Smooth first layer

Hi, I’m working on a project where the part to be printed is inverted, as this doesn’t require any supports, making the print faster and use less material. The problem that I have ran into is that the bottom surface isn’t smooth enough for me to use. I have enabled the ironing on Cura, and that does great for Z up horizontal surfaces, but does nothing for Z down horizontal surfaces. Ordinarily I’d just use the supports, but as this will be printed many times, support material will eat up too much filament driving up the cost of the final product. I’m currently running a brand new A250 that I have calibrated.

Here’s a scan of the bottom showing the roughness of the surface.

What steps can be done to make this smoother? Sanding or lacquering is not an options.



My first suggestion was going to be printing the bottom (upside down top) thicker, then sanding or smoothing. But since those aren’t options, then you need to print on something smoother than the stock bed. There are several posts in the forums about people getting a glass bed mounted on top, and that should give you a much smoother finish. It’s kinda tricky though, it’s easy to crack during calibration.

You’ll also want to make sure you’ve got your ESteps and first layer calibration perfect. Any over or under extrusion will cause imperfections.

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You can increase the flow rate and line width the intial layer and set some negative value for initial layer horizontal expansion to compensate for that on the borders. Small details are lost this way but may not be an issue on that print. Just be warned that this increases your first layer adhesion quite a bit which makes it hard to remove at the end.

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I’ll try both suggestions.

I’ve seen some 1/8" stainless steel sheet at a local hardware store, think that would work for a smoother bottom layer over the stock plate?

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I have not tried other print beds yet. Better results are probably to be expected with a glass plate. If you think that this is worth the trouble. You could also try some solvent to smoothen the surface. Like acetone for PLA. There are lot of examples for such on the internet.

Acetone doesn’t work on PLA. Only on ABS.


You are right. I mistook one with another.

I have been using a steel sign blank cut to fit my 350, has been working well with great success fo over 9 months.
Very smooth.

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Can I get some more info on the steel sign blank? For example, how is it different from a sheet of aluminum or steel that I get at lowes or home depot?

my energetic 3d pei plate gives very smooth first layers (i assume glass does too)

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Steel plate will stick to magnets in heated bed.

I got the same plate from energetic and it is awesome. Very nice adhesion and never have to use any glue sticks.

Stainless steel however does not adhere to magnets.

It is not stainless steel. It sticks to the magnetic bed just fine for me.

Thanks @scyto . Going to order a plate and try it out as well. Does using the plate make it difficult remove the final product, especially if the first layer has a large surface area?