The ruined castles: convenient hot end mount for the Ultimaker (drop-in replacement) - and an additional hotsink

thingiverse

I've recently been tinkering with hot ends and although my "banana" bushing blocks have greatly improved the process (no need to remove rods, pulleys or recalibrate), the stock head mount remains a pain to switch due to the requirement of removing X/Y small bars. I've been using an alternate butterfly mount (http://www.thingiverse.com/thing:159390) for most of my printing time, but I still needed an easy and safe backup solution for demonstrating the printer with the stock head. Hence, I created this design. It quickly slides into place from both top and bottom and has no impact on calibration or other parts of the printer. If you're curious about why I re-do certain parts of my printer, check out my blog at http://www.tridimake.com/2013/09/design-compatible-parts-for-3D-printers.html. Additionally, I added a simple yet effective passive cooling heatsink to the head, as shown in the picture. To print this design, simply print two "castles" as they are fully symmetric. I used PLA, 0.8 mm walls, and 20% infill. The strength of the part comes from its whole structure instead of the existing plywood puzzle, making it more rigid. In an update, I found that without a fan, my PLA began to loosen on the bearings. So, I uploaded a revised version with thicker walls and recommend printing in ABS or Nylon or isolating the aluminum plate/wood with Kapton tape to prevent heat from moving upwards. The default design should be sufficient, but ensure that the main holes match exactly with the linear bearing dimensions (no lateral freeplay). For mounting the castles, glue two screws for the electronic board underneath the top plate. Slide the "ruined castles" around the existing rods and insert the linear bearings from the side. Secure them with two small screws with washers on both sides. Use regular long screws through the ears to hold everything in place like the stock head mount. If needed, you can flip the small screws, add a nut on the outside, and tighten the bolt using a hex key. This design eliminates the need for the stock wall clamping bolt that unnecessarily pushed on the bowden tube. For cooling, I added an extra dumb heatsink by removing the equivalent thickness of the PEEK element from the stock hot end. The setup efficiently cools down the hot end without affecting other parts, but be cautious as the aluminum can get quite hot. Even during hour-long prints at 245 degrees C, the PLA did not soften significantly, and I could even touch the stock aluminum plate above the peek (but avoid doing so with the heatsink). If you're interested in an alternate design, check out http://www.thingiverse.com/thing:67517.