One of the ever-present features of 3D printing, especially FDM, is layer lines. Because the size of the printed plastic is still visibly large, very little can be done to minimize this. Even when using the smallest layer sizes available, layer lines are visible. They’re also noticeable on flat surfaces such as the top of the print. Interestingly, there is something that can be done about this.
Top surface ironing is a setting available in some slicing software packages. It allows you to somewhat smooth out the lines on the top of your print. It involves brushing the tip of the nozzle over the surface to soften it again. This is done while extruding a small amount of material, roughly 30% of the normal extrusion rate, to fill in the gaps between lines.
Overall, the process can leave the surface looking much smoother, with only hints of lines left, especially around the edges. If the hints of layer lines are more noticeable, especially if the gaps look like tiger stripes, the extrusion rate is likely too low. Increasing it in steps of 5, or even 10% if the issue is terrible, should fix it.
Reduced Number of Passes
When ironing the top surface, the nozzle doesn’t need to go over the whole area in as many passes. If you notice some of the newly printed material getting caught on the side of the nozzle as it makes its passes, then you may need to increase the spacing between ironing passes.
Because of how it works with the tip of the nozzle brushing the surface and extruding a small amount of material, surface ironing only works on flat top surfaces, the nozzle can’t get to any covered surfaces to iron them and can’t iron vertical surfaces at all.
Top surface ironing is a cool concept if you want to improve the aesthetics of the top of your prints. It is beneficial for large flat prints but may not have much of an effect on complex prints. Especially those with minimal flat top surfaces. Have you got any projects that you think would be improved with top surface ironing? Let us know down below.