2014 FRC's Biggest Loser

[MrForbes]

One of our students suggested last night that we weigh our robot....so I'm bringing in a scale today. My guess is around 90, we'll see.

[TheFrozenSlink]

Our robot weighs 72.75 pounds. If anyone would like to send us weight go right ahead

[BoilerMentor]

You guys are making me feel self conscious about our robot weight...

[Anthony Galea]

We are at 80.1 lbs, with a 6CIM drivetrain, a pickup, and a shooter. We still have to put on a 2 in stroke cylinder, and that shouldn't add too much weight.

[Chadfrom308]

Originally Posted by DELurker

Hoping you mean Lexan/polycarbonate/Makrolon... Plexiglas is prone to shattering.

Yes, I couldn't think of the name for it!

[MechEng83]

Originally Posted by BoilerMentor

You guys are making me feel self conscious about our robot weight...

we weighed systems last night and are coming up with 120 lbs... We're still missing some important items like the sponsor panel, which is also the entire front of our robot.

Luckily, we designed in some weight savings opportunities should the need arise. looks like we'll be diving into that.

On a completely unrelated note , anyone know where we can get a 26" long 1/2" keyed aluminum shaft? The longest I can find right now is 24"

[nathannfm]

Originally Posted by BoilerMentor

EMERGENCY NUCLEAR WEIGHT LOSS OPTION:

• Remove 2 CIMs from the 6 CIM drive (~7 lbs.)

If you end up a bit over and are not using them elsewhere switching 2 of the cims to mini cims will save you 1.3lb. I have heard they can be used in 3 cim gearboxes like this with the same gearing.

Originally Posted by MechEng83

On a completely unrelated note, anyone know where we can get a 26" long 1/2" keyed aluminum shaft? The longest I can find right now is 24"

MOE is unable to find one either, we may need to get one keyed with a mill, is switching to hex an option for you?

[MechEng83]

Originally Posted by nathannfm

If you end up a bit over and are not using them elsewhere switching 2 of the cims to mini cims will save you 1.3lb. I have heard they can be used in 3 cim gearboxes like this with the same gearing.



MOE is unable to find one either, we may need to get one keyed with a mill, is switching to hex an option for you?

It's an option, it would just require a little more tear-up and a few parts we don't have (but I think could acquire). I'm looking at the churro tube from AM if we go that route. My recollection is that it's loose in the hex hubs, which could cause a problem, so we'll have to check on it.

[Herbblood]

We're currently at about 85lbs. Much better than we've done in previous years

[JamesCH95]

We weighed in at 110lbs fully loaded.

Originally Posted by MechEng83

we weighed systems last night and are coming up with 120 lbs... We're still missing some important items like the sponsor panel, which is also the entire front of our robot.

Luckily, we designed in some weight savings opportunities should the need arise. looks like we'll be diving into that.

On a completely unrelated note , anyone know where we can get a 26" long 1/2" keyed aluminum shaft? The longest I can find right now is 24"

I would be tempted to stick two chunks of shaft together with a ferrule insert to couple them, using a key to ensure that the two shafts' keyways lined up.

Like this:

[nathannfm]

Originally Posted by JamesCH95

We weighed in at 110lbs fully loaded.

I would be tempted to stick two chunks of shaft together with a ferrule insert to couple them, using a key to ensure that the two shafts' keyways lined up.

Like this:

I am not quite sure what this is, but it got me thinking, you could get 2 pieces of shaft, tap the ends of both and connect them with a piece of threaded rod. Same concept I think.

As for hex shaft, I have found that the Vex hex shaft is extremely high quality and precision, you may want to look into that.

[Oblarg]

Originally Posted by nathannfm

As for hex shaft, I have found that the Vex hex shaft is extremely high quality and precision, you may want to look into that.

Unfortunately, I have found that the probability of a vex hex bearing fitting on a vex hex shaft without issue is about 50%, though I might just have really rotten luck.

[JamesCH95]

Originally Posted by nathannfm

I am not quite sure what this is, but it got me thinking, you could get 2 pieces of shaft, tap the ends of both and connect them with a piece of threaded rod. Same concept I think.

As for hex shaft, I have found that the Vex hex shaft is extremely high quality and precision, you may want to look into that.

That's a technique for sticking carbon fiber tubes together to make longer carbon fiber tubes.

It is the same concept, but there are two reasons to not use a threaded rod. First, the keyways would have a negligibly small chance of lining up with each other. Maybe a problem, maybe not. Second, you would have to make darn sure that threading never came apart, or even loosened a little bit. If it did, you'd have threading in bending, and that is a very bad time.

[ratdude747]

Originally Posted by BoilerMentor

With the current position HBR has found themselves in, I thought this might be a fun thing to look at.

Share your robot weight situation and describe your remedy.

Let me start by saying the number on the scale shocked me. I have 9 years of FIRST experience and I've never seen a robot look so light, but weigh so much.

Initial Robot Weight: 138.4lbs
Final Robot Weight: TBD
Anticipated Weight removal (based on list of remedies): ~21 lbs
Remedy:

• Replace 4 Mini Cims with 3 RS550's in Cimile gearboxes (~8 lbs.)
• Rebuild interface frame replacing 1/8" wall 1x1 tube with 1/16" wall (~5 lbs.)
• Replace 40" of steel 1/2" hex shaft with 1/2" aluminum hex shaft (~1.4 lbs.)
• Replace 2-1.75" bore 12" stroke cylinders with 1.0625" bore 12" stroke cylinders (~1.4 lbs)
• Rebuild intake roller with polycarbonate tubing and delrin endplates to replace 3" PVC roller (~2.2 lbs.)
• Remove excess length from any hardware or replace with a lighter option. (~.25 lbs)
• Remove webbing from the robot back plate (~2.5 lbs.)
• Remove 4 unneeded standoffs from drive modules (~.6 lbs.)

EMERGENCY NUCLEAR WEIGHT LOSS OPTION:

• Remove 2 CIMs from the 6 CIM drive (~7 lbs.)

(joking in this post)

Being 1747 alumni, I see some things never change (minus 2010).

Look at some pictures of your 2007 robot (whose name escapes me). To call that robot cheeseholed would be an understatement. It was (from what I was told at the time) accidentally made from 1/8" wall 1" square tubing (not 1/16") and even cheeseholing the frame, (if I remember right) they had to cut the tubing into angle irons to make weight. Even one frame section as cut and replaced by a carbon fiber member...

More seriously, I agree with the list... specifically the hex shaft. Usually AL is a better material than steel for hex shafts. The lone exception was the shooter shaft in Seagriffin (the 2009 robot). Being the student machinist who made the 2nd and 3rd shafts, that one had some gnarly vibrations with aluminum that steel seemed to fix. But otherwise, AL hex seems to be strong enough (although in the past, a bit less than precise when being used for pressed hubs).

[Nick.kremer]

Our 2nd year, 2012, our robot came in, 3 days before ship day, at 150 lbs....to this day I have no idea how we shed 30 pounds without sacrificing any major systems at all.

This year we are set to come in right under 90 lbs!