3DO nozzle camera mount for Prusa Core One - 5cm FPC with LEDs

This is my first stab at a mount for the 3DO nozzle camera for the Prusa Core One, designed for the 5cm FPC cable with LEDs. The LED/camera end of the FPC cable is held securely with a friction fit and the PCB is held on by two M2 bolts via two standoffs. You may be able to get away with just screwing the bolts into the print but I would recommend using longer bolts and securing them with nuts on the other side.

The view from the camera is slightly obstructed by the hotend and its silicone sock on the left and by the corner of the print fan duct on the right. I did my best to minimize the obstruction by rotating the camera mount somewhat to the right.

If you want to see this mount in action, printing the final prototype, check out my highlight on Twitch. ^_^

If you want a mount that protects the PCB more than this (which I would recommend), check out my new mount which uses the 25cm FPC.

Printing

I have printed this model many times with the base of the camera holder on the print bed, with a 5mm brim, and organic supports. I would recommend blocking supports inside of the tubular standoffs as they tend to get stuck in there and they aren't really needed. I also turn on supports only on the build plate. See the included 3mf file for my recommendation. You can also print the upper part with the M3 bolt holes without supports if you want.

Usage

To use this mount, slide the LED strip of the FPC ribbon down through the large hole and carefully push it into the camera holder. There are small hooks on either side that the edges need to slide into and the further down you push it the more tightly it should hold as the walls slightly move inwards the further down you go. Ideally you should be able to push the LED strip down to the bottom of the holder as the camera focus is tuned for this exact location.

If you find the fit too tight, open up the FreeCAD file, double click on the Spreadsheet entry in the model tree, at the very bottom, and reduce the led_strip_hugger_fraction value in cell B1 to a smaller value, such as 0.5, press enter, wait for the model to recalculate, then re-export the model (Click Camera Mount, File menu, Export, then choose STEP or STL). If the fit is too loose, try a larger value. This is a fraction, though, so going over 1.0 isn't recommended.

Once the LED strip is firmly held, attach the camera and PCB to the FPC. When mounting the PCB you can have the ribbon cable on either side of the mount. The pictures above show it below the PCB and behind the camera holder. It also will fit fine behind the PCB, above the camera. I opted for the ribbon cable outside as inside it would be directly exposed to more heat from the hotend.

Orient the PCB so that the ribbon cable connector is pointed downwards and line up the top screw holes with the two standoffs on the mount. Attach it with an M2-12mm bolt on the left side and an M2 hex nut on the back, then an M2-8mm bolt and hex nut on the right side. Tighten until it just doesn't move but don't tighten too much or you may damage the PCB or the mount.

Connect the USB cable to the PCB, then attach the mount to the heatbreak fan on the extruder. Remove the top bolt on the fan, then attach the mount with a new, slightly longer, M3-22mm bolt. Leave it slightly loose for now. Remove the bottom bolt from the fan and connect the mount with another M3-22mm bolt, tightening fully. Tighten the top bolt fully.

Route the USB cable up and through the velcro ties holding the extruder cable bundle and PTFE tube, along the metal arm, then out of the printer in whatever fashion most suits you. Running it through one of the cable holes at the back of the printer is recommended. I got the 3.5 meter high temp USB cable from KB3D to have extra options for routing to a device. Make sure you get one long enough for you.

Note that the current mount leaves the USB cable hanging in front of the heatbreak fan. This might be dangerous and might cause damage to the cable over time. You may be able to route it to the side around the extruder but be careful not to pinch or pull the cable as there is no strain relief in this mount. Leave enough slack above to allow the cable to move as needed for all extruder positions. When in doubt, test!

Clearance and Parameters

The clearance in the Core One is very tight so the PCB ends up only a millimeter or less away from the front bar of the CoreXY frame and the LED strip underneath it. I very highly recommend that you carefully move your extruder manually to the front of the printer to test the tolerance yourself after mounting. If you fail to test before running a print with the mount attached you may end up bashing the PCB against the metal bar and breaking it. I cannot be held responsible for any damage. I am also not entirely sure of the long term durability of this design or the implications of leaving the PCB uncovered. Unfortunately there is no way to cover the PCB with this design as the tolerances simply do not allow it.

The included FreeCAD file is parametric, with all of the measurements defined in the top sketch, Parameters, so if you want to play with the camera angle or tolerances you're welcome to but be very careful with the PCB mount if you do. As it is now the clearance is very tight so any change needs to be tested carefully to ensure that the PCB isn't going to hit the front bar of the CoreXY frame or the LEDs underneath it. Without the PCB mounted there everything should fit fine with just about any values but as always make sure to test. There is also one value in the Spreadsheet that you can modify to change how snugly the camera holder grabs the LED strip.

Inspiration

For the camera holder portion specifically I was inspired by this make by Clamikra, a 3DO Nozzle Camera mount for the Prusa Mk4/Mk4S. I created my own holder myself, though, with only some similar features and not using any source files from that make, so I would only call this an inspiration rather than a remix.