thin frame object printing

[gldi0001]

Hello, I'm a newbie here.
First of all I'm gladly appreciate for giving us Mr.PacmanFan this awesome community and many useful information and developed such nice manipulating software of Creation Workshop!
As to refer this forum a lot and other developers's web sites, finally I've finished build up my homemade DLP 3D printer last week.
I finished accurately 10mm square cube and some solid design small objects as the 2cm lions head I attached picture.
But when I try to print out a sort of thin frame design object currently I tested frame cube 10mm x10mm x5mm(frame diameter is 1mm on attached picture).Its base plate thickness is 1mm.

the base plate was printed out nicely but frame part was broken especially perpendicular 4 frames. 2 of perpendicular frames were barely successfully printed out but rests were disappear...
This conclusion happened after adding generic acrylic pigment into Maker Juice Sub G+.
Although before adding pigment, bleeding phenomenon occurs on every horizontal/diagonal thin frames then I added pigment.
I assumed this cause is lack of exposure time and raised it up to 10000ms but frames were still broken..
Does anybody have better idea for this?

-----------------------------------------
equipment and setting
Projector: Acer H6510BD/Brightness 50, Contrast 80
VAT bottom is 3mm borrosilicate glass is coated 3mm thickness by glass transparency PDMS(same as Sylgard 184)/sliding system/Bottom up
Z axis: Linear actuator+aluminum extrusion design+Nema23
VAT moving source: Nema17,#define _AXIS_STEP_PER_UNIT increased to 1000 on X axis of Sprinter firmware

Creation Workshop setting
Slice Thickness 0.050
Exposure TIme per Layer 9000~10000ms(tried various time)
Bottom Layer Exposure Time 12000ms x 3 layers
Z Lift Distance 2mm
Z Lift Speed 100~150mm/m Z Lift Retract Speed 100=150mm/m(tried various speed)
Slide/Tilt Value 3

Just in case for Lion head print case was
Exposure TIme per Layer 7500ms

[adambx]

holy crap, you got a madly high exposure there! I have basically the same setup, boro/pdms, and as far as I can remember with MJ resin my Exposure time was somewhere around 3000ms for layers, with maxed out pigment.
The reason why the frame breaks is that it's supported only by 4 tiny struts and the perpendicular section starts all at once. You should try to stand the structure on a corner to gradually build up the frame.

I've attached a picture of what it might look like.

I guss you don't need to have the exposure that high for it to work, this may also improve your PDMS life.

Cheers

[gldi0001]

Thank you for your reply Adambx!
As to refer your comment, I've been many experiment for few days.
Firstly I realized 3000ms cure time wasn't enough in my case even though 5500ms couldn't make it..
I assume my VAT coating with highly transparent silicone might slightly block UV light... It's not exactly Sylgard 184 but should be as same as clearly transparent.
I've also swapped old Sub G+ I added many pigment to new one(contains small amount of former pigment) but somehow it still requires at least 7500ms for solid design like a lion face above and for thin frame design 9000ms~9500ms requires I realized through several experiment.( I changed diagonal design as you attached but result was same.)

My VAT bottom silicone has 3-4mm thickness and realized several dents and crack on silicone surface by too much curing or in response to UV acrylic...
and if the printed object is projected on dent part, the rough surface pattern is printed on the object.

So what I need to experiment is
1.Try new kind of transparent PDMS and thinner than 3mm on a small 2mm plexiglass just for experiment.
2.Try short curing time 5500ms or 3500ms.
3.If 2things are successful swap main VAT coating.

Thank you and I will upload the result.

[hp_]

I've been printing this thin frame bull i got from grabcad
need to lookup the link on that one.

but here is the result. i've removed all the support and put it in my vat just to see the scale of it all.

i must say it came out awsome.

cheers,
hp

[gldi0001]

I have finished experimentations to improve conclusion quality everyday durring a week but it makes me puzzled...

As to tell the result, printed object got more worse... Even supports weren't printed out well.
And no matter what I changed frame object angle, supports arrangement, increasing curing time to 10000ms results were just collapsed objects as attached pictures.
My VAT is made of 3mm borosilicate glass and coated with glass transparency PDMS.
I assumed borosilicate glass is blocking UV light through and then I built a new VAT made of 2mm polycarbonate at bottom coated with different clear transparency PDMS but it required stilll long curing time 8500ms just to print out 1cm solid cube...
I tried several days to frame objects, cube, cup whatever but every result were collapsed.
Then I return VAT to boro which I used former and test printed with some frame object but nothing was printe exept base plate even at 10000ms curing time...
Also I tired to print out square cup but 1 wall always got a hole somehow.
Now I'm puzzled.. I'm using MJ Sub G+ with 1～2% generic powder pigment is used for UV resin nail decorations.
I also upload my DLP printer's working movie if there're some fatal mistake...
http://youtu.be/vq174sgJddA
Please check it out.I need help...

Exposure time I tried 5500,6500,7500,8500,9500,10000ms but nothing was sticked on build area less that 7500ms
Bottom Layers exposure time 8000ms 3layers
Acer H6510BD, eco mode off, brightness 60


Hello hp_ . Thank you for your reply! That's awesome printing! I'm jealous.
I'm impressed to see your flex VAT movie on youtube. Are you posting how to make it?
I really would like to know it.

[Phife]

how old is your resin, how are you storing your resin? do you mix it up well before use?

Seems to me that perhaps it a problem with your resin. Maybe try a new batch or a different brand?

[gldi0001]

I bought resin in this June was opened in August.
So it's not old as long as it's expired just in a month.
Also I always shake resin bottle to mix sufficiently 30 second before using it.
I noticed a sort of commom error on thin wall printed objects since last week.

As attached picture, there's always got a hole around 5mm height.
I increased curing time 10000ms and VAT sliding speed and distance were increased as well.
The result still have a hole on 1mm thickness wall even object was rotated 90 angle manually but still gets hole on 90 degrees rotated same position.
Z axis is moving smoothly without any backlash.

I need to keep experiment...