Working with Quickframe

[Dale]

For the past several years we've used normal T-slot 80/20 to build a prototype/practice robot and then used 80/20 Quickframe to build the competition robot. Using normal 80/20 for the prototype lets us make changes very quickly but it's often too heavy for the final robot...it depends on the challenge. Quickframe is about half the weight.

Quick frame nylon connectors like the 9250 have always worked well for us at the corners but we've never trusted the 9240 when we need to connect a vertical member mid-span. instead we've ended up making our own aluminum L brackets. This is a tedious process.

Has anyone come up with a better (faster) way of joining a horizontal 1" square aluminum extrusion to a vertical member mid span? (Besides welding...we don't have the facilities for that and don't want to send it out since we pride ourselves on being 100% student built).

[Trent B]

Possibly cut it at the point you need a vertical piece and put in a 9230?
http://www.8020.net/Quick-Frame-7.asp

This could be a hassle if it is a last minute addition but otherwise if you carefully think through the order in which you are going to piece together your frame I imagine it would work fine.

[gorrilla]

Simply cut a piece of angle, and you have an instant L-bracket, we used these all over our 09' robot and they worked great.

[Dale]

We didn't want to cut the frame's base members and use 9230s for fear of affecting the stiffness and strength of the frame. I suppose that would be fine higher up if the robot, though.

We have been making our own L brackets as described out of aluminum L material. It's just a pain and it's much fun when you're not dead on accurate lining up the holes.

[AdamHeard]

Originally Posted by Dale

We didn't want to cut the frame's base members and use 9230s for fear of affecting the stiffness and strength of the frame. I suppose that would be fine higher up if the robot, though.

We have been making our own L brackets as described out of aluminum L material. It's just a pain and it's much fun when you're not dead on accurate lining up the holes.

Why not machine/cut the end of the tubing square (the piece butting up against a frame member), then put a small triangular plate on each side as a gusset, then rivet it all together. Many teams have done this well, specifically 2056 this year.

[Gdeaver]

The quick frame connectors do have their limitation. The first year we made our frame based on 8020 quick frame we had a similar problem. We used these connectors.
http://www.eztube.com/connectors/connectors.html
Note there are 2 versions. With a steel reinforcement and without. The problem with them is that they have 2 steps and the step near the joint is to big for quick frame. We set up about 6 students with files and mics and reduced them down. Gave the students something to do while the design was being finalized.
The steel reinforced ones are heavy but extremely strong. The composites may be good enough. The tower was supported by the bottom and top frame rails. We also have filled the voids in the quick frame connectors with epoxy putty and it did add some strength and stiffness. A very thin CA can wick in and bond a joint. 1/8 pop rivet can also help. Team 104 was limited by administration policy to hand tools and cordless drills. Quick frame was great under these restrictions.

[Stephen of REX]

Any advice for a team that has not used quickframe before? Normally we use kitbot chassis, but I believe we intend to use the kitbot parts for our practice bot this year, and something new for the competition bot seems to be in order. Any tips and tricks?

[Chris Fultz]

Originally Posted by Stephen of REX

but I believe we intend to use the kitbot parts for our practice bot this year, and something new for the competition bot seems to be in order. Any tips and tricks?

One of the advantages of making a practice robot is that it can be a great working prototype "build #1" and then lead to an improved competition "build #2" robot. This would mean that you would want to use the same or a very similar chassis system for the two robots.

If you want to use the kitbot parts, you can buy a second kitbot to build robot #2.

[Chris Fultz]

Originally Posted by Dale

(Besides welding...we don't have the facilities for that and don't want to send it out since we pride ourselves on being 100% student built).

Maybe you can find a place that will weld for you, but let the students watch and learn. Seeing the capability and benefits that welding brings could inspire a student to develop that capability for you.

[Stephen of REX]

Originally Posted by Chris Fultz

One of the advantages of making a practice robot is that it can be a great working prototype "build #1" and then lead to an improved competition "build #2" robot. This would mean that you would want to use the same or a very similar chassis system for the two robots.

Well if we have enough reasons to do so, we may just go with quick frame for both. It is considerably lighter, right?

[Dale]

Quickframe is almost exactly half the weight of normal 80/20 1010 extrusion. It's harder to change your mind, though, so we like to use the normal 80/20 extrusion for prototypes.

[Trent B]

Short answer C-Base is pretty close to 8020 1x1 extrusion but much lighter than 2x1. Both are twice as heavy as a Quick frame.

.258 lb/feet

4 35" lengths, 2 28" lengths (I realize some of these would have to be shorter given the fact it would make a 40x30 frame but at those contents it would be around.

4.21lbs for the members. Throw in 4 three way corners (so you can build up) at .065 lbs a piece and 4 90 degree connectors (for the internal bars (the 2 extra 38" lengths) 9240 as an example) are .03 lbs a piece

Total 4.59 lbs with a few extra inches of quick frame aluminum that probably aren't needed.

C-Base (4 35" members at 1.25x1.13" are 1.4 lbs each + 2 28" ones about about .8 of the 1.4lbs or 1.12) total 7.84 lbs

8 corners at .24lbs each total being 1.92 lbs

Total for C-Base is 9.76 without fasteners or basically twice the weight. But the Quick frame has 1/16" walls vs C-Base 1/8" walls so it is "warranted" that the C-Base should weigh about twice as much as it has twice the aluminum thickness.

[Dale]

In reply to Chris, I'm sure we could find a place to have our frame welded, it's more of a philosphical thing with the team. The students are proud of the fact that adults never touch the robot. We don't have a lab where welding could be done, even if we developed the skills to do so.

[James Tonthat]

Gusset plates are cool.

http://picasaweb.google.com/RoboticW...31396482780482