I tried making a water block for water cooling my MakerGear hot end this weekend…

I tried making a water block for water cooling my MakerGear hot end this weekend.

I failed.
       kinda…

A bit of background as to WHY I would want to do such a project can be found at http://mike.creuzer.com/2013/01/watercooling-my-makergear-prusa-reprap.html I wanted to improve over the coil of copper being that I am about to re-install my 1.75mm hot end for a few lbs of plastic. Going to try ABS for the first time at this size. Not sure if I am going to have problems with that or not.

My fail is I was too lazy to go out into the cold to drill a hole on the drill press. I managed to salvage my stupid hole with a bit of tubing. Hopefully it doesn't cost me too much in efficiency.

I really have no idea what I am doing when it comes to using a lathe. Learning from YouTube is difficult as many of the videos posted are by people with as much experience as me (about 3 hours at this point).

Well, the next iteration should be better, right? I enjoyed making this enough I wouldn't mind making it again. But with a drill press. I think I will drill that hole first so I know it's right.

In album Machining a water block FAIL

Using my UNiMAT lathe to fix my lousy hack saw cut and bring the aluminum block down to the right dimensions.

I turned down the black insulator a bit as I don’t have metric drill bits. The bigger tube is to couple airline tubing together on the OUTSIDE so I don’t get even more restrictions of water flow.

THERE I FIXED IT. I ran a bit of aquarium air hose through the buggered up hole. I am going to lose a lot of heat removal capability, but it lets me temporarily salvage this part. The water going through is in it’s mid 60s, so there is going to be a big difference, so it should pull heat well.

Until I make a new one.

I cut a piece of aluminium in half with a hack saw. The tray did a decent job of collecting the aluminum dust. Terrible surface finish on the cut. I did not do a good job of making the cut straight.

I tried drilling the hole using a hand drill because it’s COLD out in the garage where my drill press is.

I FAILED. I totally didn’t get things where they wanted to go. I’ve a hole on the inside, and a double hole on one end.

I can JUST snap the wooden clip in place with the water block installed. It’s going to be a royal pain to un-clip it.

The water block is small and light. It should work well I hope.

Watercooling my MakerGear Prusa RepRap

I’ve been fighting with printing 1.75mm PLA. The thicker brass in the hot end causes the heat to creep up more and make the ‘melt zone’ so long and sticky that the printer jams up. The normal ‘fix’ is to have a small fan blow up  into the hot end insulator – the black plastic bit.

This sucks for me. The fans fail – stop spinning, fall apart, etc. The wires pop loose, touch each other, and short out the power mosfet on the RAMPS board. The fan falls down, hits the part, knocks it loose or causes the carriage to skip.

Fan blowing up, cooling the hot end insulator to prevent jamming
Fan blowing up, cooling the hot end insulator to prevent jamming (This is http://www.thingiverse.com/thing:13343 by the way, the best fan holder I’d found)

The irritating part is, the printer will eat 3mm PLA all day long without a problem without the need for this fan.

 

So, I fixed this issue. With one of my aquariums. As I tend to have lots of those about. I like doing funny stuff with my aquariums

I am now water cooling my hot end.

Here’s how…

(Stereoscopic images, look at them cross-eyed if you want to see them in 3d)

Parts for watercooling a makergear reprap hot end
The parts I got for water cooling my RepRap hot end. A bit of soft copper tubing and some hose.

 

water cooling a 3d printer hot end
I cut some tubing with a pipe cutter. I just kinda guessed how long it should be by wrapping my finger around the hot end and cutting the pipe at the length that seemed nice.
deburring the cut copper tube
I deburred the copper tubing with a countersink. The cutter gives me a nice outside edge to slip the tubing over. I wanted a clean inside edge for the water flow.
bending a tube over a screwdriver
I bent the tube over a screwdriver. I was going to fill the tube with sand so it didn’t kink, but I just started bending and it went around without kinking. I was also thinking of sliding some flat metal inside and hammering it down before it bent, but the bend just kinda happened successfully.
bending copper around the hot end
I bent the tube around the hotend. I used the pliers to snug up the bend. It’s not really tight, and I wish I had some heat sink compound to help improve the contact between the two surfaces.
water jacket around the hot end
The ‘wide’ side of the tubing wrap is taking up nearly all the space available along the hot end insulator.
tubing on the water cooled hot end
I measured out a bit of tubing, cut it off, and slid it onto the copper tubing.
water cooled hot end
I think that the water cooled hot end looks pretty good.
temperature monitoring the hot end cooling
I slid a thermistor between the hot end and the water jacket so I can measure the effectiveness of the water cooling.

The task of installing all of this was almost challenging. There was just enough room to be able to slide the hot end up through the carriage, slip on the groove mount, and get it all positioned. The one bolt hole was kinda hiding above the copper tube, but the tube can be spun around a bit so everything can be bolted up snug.

water cooled hot end installed
Here is the water cooled hot end installed onto the X carriage. You are seeing most of it in the reflection of the mirrored print bed.
looking up at the hot end and at the glass clamp
Here we are looking up at the hot end water line routing. Also note the drilled holes in the binder clip. This takes a lot of the strength out of the clip so it’s less likely to break the glass or jump off the print bed and land on the far side of the room.
water pump in aquarium
Here is the water pump in the aquarium. Just straight fish-poo water. It’s not touching the printer, I am not worried about it. More concerned about the toxicity of the copper to the fish than the toxicity of the fish to the printer.
reprap 3d printer next to aquarium
Here is my RepRap 3D printer next to the aquarium that is cooling it. Or is this a photo of my aquarium with the overly expensive electric water heater that happens to print plastic parts? Hard telling…
water and electric wire routing
I ran the water and electric wire routing next to each other. The water and thermistor are not part of the ‘main’ wiring harness as I switch between 3mm and 1.75mm nozzles.
water line routing
Note the pretty hard bend in the plastic hose. If it’s less than this, it hits the mount for the X end stop.
water flow
The water flow through the hot-end is pretty good using the tiny pump I have. I am not seeing a significant difference in temperature from the tank temp to the water from the hot end cooler.

The whole assembly was pretty quick and easy. When I installed the water cooling, I also incorporated the temperature monitoring and soldered the USB cable to the arduino board as the USB-B port got sloppy and would disconnect on me mid-print.

As for some numbers as to how well this works. With no water running through the copper tubing, I am seeing temperatures over 135f after 10 minutes. Yeah, Yeah, I know, RepRaps are metric, but it’s an easy value to convert, go too it. With water running, the top temp I’ve seen is 115f. It likes to run closer to 100-110f. My longest print so far is close to 4 hours without any problems. Without any cooling (and the copper not installed) I’d start to see jamming problems around 1 hour at .1mm layer height. .3mm layer heights would go much longer without problems. I am guessing that the plastic flow volume keeps pushing the heat down the barrel and doesn’t let the transition zone get too long.

I’ve not weighed the copper, tubing and water to see how much extra this weighs over the fan and mounting hardware.

I may run the water around the extruder, X and Y motors to help cool those. Not that they get hot really.

I think I want to mount some SMD LEDs against the tubing for some neat lighting effects. Just so it looks cool.