pic: REV Robotics building system

[BJC]

Originally Posted by Greg Needel

snip/

2) Linear motion is normally hard or expensive. Over the past 13 seasons I have been involved in FIRST there have been many amazing products which have changed the game (things like the shifting transmission, systems of gearboxes, sprockets, and wheels that just work together). The one thing that has remained hard for teams is linear motion. There are low cost options like drawer slides and more pricey solutions like ground rods and linear bearings but up to this point nothing that was designed with building a robotics elevator in mind. The V groove bearings and integrated features in the 1 inch profile allow for super easy integration anywhere in your mechanism.

/snip

It seems to me that the x shape and the very thin material that allow for the nut pockets on all four sides make this extrusion very susceptible to twisting loads. I noticed above you advocated using this for an elevator. Currently, many teams prefer 2x1 rectangular tubing for an FRC-type elevator because (among other reasons) its resistance to twisting is highly desirable to prevent binding. While it is probably serviceable in shorter/low loading situations, in a game such as 2011 Logomotion where elevators where the full 60" tall I don't think this extrusion would function very well in place of 2x1.

I do think that this is a really cool addition to teams' resources though. With the sliding nuts on each side it could especially have FRC applications in rapid prototyping.

Cheers, Bryan

[sanddrag]

Generally, with this type of profile available from other manufacturers, the purpose of the T-nut is to drop it in anywhere on the profile, and then it rotates into place before tightening. This allows for easy additions of brackets to the middle section of the beam, even if the end sections already have brackets and hardware installed.

How would this be accomplished with normal hexagonal nuts? Would you pre-load the profile with any and all hex nuts you ever intend on using, and let them float free until you do? Or would you need to disassemble bracketry on one end to add something more to the middle?

[JB987]

Originally Posted by sanddrag

Generally, with this type of profile available from other manufacturers, the purpose of the T-nut is to drop it in anywhere on the profile, and then it rotates into place before tightening. This allows for easy additions of brackets to the middle section of the beam, even if the end sections already have brackets and hardware installed.

How would this be accomplished with normal hexagonal nuts? Would you pre-load the profile with any and all hex nuts you ever intend on using, and let them float free until you do? Or would you need to disassemble bracketry on one end to add something more to the middle?

Or perhaps an actual drop in t-nut would also work on this extrusion?

[Greg Needel]

Originally Posted by BJC

It seems to me that the x shape and the very thin material that allow for the nut pockets on all four sides make this extrusion very susceptible to twisting loads. I noticed above you advocated using this for an elevator. Currently, many teams prefer 2x1 rectangular tubing for an FRC-type elevator because (among other reasons) its resistance to twisting is highly desirable to prevent binding. While it is probably serviceable in shorter/low loading situations, in a game such as 2011 Logomotion where elevators where the full 60" tall I don't think this extrusion would function very well in place of 2x1.

I do think that this is a really cool addition to teams' resources though. With the sliding nuts on each side it could especially have FRC applications in rapid prototyping.

Cheers, Bryan

The profile is actually much stiffer in torsion than what you would expect, but yes a 2x1 would be be stronger. You nailed it, as the implementation of the system is game specific, as some time a bit of twisting is acceptable (light game objects such as 2011). If people wanted to use this with heavier or more stout assemblies you can do a braced 2 post lift style (which I think is actually more common) and where the twisting on the individual member is less of a factor.

I agree about the prototyping, there have been many years when even if our extrusions don't end up on the robot the flexibility to prototype with them is huge.

Originally Posted by sanddrag

How would this be accomplished with normal hexagonal nuts? Would you pre-load the profile with any and all hex nuts you ever intend on using, and let them float free until you do? Or would you need to disassemble bracketry on one end to add something more to the middle?

Generally speaking you would load the rails from either side with nuts, but another method I have tested is to cut a clearance hole (just over 3/8) in the channel where you just remove just the retaining flange and then you can drop them in. This almost has no strength loss (bending) and is easy to do with a cordless drill.

Originally Posted by JB987

Or perhaps an actual drop in t-nut would also work on this extrusion?

I have tested a bunch of t-nuts with the system and some work and some don't. Most 1" profiles use 1/4-20 hardware, where this system uses 10-32 (or 24) so the nuts are bigger than the channel due to the corner holes in the profile. There are some smaller t-nuts designed for smaller profiles that do work with the system. We are not planning on selling t-nuts but if teams find ones that work we will be sure to link them from our product pages so a team can use them if they want that feature. In the future if people really want a drop in t-nut we can investigate making one specifically for this profile.


I love all of these questions! Right now REV is just a small start-up who wants to bring value products to the community. We will always be open to feedback from you all to help make our products better.

[aldaeron]

I know details are coming "very soon" but would you be willing to share the material, MOI, weight per foot and (approx) cost per foot of the two extrusion profiles now? I am sure there are lots of fancy add on plates and connectors that we will see soon on AM.

Thanks!

-matto-

[Chris_Elston]

Very happy to see something for FRC in linear rail. We've used some openbuild rails before with a V-Groove channel. Great stuff to work with. Easy to use. AFFORDABLE and not like 80/20 or Item, especially the PRICE. We live 20 miles from 80/20 and it still cost us alot of money to purchase 80/20 direct from them. We had over $1000 in 80/20 for our pit organizer "general store" we call it. Most of the time we try to have Neff Engineering donate what we need.

