Yeah, those green power connectors on RAMPS are horrible. They aren't even rated for the current that the board can draw with the hotend and heated bed running, so even if the screws don't come loose you can have a meltdown. The protection circuits aren't great either - a lot of people replace them with automotive fuses for security as well.
My upgrades have been a little stalled out. I got all the parts from openbuilds for my X but have run into some issues printing the printed parts for the X upgrade. I've been slacking posting about it because the bulb in my good lamp died so it's tricky to get detailed photos of the black filament I've been using...so please excuse the photo quality in this post, I hope to get a new bulb this weekend so I can get back to my usual quality
The problem is the parts are almost all designed to be printed with supports...LOTS of supports. And frankly I've never had a ton of luck with slic3r's supports and PLA. With ABS - no problem, supports pull right off. But with PLA or PETG - they never come off cleanly.
The tanish piece was my first attempt, printed as it's sitting with full supports. Removing them was a major pain...and I still didn't get them all. I could make the piece work but it would be ugly.
So I decided instead to try rotating it 90 degrees to the right and printing it with supports only on the bed. This is the orientation I next tried printing the pieces in.
That worked better...but the inside of the square section of course wound up with one side that wasn't great since it was all bridged.
I could probably get it cleaned up and get the V rail in there...but wanted to do better...So tried redesigning the part in Onshape so it could print without supports but would give up a bit of constraint on the V rail:
The photo doesn't show it great...mostly shows off the way I filleted the part to make it smoother and fit my aesthetic better. But if you look closely you can see that the back is now a J shape that loops over the rail and has holes to attached with T nuts on two sides.
That worked...and test mounting it I was pretty sure it would work:
Except....I forgot that the belt has to pass through the groove on two opposing sides. So T nuts on sides 90 degrees apart isn't an option. Crud. I had also opened up the square section for the V-rail a bit more the original design was 20.3mm on both dimensions and was SUPER tight, I opened it up to 20.5 but had a bit more slop than I liked.
On on the next revision I shrank it down to 20.4 but still had a tiny bit more slop now that I didn't have to try and get it to clear on all four sides. I also removed almost all of the 3rd side since the mounting holes over there were worthless. And finally I further refined the overall shape a bit more for cosmetic purposes:
But - with that 3rd side that short and still having a bit of slop I just don't trust it. Even though it feels good once I tighten up the T nuts on the top I worried that they could come loose over time and cause an issue. So I tried another revision with the opening down to 20.2 (smaller than the original!) It needed support again but with one side open I figured it would be easier to cleanup:
Well, there's a reason I only have a rendering to show. The supports failed and caused the whole print to fail
And the bits that did come out showed that 20.2 was probably too tight. So...back to the drawing board.
I went back to the J shape, and decided to keep both sets of holes even though only one can be used at a time. That was the same parts could be used whether the gantry is mounted on the front or top of the rail. The original design puts it on the front with the extruder cantilevered off...but some people have done designs with the gantry on top which I prefer since it puts more weight over the rail instead of hung off it and it makes for more Z clearance. I kept the tight 20.2 spacing since this is only constraining the V rail on 3 sides...I may have to revisit that...but since this will print without supports again I think it will do better, I haven't had time to try printing this version yet though:
You'll notice I also simplified the bearing retention to make it easier to print. Honestly I've been running my printer for a year and a half without even installing the screws on that part since the bearings are held so tight even without them...and I confirmed that this design does just as well. In fact the only reason I kept the Tabs is so I can use a screwdriver to wedge it open to make installing and removing the bearings easier. I left the holes for the screws in case anyone else wants to use them but I won't be bothering again.
I'm hoping to print this tonight and am quite hopeful that it will work. I think with 3 sides constrained and the two T nuts it will be retained well enough for me to trust it.
I've also been working on tweaking the tensioner setup. My first take on it was almost purely cosmetic, though I did open the inside up just a TINY bit so the V rail would fit easier and so the tension slider could move more easily. The tan version is the original, the black is my first redesign:
The original design attaches with 2 3mm screws in T nuts. But since this is the tensioner it's under tension and I worry that that wouldn't hold up to the tension. So I added a bit more material on the sides the belt doesn't run on so the part had shoulders that would rest against the edge of the V rail and keep it from sliding under tension:
That seemed to be an improvement. Except the extra material took up enough room that the tension slider only had 1 or 2 mm of travel now
So...one more revision which I haven't had time to print yet:
It's a little longer and I rounded over the shoulders so they don't take away as much travel. This should allow for 10mm of travel by the tension slider. Where the shoulders meet the verticals it's a little wonky...but I can live with it.
It all looks pretty good in a full mockup:
I've also done a bit more work on the extruder...but ran into an issue there. I forgot about the gear. I haven't figured out how to draw the herringbone teeth yet...but got the gear mocked up enough to check for clearance issues...and realized that hanging the extruder off the front of the rail is going to be harder than I expected due to the gear:
So at this point I'm looking at either just attaching it to the front like I wanted to avoid...or completely redesigning the extruder. Not sure what I'll do there yet.
Of course since I'm doing all this in Onshape the files are public and anyone who wants to can copy them and make their own changes:
Tensioner:
https://cad.onshape.com/documents/9...901cb9c50ca6ff6a8d/e/7412a708345fbf6cd32a335d
Rail mount:
https://cad.onshape.com/documents/6...956c112e200b085b34/e/f632515d3e9efa2b65deb9fc
Extruder:
https://cad.onshape.com/documents/9...820a13b2b966007e16/e/71d28df4713c24f87449198c
Assembly:
https://cad.onshape.com/documents/2...60693bcf913ac44d0f/e/bc47b5b5b9859cd11073dd2d
Should also have a new aluminum bed arriving today which I'm curious to see if it will stiffen the bed further and give me more consistent probing with my inductive sensor. If not...well I can build a mount to put it on my MPCNC and have an easier to level bed on there so I can start using it as a printer as well