I was doing some Mendel study and discovered this great video about how it's axes work: http://vimeo.com/6982104
It inspired me to try to build my own, and obviously, I started with Makerbot's y-stage.
There are two versions of the design: (one for old-school makerbots and one for the new guys)
The makerbot who is axes I am redesigning is super old school and has the original 8mm steel rods (instead of the present ~6.3mm). Luckily parametric modeling means changing the layout to accommodate the sticks was as simple as changing two measurements.
I've done a bunch of testing using the y-stage (both versions) and have discovered that it works incredibly well. A few benefits of this more complex and arguably over-kill layout:
- It doesn't matter where the drive belt applies the force to move the point. No torque will ever jam or stick the point.
- This means you may turn the power WAY back on the y-stage. My bot is now about as close as you can get to quiet when it moves straight in the y-direction.
- It manages variability in the rods far better than the current layout. Even if the rods aren't perfectly parallel, it'll work just fine.
This design is just 90% complete however. Everything works awesomely except I am stumped as to a fantastic way to attach and organize the drive belt. As it stands I am just using a bolt and a few washers to fasten it and letting the other side of the belt (which moves in the opposite direction) rub against the inside of one of the printed parts. Far from ideal but it works.
I'm going to try to attack the x-stage soon and possibly arrange the y-bars a bit differently to see if I can come up with a solution there. I'll keep you posted.
Also... A movie of some early testing:
There are two parts to print: y-stage and y-stage-2 (select the one's that fit your makerbot's batch)
(I have a batch 7 bot and I believe those'll work for some of the new guys... I forget which batch it was that first introduced the slimmer bars)
There was a flaw in the original batch7 layout that I uploaded. I didn't account for the difference in build platforms. Changes are made and the documents should be all set to print today. Sorry for any inconvenience.
There's some essential hardware listed below.
It should be pretty simple to figure out but remember to always have a washer on both sides of the bearing so that it moves nice and easily.
Solidworks files are in the . Zip to your editing and perusing pleasure.