Would aluminum carriages be worth it? (Page 1 of 2)

Link to the video? I've had thoughts of printing mine in T-Glase for strength without adding insane mass. Most expensive carriages in the universe . . .

Hmm, community order of machined aluminum carriages??

My thoughts on it though are that it would add unnecessary mass, I would assume. When it comes to the carriages I don't think there's really any slop in the printed parts. Printed at 100% they are tough and can handle the tension of the belts or line. More mass just seems like more resonance to me. But on good bearings perhaps more mass takes away additional play and allows for more precision movement at higher speeds. Hard to say! Sounds neat.

LOL  Like which came first the chicken or the egg?

That would be awesome! Does anyone know how to design this? I can 3d model stuff for printing, but modeling something for machining seems like it would require more/different skills.

Ugh if only I was going to be near my machine sooner than January Id be happy to try to whip something up. I have Autodesk inventor which can make dimensioned drawings pretty easily (in fact it's part of my routine workflow).

One important thing to keep in mind is threading. Since it would be aluminum you don't need nut traps and could tap the threads right in.

I'm all for it and would give it a go, and pitch in for a quantity parts order. For science!

But no chance of me being able to help much with any design until January.

What hot end is that in the video?  I would drop ~$50 on metal carriages if there was a group buy option.

The proper method is thermal expansion - freeze the bearing, heat the mount with a heat gun or oven.

Makes sense, thanks.

One other thought I was having is related to the X rod spacing. Wardjr and I were discussing vibration of the extruder motor during direction changes. He hinted at spacing the rods further apart as a potential method to reduce this. I don't know how willing folks would be to experiment with this idea, but it's one I wanted to throw out if we're talking about new carriage design.

I can't think of any immediate additional features I'd like to see on the carriages. So far the accessory mounts on the lawsy carriage have been sufficient for me.

10mm hole, 6061 alloy (~20*10^-6mm/mm per degreeC), 300C dT:

60 microns. That's not a tough tolerance to hold on a CNC, and that's before cooling the bearing.

Could also do a clamping style mount, like E3D uses on their heater cartridges - that copes with variations of almost 10% of the diameter.

Yes. They are 8mm rods along X and Y.  The bearings for the lawsy carriage are LM8UUs for the 2,3 and 4.

For the record, I much prefer the idea of squishing the bearings in like e3d does with their heater cartridges. It's less permanent. Higher quality LM8UUs are like $5 a piece and I'd hate to sacrifice them permanently.

IronMan, if you're going to give it a shot I have one more idea. Can we get a bearing on the X pulley? I hate the idea of it riding on a screw!

OK...here is a start:

Linear Bearings not shown...chose to go with the clamping action on the gantry sides per elmoret's suggestion; then use a half-clamp for the carriage.  Need to pop on a front plate for the stepper motor and hotend mount...

3D PDF attached.

Feedback?

I like the simplicity of the Y-rod carriages.  I think the X-carriage is limited in the area of mounting/extruder options.  I would imagine printed adapters would work though.
Here's the thing about all of this (an effort I support) I think we tend to get all excited over the whole "Speed" thing.
I have watched that video over and over,  I am not convinced I can't already print that fast.  Of course I don't know what the actual numbers are so I have to just try and judge it.  What I see is the Y-belts flopping during direction changes and no matter how solid we make the carriages backlash is still backlash.  And although with a print of that nature it is difficult to see any ill affects from the backlash, it must be there.  So was the extrusion rate manipulated to cover some of that up?

I guess what I am getting at is for those of you that have not yet upgraded to the fishing line,  wouldn't that be a much cheaper and effective upgrade?  I have been swamped with year end stuff at work but when I get time I am going to print that (fast) and post up a video.  I think you will be amazed at how rigid everything is.
So for as much as I like this idea I really enjoy being able to design and redesign the carriages based on my needs.  Lets face it things change a lot in the world of 3d printing (Think the next Bulldog or E3d).   

So for now keep up the good work and let me know if there is anything I can help with