Grey v4 always slightly deformed/skewed


#1

Hi Guys,

I’m wondering if anyone could help me regarding slightly deformed/skewing of prints?
I’m try to print jewellery designs which need to be quite accurate, and being an obviously visual item they need to look nice and as close to perfect as possible (who wants to buy a misshapen ring?)

Here are a couple of images to show what I mean:

When compared to the CAD model, the cut outs that go under the stones are not coming out sharp and squared in the print, and also the left hand wall edge of the print is rounded when it should be a lot straighter. The middle settings are also deforming a bit and filling in-between the out wall and setting edge.

My settings are based on Preform auto orienting the model for me, using standard Grey v4 and 50 microns. The resin was shaken and a new fill in to the tank (no clouding).

Any advice on how to compensate/fix this would be invaluable to me.

Many thanks,
Gareth


#2

That’s always going to happen, any surfaces that are downward facing will have some extra resin cured on them, this is due to the inability to prevent the light source from curing beyond the current layer. Since the light is going through the layer it can cure extra material on the underside. The effect is more pronounced on areas where the resin gets into corners since the resin isn’t able to flow as easily. For gaps, if the surfaces are close enough then they can get filled in for the same reasons.


#3

Other people have not been happy with Grey V4, especially for very detailed designs, and had more success with 3rd-party resins. Shame that Formlabs apparently switched to an inferior formulation compared to V3…


#4

I’m not sure if it is something I’ve imagined, but I think I read somewhere that setting the Form2 up as if it’s using v3 resin (but its actually v4 in the tank) that it uses a stronger setting for the laser and cures the resin harder. Does anyone know if this is true, and if so how would I do this so I can give it a try?


#5

Using a setting that would cure it for longer would make the effect worse.


#6

We’ve been doing extremely precise work with Grey V4 recently and have had no issues. Stacks of cylinders of approx 35mm in Ø with canals for fluid on the faces and <Ø1mm through-holes in them. Of course we have tofiddle a bit because this is touching the limites of the repeat-ability of the machine but we definitely didn’t see anything like @Gareth’s photos.

Actually we have had greater precision and reliability with Grey V4 than with Grey Pro for small parts, which is kind of a letdown from your Grey Pro expectations but hey, it works with Grey Std so…


#7

Does this happen wherever you but the piece on the build platform?

It looks to me as if you have a dirty optical path so running the optical test would be a good idea.


#8

Hi guys, thanks for your replies.

I’ve done an optical test and this is the result I get:


The middle part with the posts sticking up doesn’t look so bad but is missing one of the posts, and the numbered stacks clearly have problems towards to top.

Does this indicate anything obvious to anybody?

Thanks, Gareth


#9

Time to clean your optics!


#10

Thanks for the reply. By the cleaning the optics do you mean going through the cleaning procedure in the “Cleaning the Form 2 Galvo Mirrors” guide?


#11

Correct.