Here’s a stabilized x carriage redesign that we’re testing out at AOHQ. It’s a direct replacement for the stock X-carriage on the AO-100 and AO-101, and it reuses the stock hardware - no vitamins needed.
The redesign stretches the x-carriage by 40mm without compromising print volume, and should keep your parts crisp and clean even with worn bushings.
Stl, gcode and FreeCAD source files can be found here:
http://devel.lulzbot.com/AO-100/hardware/stabilized_x-carriage/
Happy printing!
-Brent
Do you have a photograph of it in action? Have you been able to mount a fan by using the belt clamp holes as well?
I haven’t tried a fan yet, although I expect not. The belt mount holes are farther apart than on the original, it’s a quick change if anyone is interested in trying.
Make sure you turn the x endstop upwards to clear the rear bearing before starting printing, the x home position shouldn’t change much.
Cheers
-Brent
lol@ “the carriage not in action”
Thanks! It looks good!
Modeled in FreeCAD! Cool! 
This is definitely an upgrade that is worth doing, if you have an AO-100 or AO-101.
Why 3 pillow block bushings instead of 4?
4 bushings over-constrains the x plane; it’s fine if they’re all perfectly aligned but it can cause the carriage to catch and skip if the bearings wear unevenly. I think this is a big part of the reason that we’ve never had a TAZ skip or produce serious rippling on part surfaces.
I’ve got an earlier dev version for 4 bearings if you’d like to try it out, but I really think that 3 is the way to go
Nah it’s good, I’ll try this out when I find the time. Thanks!
Make a quick-fit compatable variant and I’ll take it for a spin!
Can you explain what is a quick fit? I’ve seen this to describe some extruders but I have no idea what it is exactly.
It’s a quick disconnect standard that many extruders have been modified to utilize. it’s certanly not the only one out there, but it is the most prevelent. Basically your extruder becomes a removable component that locks into a socket on the x carriage. The advantage being ease of access, or with a bit of wireing harness work, the ability to completely swap in a spare extruder or a different type of extruder (standard to polyschnozzle, or go from dual to single extruders when you want to print something quickly and don’t want the extra weight, etc) Theres one that will fit the A0-101 with minimal modifications already, it works pretty well. The disadvantage is usually slightly additional width and a bit more mass on the x carriage. the wider bearing stance has actually improved my z wobble issue though somewhat.
Sounds cool, I’ll try to fab one up when I can find some time. Is this the style of quick fit you’re talking about?
http://www.thingiverse.com/thing:19590
How’s it deal with high speed printing? It seems like it would introduce a bit of slop.
-brent
I’ve been using this one specifically: http://www.thingiverse.com/thing:67855 which is slightly wider than the stock AO-101 carriage. It’s actually improved my print quality slightly even at the highest speeds by placing the bearings further appart. The extruder itself is locked in place so it doesn’t move at all. There is a bit more mass to it than the stock one, but it hasn’t been a problem for the machine to handle, especially after I added the X axis belt tensioner and tightened that up significantly. There some pictures of it and a link to the budaschnozzle compatable quick fit gregs extruder in the thread here: https://forum.lulzbot.com/t/ao-10x-with-a-quick-fit-extruder/268/1 No one makes a hinged accessable extruder for quick fit and a buddaschnozzle yet, so i’ve been just modifying that one after printing since I haven’t had time to draw one up.
Tim
Thanks for the explanation. Something more to keep in mind when I come around to making these upgrades!
Here’s an in progress potential Bam style quick fit carriage. I’ve had to make some compromises that I’m not entirely happy with yet. Bearings mount via threaded M3 heat set inserts on the bottom, along wiht inserts to mount the belt tensioner, etc. I left a fan mount hole up front. ideally it needs to be thicker, but my model is giveing me fits at the moment given the core I started from. Part of the problem is the quick fit extruder package ends up being a bit lower to the carriage deck, so the motor and front gear clearance start becoming issues quickly Once i’m happier with it, there will be a matching tensioner, etc. But for now if anyone wants to play with it, here it is.
xcarriage_Bam-ish_1_a.stl (381 KB)
I have been wanting to incorporate some LED lights that I bought and a fan duct to the upgrade. Lastly, the self tightening mechanism is on the back portion though not all the components are shown…
What do you guys think any comments or suggestion?
Also none of these ideas are original, I have just combined, redrawn and integrated.
That layout looks like it will work fine. Nice design The one consideration with those LED lights would be additional mass on the carriage. The more weight you have on there, the slower it can move, also the more deflection you get in the middle of the smooth rods in theory. Thats the main reason I haven’t added LED’s to my nozzle itself.
As far as the air duct, having the air blow onto the barrel of the hot end will help for printing PLA, it won’t really help with printing ABS. the down nozzle will help PLA printing in general, and ABS bridging, but it will hurt ABS regular print quality. You could always turn the fan off for ABS.
SHiny render!
Piercet,
That is good point. I will see what I can do to shave off some of the weight. The LED arrays themselves are pretty light so maybe if I reduces some the weight of the plastic I can get by. As for the fan duct maybe I should do one for ABS (only blowing on the barrel) and then revise the existing to blowing on barrel in additional to the print.
Why does it t hurt regular ABS printing? Does it solidify before it can adhere to the next layer or does it cause warping and cracking?
-John
ABS doesn’t need barrel cooling at all. the only rason PLA needs it is PLA transmits heat alot further than ABS does, so the heat from the hot end can leach further up the bore with PLA and cause jams before the plastic filliament enters the melt chamber proper.
A fan on ABS causes bridging layers to cool quickly and helps for bridging long gaps. but otherwise the air tends to distort the cooling plastic, which can cause uneven surfaces, layer splitting due to uneven cooling, warping, cracking, etc. PLA on the other hand benifits greatly from that same fan.
