Been working on/off progressing with the Ender5 plus. I have actually made a decent amount of progress so this post might be longer. My focus has been deciding how all the components would be installed. In my head, this is the most important detail is planning all of this ahead of time so that everything plays well when finished. I settled on the overall layout of components for the hood and the front panels. I spent some time redesigning the extruder mount and made a first pass at testing the thermals of the enclosed hood.
Hood
If I had to break down the printer into individual parts there would be three; the base, printer frame and hood. I have been focused on getting the hood done properly first because it allows placement of other components like the printer frame. Seeing what space is available for placing other parts just allows me to settle on one Having this done opens a lot of progression paths for multitasking.
I am trying to be cost conscious where I can, but functionality is also important. The hood is an extruded aluminum frame with PETG sheets. I ordered thinner sheets to keep the hood lighter and to avoid breaking the bank. The downside here was that there was a considerable air gap between the frame and these sheets using screws for mounting.
The solution? TPU angled wedges. These would compliment the bending of the sheets along the edge of the frame and slot into the extrusions. Unfortunately it took about a month to get one of the other printers to print TPU consistently. I had used TPU in the past, but not on mass scale like I wanted to do here. My problem ended up being a combination of extrusion multiplier and needing to constrain the filament path. Luckily the Di3+ came in clutch with its titan Aero and a quick mod to constrain the filament path properly. Once printed and installed, the air gap is basically gone and the sheets are properly installed.
I went with dual doors placed at a height were prints could be removed from the printer when the bed is at its lowest position. Two doors allow for use of the thinner PETG sheets without bending too much when being opened. These actually turned out pretty good and I even managed to get the same hinges used on my first printer enclosure. Not having full height doors was intentional. The strip above the doors is small enough to be sent through my relatively smaller CNC. This allowed the cutout of fan holes to be used for cooling later.
The frame locks to the base with printed tabs and can easily be removed. So far the weight of the hood is great and remains practical for disassembly.
For the frame, there is still a small list of items that need to be finished. The Octoprint camera will need to be mounted. Fan and air intake grills will need to be mounted. LED strips will need to be added to the already installed LED bars at the top of the frame.
Thermals
Stay with me here... temperature control is a bit involved.
As a very basic test, I decided to place the 100 watt heater loose on the enclosure and see where the maximum temperature ended up. Temperatures rose to 33c and leveled off. Not exactly an amazing result where the goal is maintaining ~50c when printing high temperature plastics. This indicates the minimal air gaps in the doors and frame are the issue, or more likely; the hood's thin PETG sheets transfer a high amount of heat to the room.
There are a few variables when it comes to maintaining enclosure temps. During normal printing, the extruder and more importantly; the heated bed can produce a good amount of heat. The bed on this printer is about 500 watts, so should contribute to higher temperatures depending on the filament bed requirements.
Ideally while printing high temps plastics like ABS, ASA and PC, you want to filter the air properly with HEPA filters and activated carbon for odor control. You also want to keep negative air pressure inside the enclosure by sending a portion of the filtered air outside the enclosure. This ensures that non-filtered air doesn't waft outside. The downside is that this actively cools the enclosure by trading filtered heated air for cold air.
Overall, I expect heating will fall short of 50c with the thin PETG sheets and the filtering cooling system running. To fix the problem I will be installing reflective foam core insulation between the PETG sheets and the Aluminum frame of the hood. I might also need to seal the air gaps where the doors contact the frame.
While printing with lower temp filaments like PETG and PLA my experience has been that you want the enclosure temperature much lower. Just above room temperature is great, otherwise the part cooling fan is not as effective and the extruder fan isn't able to keep the cold side of the extruder cold. This causes "heat creep" which results in the extruder jamming after printing for some amount of time. This plagued me when I set up my first enclosure.
Luckily Heavy Tombstone should be immune to heat creep due to the liquid cooling system that replaces the extruder fan on other printers. Even while running 50c inside the enclosure, the cold side of the extruder's heat break should be close to room temperature.
The insulation installed to increase ambient temps for high temp filament fights us here, so an active cooling solution is needed when printing low temperature filament. Luckily the temperature controller we are using has both heating and cooling relays.
The thermal issue I always get hung up on is getting a cooling solution that doesn't need an open fan path that would counter the active filtering we are trying to do when printing with high temperature filaments. The old enclosure does have an open fan path that does nothing while printing ABS, but this does allow wafting during normal operation. The old enclosure also does not have a HEPA filtering system.
The solution here will either be a one way finned fan exhaust or using something like a piece of paper towel as a permeable heat/air barrier when the fan isn't running. There are pros and cons to both of these methods, and the pick will come down to how effective each is when the printer is otherwise finished and temps can be tested while all components are running.
Extruder Mount
The extruder block is a bit different due to being liquid cooled. I also opted for a genuine bon-tech extruder in a somewhat direct-drive mount. I also incorporated the bltouch mount to the front of the assembly. I plan to re-use the bttouch that came with the printer. I assume I will need to make a modifications to add mounting points for the liquid cooling tubes and wires.
Front Control Panels
The front control panels super important to make the printer easy to use. Designing these to provide the right feedback on printer status and control defines how easy it is to start/monitor prints and to debug problems.
I am limited currently by the print bed sizes of the other printers. As much as I wanted one big long control panel, this wasn't possible. I settled on a modular system where the plates could be swapped out if changes to the components were made. The panel frames are also able to be removed, although I don't think this will be too useful once the cables are run properly. I expect these panels will remain mounted if the printer is moved.
I went with analog voltage/amp meters to display the voltage of the AC input current and voltage as well as the DC voltages of the regulator outputs. The main reason I chose these is because they are hot af, and because they are not backlit. Too many lit LCD screens on a device can be obnoxious in my opinion. The Main power switch is overrated, but is also dual channel. This will allow cutting of wall power to both the Neutral and Line wires at the same time.
The three upper panels will be for recessed control switches to enable different system components as well as control components. Restarting the Raspberry Pi 4 hosting Octoprint will be simply the flip of a switch for example. The switch that controls the power to the printer board sits next to the printer LCD screen and recessed so it isn't easily bumped by accident.
Covered cable trays lead back to the rear of the printer where wall power and the regulators are mounted.
To Do
There is plenty to get done, but at the foremost is the AC wiring and cabling to feed the regulators. I have also been cleaning and the workshop needs a thorough organization spree. Designing the LED Arduino control board and mainboard/heatbed mosfet enclosure also need to get started.
Wiring in general has not been done yet and finding the limits of what can be wired where is important for the wiring harness of the printer frame. Starting with the mains power and working out from there makes sense and allows components to be turned on and tested as they are added. The printer frame harness will be a bundle of wires in motion for the X and Y axis and the extruder. It also needs to incorporate the liquid cooling pipes and the filament path. Its pretty important that this motion does no wear any of the wires or tubes.
Cleaning is cleaning. I have had some issues finding component I bought a few months ago for this project and tracking down the right box has been demotivating.
The enclosure's LED strips will be controlled by an Arduino nano. I need a small proto-board with buttons and potentiometers made and mounted to the third upper control panel so that the LEDs cab work properly.
There are a few critical components like the printer main board and bed mosfet board that need to be actively cooled and enclosed. I'm still deciding just how to mount these.. I really don't want the upside down on the bottom of the enclosure because access will be pain, but I also cant have them in the heated enclosure due to temps, so I might do something clever to have my cake and eat it too.
As a side note, in the last post I said this might live in the basement... there is absolutely no way this thing is making it down my basement entrance.