New Compact Carriage

Hey Eric,

I noticed you uploaded a new compact carriage and XY side carriage components. I printed them, and was curious if you had any feedback, negative or positive.

I want to switch from Walters’ Mini Space Invaders carriage to something a little easier to work on, has better cable support, and provides easy access to the hot end.

Sean

I will be honest, I designed it for the group, but never utilized it myself. I know a few have had good luck with it. My opinion on it is, I would like the cross rods to cross closer to the centerline of the axis of the nozzle for stability, but geometry of the Extruder limits this. I would love some critical feedback on improvements I could make. Note the carriage is designed to use heat set inserts in a few places, which gave some people issues to source depending on their location.

I know CNC kitchen on YouTube made a good video about them recently. And there are a few sellers on AliExpress that started selling the nice ones.

An example: Brass Hot Melt SL-type Double Twill Knurled Injection Brass Nut M2M3 100Pcs
https://s.click.aliexpress.com/e/nQ9oF7HQ

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I have found the ones at Trimcraft to work really well. They appear to be real, OEM EZ-Lok’s. Gino’s prices are fair I think. I got 100 pcs of the double fins from McMAster too.

https://www.trimcraftaviationrc.com/index.php?route=product/category&path=75

You also want to try and taper the bores to seat these in. Look at the E-Z Sonic data sheets for geometry. I have had the best luck with respect to location and pullout by making a trancated cone of the OD’s D & S for overall length.

All I can tell you is when I try to recycle a part and pull the inserts out, its a real b*$ch to pull them.

I also use a piece of metal as a heatsink of sorts to put over the insert when I set them- even a v6 heatblock set on top of the part to keep the insert seated and pull the heat ‘out’ of the insert and keep it flush at the top.

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Gino is great. Love trimcrafts selection, and prices are always good.

That remindes me. I am due to restock my at home printer hardware store. I have built enough I am running low again.

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Hey Eric,
I have my printer pretty well disassembled, including all electronics ripped out and carriage and XY mounts disassembled. I was about to assemble and realized there are heat set insert spots in the X Y carriers. I am assuming these are sized for M4, but wanted to confirm. I am also adding a sneak peak of my assembled carriage with Microfit connection! I tired doing microfit a few years ago but gave up and made an ugly collection of wires and soldered joints instead.
I finally ordered a a set of PA-09 crimpers and they work wonderfully for Dupots and molex connectors.
As far as design of the compact carriage, I would make the holes deeper for the press fits and allow for expansion of melted plastic/pass through of screws. The top of the BL touch mount should be angled slightly. When trying to install the microfit connector there is next to no room, and as a consequence the wires get bent pretty severely going into the connector mount
On a complete side-note I am not a huge fan of the Acetone press fit technique and wish this was more of an epoxy connection. y prints always split just a little bit when the bushings are pressed in, no matter how much I ABS soften the surface. Additionally I understand that ABS decreases the strength of ABS plastic.

I know what you mean about the tight wire routing. It’s doable… but requires adding some serous bend into the wires. I thought about spreading things out… but figured compact carriages main point was to increase printable area, so I left it really compact.

What area do you think sloping could help? I can get that added to the model. If I roll over this edge, and open up the pocket underneath… would that help?


All my heat inserts were M3. There are so many varieties of those inserts (different ID/OD/Depths). I should probably call out the ones I use with some notes. But I think I can increase the space below the inserts for thermal squeeze out during insetting. That being said my inserts are tapered m3 heatset… so I had almost no squeeze out during install.

For the bushings, I could make a version with larger bushing holes or some glue channels for epoxy-in methods. Just need to be careful not to get the glue in the self aligning portion of the bushing. Plus if the part is to dimension… it should have room for some glue as designed (See Picture)

Sorry for not responding for a while, was on a business trip. The M3 type inserts I was using were cheap chinese ones with a straight knurl on both sides. I have since purchased some tapered ones with a little more sophisticated geometry, these appear to seat a little more firmly in the XY carriers.

The tight wire routing is actually for installation of the molex fitting (or removal).


I added a chamfer, see above image. It might be too much as it appears to be close to interfering with press-fit holes. Ideally the chamber should only go on the outside edge to facilitate the molex sliding in at an angle.

On a side note, the XY carriage assembly needs M3 pressfit deep into the housing correct? How deep did you go?

Lastly, instead of reprinting the carriage I was going to try heat setting the bushings instead of ABS. Have you ever tried this? Heating up the bushing like you would a press-fit insert? I would hope this would reduce the stress on the layers as ABS is pretty damaging.

Insert doesn’t go deep in the hole. The extra depth is for bolt clearance after the insert for threading in the bolt. For the self alignment bushing don’t heat it. It’s epoxy potted internally for the spherical joint. Heating it will crack the epoxy… Ask me how I know that tidbit of knowledge :slight_smile:

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Thanks for that tidbit of info, I thought I remembered reading they were epoxy set, glad I asked. I’ll just stick with and method for now. I just finished inserting the m3 inserts, they went in nicely, so the holes are perfect as they are. I will probably go back and pull out the low quality inserts to prevent headaches in the future, especially for the hotend mount.

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