I decided I wanted a larger printer a while ago and began looking at options. In my search I ran across Tech2C's video and I knew I found my project. I settled on a 300x300x300 build size with a dual Z axis implementation as that seemed manageable and meant I wouldn't need to worry about the larger cantilevered bed tilting.
Dimensions of the 2020 aluminum extrusion:
4 x 440mm (X)
4 x 440mm (Y)
4 x 555mm (Z)
2 x 420mm (Bed) (these should have been longer to avoid needing customized parts... 435mm?)
2 x 235mm (Bed)
I also ordered an additional 4 rails of 440mm to allow a build space at the bottom of the printer. The lowest rail is at the bottom of the Z rails while the mid rail is spaced 50mm above the lower rails. this configuration allows for a bit over 300mm of build space.
I managed to source, indirectly, 10mm anodized aluminum tubing from Germany. The only problem was they don't ship to the USA, so I had a coworker in Germany buy it and reship it to me. That should arrive in late May.
The build is configured with dual T8 lead screws and 4 8mm guide rods for the Z axis. This is powered by independently driven dual steppers via the RAMPS board. The Y axis was upgraded to 10mm rods due to the increased length.
Due to the size of the heated bed I chose to go with a dual supply configuration. The Arduino Mega 2560, RAMPS & all the other electronics is powered by a 12V 30A supply, which is overkill, and the MK2a Aluminum bed is powered by a separate 24V 14.6A supply. The current on the 24V supply is limited by restricting the duty cycle in the configuration.h file to 80% of max value so it doesn't exceed the rated value. Both of the PSUs are separately switched and also run through V/A meters to monitor system status.
All of the electronics is housed in the bottom of the frame. Each component is attached to the bottom plate (a scrap piece of diamond plate which I picked up for $10 and happened to be the right size) using M3 screws and brackets found on Thingiverse or custom designed / printed. I plan on putting some sort of a cover over the electronics in order to keep out the junk but for now it's open. The bottom perimeter is enclosed on all 4 sides using multiple custom designed lattice pieces which simply snap into place using the channels of the 2020 extrusion.
I encountered a few issues during the build process, none of which were insurmountable. These included
- It was necessary to estimate how long the bed rails needed to be for a dual Z axis build. I wound up allowing 10mm clearance on each end but in reality that was way too much. I got the extrusions to work OK by making slightly longer Z guide rod supports and modifying the bed supports so that they didn't stick off the end of the bed extrusion.
- Due to the increased frame size it was necessary to extend all of the endstop wires so they would reach the RAMPS board. The same applied to all the cables coming from the extruder including the fan cables, heater, thermistor & probe.
- Because of the dual Z axis it was only possible to add LED lighting to 2 sides of the frame. I modified the corner bracket to elevate the lighting 16mm which then permitted the LEDs to fully enclose the frame and evenly illuminate the build area.
As noted, none of these were insurmountable and some had straightforward solutions while others needed to have solutions engineered.
4/4/17 - Decided to build Hypercube instead of buying Flyingbear P902
4/5/17 - Busy day. Began pricing 2020 extrusion for 300x300x300 build. Also ordered bulk of parts from Banggood
4/6/17 - Ordered more parts from Banggood, eBay and Amazon.
4/7/17 - Ordered frame from Framing Tech (440x440x555) for a dual Z axis build due to the bed size.
4/8/17 - Still more parts from Banggood.
4/15/17 - Started printing the 3D parts using my Maker Select. Also wired up some of the electronics while waiting on parts from Banggood.
4/17/17 - Based on tracking info stuff from China should be arriving in a day or so. As soon as the screws and brackets show up I can build the frame.
4/22/17 - Assembled the electronics on the bench to confirm operational while waiting for parts to arrive.
4/25/17 - Began assembling the frame
5/6/17 - Completed enough of the build to bring up the system. Still a fair amount to do before a first print.
5/12/17 - Still more to do but I printed my first test cube at 60mm/sec using PLA (https://youtu.be/dYyuXtB_adU). It turned out great for a first print though there are some issues which need to be resolved.
5/14/17 - Added LED lighting using the 2020LED Lighting Mount (http://www.thingiverse.com/thing:2009479). Still waiting for the dimmer controller to show up but it's ready for it when it arrives.
