>I'm only vaguely familiar with resin printing. All about that would be good.
There are probably people out there that have explained everything you'd want to know way better than I could. Stretch your google-fu. For designing parts to be printed there are a few major things that I like to keep watch of:
- The orientation of any critically flat surfaces, such as mating surfaces. These must be facing away from the build plate, or else sagging artifacts will be present.
- Whether or not the part will have cause "cupping" when printed at a said orientation - If you try to print an upside-down bowl, or any geometry approximating one, on an SLA machine, you create a sealed pressure chamber that can cause the print to fail. Vent holes may need to be added, or other changes made to avoid the "cup".
- Generally what orientation to print the part in. This is determined by many things: The positioning of mating surfaces or functional features (want to be kept away from supports at a positive angle), what areas need good surface finish (these also need to be kept away from supports, unless you want to spend all day sanding), how many separate "islands" the part will form on the printer as (if you print a "V" shape with the top towards the build plate, the 2 sides of the V are separate parts until the end of the print. This mating will cause some amount of deformation, and small extremities printed this way might fail altogether), the print time, and more.
SLA is not ideal for mechanical parts, and it mostly comes down to trial and error.
>How you worked out the design process.
I believe I started by importing a reference drawing of RiCO as well as a mesh someone made into Fusion360. Then I loaded in a 9G servo model and laid out where all the servos could fit. Once I knew what joints I could have and where the motors could go, I more or less modeled her from the outside in - first creating a solid form, then hollowing it out to create a clamshell and adding the pivot joints, servo mounts, screw bosses, and other internal features. These parts were inspired by how the injection molded housings for power tools and small appliances are designed. This relatively primitive design doesn't have bearings for each joint, only plastic-on-plastic fits. They will wear out eventually, but this was designed more as a "first build" project, something cheap(er) to put together. If you do build it, put some grease on the joints to prevent early destruction. The cheap RC servos I picked will almost certainly break first (and they don't have real bearings either). I really encourage you to load up the CAD file I posted and look through it, a 3D model is worth a million words.
>How did you create the mold for the silicone, then pour it/fashion it.
I posted some details about the material on the old thread, check that out. I took the mesh file for RiCO (the head is the only place I used an existing mesh model instead of re-drawing in CAD) and, in Blender, created a 2 part mold like you see here. I don't recall the exact process I used to create the mold, however I do remember it being tedious. A lot of use of the "boolean" modifier. Note the pink pieces and how they're covered in cones that "lock in" to the molded silicone, these pieces have screw holes on the other side to allow for easy mounting to the main assembly. Everything here was FDM printed except the gray piece which was SLA for a smooth finish.
>More about how you plan to articulate her.
For everything I've completed look at the CAD model, it should be self explanatory how it works. For the non-completed parts: the waist I plan on having a 2 or 3 axis tilt mechanism, similar to the neck but stronger to handle all the weight, and surrounded in a silicone casing to mach the reference. I don't even know if it could fit, I haven't gotten to designing it yet. Any plans beyond that are just ideas at this point.
For electronics: Motion control is accomplished via ESP32 (mainboard with camera mounted in the chest) receiving commands from a host PC via TCP over wifi. The commands are stored in a buffer. When a special playback command is sent, the last command from the buffer is converted from direction-velocity to a sweeping PWM signal sent to a pair of PCA9685 servo drivers. Simultaneously, another thread on the ESP32 is broadcasting a camera feed back so the host PC could do object/person tracking to facilitate user interaction. (Note no PC software has been written yet!)