Poor surface finish on support side?

Hi All,

I have been using for original Form 1 and recently upgraded to the 1+. I’ve noticed this issue with both, there seems to be no noticable improvement with the 1+.

This issue is that the non-support side of the printed part has a very nice surface finish, but the side with the supports is very poor. Clearly there need to be supports, and the “dimples” left by the supports are to be expected. However, even where supports don’t contact the surface of the part, the surface is very wavy and not smooth. See images below. Is this poor finish normal for everyone else on the support-side surfaces? Is there any way to improve this finish?


Hi Aaron,

Unfortunately, there is no good way of improving that on the form1. One side or sometimes 2 sides depending on your orientation and where the supports are located will always have poor surface quality.

This is usually the nature of SLA printing, unless there is some very complicated variable curing techniques that are going on, seen mostly in very high end SLA printers.

It’s possible to increase the surface quality of the support side, if there is enough pigment to stop the light from bleeding through the layers and partially curing resin past the layer thickness it’s supposed to cure.

Hope that makes sense.

WOW that really sucks. But it is consistent with my results also.

I do too not get the best results on the supported side. I notice you are also printing in grey.

Thanks for the response! Does that mean the black resin should produce the cleanest results since the pigment is the darkest of the available Form materials?

@AaronMoncur That’s some awesome print.

Certain colors help block more light, however it’s the amount of the pigment too that will stop the light from curing past the desired layer thickness.

Also there is another thing that can mess up the quality of prints. Scattering of the light. Some colors, like white and yellow, can scatter the light in some directions, resulting in the “jelly resin” some people have seen in their tanks after many prints. Scattering can even cause skewed prints. This has happened to me with some semi-clear orange resins.

I have similar results and it bothered me enough to contact formlabs about it.

They said its about resin flow between layers, and as monger said, it’s part of the process we have to work with…

It can be helped by reducing the amount of supports you use on the model, something I have been playing with on a few parts myself. Check other posts on here about that, but I have been finding that some parts require all the support pre form lays down!

Secondly, another post on here talks about cleaning the models, and they suggest using a tooth brush to scrub away resin residue trapped between the support tabs. Rinse your models in IPA as usual, then clip away the supports and then continue to scrub the part, then rinse again… So far it has been giving me slight improvements to finish…

Ed

I want to know if this happens with all other resins. So far I know all of us on this thread are using grey.

I have been using my Form 1 professionally for about a year and as others have said, it is the nature of the beast. Here are few suggestion of what I do to minimize support blemishes.

  • Make sure you build your model so that the least seen side of the
    object can be supported. If you are building components that need to
    fit another object precisely, do not use this side for supports.
    Keep this in mind for threads and other tightly fitting parts.

  • Design your models to disguise support blemishes… My “Ducati Girl” is
    an example of this. I designed dimples on her racing suit to blend
    in along the areas I knew would require supports.

  • Break off your supports before you dunk your model into alcohol. I
    have found the supports to be less hard and easier to break off
    with less blemishes.

  • Make sure you resin is thoroughly mixed. Early on I had models that
    had a mottled or splotchy patches due to not mixing the resin
    thoroughly. The tint will settle both in the bottle and in the tray.
    If you leave your resin in the tray, make sure you mix it before
    printing by running the paint scraper/part remover gently back and
    forth, applying gentle pressure only on the return stroke, NEVER
    on the forward stroke and gouging the silicone bed layer.

  • Invest in variety of very fine grit sandpaper, nail files and most
    important nail buffers. Use the rougher files to quickly remove the burrs and
    then use the buffers to smooth the area.

  • Spray your models with coat of paint or clear coat. If you do not
    want to do this, then use mineral oil. I do this especially for clear pieces
    prevent them from yellowing.

  • Purchase a 405 nm point laser (and safety glasses) on eBay and add
    layers of resin with a fine paint brush over the areas of concern.
    Sometimes adding a drop and letting it flatten out will reduce the
    blemish or at least reduce the contrast in color. Depending on
    you the wattage of your laser, determines the amount of time. I
    normally wait 30 seconds. NOTE: Depending on the wattage or time,
    do not hold the piece in your hand, you can burn yourself and not
    even know it. Use tweezers or a helping hand tool.

I hope these tips help. I am also the producer of the podcast ‘All Things 3D’ http://allthings3d.net . If you have nothing better to do on Friday morning at 9:30 a.m. PST, you can find us on ‘Google Hangouts On Air’ doing “3D in Review” weekly. I plan to show off the unfinished “Ducati Girl” and show how to apply unfinished resin and cure it.

4 Likes

^

Which is something I noticed and sparked my most recent thread.
It is easier to disguise with character; folds on clothing etc, than is it on a flat mechanical part…

Again, I am starting to think that while the form 1 is a great machine it just doesn’t meet the requirement of a mechanical designer in terms or part accuracy and at least provide a consistent finish. This printer when compared to a makerbot (which I have access to) does not produce what I call a dimensionally accurate representation of what is designer in the CAD application. I am hoping the FormLabs is able to address their resin forumulation (maybe its a new resin).

Hello Michael,
I agree with your suggestions and I add one other more: sometimes is hard to see correctly our surfaces’ details of prints made with white, trasparent and grey resins. that because the SSS effect of the surface and/or trasparency - shining.

An easy way is to buy a cheap UV bulb (I use a neon low-power one) and ispect the surface under that light. You no need stay in full black room. Just move your surfaces near the lamp in a middle-lighted room and the fluorescence of the resin will turn the shining-trsaparente or semi trasparent surface into a perfect matte and semi opaque one. This will show you all the gaps, holes, scraps and problems on your surfaces.

Obviously the UV light have the effect tu cure the resin: so if you are using that lamps during fixing with laser pen and liquid resin, take care to don’t stay long time with the liquid resin under the UV light.

My workflow is: print the object, remove the supports, wash into IPA, turn on a UV lamp and move closer it the area that I’m ispecting, find the issues, moving little far the object from UV bulb and with a glass of liquid resin and a laser pen as tools, start to fix and glue the parts of my prints. Then check again if the fixing operation fit well with my purposes.

I’ve tested this workflow with grey resin, because I’m used to print surfaces 2 mm thick, so the subSurface Scattering effect and the partial trasparency will make me crazy to see all the surface’s details.

UV light will help to make the apparence more matte and less trasparent.

Hope this helps,
Mattia