I have seen as well heard about the qualities of 80/20 and its linear motion ability.
We are looking into different methods of linear motion and when we came to 80/20 we could not understand how many teams have done it in the past.
We looked into their specific linear bearing(40-6800s if you have book) that use some sort of plastic to slide ontop of the rails, however we were worried alittle about binding as well as speed. We then came across their roller wheel assemblies(28-2200s in book) which seemed to have a wheel that ran inside the channel and looked like it would be both strong and fast, however we were worried about side load if just using a single wheel…hopefully we can get some to test.
Just wondering if anyone has had any experience with these types of 80/20 linear motion
Also if there is some other way to make linear motion work with 80/20 that you have found to work
In the past we have run 80/20 lifts with a chain and sprocket system. Be careful about using the slide bearings that are commonly found. The higher your tower goes, and the more load at the end of sed tower, the higher chance of binding that the bearings carry. We had in the past constructed our own slide bearings out of lexan and tried a few other tricks to prevent binding and have been very successful. 80/20 is a great material for both simplicity of design and rigidity. I highly recommend its use for lifts.
We have had great success with the 8020 linear slides in 2005. I would highly recommend them if you are looking for a light-weight, off-the-shelf solution. We used the 6760 (english dimensions) bearings, which proved to be very reliable and smooth over 3 or 4 competitions. I’m sure that many other teams (20 and 222 specifically) will agree with these statements.
I will issue a warning with these 8020 linear slides, be sure to loctite ALL of the screws/bolts in these bearings. The do have a tendency to come loose, which will cause the plastic slide to fall out the bearing. (Not good.) This event has happened to us, as well as a couple other teams. With this quick, and simple fix, you will find that these linear slides are a great product.
You can view pictures of our elevator from 2005 here. Feel free to ask any and all questions.
Here’s a diagram of the setup we used for the linear bearings/elevator on our 2005 robot. (See Ben Piecuch’s post.)
Linear bearing “a” was attached to the back (non-moving) 80/20 member, while linear bearing “b” was attached to the bottom of the elevator extension. Here are a few pictures of the linear bearings and our elevator. The first two pictures are when we were working on the robot, so many many of the protective panels were removed from the 'bot. (Click to view larger versions)
Our team uses 28mm extrusion, and instead of using any form of linear bearing we have always used a special delrin slider attachment which fits into the extrusion and acts as a linear bearing (as delrin is self-lubing). the advantage of this is that there are no moving parts really like in bearing, and it gives a more solid connection the more the delrin and aluminium overlap.
please excuse lack of pics. can`t find my CAD files.
In 2005, I believe we used 80/20 linear bearings. We never had a problem with them binding, even with the tetra up 12 feet pulling on our bearings. I can’t get you part numbers now, but I might remember to come back and get you them.
We found that the rail they slide on is very, very heavy, especially for the “light-weight” game of 2007.
Each peice we used was over 5 pounds.
We’re planning to use a similar system to lift tubes this year. We have plans to improve on it, and to make it much faster (full travel in less than one second (/me crosses fingers)) and lighter. We’re only moving a pound of tube
Here are the part numbers and prices of the 8020 slides we’ve used in the past years. These prices are from 2005, so they have probably changed +10-20% or so… Also, we’ve been receiving a 50% discount over the past few years.
All of these parts are compatible with the 1010 extrusions.
6760 - Single UniBearing - $12.50
This comes with all the necessary pieces. We used 4 per stage (2 on each side of the extrusion, 2 on each end of the elevator stage) Extra glides are as follows:
6790 - Single Keyed White Bearing Pad - $1.80
6780 - Standard Shim Stock - $2.60
6792 - Double Keyed White Bearing Pad - $2.85
The sliders listed below can also be used as an alternative, depending on how you’re bolting additional pieces on to your stage, or if you need a longer bearing.
6762 - Single UniBearing (4") - $16.00
6715 - Single Flange Linear Bearing (2") - $32.50
6716 - Single Flange Linear Bearing (4") - $42.90
Oh, other people were wondering where to purchase this material. Goto www.8020.net and use the distributor lookup tool. This is the only way (I know of) to purchase the material. Turn-around time in a couple days. ALL of their parts ship from Indiana, as the distributors don’t really carry much stock. Feel free to PM me or ask more questions here on the forums. I’m happy to help!
The slides used I believe are the 80/20 UniBearings. These come in a wide variety of styles, Doubled, long, and can fit any type of 80/20 (1010, 1515, and metric sizes). Check the catalog for more details.
I have been looking at the pictures that they have posted and I don’t see any of the unibearings or any bearings for that matter. If I can figure out what they used for the slides, then I can easily cut about half of the weight out of our elevator.