Ridges on top surface of the printed structures

Hi there, lately I am trying to print structures, which are protrusions against a flat surface. The structures are small in micrometer scale. The problem is that post print always end up with prominent ridges on the structure and surface. I have tried increasing the print resolution down to 0.025 mm. I have tried acetone fume smoothing and sanding. Problem with acetone fumes is that they do nothing to the surface. Problem with sanding is that structures are small and very close to each other so it does not remove ridges along the structures and between those structures.

Can anyone suggest how to achieve ridge-free printing using either clear resin 2.0?

Hope I find something here because Formlab support helped me with nothing.

Hey Chandra,

I find it hard to understand what it exactly is you want to achieve. Do you have some pictures which would help with the explanation or perhaps the formfile?

It seems you want to print very tiny spikes on a flat surface? How tiny are these spikes. Keeping in mind that the minimum laser feature size is 0.3mm

I have 500 X 250 micron wall posts printed on the surface along X-axis usig Form1+. The problem is that besides having these wall posts along X-axis I also have lines through out the surface along Y-axis which literally covers the whole surface and as long as the surface is. I think these unwanted lines lines, which I call ridges, are the left overs of the print out. Assuming that this is a technical limitation of 3D printing. I was wondering if these can be removed by some post-printing tools somewhat similar to acetone-vapours for ABS structures.

I can’t send you the pictures because my camera is not able to capture that detail.

Are you able to make screenshots of your model in preform? I don’t understand if the lines on the Y-axis are on the model itself, or they appear after the print?

Still, uploading the form-file would be best to understand what you’re dealing with.

Are you talking about the resin layers like in this image?

That is completely natural for anything coming off of a 3D printer. To get rid of those, your options are to wet sand, or skim coat like 3D-XTC. I’ve not used the product, but It was recomended to me.

Also mentioned here:

Alex, these ridges are not on the drawing and these are something what Paul has mentioned with the image.
Thanks for your suggestion Paul but the problem is that my structures are around 0.5 mm apart to each other and sanding between those is not possible. And, if I try to fill these ridges with something then I am losing the height of the printed structures, which is crucial for my application.

Still, I will try to sand it off. However, do you guys know of any chemical treatment that might be helpful, something similar to acetone vapour as they use it for ABS polymer?

@Chandra_Dixit, anything that takes the ridges off is going to do a number on your tiny features as well.
We’re still stumbling around in the dark until we can get a good picture though. I might be picturing things completely wrong.

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