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Geometry Accuracy

Posted: Mon Dec 15, 2014 2:52 pm
by qnzhou
Dear all,

I just want to know what kind of accuracy you guys are getting from B9Creators? With the cherry resin and printer adjusted for XY 30 micron and Z 30 micron, I have noticed X and Y dimension are consistently 0.15 - 0.2mm thicker, and Z dimension is consistently thinker by 0.2mm. Is this on par with the expected error threshold, or there is something I can do to improve the accuracy?

best,
James

Re: Geometry Accuracy

Posted: Mon Dec 15, 2014 4:32 pm
by akgold
You need to use 50/50 mix of cherry and red for the best results on small items. HD 30 1.2 and 1.1 versions.
without any info from your settings no one can help you

Re: Geometry Accuracy

Posted: Tue Dec 16, 2014 12:47 pm
by tim.yoshi
I'd say that this is normal. I never was able to achieve 100% accuracy. Usually no one won't notice it, but when we are talking about some really crazy requierements like 0.1 mm this is where I don't think it is possible. Or if you really want to, you could do a lot of experimentation. And meaybe someday you'll achieve accuracy like you want.

Re: Geometry Accuracy

Posted: Thu Dec 18, 2014 9:43 am
by qnzhou
thanks guys. I am not going for 100% accuracy, just trying to learn the limit of this printer. If there are still room for improvement, I would gladly try it.

Re: Geometry Accuracy

Posted: Thu Dec 18, 2014 12:48 pm
by Robert Howle
I scale all pieces 3d at 1.5% to 3.0% depending on how heavy the finished piece wil be. Most is done at 1.5%. This is to compensate for shrinkage in curing (layers and post cure). This helps with finger size and stone seats.


Robert

Re: Geometry Accuracy

Posted: Thu Dec 18, 2014 1:11 pm
by Metalcaster
Hi,
What I do when the customer requires really consistent accuracy, I ask them to create a rectangular box made of 2mm square wire, then, if needed , add 1 mm dia . prongs 3 mm tall on 1 surface.
I then print their file as is in 1 orientation on the platform.
After printing, We measure all the areas and now we can tell the customer what to adjust in his file so we can grow an item accurately.
It is important that the item stay in the same orientation on the platform.
Also, this works only when you use the exact same solution ... If you change solutions, then you have to redo all your calculations.
real pain

Re: Geometry Accuracy

Posted: Thu Dec 18, 2014 1:59 pm
by Robert Howle
Thanks for Sharing Daniel. Good idea.

Robert Howle

Re: Geometry Accuracy

Posted: Fri Dec 19, 2014 7:17 am
by tim.yoshi
Don't froget about calibration. If you do print some boxes on one calibration, then adjust, wait some time, calibrate projector again... you will have different accuracy :)