5/20/17 - I had a noisy Y rail LM10LUU that was causing some vibration which was showing up in the print. I had originally placed these in the XY Joiner prior to installing the joiner on the Y rails so I figured things should be good. During my investigation I removed the clamp and confirmed there was a bit of play between the bearing and the rail so I was figuring on switching to bushings. However when I reinstalled the bearing in the XY Joiner and tightened things back down everything must have realigned because as far as I can tell all the vibration and noise is now gone. I'm guessing there was a slight misalignment due to the fact the XY Joiner is a 2 piece clamp.
5/29/17 - Ordered ATP-5 tooling plate for the 300x300 bed in .250 for $40 shipped. Should arrive next week. This is expected to resolve issues related to my current ALU build plate being slightly warped. I'm going to try and mount this on top of the current heated platform using mounting tape.
5/30/17 - Received & installed my anodized aluminum rods on the X axis - which now moves much more smoothly. However I still had chatter on the Y axis due to the loose fit of the LM10LUU on the steel rods and the print quality still suffered. I bit the bullet and installed anodized rods and bushings on the Y axis and the print quality improved dramatically. I'm still working on resolving some binding when at the end of travel but should have that resolved in a day or so.
6/5/17 - Installed the dimmer/controller for the lighting control.
6/6/17 - No more warped bed! I installed the ATP-5 Aluminum Tooling Plate for the heated bed. After marking & drilling the mounting holes I deburred the edges using a file. The size came out great and matched my existing ALU bed perfectly. I mated the two using 3M 468MP 12"x12" mounting tape normally used to install PEI sheets. I added some Kapton tape to the top for the print surface and all was good. Takes longer to heat up than the thinner bed but maintains the temperature very well due to the larger mass. Best of all is it's FLAT.
6/9/17 - Installed a Raspberry Pi with OctoPi along with an LCD display and camera. The case and brackets I made can be found at https://www.thingiverse.com/thing:2392314
7/1/19 - Converted the controller from an Arduino + Ramps to the SKR V1.3 32-bit board + 5 TMC2208 UART drivers. Marlin bugfix-2.0.x works but some of the features, such as Linear Advance, still have issues with the TMC2208. After some tuning I am able to print the 3DBenchy model from the USB card using Cura as the slicer @ 80mm/sec with minimal issues and it's near flawless @ 60 mm/sec. Using Slic3r the print @ 80 mm/sec looks nicer but it has a major flaw in the hull when the transom start to print although the gcode looks fine when imported into Cura. Same thing @ 60 mm/sec so not sure what's going on there but it looks like it added one more perimeter wall - but that doesn't show in the imported gcode.
7/24/19 - Switched to Klipper and also added a Zesty Nimble remote extruder. Once everything was configured and tuned prints @ 120mm/s look good and lower speeds look even better. 3DBency @ 80mm/s is very good and @ 40mm/s looks near perfect.
12/24/19 - Upgraded to Linear Rails on X, Y & Z (https://www.thingiverse.com/make:741908)
1/31/20 - Switched out the T8-8 lead screws to T8-2 lead screws as after adding the linear rails and a magnetic bed the bed assembly would fall when power was removed from the steppers. The shallower pitch of the T8-2 stops that from happening. The Z steppers now need to turn 4 time faster but that's not a problem - though it sounds a bit odd when moving a long distance.
Customized parts can be found at https://www.thingiverse.com/thing:2330651
A bracket to help hold up the wiring harness for the hotend can be found at https://www.thingiverse.com/thing:2426833
6/10/17 - My 24V power supply for the heated bed died in the middle of a print. It was one of the cheap LED units from Amazon. I'm checking with the vendor to see if it's under warranty or not but I did manage to open it up w/o destroying the warranty tape and it looks like the NTC 5D-15 MOV failed. It's an easy part to replace if there's no warranty. Until I get an answer there's no heated bed.
6/12/17 - Amazon handled things and a replacement PSU (same make) was sent. The replacement failed in under 10 minutes so I did a return and bought a different brand.
6/13/17 - The replacement PSU arrived and worked fine. It also runs much, much cooler than the original version even though it's the same inexpensive design so there's some components that must be different. Hopefully this one will last. One other issue I ran in to was that the power switch on my printer for the 24V side failed as well. Whether it's coincidence or not I have no idea.Fortunately I had a spare so I swapped the switch portion of the power socket.
11/19/2017 - The replacement PSU died as well. I contacted Amazon for the warranty info since it was outside the return period and they stepped up and just refunded the price with no return needed. I opened it up and it failed the same as the prior unit in that the NTC 5D-15 had died. This time around I bought a Meanwell LRS-350-24. It was only $14 more but hopefully it's much better built.