After printing nice skirts, new lines come out poorly [Solved]

Hey guys I'm having a problem that's making it impossible to print small parts.

My printer makes beautiful skirts, then lifts to begin the shape. The very first section of the line it prints has its tip lifted up. If they piece is large, usually on the next pass this is taken care of because the adhesion of the plastic stuck to the bed allows the part sticking up to melt. However on small parts when this piece is a significant portion of the print, it ends up catching and just ripping everything up.

I'm almost positive it's not an adhesion to the bed problem because my larger prints come out great and are difficult to remove. Also my skirts look great too.

I'm printing PLA at 200 and have the bed heated to 50. I will try to put a video below.

 

The video is marked private.

 

Your hotend temp is probably a little too high for small prints.

Either lower hotend temp a bit or increase your minimum layer time setting.

 

That should be fixed now.

 

What does the minimum layer time setting do? Could you explain that one to me?

 

When you're printing small object, each layer takes less time to complete. The time may be too short for the finished layer to cool down enough to allow proper laying down the next layer.

Increasing the minimum layer time would improve the print quality in that case.

 

I gotcha, so you could tell it never to do a layer in less than 10 seconds or something like that?

 

There should be a setting in your slicer.

 

When the print is difficult to remove from the bed, usually means you are too low. Will halo on keeping the print on the bed but can cause issue with consistent layer height and will move or cause problems with your extruder sometimes jamming the filament or moving the head causing leakage.

If the head is slightly too high off the bed, your print will not stick very well.


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I think all my heights are good. It may be a temp. issue but matter control seems to set the temp to anything except what i've entered. Anyone have any ideas after seeing the video?

 

That minimal layer time setting is usually under the cooling settings at least in Slic3r it is. You can also bump up the maximum cooling fan setting.

Also make sure your cooling fan is working and turns on.

 

In Matter Control you have to go deep into the settings under filament and set the extruder temp there. Not on the main screen.


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I messed with a few of those things. No change. I bumped the temp down to 195, same results. I extended the minimum layer time, also the same result.

The problem is occurring all on the first layer.

It only happens at the beginning or the end of a line. Either the very beginning is not cleanly adhered, or the extruder makes a sharp turn that lifts up any sharp points that did go down cleanly. It's the sharp change of direction that causes it to pull up whatever it just put down.

 

Another example of what happens is when I try to print the octopus http://www.thingiverse.com/make:79254 Ive managed to successfully print it, but I had the first 3 prints fail because when it attempted to do the first layer of the pointy arms, the corners lift off as soon as the extruder gets to the pointy tip and reverses direction.

I may not be explaining it well, so if its unclear please let me know.

 

What are you putting on the bed for adhesion? Glue stick? I suggest that you try Aquanet Extra Supper hold hairspray in the purple can or equivalent, http://forums.robo3dprinter.com/index.php?threads/hairspray-survey.1532/. Spray on a cold bed, heat to 60C for a few moments to dry, print at around 50C for PLA, 110C for ABS. Do all your filament types/colors/brands do this?

 

Wasn't able to watch your video yesterday.

After reviewing your video this morning, it looks like the middle section did not stick to the bed platform at all. Yes, try SteveC's suggestion on the hairspray above.

 

It looks exactly like that. Nice flat even lines that bond together at their edges.

The problem occurs when the nozzle lifts to go print something that doesn't start and end in the same place. The beginning of a new line isn't clean. It leaves a tiny jagged edge that inevitably snags on the nozzle when it comes back around. If printing a circle, or a square, or any other similar shape, when the nozzle comes back around in the same direction its able to melt the plastic and seal the floating end.

Also as another example, imagine a fork shape. If you start at the handle and move to print one of the tines, the printer will go to the end of the point but when it doubles back on itself it will lift the point up and begin to drag it back on itself in the opposite direction which peels the cooled plastic off. On larger parts this largely fixes itself, but on smaller parts they almost never sucessfully print.

Just wondering, is the video visible now and is it helpful in describing the problem?

 

PLA is notoriously difficult to get a nice first layer without lifting. You should use a lot of hairspray/glue/tape, whatever you find works.

Then get the first layer lower. You want JUST above wagon wheels. even if it's flat ribbon it still might not have a strong adhesion.

This is why I like ABS. The first layer Just Sticks™. Granted it also likes to warp and lift on later layers, but getting the first layer down is much easier than ABS.

Keep at it, you'll get there eventually.