ULTIMAKER SeeMeCNC bowden extruder nozzle

thingiverse

Convert Ultimaker to 1.75mm system for easier filament access in the US; SeeMeCNC's dual-purpose extruder handles 3mm and 1.75mm, with a hot-end setup for bowden printers that allows smaller nozzles. Swapping out the hot end takes only 30 seconds, and accessories like a micrometer clip can be added to the second hotend slot. Print area is reduced by half an inch in X and Y but gains half an inch in height. Fan shrouds and brackets are available for unmodified Ultimaker. Three options for 12V setup: step down 19V with a power resistor, use a relay with a secondary power supply, or purchase new heater resistors. A 2ohm 25w power resistor between the heater power and nozzle heater lines is recommended; choose lead-free solder for the nozzle resistors to prevent melting. Parts include SeeMeCNC's bowden extruder kit, a small thermocouple, high-temp RTV, 3mm nuts, a 25mm length screw, and linear bearings. Carriage modifications involve adding linear bearings, removing original XY carriage retention mechanisms, and sliding on the new carriage with hotend and blank in place. Attach limit switches after slotting holes for accommodations. Use the blank piece to fill the void left by the second extruder. Extruder bracket assembly is straightforward. Before disassembling Ultimaker, test everything, including the hot end, thermocouple, and extruder. Flip the E stepper direction in Marlin for proper mounting on Ultimaker and calibrate the extruder using CURA's 100mm extrude test. First run may produce a smell; open a window. Videos of first run available.