Geeetech Prusa I3 Stepper Mounting Plate for Bowden Extruder

thingiverse

This mounting plate allows you to securely attach a MK8 extruder stepper motor (for a Bowden Extruder) to the frame of a Geeetech I3 with an acrylic frame. My printer is a I3 Pro Dual Extruder, so I know for sure it fits that model and probably all of the I3s that were made with that frame. Update 1/22/18: I added a new mounting plate that moves the stepper motor forward. This allows the X carriage to move higher without hitting the Bowden tube. The collars on the rods limit the carriage movement at the top of the frame. If the collars were smaller or ground down, the carriage will be limited only by the top of the frame. It's probably not the best placement, but it required the least redesign. The plate secures the stepper mounting frame to the printed plate with only two screws. The filament load lever MUST be opposite the screws, so pressing down on the lever causes the stepper motor to be forced down into the printed plate. It may work the other way, but probably not for very long before the plate cracks. It's tricky to figure how it mounts; look carefully at the photo. Update 5/10/16: This plate limits the vertical travel to a bit more than 160 mm. The motors will have to move towards the front of the printer to move the Teflon tube away from the carriage to get more clear vertical travel. A project for later date, when there's a need. With the extruder motors off the carriage, you can use a different hot end, and feed the filament using a Bowden Extruder scheme. In the photo for the new plate, I'm using the 2-to-1 Switching hot end (one of MY THINGS). This hardware can be used to switch between two filament colors. Notes about Bowen Extruder 3/5/18: If you are going to add a Bowden extruder to your I3, sooner or later you will find that the drive gear does not provide enough force and fails occasionally with a ticking sound under some extrusion conditions. The easiest and cheapest solution is to replace the drive gear with one with a half-round filament path. There are two gears that will fit the steppers used, the MK7 and MK8 hobbed drive gears. Both will provide improved performance from the straight tooth drive gear, but the MK7, being smaller will provide the greatest torque. When you change the size of the drive gear, most, if not all of the screws you need to mount the extruders might be available as left-overs in the hardware that Geeetech furnished with the printer. You need a couple 19.5/20 mm M3 cap screws and three M4 6 mm cap screws. You also need the sheet metal bracket that mounts between the stepper motor and the mounting plate. These are available from Geeetech, Aliexpress, and eBay. You probably will want to replace the dual extruder bracket on the carriage with a mounting bracket for a single extruder. It is available from the same sources as above. You gain about 30 mm of usable bed in the X direction when you remove the dual extruder mounting plate. The mounting plate will handle a left and right hand extruder without any modifications. If you have two of the same, then a small amount of material will have to be removed form the original acrylic top plate, or the plate will have to be made thicker to countersink the screws because of interference with stepper motor mounting bracket. If you are adapting a I3 Pro Dual, then extruder #2 mounts on the left side and #1 on the right (as you face the printer). The motors turn in opposite directions, so there is no choice about the mounting unless you modify the firmware or the plate. If you use the mixing hot end like Geeetech uses, you also need a mounting plate between the hot end and the carriage bracket. Check out the mounting plate I made for the 2/1 extruder that is available now from many sources. http://www.thingiverse.com/thing:1496657 Post-Printing: Just normal cleanup. Clean out the holes so the screws fit easily. How I Designed This: Sketchup Make 2016