First print layer question, New User

[attaklysm 0]

Hello,

I just got an Ultimaker 2, very happy with the purchase and the quality of my first few prints :smile:

I just had a question regardiing the first few print layers.

I've noticed that the printed pieces flair very slightly at the bottom. What is the best way to compensate for this? is it because the build plate is too hot?

I was considering introducing a small chamfer/fillet to the edges on the bottom layer to eliminate the flair. Does anyone do this?

Any help is greatly appreciated.

 

[jonnybischof 60]

Can you post a picture?

I've fiddled with small chamfers on the bottom as well. I think you can get the brim off better if you add a 0.3mm chamfer. 0.2mm bottom layer thickness. That should also get rid of the "flair" (not sure if I understand that word correctly).

I usually don't make these chamfers anymore because it takes a while to design them, but only a few seconds to correct the parts after printing...

 

[attaklysm 0]

Thanks for the reply :-)

Yes, you are interpretting my wording correctly :-) just my way of describing what I'm seeing, I'm not sure of the correct terminology.

I'm in work at the moment, so don't have the parts at hand. I'll try and get a photo later.

How do you go about correcting the parts after printing?

 

[skint 62]

If your printing at the standard setting, which is 75C degree for the build plate... drop it down to more like 60-62. No point designing chamfers onto your parts unless your part needs them, although chamfers do help if your not bothered about them on the part.

 

[3dmaker4u 0]

This "effect" on the bottom layers should ideally not appear only if you have a perfectly leveled bed, which is not heated, but has perfect adhesion and you print with filament that do not weight anything. Pretty ideal, huh?

In practice, due to a combination of the factors above, the first few layers (1-3) will exceed a bit the designed contour of the piece you print. How much "a bit" depends on the aggressiveness of the settings (e.g. temperature of the heated bed).

Depending on the kind of piece I'm printing, I use a 0.25-0.5 mm chamfer (especially for mechanical parts I design) or opt for filing the piece after printing (particularly if I cannot alter the model), while some other parts I left them as they are

 

[attaklysm 0]

Thanks for your replies, they have been really helpful. I will have a play around tonight to try to find the best way to mitigate the effect based on your recommendations.

I only noticed the "spreading effect" (thought I'd throw in another description :wink:) when i went to fit a circular disc piece, I had made into, its related clearance hole. It's not immediately obvious to the eye.

What would you recommend for filler?

Thanks again :smile:

 

[gr5 2,224]

If the part is too small near the base it's probably the heated bed too hot. Or the fan is coming on too fast and cooling the nozzle for a minute and you get a little underextrusion (not likely).

If it's too large near the base and it's only 2 or so layers it's probably levelling.

If it's too large near the base and it's several mm tall then it's probably nozzle temperature a little high or a fan issue - you might want the fan to come on sooner.

If you have the heated bed below 70C and the fan comes on at 1mm and you still have a "flair" you can just compensate in the CAD model.

 

[yellowshark 153]

If I suffer this and need to fix it, e.g. printing a circular bolt that needs to go through two other pieces to hold them together, I design the bottom layer of the bolt cylinder, i.e. 0.3mm of the bolt to have the diameter reduced by 0.1mm or 0.2mm. This normally fixes it for me so that the cylinder is 100% consistent.