ULTIMAKER SeeMeCNC bowden extruder nozzle
by chasmaker, published
I really wanted to convert my Ultimaker to a 1.75mm system. Way easier to find a variety of filament in the states. SeeMeCNC had a dual purpose extruder which handles 3mm and 1.75. They also have a nice hot endsetup for a bowden style printer that allows me to use smaller nozzles and they also sell blanks for making your own. The advantages of this setup is it only takes 30 seconds to swap out the hotend. I made an accessary clip that goes in the second hotend slot for a micrometer. You could also make this hold a pen or some sort of digital bed leveler etc.
FYI this will reduce your print area slightly. The Y and X print area is reduced by 1/2" but you gain about 1/2" in height.
Fan shroud and brackets are now in. There is a left and right and a double that will print on an unmodified UM.
This is for a 12v setup. You have three options;
1) You could step down the 19v from the ultimaker with a power resistor.
2) Setup a relay with a secondary power supply.
3) New heater resistors
Here was the solution I found:
Use a 2ohm 25w power resistor in between the heater power and the nozzle heater lines.
Also you might not want to use cheap leaded solder on the nozzle resistors. Turns out the wires get pretty hot and will melt cheaper stuff.
Here is what I used:
Bowden extruder kit from SeeMeCNC.com
Small themocouple: (this is the one I picked up)
Print the parts (I would suggest in ABS, have no idea how the heat will affect PLA)
A couple of 3mm nuts
A 3mm 25mm length screw for the head retaining clip
A couple of 3mm screws for screwing the themocouple board to the top.
A 3mm tap for tapping out the screw holes
I would pick up some new linear bearings so you don't have to remove the bearings from the Ulitmaker carriage.
1) Push a nut into the backing hole behind the carriage. I put a nut on a longer 3mm screw, pushed it though the access hole in the back and pressed it into place.
2) Press in the linear bearings. If they don't go in clean out the holes with a dremel and grinder. Don't remove to much material, you want the bearings to stay in there with tention.
3) Pull the XY 8mm bar rentention mechanisms apart and remove the original XY Carriage.
4) Slide the new on on and square off everything like the original assembly instructions.
5) Wire up the new SeeMeCNC nozzle. The resistors are wired in parallel.
6) Insert the thermocouple into the shallow hotend hole. Hold it in place with high temp RTV
7) Attach the hotend retainer with a 25mm bolt to the front of the carrage. Keep it loose for now.
8) Slide in the hotend into one side and the blank into the other.
9) Tighten the screw.\
10) Slot the X limit switch holes so you can move the limit switches in to accommodate for the wider cariiage. I think they are slightly over 1/3 of an inch on both sides.
11) Slot the Y limit switch hole at the front about 1/2 inch. If you have a router attachment for a dremel it takes 5 seconds. If you don't (like me) you use a drill and make it look pretty ugly.
12) use the blank piece to fill the void left by not having a second extruder.
13) Cabling comes up through the retainer clip slots (there are two retangular slots) and I piped them up next to the bowden. Hopefull you can see it in the pictures. I'll try to do a ISO drawing this week to clear up some of the assembly instructions.
1) pretty self explanatory.
I tested everything before disecting my ultimaker. Hooked up the hot end to the motherboard, and the thermocouple. Tested the extruder. Once you get everything extruding then take a part your ultimaker. You don't want to have to put it back together if you forgot to print a part or what ever.
The extruder is mounted backwards from the stock UM. You will need to flip the E stepper direction in Marlin. Use Daid's build me marlin tool to do this easliy. You also will need to calibrate the extruder. Use CURA to calculate the extrude steps using the 100mm extrud test.
Open a window... the first run on this thing can be smelly.