A major benefit of the P3 Origin One from Stratasys would be the versatility displayed by its open material license (OML settings). Most importantly, the freedom of creating custom settings and material profiles for optimizing prints with validated and non-validated photopolymer resins.
What is an Open Material License?
An open material license allows users to print non-validated materials from third party photopolymer companies. By using the OML the user is given the ability to print resins that do not have validated settings readily available in GrabCAD Print. Therefore, the OML opens the door for the enablement of creating custom settings and material profiles that optimize printing based around resin chemistry/viscosity, green state properties, desired part geometries and improved build times.
What is the Green State?
In resin 3D printing, the printer will complete a build and its part(s) will need to be taken off a platform. After being taken off the platform, excess resin needs to be cleaned off the parts before they get put into a post curing apparatus (PCA) for its final rate of UV exposure and then sometimes a thermal post cure. Typically, when photopolymer materials are printed, they are not cured entirely upon build completion which is why they need to get more UV exposure in a PCA. The time in which a part has been built or grown, until the time it enters the PCA is called “the green state.” If a build is only halfway complete, the half of a build that has been completed would contain parts that are in the green state.
When printing with an origin, parts in the green state are typically still being submerged in resin or may be entering and/or exiting the resin surface before the build is complete. This can bring a few variables into play, for example, what are the green state properties of the material you are using? How can the print parameters of the material you’re using influence your geometries early throughout the print? What is your resin level?
Under the OML, you’re given the ability to control your resin settings and optimize the P3 printing process to accommodate problematic variables that come with printing complex geometries in various viscosities.
Important Resin OML settings:
The exposure duration can be an important setting to develop because you’ll want to ensure that you are curing the part properly layer by layer. The first layer can be adjusted around the amount of surface area you are trying to adhere to the platform and how well you’ll need it to hold based on your parts geometry. With the burn in layer typically being much longer than the model region, finding the exposure rate of the transition layers is important but can be developed from your initial burn in rate. Going from burn in layer directly to model region typically will not resolve, so you will need to slowly work your way out of burning the material and into a standard green state cure rate using your transition layers. The exposure duration in the model region is important for sidewall quality in the final part and will predominantly be the average rate of each layer.
Approach Distance and Speed
Approach distance/speed can be important when enhancing accuracy or adjusting for fine print qualities along with optimizing build times in some instances. The approach can be very influential because it determines the distance and speed of the platform as its travels through the resin before approaching its proper height above the glass prior to receiving the next projected layer. If your approach is too fast, then you could sacrifice feature resolution or quality. If it’s too slow then you aren’t taking advantage of optimizing your build speed. For example, if you are printing with a viscus material, something like 402 that has a 14,500 cP, then you’re going to want to slow your approach down depending on the geometry of your part. This will allow your thin/smaller features to travel through thick resin at slower rates prohibiting the viscosity of the resin from influencing part quality or geometric resolution. Resulting in the *final part to be free of undesirable supports demonstrating its well-known, high quality surface finish.
Separation Distance and Speed
Separation distance/speed is just as important as your approach. In this instance, separation is the exact opposite of the approach, it’s the distance and speed in which the platform separates from the Teflon surface after printing a layer. Therefore, when the platform pulls up off the Teflon, a slight suction forms around the build head as it pulls resin in toward the center. The rate of suction is based on the separation speed vs. resin viscosity. This can initiate failures or disturbances in prints by disrupting features with trapped volumes or small/thin features that are difficult to support or are ineligible for thick supports given the desired part orientation. In conclusion, high viscus resins will need much slower approach and separation speeds while lower viscosity resins with rigid green state properties can be much faster for improving daily turnover rates.
With the focus here being optimization, the OML was certainly created for an increased user experience with detailed end results, exceeding expectations. Based on first-hand experiences adjusting settings with OML can not only provide great overall results but can also optimize tight tolerance callouts, resolution, while also opening the doors for any DLP photopolymer resin.