FT5 Double X Slide Carriage

[dawjr]

I've had a stock Folgertech FT5 R1 for about a year now and have hundreds of hours of good successful prints with it. Many have modified theirs and that's part of the fun of printing, modifying and improving the machine. Of course many mods have perceived improvements of print quality, many are just wish-list, and some are actual worthwhile improvements.
The only thing that has bugged me about the physical part of the machine is the single linear rail on the X axis, the rail that supports the extruder. Linear bearings are very good in limiting "play" in many directions, but due to the nature of the bearings there is inherent play in a "rocking" moment - in the case of the FT5, this translates into play fore and aft at the nozzle end.
My answer to solve this and remove all unsupported movement is to add an additional linear bearing and rail assembly under the existing gantry extrusion. The rail is readily available from Amazon in a 350mm length and the cost is low. Link to Rail
The attached files and pictures show how I accomplished this. Essentially an elongated version of the melamine FT5 carriage, with some improvements in rigidity and print cooling. Of course we lose 15mm or so in Z capability, a small price.
If you only have one printer you'll have to print this first of course. The assembly procedure is to leave the existing rail in place, mount the new carriage to the top, then tighten, shim, adjust the bottom rail bearing until free movement is achieved. Patience will be rewarded with rock solid, smooth moving carriage that will be free of play and increased resolution tightness layer by layer.
The carriage is available on Thingiverse - Link to Carriage

[Dave]

Looks interesting!

I wonder if the aluminum extrusion is even necessary once you have the extra strength of a second rail? Maybe the whole assembly could be simplified to just a pair of the linear rails, directly bolted to each other, as the X-axis span?

[Ron]

I suspect that the problem would then become the attachment points of the longer (top) slide to the two Y carriage rails.
They might be too flexible.
Also, part of the appeal of a mod such as this is that the two slides are separated by some distance, in this case of course- 20mm.
That makes a wider base distance upon which torque forces from extruder carriage inertia would be acting.

Actually, this is quite an interesting modification.

[BRLewitt]

I've been experiencing play at the nozzle because of the play in the X bearing too and saw this and it looks pretty neat but not sure about the weight it'd add to the assembly. But I wonder if a similar effect could be attained by having a v-rail wheel ride the bottom of the aluminum extrusion.

Ben

[dawjr]

Hey, Ben - Your thoughts about a v-rail bearing are also good ones. Many 3D printers use just that for most if not all of their guides, the CR10 comes to mind - and they get really good results too. You'll have to redesign the mount to accommodate the wheel and axle and more importantly, the adjustment that will be needed to get the right amount of resistance. - Good luck and let us know how it turns out.

Also, to answer your question about weight - the real issue to consider is inertia and the speed at which you print - I very rarely print over 40mm/sec, but I feel this setup would be just fine for up to 60mm/sec. I've had no issues with the modification.

All the best, Don

[Wyvern]

Very cool, I too have OCD about the wobbly backboard.

I was going to do one of 3 things.

1, Design a sling that goes under the motor and back onto the front of the backboard.
2, Copy the design with Fusion and send the file to be cut in thick Carbon fiber, no flex in that stuff!
3, Wait around till the alloy upgrade is available

The bearing it'self is next to zero, WAAAAY better than the poly wheels that the CR10 uses (axial bearings have issues with side load an play, when I had the CR10 I was driven batty with the bearing play)

The problem is the ACM, its stiff, but not stiff enough IMHO for direct extruder cradle duty.

[dawjr]

Hey,
Guys and thanks for your comments. Well it's been 2-1/2 years later
and I've just upgraded my machines to 32bit, BLTouch and Titan Aeros.
What started the upgrade is that I began to print with higher temp
filaments which needed higher temps on the bed. This warped and damaged
the PLA carriage, notably where the extruder motor connected. This
allowed the whole assembly to sag over time. So I redesigned the
carriage to accommodate an 1/8" aluminum angle capturing the bottom
bearing and the back of the extruder. This time I printed out of Prusa
ASA filament, a much higher temp material, this stuff has great
qualities. Very high tensile strength which means great sanding and part
post processing.

The double bearing/rail worked well for years, but I began to question
it when I was assembling the new carriage. I found that I had
intermittent snag/hesitation when test moving by hand. This happened in
different areas of the rail so it was not related to rail or bearing
geometry. I had the same problem with the initial assembly, but went
ahead with it and it never was a problem that I was able to determine. I
chalked it up to ball transfer in the bearings.

But on the new assembly I decided to change. The Titan Aero is a bit
heavier than the MK8, so i decided to eliminate moving mass by taking
off the TOP rail and bearing. This has the assembly essentially
"hanging" from the bottom rail, much closer to the nozzle than stock.
Movement is perfectly smooth with the single bearing. Subsequent prints
are just as good as the double and better than the the top single
original Folgetech design.

The new carriage is a bit of a better design too with replaceable cooling fan nozzles, easier to change that design if needed.

Let me know if you (or anyone else) is interested in the new design and I'll upload that too.
All the best, Don

[csorrows]

This post is highly necro but I'll let it go because it adds a lot to the thread. Please try to post additional info into a new thread. You can always link to this one and it will connect the 2.

Thanks for the follow up on your design.

[Ron]

Too funny.
I am actively into the process of converting my FT-5 into an H-bot drive system.
I have been running an ABS custom carriage for about a year and a half now that doesn't warp or melt.
If the conversion is successful I will post something about it in a new thread along with the .stl part files should anyone be interested.

[csorrows]

My carriage has been PLA for a few years now. Not a single issue.

[Ron]

I'm sure it has to do with how close to heated parts the PLA pieces are located.
On mine the carriage pieces are more or less where the stock FT parts are with the exception of the part cooler nozzle.
The only problem I have had with it is a tiny bit of material creep due to the clamping force of a couple of horizontal bolts.
I have just been too lazy to put load spreader washers on them.