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help with priming for first layer

Posted: Sun Jan 10, 2016 12:33 pm
by dansrogers
Hi,

I am trying to start my first print (the PEEK fan bracket), and I'm having a lot of trouble getting the first layer to stick.

First off the hotend leaks when I'm retracted to the home position.
Then, when it starts printing the skirt, it does two loops and sometimes the plastic doesn't start extruding until the second loop is almost done.
Third, once the raft starts, it doesn't stick until it's laid down a few centimeters, but by that point it's too late and the part that didn't stick, catches on the hotend next time around..

The max temp my bed will do is about 80 degrees, which is what I'm using. I'm using a UHU stic glue stick to stick stuff to the bed.

Re: help with priming for first layer

Posted: Sun Jan 10, 2016 3:25 pm
by Eaglezsoar
dansrogers wrote:Hi,

I am trying to start my first print (the PEEK fan bracket), and I'm having a lot of trouble getting the first layer to stick.

First off the hotend leaks when I'm retracted to the home position.
Then, when it starts printing the skirt, it does two loops and sometimes the plastic doesn't start extruding until the second loop is almost done.
Third, once the raft starts, it doesn't stick until it's laid down a few centimeters, but by that point it's too late and the part that didn't stick, catches on the hotend next time around..

The max temp my bed will do is about 80 degrees, which is what I'm using. I'm using a UHU stic glue stick to stick stuff to the bed.
What type of filament (PLA or ABS) and what is the nozzle temperature?

Re: help with priming for first layer

Posted: Mon Jan 11, 2016 1:29 am
by dansrogers
The filament is ABS and the hot-end temp is 228.

I've tried a few things and made a lot of progress.

I addressed the first layer sticking problems by changing from UHU Stic to Elmer's purple and changing the first layer extrusion width to 0.6. That helps the brim stick. I also changed the number of loops to 3 to make sure I get a couple of good loops in and help with the loss of priming when leaking in the home position.

I changed the retraction to 10 mm to help with the leakiness. That also helps the part finish quality. However there is still some leakiness. Should I always expect the hotend to leak when retracted?

Re: help with priming for first layer

Posted: Mon Jan 11, 2016 7:52 am
by magicmushroom666
yeah if its heated and in the home position, I find mine always oozes a little, there should be no need for the printer to just sit like that though. I tend to do a 10mm extrude in the air before pressing start print which gives me something to grab hold of to remove, and gets things nice a primed ready to start.