Ember has 34 different print settings. This article will walk through the different parameters to help you optimise the settings for your prints.
Step 1: Material
Each material has different properties and therefore requires different print settings.
If you are using a material not listed in the drop down menu check out this excellent Ember Instructable for guidance on how to determine the print settings.
Step 2: Layer thickness
The relationship between layer thickness and exposure time can be roughly approximated as:
ln (Time to cure) = a0 *exp ( a1 * layer thickness)
Where a0 and a1 are constants to be determined experimentally for each material.
If you are changing the layer thickness from the default settings check out this Ember Instructable for guidance on print settings.
Step 3: Variable Strength Exposure
Large features (>20mm^2) tend to cure quicker than small features (<1mm^2). Checking the variable strength exposure box varies the intensity within a slice (left hand image) so that large and small features get the optimum exposure.
If you are only printing small features you could turn the variable strength exposure off (right hand image).
Step 4: Definition of Layers
Three types of layers are defined in the print settings.
- First Layer
- Burn-in Layers
- Model Layers
This is the first layer that is built on to the build head. For a successful print, it is crucial that the first layer sticks to the build head. You can specify settings for the first layer to promote adhesion.
These are the layers after the first layer. You can specify between 0-n number of burn-in layers. Burn-in layers are used to further increase adhesion to the build head.
These are the layers after the burn-in layers. Settings should be selected to give optimum performance for the resin and your geometry.
Step 5: Exposure time
The exposure time determines
- the layer thickness: thicker layer require longer exposure times
- the minimum feature size: smaller features require longer exposure times
There is balance to be struck between exposure time and resin tray jamming, check out this excellent Ember Instructable for further guidance on how to determine the right exposure time for your application.
Step 6: Slide Velocity
The slide velocity (in RPM) is the speed at which the resin tray rotates. You can independently change the slide velocity for
- Separation: Immediately after the layer has cured the resin tray moves clockwise
- Approach: When the resin tray returns to the print position
Two scenarios where you might want to changing the slide velocity are
- A viscous resin (>100CPS): a lower slide velocity (<12RPM) will reduce shear forces and therefore the likelihood of resin tray jams
- Large cross sectional areas (>30mm^2): a lower slide velocity (<12RPM) will reduce shear forces and therefore likelihood of resin tray jams
Step 7: Z Axis Overlift
The Z Axis Overlift is the vertical distance (in microns) that the build head lifts up each separation cycle.
Step 8: Z Axis Velocity
This is the vertical speed (in microns/s) at which the build head moves. You can independently change the velocity for
- Separation: When the build head moves up by the overlift distance
- Approache: When the build head moves down by the overlift - layer thickness distance
Step 9: Angle of Rotation:
The angle of rotation (in degrees) is the angle through which the resin tray rotates as is separates and approaches. This is fixed by the hardware at 60 degrees.
If you have modified your resin tray you can change this parameter.
Step 10: Wait
Before Exposure: Immediately after the resin tray has rotated counter-clockwise and after the build head has returned to the exposure position you can can add a pause time