Mounting Plate for 2 in 1 out Switch Hotend for Geeetech Prusa I3 by DougInAZ

Last crawled date: 3 years ago

Update 12/6/17 I AM PLANNING ON CHANGING THE COOLING SCHEME FROM AN AXIAL FAN TO A RADIAL FAN. I ADDED THE FIRST CUT AT THE DUCT AND A TEMPORARY TRANSITION PIECE USING A 30 MM AXIAL FAN . THE DUCT MOUNTS ON THE BACK, NEAREST THE LINEAR BEARINGS, SO IT DOESN'T INTERFERE WITH THE LAYER FAN AND MAKES IT EASY TO CHANGE HOT-ENDS. I HAVEN'T TRIED IT YET, AND IT MAY BE IN-PROCESS FOR SEVERAL MONTHS. PLS LET ME KNOW IF YOU TRY THIS AND HAVE ANY SUGGESTIONS.
Update 4/16/17 Added link to information on using a Y-block hotend. 4/19 https://1drv.ms/w/s!AoMNMLsOFAgFj-AnywOk94qGBizVrg
Update 3/30 Changed spacer and plate with closed bottom to 3 hole version.
Update 3/15 I found that this hotend requires a higher filament temp than the one I had been using. Also, the extruder PIDs needed adjustment to keep the temperature more constant than the larger one I had been using. I used to get good results with one PLA type at 193 deg. Now I believe something over 200 is required for the same filament. The following PIDs seem to work well at a print temp of 202 C: Kp 13.5 Ki 0.8 Kd 57.6. The heater block is uninsulated at this time. I've found it's worthwhile to add some insulation to the block. I use cereal box paper secured with kapton tape.
Update 3/13/17 Added a couple photos of the part installed in a very thin test print of the bracket. The part looks very good. So far, I've only used it as a single extruder. The heat break is very effective. The upper part of the block stays very cool when printing PLA, even without the fan running. There are holes on the back of the upper block for a layer cooling fan. I've removed my cooling fan temporarily from the extruder bracket while I'm testing things. More updates as I figure out the scripts required to make it function as a switcher.
Update 2/27 minor tweak in cavity dimensions. Added 2 mm Spacer.
updated 3/17 I only printed this part as a lite-weight test-prototype. It is for mounting a new 2-to-1 hot end that is similar to a Cyclops, but permits two filaments to be switched between one output. It will not mix two filament streams and does not have the backflow problem if you only load one filament in the block. ==============================================================
The plate is intended to mount on a single extruder mounting plate like that furnished with the Geeetech I3 Pro B printer with 50 mm mounting centers. When this design is proven, I expect to be able to switch between the Cyclops/Chimera clone setup I have on this printer and this 2 to 1 switch hotend with minimal readjustment of the printer. That means I will adjust the bracket as necessary to get close to the same vertical height as I currently have on my Cyclops clone using the mounting plate and spacer I designed. I expect the plate will mount on top surface of the extruder bracket with the hotend mounting holes below the mounting plate.
I recently received the part, but have done little testing. I found it on AliExpress. I also found it on eBay when I was researching a new extruder today. You can probably find it as I did by searching for: HOTEND 2 IN 1 OUT.
A first look at the part shows that it runs much cooler than expected in the area of the mounting holes, so PLA will probably be what I'll use for the final bracket. The part mounts through the rectangular hole in the plate, but the .STL file has a thin surface covering this hole. The purpose of the surface is to keep the plate bonded to the bed during printing if you use ABS; being only 0.6 mm thick, it can be easily cut out when finished. I also added a version with the hole open.
I have high hopes for this part for use as an easy way to switch between filaments during a print. My Cyclops setup is OK as a mixer but tricky when trying to use it as a switcher with high ratios between the two filaments. The printer manager will require some code to retract the unused filament back into the cool zone and advance the other filament when the extruder is switched.