Now that a lot of you are receiving your Photons, I thought it would be useful to share some of my workflow and findings.
Important settings in bold. Once the model is ready, I use Netfabb for adding supports. There are different tiers of the program, but if you download the trial you'll get premium features for 30 days, then it will revert to the free basic tier. Looking at the features by tier, the basic should include everything we need anyway. Netfabb is lightyears ahead of the Photon Slicer when it comes to adding supports. Since its free, I highly recommend using it!
I export my models from Maya as .obj and import to Netfabb. Upon import, it runs a repair script to clean up degenerate triangles, fill mesh holes, and join touching shells to a single part. Think of it kind of like vacuforming your model.
Once the model is in Netfabb,
I position so the lowest part of the model is 4.5mm off the deck. I find this is the optimal distance to allow support platforms and trees to form and normalize before the first part layer.
When you enter "Generate Support" mode, Netfabb will analyze the part and highlight all bottom/overhang surfaces in red. (Yes technically top/underhung surfaces because it prints upside down from this orientation, but you get it).
You can specify the value for critical (red) and caution (yellow) angles, I use 35 and 40 respectively. Zero is a dead overhang, 90 is a wall. Anything above a 40 degree angle can "
Brick Balance".
Once you have your critical angle surfaces generated, you can build scripts to generate supports for a given surface zone, or add individual supports manually. You can also adjust almost every attribute of the supports, whether scripted or added manually, and independently of other supports.
So far I've just been adding supports manually by clicking on the model where I want the support to connect, right clicking on that anchor and choosing "Create Bar". Here are the attributes I use by default, and I'll adjust them individually if necessary.
Bar Contour: Solid Bar
Distance to part: 0.00 to -0.20mm
Width on Part: 0.30mm (For areas that will be closer to the edge of the build plate, I'll use
0.40mm, and sometimes 0.50mm. This compensates for bulb falloff)
Width on Platform: 1.00mm
Right Angle on Part: No (sometimes Yes)
Pad on Platform: Yes
Pad Width: 10-12mm
Pad Height: 0.40mmOnce the supports are added, there is a manager to convert the support tree to its own .STL I then select the Support STL and the Model and export the two parts as a single prepared .STL for DLP.
I also save the Netfabb project as it will allow me to make minor adjustments to the supports if necessary. Unfortunately, if the part must be re-oriented, you'll have to start supports over from scratch.
Now I open the Photon slicer and import all the prepared STLs I want to print in one run, position them and set my layer and exposure settings. Hit Slice!
When the slicer is done, it will notify you with the time the print will take. You can choose "Ok" to close the window, or
"Show Preview". The preview opens another window with a slider that lets you scrub through each layer and confirm all details are present and check for floaters. I also use this to judge if too much is being exposed on a given slice in relation to the amount of supports under it. Too much at once will risk sticking the layer to the FEP, ripping it away from the supports when the build plate moves.
If anything needs to be addressed, it's back to Netfabb to re-orient and re-generate supports.
Yes, this takes awhile as you're basically starting over with the supports, but you learn quick how to do things correctly the first time. And the bright side is once it's finalized, it's finalized.
And there it is, the part is finally ready for the USB stick!
I know it sounds like a lot of work, but after 4 or 5 parts, it only takes a matter of minutes to build a support tree.
