The focus this week has been wiring primary power so that I can actually start testing other things as they are added to the enclosure. AC power is more or less done, with the regulators and front panel meters wired. The insulation for the hood arrived Friday and was installed/tested. Crossbars had to be installed on the interior of the enclosure and the Hood LEDs were installed. Ive also got a new tool coming to help with the heat testing of the enclosure.
AC and DC Wiring
Wiring primary system power was just a bit involved, but the lack of power has been holding things up. I focused this week on getting as much of it done as possible and getting the front panel meters running. After powering up the regulators, its obvious I will likely need to look into replacing the cooling fan on the Meanwell 24V unit. It sounds like a small vacuum cleaner.
The regulators themselves do not have the pin density for all the components, so two distribution blocks were installed near the front of the enclosure. The only components that will not be wired directly off of these will be the 100W AC heater, Print Bed Mosfet, and the SKR mainboard. The latter two will be directly wired to the 24V regulator which has three pairs of connections.
All the front meters work as expected and the primary "welding" switch with dual channels works well if not overrated and is a clear on/off visual indicator. The temperature controller is now powered with the temperature thermistor connected, but the relays have yet to be populated.
Hood Insulation
The insulation for the hood is about as what I expected. Aluminum sandwiching foam core. This is pretty flexible, so reinforcing it with the existing petg panels seems to be a good move. It also looks pretty good in my opinion, even if it limits the ability to see prints while they are happening from the sides. I have installed it on all hood surfaces aside from the front at this point.
Now that I have the temperature sensor installed and working, I can check the thermals inside the enclosure properly and stop using a cheap Chinese tachometer that happens to have a temp sensor built in. It wont be apples to apples with previous tests, but much more accurate.
Running the 100W heater powered through the enclosure door; temps eventually leveled out at 107F (41.7C). This is substantially more than 91F (33C) obtained before. Ambient air temperature was actually colder during this test by about 5F. Again, this is without the printer itself contributing or the HEPA filtering system running. Overall I am pleased and more can be done later to seal up the front of the enclosure where the doors meet the frame.
Hood Crossbars
The TPU wedges to shape the PETG (and now foam) panels on the side of the hood guarantee that the panels form an inward concave shape. I found it to be move extreme that than expected and came into contact with the X-Y gantry as it would Travel along the X axis on the sides of the enclosure.
I ended up deciding to reinforce the enclosure along these surfaces with some extra 1515 extruded aluminum I had left over from the old open air Bitcoin mining computer case that was retired and rebuilt into a DOS gaming rig. The extrusions were cut with the help of my grandfather (he has better tools for that kind of thing) and installed while the hood was being worked on this weekend.
The XY Gantry can now move freely and has plenty of room on either side of the enclosure. The rear of the enclosure now contacts the stepper motor that drives the X movement, but the soft foam surface seems like if wont cause much problem. If nothing else, I will need to watch this and make sure it does not overheat because of this insulating contact.
Hood LEDs and Camera
The LEDs have been the one thing I have been kicking myself for not getting done sooner. The excuse I had been using was that power was not done and there was no point. With 5V power run, I really don't have an excuse now and decided to commit to at least getting the lights mounted.
When the hood was torn apart to install the crossbars, I decided to solder LED strips into place and also replace the part that would be used to mount the camera. Getting the camera in place looks good. Having it mounted to hood instead of the printer frame should reduce the amount of vibration as the printer is running.
The wiring is a little odd at first glance, but its done this way intentionally. The serial data line is in a complete circle, while the power and ground is split in two directions. This makes the 80 LEDs individually addressable, but the voltage drop across LEDs in series is mitigated by half. This is made pretty easy due to the circle arrangement of the segments.
I am using the fursuit LED control board I set up last year for testing. Apparently the control signals are the same between the two LED types I bought for each project. The logic of the fursuit controller is much more advance than what this enclosure needs. I took some time last night and partially programmed and soldered up the control board for the enclosure. This wont need eeprom memory or blutooth module, but I will be adding potentiometers for intensity and pattern controls if I decide I want to rave while printing.
These light suck a decent amount of power while turned all the way up. Having the dimmer set to a potentiometer gives the option for fine adjustment. Overall the lighting is leagues ahead of the old enclosure and the build plate is lit from all sides. The print head cant block the light regardless of its position. The clear PETG covers diffuse the light well enough so that its not too harsh at specific points.
I am concerned about heat issues with these LEDs, but if I have issues losing LEDs/flickering I might redesign the covers to let air circulate better.
Up Next
I need to mount the HEPA filters units and the 100W heater. The real trick will be deciding where it makes the most sense to for these functionally. The housing for the SKR controller, heat bed mosfet, and rpi needs to be designed and mounted. I also need to formalize a path for the liquid cooling, wires and filament to the hotend.
There needs to be a path for wires go in-out of the inside of the enclosure. I have not decided on how exactly to do this yet. I think this will be apart of the mainboard enclosure in some way, as a lot of the wires need to go into this anyway.
I have ordered an iPhone Flir One Pro thermal camera. This will allow me to get a better idea of how thermals are behaving inside the enclosure. It will also help debugging bad wiring which does worry me when dealing with relatively higher currents. If one of my solder connections has a problem, it should generate more heat and I will be able to pick this up on the thermal camera when the printer is running. Its a useful tool and compliments 3D printing in general.