But for parts on the robot a v-slot linear rail like this is awesome to see, especially if it will be tailored toward FRC. Here is a sample of openbuild v-slot we've been toying with.

https://www.youtube.com/watch?v=584Z...lQzERoYxWPeI1w

[JB987]

Originally Posted by Chris_Elston

Very happy to see something for FRC in linear rail. We've used some openbuild rails before with a V-Groove channel. Great stuff to work with. Easy to use. AFFORDABLE and not like 80/20 or Item, especially the PRICE. We live 20 miles from 80/20 and it still cost us alot of money to purchase 80/20 direct from them. We had over $1000 in 80/20 for our pit organizer "general store" we call it. Most of the time we try to have Neff Engineering donate what we need.

But for parts on the robot a v-slot linear rail like this is awesome to see, especially if it will be tailored toward FRC. Here is a sample of openbuild v-slot we've been toying with.

https://www.youtube.com/watch?v=584Z...lQzERoYxWPeI1w

Fantastic product with tons of great potential. Any idea of the per foot cost for rails and cost of some of the roller components? I wonder if they would offer any discount to FIRST teams.

[Monochron]

Our team has recently looked into OpenBeam after having it recommended to us by a nearby team. OB also claims to be interfacable with common hardware and not specialized stuff, though it doesn't seem the have a good V channel like some others. Can't quite tell whether your offering is better just yet, though the fact that you are advertising it on CD is certainly a good sign.

[Tristan Lall]

Will you have datasheets with more detailed information like:

• Fully dimensioned drawing of the profiles;
• List of available lengths;
• Tolerance information (whether complete as if for manufacturing, or limited to that which would be useful for interfacing), including some measure of twist per distance;
• Standard structural constants (like section moduli) for quick comparison with other systems;
• Alloy specifications including composition and temper;
• Finish specifications including surface treatment (composition, thickness, hardness) and bulk material properties (hardness, roughness);
• Recommended tooling; and
• Warranty?

[Greg Needel]

Originally Posted by Chris_Elston

Very happy to see something for FRC in linear rail. We've used some openbuild rails before with a V-Groove channel. Great stuff to work with. Easy to use. AFFORDABLE and not like 80/20 or Item, especially the PRICE. We live 20 miles from 80/20 and it still cost us alot of money to purchase 80/20 direct from them. We had over $1000 in 80/20 for our pit organizer "general store" we call it. Most of the time we try to have Neff Engineering donate what we need.

But for parts on the robot a v-slot linear rail like this is awesome to see, especially if it will be tailored toward FRC. Here is a sample of openbuild v-slot we've been toying with.

https://www.youtube.com/watch?v=584Z...lQzERoYxWPeI1w

Originally Posted by Monochron

Our team has recently looked into OpenBeam after having it recommended to us by a nearby team. OB also claims to be interfacable with common hardware and not specialized stuff, though it doesn't seem the have a good V channel like some others. Can't quite tell whether your offering is better just yet, though the fact that you are advertising it on CD is certainly a good sign.

I love some of the innovations that some other companies have been coming out with. Things like Open Beam, Maker Beam, Maker Slide, 80/20, ITEM, V-slot, etc. When we were designing these profiles we had to think carefully to optimize what FRC and FTC teams would want in their ideal profile. In keeping with this all of our designs will also be opened sourced so people can build on them and make new advances for their own specific applications.

Originally Posted by Tristan Lall

Will you have datasheets with more detailed information like:

• Fully dimensioned drawing of the profiles;
• List of available lengths;
• Tolerance information (whether complete as if for manufacturing, or limited to that which would be useful for interfacing), including some measure of twist per distance;
• Standard structural constants (like section moduli) for quick comparison with other systems;
• Alloy specifications including composition and temper;
• Finish specifications including surface treatment (composition, thickness, hardness) and bulk material properties (hardness, roughness);
• Recommended tooling; and
• Warranty?

Yes, we will be releasing most of the information you requested. Here is some basic info now.

Both profiles are 6063-T5 clear Type II anodized. With 2 mm flatness and 3/4 a degree twist tolerances per meter of length.

The Extrusions will be sold in single length options (to reduce shipping costs)

6ft lengths of the 1inch
1 meter lengths of the 15mm

[Richard Wallace]

Originally Posted by Greg Needel

The Extrusions will be sold in single length options (to reduce shipping costs)

6ft lengths of the 1inch
1 meter lengths of the 15mm

If your choice of lengths is not final now, may I recommend a shorter length for the 1"?

72" (6ft) of this extrusion is too long for most uses on a FIRST (FRC or FTC) robot, and makes for awkward scrap. One meter would be more generally useful, IMO, and would allow you to standardize on packaging for both of your sizes.

[MrRiedemanJACC]

Do you have a Solidworks profile of the extrusion yet? Would love to have students start throwing into there and "playing" with it!

[ttldomination]

This is super intriguing. Even some of the other posts in this thread are pretty informative; I didn't know 80-20-esque solutions existed that were linear motion friendly.

I would be interested to see...

1) The final specs relative to 8020
2) The final price
3) How well this interfaces with the existing 8020 solutions.

I think (3) is of particular note. While this solution seems to "free" teams of some of the restraints of 8020, the same teams have often invested significant capital into 8020.

Originally Posted by Richard Wallace

If your choice of lengths is not final now, may I recommend a shorter length for the 1"?

72" (6ft) of this extrusion is too long for most uses on a FIRST (FRC or FTC) robot, and makes for awkward scrap. One meter would be more generally useful, IMO, and would allow you to standardize on packaging for both of your sizes.

I believe the idea is to cut the larger pieces down to size. In the past, my teams have purchased 8020 in 10' lengths simply because it's a bulk purchase. Additionally, if the longest rails are ~3', then teams would probably look over this solution if the game involves reaching particularly high (don't get to maximize the presumed 60" height limit).

- Sunny G.