printing question. I'm printing something that is essentially a flat rectangle with some holes

printing question.

I’m printing something that is essentially a flat rectangle with some holes in it, each about 3mm across. The edge of the rectangle prints fine, no lifting or warping, when I use a brim. The circles don’t print properly, though. The printer runs the perimeter of the rectangle and then each internal circular hole. The first layer of these internal perimeters doesn’t stick, causing later layers to look wonky. Are there any settings I could use to get small disconnected perimeters to print better? Maybe a way to have them be attached to the main perimeter so they stick?

I usually have to set my Z home a little low to squish the first layer a bit. You could also try slowing the first layer quite a bit and/or printing the first layer a bit hotter.

What slicer?

Slic3r has a “small features” option - which can slow down the print for those pesky bolt-holes etc - I usually go somewhere 10-20mm/s for small perimeters, faster for larger ones.

@Carlton_Dodd has the right idea too - your first layer should be a bit squished… this helps it stick to the bed.

One last thing to check is: ABS - your bed temp MUST be high, if you’re aiming for 110-120 but only getting 90-95 (has happened to me) it will cause problems…

PLA - if you’re printing onto tape it has been found that the material under the tape DOES matter - if you use an aluminium plate for example, aluminium is a good conductor - it RAPIDLY draws heat out of the plastic and cools it too quickly, often resulting in the ends curling up, possibly ruining the whole perimeter. - I’ve had GREAT experience lately in setting my heated bed to a ‘nice warm day’ temperature (technical term :wink: just to take the edge off (because you shouldn’t run it TOO hot with blue tape, it’ll get ‘icky’) 40 deg C is my recommendation for aluminium under blue tape.

It’s the latest Slic3r.

Sigh. Temperature seems to be the hardest part of 3D printing. Yes, I upgraded to an unheated aluminum bed on my Printrbot Simple recently. I’m running PLA. I suspected the new bed was causing edge-lifting problems by sucking the heat away too fast. To address it I’ve been doing double layers of blue tape. That works okay but doesn’t seem to be enough to help on the small holes. Even cranking the temp for the first layer up to 210 and making it slow and thick. I wish Printrbot sold a heater to attach to the aluminum bed.

You could potentially get your first layer down using a hair dryer to warm the aluminum first so its not as harshly-cold - or insulate it from the tape, put tape onto thin piece of wood perhaps?or cheap n nasty, you could try cut some cardboard, tape on top of it and clamp it to your bed - it’d wanna be clamped very well though or the plastic may contract and bend the cardboard!

Plastic would work as an insulator too - you could potentially print a bed if large rectangles work out ok? But best bet is wood bed or slightly heated bed -

aluminum + tape = problems!

I regularly print PLA (200C) on an aluminum bed (65C) covered with kapton tape. First layer thickness between 0.1mm to 0.2mm. First layer speed ~20mm/s. The plastic sticks really well under this setting, provided your bed is well calibrated. A well calibrated bed works like magic.

kaba

prex

It sounds like an aluminum bed just doesn’t make sense if it’s not heated. It sucks away too much heat. I’ve switched back to my wooden one and I’ve already seen improvements. Identical g-code is adhering much better.

That’s awesome @Joshua_Marinacci - glad you’re getting better results :wink: