Description This is a quick-fit carriage-system which can be equipped with different heads including a FDM head, a mill-head, a custom laser head and other. Changing the head takes only a few seconds. All(!) electrical contacting is realized by a SUB-D connector. Stability is provided by an easy but effective clamping design. Design your own head based on the provided custom-plate. Turn your Prusa into a ZMorph.
Other fitting parts:
I made other fitting plates for various other tools. I keep them in separate pages to not to clutter this page. You can find a list of all fitting parts here:
The extruder-plate-thing is compatible with this fan duct: http://www.thingiverse.com/thing:1392612 and the "fan-duct-1" from http://www.thingiverse.com/thing:1275203.
Contacting The electrical contacting is realized by a SUB-D HD 26 connector which offers enough pins for different heads. A typical single-extruder head requires 14 pins which leaves the rest for a leveling probe, a servo, a USB or I²C connection and additional power lines. It even offers enough pins for a dual-head setup.
Mechanical compatibility It is designed for a "Geeetech i3X" (and its MK8 extruder) but should be usable for any Prusa i3 variant. It is made for a X-rod separation of 45mm and a 2mm GT2 belt and fits bushings/bearings with a diameter of 15mm (default) or 16mm (select proper model file). The width of the base-carriage is 86mm, the height is 78mm and the depth is 31mm. The extruder-plate is designed for a proximity sensor with a diameter of 18mm. (Let me know if you need another diameter.)
Effort Be warned, soldering of all the wires takes some time. The wires have also to be placed carefully within the provided limited space. But you will be rewarded with quick head change and faster nozzle change.
Some design decisions I made
- Clamping without screws -> faster change, but there was no room for screws anyway
- Bushings/Bearings are held in place by friction
- Carriage width of 86mm -> enough room for the cables/connector/belt
- Z-min actuator (the upper horns of the plate) is located at the changeable plate -> you can tune Z-min by adding or removing material from the actuator
- All connections are open if nothing is attached -> you have to simulate the hotend temperature sensor by a 100k resistor (You have to simulate your distance sensor too if you use one)
- Mill head fits a rotary tool and not the flex shaft -> the weight of the rotary tool helps milling
- Base part: Female SUB-D HD 26 connector, M3 screws 3x 20mm , M3 nuts 5x, M3 washers 4x.
- Extruder part: Male SUB-D HD 26 connector, M3 screws 2x approx. 6mm, M3 nuts 2x. (Optionally: If you want to use a Z-probe in series(!) with the Z-min-switch you'll need some electronics parts given in the drawn schematic.)
- Mill part: Male SUB-D HD 26 connector, M3 screws 2x 10mm, M3 nuts 2x. A 100k resistor as thermal sensor simulation. (Optionally: If you want to use a Z-probe in series(!) with the Z-min-switch you'll need a short wire.)
- Custom plate: Same as mill part plus your custom things.
Let me know if you encounter problems or need changes.
- Added v2 for "Plate-Extruder-MK8" which should hopefully not sag. It has an additional supporting structure and two holes for 2x M3 50mm screws which should prevent bending.
- Added 12mm sensor option for "Plate-Extruder-MK8" (Plate-Extruder-MK8_with_support_v2.STL)
- Added v3 for "Plate-Extruder-MK8" which has an additional bracing which will cost you ~4mm of X-movement but prevents sagging of the part.
Some parts have to be reoriented for printing.
Base part (Base~.stl, Cover~.stl) Select default (15mm) or 16mm-bushings/bearings version. Manually designed supports are provided. A version without supports is uploaded too. I'd suggest an infill of 30% to have a high stability for milling.
Extruder part (plate-extruder-mk8~v3.stl different options and versions (12mm sensor, 18mm sensor, with and without supports, v1-v3 for MK8 extruder) Manually designed supports are provided. A version without supports is uploaded too. Infill above 33% is suggested to prevent sagging.
Mill part (plate-mill-pt1~.stl, plate-mill-pt2~.stl) Manually designed supports are provided for the first part. You have to generate support for the second part.
Custom part (custom-plate.stl) Manually designed supports are provided for the SUB-D mounting.
Soldering and assembly
Soldering in general Use one pin for everything except the hotend-heater. For it i used 2 pins for each cable to handle the current of over 3A. I've attached a suggested pin-layout. Solder the middle pins first, then the lower and upper in order to have good access with the soldering iron. Use heat shrink tubing to prevent short circuits. The wires have to go down or up immediately after the connector because there are only a few mm of space behind the connector. Be careful with the wire layout: The wires on the opposite connector are mirrored. Keep a clear head. Triple check the layout of the wires! Also check for undesired short circuits between the wires! You could kill your board, motor or sensor.
SUB-D connector in general Ensure that both opposite connectors are fixated at the same height (M3 holes have some play). If you wish, you can even keep the connector on the tool-head-side slightly loose by using soft rubber washers on the proper side.
Base part Connect all required cables to the not-powered(!) board, arrange them, tie them together temporarily and cut them at the position of the print head.
- If your connectors are small and fit though the back-cover-tube: Remove the cables from the board. Solder the cables to the female connector and use thermal shrink tubing. Put the cables from the flat-side through the base part and the back-cover.
- If your connectors are big and don't fit though the back-cover-tube: Pull the cables though the cover and the base part. Solder the cables to the female connector and use thermal shrink tubing.
Attach the connector with 2 20mm M3 screws and 2 nuts, place the cover and fixate it with 2 washers and 2 nuts. Connect cables to the board. Use a M3 screw, 2 washers and a nut to fixate the lever to the base part.
Extruder-part I'd suggest to use 5 additional Molex connectors to be able to disconnect the extruder from the plate to change the nozze or for other reasons. I used 3 2pin connectors for the 2 fans and the thermal sensor, a 3pin connector for the leveling probe and a 4pin connector for the 2 wires of the hotend heater. I placed the circuit (see photo) of the leveling probe at the extruder-plate.
Solder the wires to the various connectors and then to the SUB-D connector. Push the cables and connector from the flat side into the SUB-D connector hole. Fixate the SUB-DD connector with approximately 6mm short M3 screws. You'll probably have to cut the screws. Fixate the extruder, the fan duct and the sensor.
Mill-part Solder a 100k Ohm resistor between the pins to simulate a thermal sensor. (If you use my circuit and a Z-probe solder a short circuit between a connected GND pin and the Z-sensor pin. Be careful, connecting anything else (12V, fan or motor pin) to the Z-sensor pin will kill your Microcontroller on the board.). Fixate the SUB-D connector from the flat-side into the hole with 2 M3 screws. Put both mill parts together and fixate them with 2 M3 screws and nuts. Use 2 M3 screws, nuts and washers to clamp the rotary tool.
Custom-part Solder a 100k Ohm resistor between the pins to simulate a thermal sensor. (If you use my circuit and a Z-probe solder a short circuit between a connected GND pin and the Z-sensor pin. Be careful, connecting anything else (12V, fan or motor pin) to the Z-sensor pin will kill your Microcontroller on the board.). Fixate the SUB-D connector from the flat-side into the hole with 2 M3 screws.
It might be necessary to use a pliers to bend the skirt of the male connector a little outwards. In such a way the connectors will easier mate.
My gcode for homing
This code requires the mechanical Z-endstop and sensor-endstop being wired in series. The homing is performed after(!) heating the bed and hotend.
; ### mechanical home ###
G28 ;home Z with meachnical endswitch
; ### set temperatures ###
M106 S255; fan on, starts cooling of nozzle
M140 S[first_layer_bed_temperature] ;set bed temperature
M190 S[first_layer_bed_temperature] ;wait for bed temperature
M104 S[first_layer_temperature] ;set extruder temperature
M109 S[first_layer_temperature] ;wait for extruder temperature
; ### sensor home ###
G1 Z6 F180 ;lift to inactive sensor height
G1 X127.5 Y168 F6000 ;move sensor to exact center
G28 Z ;home Z with sensor
G92 Z3.95 ;adjust this height difference of sensor and nozzle
G1 X70 Y0 Z0 F6000 ;move away from print bed
; ### prepare filament ###
G92 E0 ;zero the extruded length
G1 E8 F100; extrude filament
G92 E0 ;zero the extruded length again
G4 S3; wait 3 sec
M300 S200 P100 ;beep