Smooth Printing where the supports are connected

[ERi]

Hello
I am experiencing some problem with printing Formlab3 Castable wax resin. The side where are connected supports the quality comes deformed like melted and not sharp.
what is the problem with this? Can anybody suggest any soltion ?

[keweenawkarl]

I can’t suggest a solution, but rather an explanation of what is happening.

When you print a layer, some of the laser light will travel through that layer and cure additional material on the back side. Because that excess light is diffused by the build layer, the additional buildup on the backside is smoother than the build layer, as any shallow texture gets more light than high points.

[luben111]

This is so called “parasitic curing of residual resin” effect- see this post (maybe you need to scroll down little bit when open the link)

Bad prints out of brand New Form 3

True point but I doubt it’s very relevant here. I’m on a road up a mountain with zero traffic. My Form 3 and Form 2 are right beside each other, and I’ve done identical prints (simultaneously, and one printer at a time) which come out with creases / ripples on the Form 3, but perfectly on the Form 2. Did they let you do a return for refund?

In short - if the area where the supports are touching the object is close to horizontal, the resin can’t flow away easily and stays for longer in this place and becomes semi cured from the reflected laser light around. See the images in the link I sent you - it’s visible how the supports leave “shadows” on the object surface.

The solution is - tilt the part to avoid horizontal sections with supports in order to allow the resin to flow away, also if possible decrease the number of supports in horizontal area as each support “attracts” the rubber due to the surface tension effects.

The effect is not officially mentioned in FormLabs documents and the software is not taking it into account, it’s up to users how to deal with it.

[ERi]

Thank you for you reply !