Standard vs. Custom Frame

[Cody Carey]

Originally Posted by Viper37

Disingenuous from your point of view, not my own. Save the rhetoric.

The kit bot material is weak. Wack 2 pieces togeather and note the fat chunk of aluminum missing. That is what happens to low quality aluminum stock such as what we are provided with.

On another note, last year bumpers were few and far between, seeing as just about everyone couldnt make it up the ramp with bumpers.

Im not saying this on baseless grounds. Pleanty of people agree with me.

Ok... The Idea of the kitbot frame being weak is something that I had to batter out of my teammates' collective heads when it first came out. The arguments came up of weight, strength, and versatility in designing additional components. Weight was no problem, we just took a 2' length of extruded and a 2' length of kitbot rail and weighed them... even though the kitbot was slightly heavier, the difference was so slight that it didn't matter. Strength was a little harder, and after thinking it over, we decided to test this by smashing samples of both materials in an Arbor press. The Kitbot rail performed exceedingly well. After a little discussion about the ease of adding functional modules to the evenly spaced holes in the kitbot frame, we decided to go for it. We liked the way it held up the first year, and decided to use it again last year.

Last year, we were one of the most physical teams on the field, and the kitbot frame stood up to everything we could throw at it: High speed collisions, 5 robot pile-ups, everything. All with no bumpers and a removed front rail... with the default configuration. The frame is still as structurally sound as the day we shipped it.

The only problem we've had so far, is that the middle axle hole in the frame oblongs and causes drive-chain issues. We only noticed this last year, after two regionals (one of which we won), championships, and an off-season comp.
I believe that signs of wear can and should be expected after the battering we put it through in those four competitions.

And as for This comment:

Originally Posted by Viper37

You must not get very far then.

2 years running we have used the kitbot frame. 2 years running the front and rear are badly smashed in.


Time to get our brand new TIG/CNC Aluminum frame from HP's machine shop!

We won the Philly regional last year.



I did not write this post on baseless grounds, either. I wrote it on two years of experience with the kitbot frame.

[=Martin=Taylor=]

Instead of guessing at whether the kit bot is "strong" or "weak" maybe its time we actually did some tests and found out...

These are stress analysis tests my team did with inventor 10. All peices are the same length, and subject to the same variables, so it should give you a pretty acurate comparison.

Kit Bot Side Rail:


10-10 80/20:


Al Tube Stock:


These are all deformation tests. You may be suprised to find that the kit-bot rails are the strongest (which makes sense considering their profile).

I have only the vaguest understanding of how these tests are done. One of our mentors did them.

Despite these tests my team has decided to use 80/20 in our drivetrain b/c it will make chain tensioning easier (we had more problems with chains then frame breaks).

[Viper37]

We were going to use some great tensioners last year but ran out of weight budget. Ill find them.

They are nice because they mount nowhere, and straddle both sides of the chain.

[TVan]

Team 85 used the kit frame the past two years with great success.
We used the kit frame to free up time to focus on the challenge.
I can not say if we will use the kit frame this year, Our students will make all the tough decisions after kick off.
I think the kit frame is a very good stock frame.
And you can win using it.

Tim

[Veselin Kolev]

Custom frames are by far the superior in performance, lightweight and strong if well designed.

However, you must design everything first. Randomly drilling mounting holes afterwards with a hand-drill is unprofessional and mistakes can happen.

I design the entire robot first, including electronics and wiring. Then you make everything. If you're good, you can machine and weld the frame in 20 hrs work or less.

[Viper37]

So my reply was deleted...

Ok then.

Ill just retype it.

Im speaking from 2 years of using the basic kit as well.

[Madison]

Originally Posted by Viper37

So my reply was deleted...

Ok then.

Ill just retype it.

Im speaking from 2 years of using the basic kit as well.

Your reply consisted of nothing but a smiley face. If contributions aren't relevant to the thread or forum, they'll be deleted.