Alternative to T-Slot wheels?

I'm building an XYZ machine out of extruded aluminum and briefly but seriously considered v-slot. But it turns out that the cost of the wheels alone (at almost $5 each!) quickly got out of hand and became the single most expensive component of the whole project.

I imagine these wheels are designed to withstand immense forces and hold up in the most demanding of applications, but a simple reprap is not a demanding application. My back-of-the-envelope musing suggests that a simple bearing, screws, washers, and solid but not unicorn-tears-imbued wheel should run around $1.50 each, perhaps less at scale, and even less from the vendors you find on ebay and aliexpress.

Do we have any other options for v-slot wheels than buying the premium OEM parts or machining our own?

You are right, there are better ways, and they can be cheaper if you are willing to put in some effort to find deals. Look into used linear guides via ebay. There is almost nothing more precise. Used linear guides are usually about the same cost as a V slot extrusion, a bunch of wheels and the hardware to hold it all together, and they are much more compact.

Here's the X axis in my printer:



Here's a photo of it prior to some small modifications:



It's a fully modular X axis that is held on the Z screw assemblies by just two bolts and can be removed for service quickly and easily, then put back just as quickly and easily. The linear guide is screwed to a piece of 1"x1" aluminum tubing which also supports the printed motor mount and belt tensioner/idler pulley. The extruder carriage is a piece of aluminum tubing and an L bracket. There is no easily detectable play in the bearing block and the resulting print quality is nothing short of fantastic. I bought that linear guide with two bearing blocks via ebay for $60.

I used 1.5" x 1.5" 8020 type extrusion to build the printer's frame- the 20mm x 20mm stuff is too flexible for any but the smallest printers, in spite of what you see being sold in the hobbyist printer market. I picked up my 8020 at a local scrap yard for $2 per lb.

You can see what the X axis used to look like here, before I redesigned and rebuilt the whole printer:



You can see the current version of the printer by following the link in my sig, below.

You can see the X axis in action, here:
SoM print bed flatness scan

Edited 2 time(s). Last edit at 10/19/2015 08:44PM by the_digital_dentist.

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Ultra MegaMax Dominator 3D printer: [drmrehorst.blogspot.com]

I just finished getting rid of my linear sliders. They came with my Folger Kossel kit, and were a real PITA to clean up and get somewhat smooth. Even then, they took constant lubing while printing.

Looking at the options, I felt that wheels on bearings would have their own issues.

I've had experience with using HDPE blocks on round linear rails with my cnc, so I came up with the following:




The carriage blocks are from dc42 on thingiverse, and the green blocks are oil impregnated nylon from mcmaster.com . So far, I haven't needed the tension screws as the blocks are under tension from the side arm of the carriage block itself.

Rick

That's an interesting approach Rick... How much mileage do you have on your setup? How smooth is the movement? And..how long do you project the nylon will last?

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simspeed
That's an interesting approach Rick... How much mileage do you have on your setup? How smooth is the movement? And..how long do you project the nylon will last?

It all got together this week, and I have a few prints on it so far with no issues. The nylon blocks don't get any wear, like the ones on my CNC, so that won't be an issue.

Rick

If you get a chance, show some of your prints close up so we can see the layer detail. I'm interested in the application of impregnated plastic for the bearing contact. Thanks...TP.

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simspeed
If you get a chance, show some of your prints close up so we can see the layer detail. I'm interested in the application of impregnated plastic for the bearing contact. Thanks...TP.

That would only be useful if I had a print from before where the only change was the slides so you could see a before and after.
Sorry, but I have made other changes also. Sigh.

Rick

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llamatrails

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simspeed
If you get a chance, show some of your prints close up so we can see the layer detail. I'm interested in the application of impregnated plastic for the bearing contact. Thanks...TP.

That would only be useful if I had a print from before where the only change was the slides so you could see a before and after.
Sorry, but I have made other changes also. Sigh.

Rick

While not a before/after comparison, here are some shots of a print done in PLA today:





Rick

Edited 1 time(s). Last edit at 10/27/2015 05:30PM by llamatrails.

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tylerl
I'm building an XYZ machine out of extruded aluminum and briefly but seriously considered v-slot. But it turns out that the cost of the wheels alone (at almost $5 each!) quickly got out of hand and became the single most expensive component of the whole project.

You don't have to pay 5$ per wheel, this is the price for the package : wheel + bearings + Shim.You can buy the wheel alone and then a pack of 50 bearings in china. Then the price drops to 2€ per wheel. I did that for my x and Z axis and it works very well, the carriages are very smooth and have absolutely no play.

Edited 1 time(s). Last edit at 10/29/2015 07:30AM by dewasa.

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llamatrails

While not a before/after comparison, here are some shots of a print done in PLA today:

escher-1024x768.png

escher-closeup.png

Rick

Everything looks sharp Rick....what were the layer settings?

Received 20 sets of wheels for 32$ total. Includes wheel, 2 bearings, washer, shim, shaft and lock nut a set. 1.60$ per set.

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Putzer
Received 20 sets of wheels for 32$ total. Includes wheel, 2 bearings, washer, shim, shaft and lock nut a set. 1.60$ per set.

Can you share where you got these from? The best I can seem to find is around US$3/wheel.

Not the US, but a reputable Chinese vendor:

[www.robotdigg.com]

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