Updated 2/11/17 - Moved clip over 0.7mm to account for printer assembly tolerances. Should have plenty of clearance for small extrusion gear. Please make sure you use the latest STL file! Enjoy!
The Lulzbot Mini is a very powerful printer. However, if you switch between the standard printhead and the flexystruder, the one annoyance I've had is that you're required to cut two zip ties and use two new zip ties every time you switch the head.
I set out to design a solution that would remove the zip tie requirement AND not require any modification to the production parts.
The solution I created is a small clip that holds the wires in place that mounts using the existing zip tie holes. The clip is held firmly using M3 screws and can be removed at any time.
To complete this project, you will need the following
1 x Printed Clip made from ABS/PETG/HT or some other high strength/high temp material.
2 x M3 x 10mm Socket Head Cap Screws (https://www.mcmaster.com/#91290a115/=167o61s)
2 x M3-0.5 x 3.8mm length heat stake inserts (https://itworks3d.com/product/metric-brass-heat-set-insert-plastics/)
- 1-2x small zip ties (only need to do this one time)
Tools: A 5mm drill bit, a soldering iron, and a 3mm and 5mm hex key
Wall thickness: 1mm
Standard ABS print settings should work fine. I got the best part while using a brim to keep warp to a minimum.
Step 1: Ream Holes
Orient the part on the print bed so that the clip cylinder is vertical. Print with supports and a brim.
Once the part has finished printing, notice it has 2 holes. These two holes will be used for the heat stake inserts. In order for the inserts to fit correctly, the holes need to be 5mm diameter for the heat stake to work properly.
Use a 5mm drill (or english equivalent) to ream the holes to the appropriate size if necessary.
Step 2: Use Heat Inserts and Stake
As shown below, gently press the inserts in the orientation shown below.
Use a soldering iron to heat the inserts until they press into the part and are flush with the surface. See images below. Heat stake both inserts.
Step 2: Orientation of M3 Heat Inserts
Step 2: Use soldering iron to heat inserts into part
Step 2: Final position of heat inserts. Inserts should be flush with ABS surfaces.
Step 3: Remove old tool head
Step 4: Install Wire Clip
The new clip installs in the same place the zip ties once threaded through.
See the image below to see how the holes line up with the inserts. There should be NO required modification of the existing black X-carriage holes.
Slide the clip onto the X carriage and align the holes.
Use 2 x M3 - 10mm SHCS to attach the clip. Note, lower screw should attach through the front while the upper screw should attach through the back of the x carriage. See images below that show the installed screws.
Step 4 : Align and orient the clip with the existing zip tie holes
Step 4: Front of Clip, Lower screw installed
Step 4: Back of Clip, Upper Screw Installed
Step 5: Install New print Head
Using the Lulzbot OHAI install guide, install whatever printhead you want to use.
In step 10, instead of using zip ties to install the cable, just press the wiring harness into your new clip.
Use 1-2 mini zip ties above the clip to wrap around the panduit corrugated cover. Note this is not to retain the wires to the carriage, more to keep the wires from popping out of the slot in the panduit covering. These zip ties can be left installed forever.
See the video below on how the wires install into the clip.
Step 5: Installing the wiring harness into the clip
Step 5: Note where the mini zip ties are installed around the panduit in the image above. These are installed perminantly to keep the wires contained inside the panduit cover.
Step 6: Done
Enjoy! You shouldn't need to cut or buy new zip ties to swap print heads.