/Moir%C3%A9_pattern).
See this link on adjusting the stepper motors:
http://www.solidoodle.com/how-to-2/trou … /#steppers
For me, I adjusted the extruder stepper, VERY CAREFULLY, while it was printing; until the prints looked better. If you're not comfortable making the adjustments while printing, I would turn the trimpot an eighth of a turn to the left to see if that helps.
As for the temperate, 165C doesn't sound like it's too far off, but from the pics I would take it down in 5C increments to if that helps as well.
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Re: Intermittent blobs on first layer with PLA
Actaully, this loooks more like a problem with the Extrusion factor in Slicer. He does not have the problem with ABS, so I am guessing he has not calibrated for the the different filament. Print a single walled cube and measure the wall thickness for PLA.
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Re: Intermittent blobs on first layer with PLA
I did the PID autotune, I changed the retraction, and I have played with the extrusion factors and that helped but only too an extent. I will report back with the effects of the new changes in a while