Now it’s time to see the parts that I had to print to make this thing work. The list is as follows:
- Camera horizontal mount
- Camera horizontal roller
- Camera cradle
- Film gate mount and servo clamp
- Film gate clamp, gate fastener, and film gate switch mount
- Film gate desk clamp
- Battery box and lid
- Film spool frame
- Takeup spindle
- Takeup spool
- Film transport switch mount
- Lamp mount and light tube
These are numbered in this image, which is a Blender render.
The print jobs are all contained in one Blender file, and they are then exported into the STL file format in batches. The batches, such as the film gate mount and associated parts, the horizontal mount and takeup spool spindle, and the takeup spool with the film transport switch mount, take about 2 to 3 hours to print each. The largest print is the film spool frame, which looks amazingly much like the trebuchet I made way back. It is indeed the same object – why redesign when you can reassign? Especially since it takes almost exactly 5 hours to print.
In retrospect I managed the project with a minimal amount of redesign. The film gate mount was the only part that I redesigned and printed 4 times, and that because I at first had not accommodated the film gate servo on the same object (for some godforsaken reason). Also, the movement of the film gate casts a shadow on the film, and I couldn’t move the lamp far enough to the side to prevent that, so I had to widen the light path as well as reassign the lamp stand to a new location on the baseboard.
You should note that in addition to these printed parts, I reused some bits and pieces left over from previous jobs. The film transport switch, for example, needed a little bridge on which to glue the switch, so I rummaged through my failed prints box and found just the right piece. You shouldn’t throw away prints that can be used for supports and other non-vital roles, it’s better to have them handy in case you need some. ABS is also easy to saw and file to fit into various places.
Printwise these are not very interesting. All of them are ABS, with 20% rectangular infill, and there is no need to have the infill at a larger setting. Even the camera cradle, whose horizontal floor is rather important for the stability of the system, works just fine with that fill. Detail-wise, only the switch mounts are very critical. They needed to be of exact measurements to help manage the switches to operate at the right moment. The film gate mount has holes for all screws needed, ie. the gate clamp and servo clamp had holes printed directly in place, which makes for easier assembly.
Attaching the film gate to the servo that runs it was a little hard to figure out. In the end I managed a good connection by printing a short rod. I took a servo horn, clipped off all the but the center of it, and glued the printed rod into the servo horn centerpiece.The film gate has a brass gear at the end of the operating rod, so I took some shrink tube (the white tube in the image), inserted the rod into it with some cyanoacrylate, and pushed the end of the tube onto the gear. A little hot air crimped the tube on the gear and the connection has stayed firm ever since.
The red and blue part in the image is the switch lever. Again, a little crimp tube seems to work fine – I just took some single-wire lead, twisted it into a stiff rod, then hung this on the side of the film gate. The red crimp tube holds it in place. The blue part merely makes it stay together and it was also easy to cut into size when configuring the proper operation of the film gate switch. I did have some trouble with a persistent shadow that the red part threw onto the film, but I got rid of that by realigning the lamp assembly a little off-axis.
If you plan to build one like this, I will post the .blend and STL files on Thingiverse in the near future. You may want to wait a little more so I can post the fourth part of this series which describes the wirings and programming of the Arduino robot that runs the whole show. I am also (slowly) writing a tutorial of this to be posted at Instructables.com.