Poor print quality
Posted: Sun Aug 02, 2015 8:38 pm
Hello guys!
I have had a problem with my freshly developed Sla printer. Everything seems to be normal half way through the print and then it won't handle the the remaining half. The printer is simple, only a moving z axis with no tilt or slide option for the VAT.
You can see that the first half of the hole/circe on the cube(10x10x10mm) is fine, then it starts to become a mess.
I have an Optoma Hd65 DLP projector with no colorwheel. There seems to be no problem with the anti-stick coating.The VAT is coated with sylgard 184.
The resin level reaches 3mm in the VAT. Bought resin from makerjuice. Standard sub g+ with no pigment. 8 months old
Gcode seems alright all the way. The print height(z axis) corresponds to the 3d models size and its proportional to the x and y axis. The focus from the projector has been adjusted several times, with different focal lengths but no success. I have tried a number between 1-5 mm in lift height between layers for 5 test cubes. Lead screw is really solid and the nut is anti-backlash.
Motor and driver never gets hot. No missing steps or unusual sounds. Layer slices are timed evenly through the print.
I have tried all different types of exposure times but the same problem remain. I cant go lower than 3600ms or the layers wont cure properly. haven't tried anything over 7500ms. Buttom layers are 4 x 20000ms
Same thing goes for the lift speed, tried many options.
The only thing that has been constant through all tests is the retract speed which is at 100mm/m. But I dont see why that
would make any difference. The resin get at least 1 sec to cool down its movement before the layer exposure.
I get the feeling that the resin cures to thick at the end and the only reason it doesn't show before the second half is because each layer becomes increasingly larger at that point and allows the uv light to cure resin through a level it isn't supposed to.
I would really appreciate some help from an expert because I cant find someone else with this problem anywhere, right now I am running out of ideas and I have no clue what to do next : (
I have had a problem with my freshly developed Sla printer. Everything seems to be normal half way through the print and then it won't handle the the remaining half. The printer is simple, only a moving z axis with no tilt or slide option for the VAT.
You can see that the first half of the hole/circe on the cube(10x10x10mm) is fine, then it starts to become a mess.
I have an Optoma Hd65 DLP projector with no colorwheel. There seems to be no problem with the anti-stick coating.The VAT is coated with sylgard 184.
The resin level reaches 3mm in the VAT. Bought resin from makerjuice. Standard sub g+ with no pigment. 8 months old
Gcode seems alright all the way. The print height(z axis) corresponds to the 3d models size and its proportional to the x and y axis. The focus from the projector has been adjusted several times, with different focal lengths but no success. I have tried a number between 1-5 mm in lift height between layers for 5 test cubes. Lead screw is really solid and the nut is anti-backlash.
Motor and driver never gets hot. No missing steps or unusual sounds. Layer slices are timed evenly through the print.
I have tried all different types of exposure times but the same problem remain. I cant go lower than 3600ms or the layers wont cure properly. haven't tried anything over 7500ms. Buttom layers are 4 x 20000ms
Same thing goes for the lift speed, tried many options.
The only thing that has been constant through all tests is the retract speed which is at 100mm/m. But I dont see why that
would make any difference. The resin get at least 1 sec to cool down its movement before the layer exposure.
I get the feeling that the resin cures to thick at the end and the only reason it doesn't show before the second half is because each layer becomes increasingly larger at that point and allows the uv light to cure resin through a level it isn't supposed to.
I would really appreciate some help from an expert because I cant find someone else with this problem anywhere, right now I am running out of ideas and I have no clue what to do next : (