22-05-2015 18:58

Mike Marandola

Re: pic: GBX-123 chassis example

How thick is the G10?

22-05-2015 19:24

asid61

Re: pic: GBX-123 chassis example

Quote:

Originally Posted by Mike Marandola How thick is the G10?

22-05-2015 19:32

Greg Woelki

Re: pic: GBX-123 chassis example

Quote:

Originally Posted by asid61 1/16".

22-05-2015 19:40

asid61

Re: pic: GBX-123 chassis example

Quote:

Originally Posted by Greg Woelki Are you envisioning mounting electronics to the G10? I am curious about what, if any, stiffening supports would be needed with that thickness. I would be happy to hear from anyone with experience with this.

22-05-2015 19:45

R.C.

Re: pic: GBX-123 chassis example

Quote:

Originally Posted by asid61 I'm going off what AdamHerd said about bellypans; I haven't used it before.

22-05-2015 19:55

PAR_WIG1350

Re: pic: GBX-123 chassis example

Quote:

Originally Posted by R.C. lol I think he's changed his mind since then

22-05-2015 19:59

asid61

Re: pic: GBX-123 chassis example

Quote:

Originally Posted by R.C. lol I think he's changed his mind since then

22-05-2015 20:17

AdamHeard

Re: pic: GBX-123 chassis example

Quote:

Originally Posted by PAR_WIG1350 Is there a story behind this?

22-05-2015 20:33

TheOtherGuy

Re: pic: GBX-123 chassis example

Quote:

Originally Posted by AdamHeard Plywood Yo

22-05-2015 20:33

asid61

Re: pic: GBX-123 chassis example

Quote:

Originally Posted by AdamHeard Plywood Yo

22-05-2015 22:23

asid61

Re: pic: GBX-123 chassis example

Checked the weight in SW, plywood is only 0.3lbs heavier than a garolite bellypan. And it's cheaper and easier to work with, so we may well end up going that route.
Would 7/32 or 3/16" work instead? The last bit of extra weight is killing me.

22-05-2015 23:20

Greg Woelki

Re: pic: GBX-123 chassis example

Quote:

Originally Posted by asid61 Checked the weight in SW, plywood is only 0.3lbs heavier than a garolite bellypan. And it's cheaper and easier to work with, so we may well end up going that route. Would 7/32 or 3/16" work instead? The last bit of extra weight is killing me.

22-05-2015 23:31

cxcad

Re: pic: GBX-123 chassis example

Quote:

Originally Posted by asid61 Checked the weight in SW, plywood is only 0.3lbs heavier than a garolite bellypan. And it's cheaper and easier to work with, so we may well end up going that route. Would 7/32 or 3/16" work instead? The last bit of extra weight is killing me.

23-05-2015 01:12

asid61

Re: pic: GBX-123 chassis example

Quote:

Originally Posted by cxcad That little bit of extra money though...

23-05-2015 01:21

AdamHeard

Re: pic: GBX-123 chassis example

Quote:

Originally Posted by asid61 Can't argue with that. However, it's going to be tricky to convince the team that plywood makes for a good bellypan. Usually our issue is with weight/design, not money.

23-05-2015 01:26

Rachel Lim

Re: pic: GBX-123 chassis example

Quote:

Originally Posted by asid61 What are the advantages over G10 though? Is it lighter?

Quote:

Originally Posted by AdamHeard I posted in a bellypan thread the tradeoffs between several options but am on mobile and can't hunt it down.

Quote:

Originally Posted by AdamHeard I'm going to toot my own horn for a moment.... We've done 1) 1/16" G-10/FR4 Garolitem (2009, 2009 offseason, 2010, 2012) Pros -Looks darn good (glossy black) -Very Stiff/strong -Easy enough to drill, but vacuum the mess! Cons -Expensive -Waterjet delaminates it, so they pierce 3-4" away from final cut and feed over. We did some external slots to act as rivet holes, then match drill rest on robot. 2) 6mm (~1/4") 5 ply baltic Birch (2012 offseason, 2013 season, 2014 offseason, 2015 season) Pros -Easy to cut -Cheap -Very HIGH stiffness to weight -Can thread fasteners right into it for components -When painted, looks nice enough. Cons -Termites -Ignorant teams look down on it. This is fine, it just points out their lack of understanding of material properties and basic math 3) .125 6061-T6 diamond pattern (Waterjetted/lasercut). (2011 season, 2011 offseason, 2014 season) Pros -Hypetrain -Forces you to do layout Cons -Expensive resource wise -Not as stiff as the other 3 items -One and done, no mods 4) .25 ABS (if you count 294). This is similar enough to (2007 season) -It's really just a heaver version of plywood. I'd use plywood over this. I highly recommend the wood, no need to laminate or do anything to it. Just use it as is. If your frail ego can't handle the wood, garolite is a great option at 1/16" thick but requires more tools to work with. The diamond bellypan is nice... but in nearly all cases is a huge resource waste. Many subsystem gearboxes and gussets could be cut in the same time.

23-05-2015 01:36

asid61

Re: pic: GBX-123 chassis example

Quote:

Originally Posted by AdamHeard Why? Analayze it from an engineering sense and explain the tradeoffs. Most teams are several orders of magnitude away from being optimized enough for bellypan choice to even matter much anyway. I posted in a bellypan thread the tradeoffs between several options but am on mobile and can't hunt it down.

23-05-2015 03:26

chrisfl

Re: pic: GBX-123 chassis example

Another really lightweight pption is 1/2in or3/16in corrugated plastic. That stuff is sure light and great for electronics boards. We've used it the past few years and have seen many teams using it before. You can even get it in colors to look good

23-05-2015 10:39

philso

Re: pic: GBX-123 chassis example

Quote:

Originally Posted by asid61 We're usually somewhat of a tradition-led team. We recently changed officers, so I'll have to speak with the new officer team about their thoughts on plywood. Compared to the punched 1/8" 5052 we use now, pretty much anything is better. Garolite makes it look more "professional" compared to plywood, but I feel like we could just paint over it.

23-05-2015 13:54

MichaelBick

Re: pic: GBX-123 chassis example

The biggest negative (performance wise) to plywood over G10 is that it is thicker. If ground clearance is important it can make a difference. Otherwise its much easier to manufacture and secure components into(pre drill and then self tapping screws). The extra weight is negligible because it is so low to the ground.

24-05-2015 00:19

highlander

Re: pic: GBX-123 chassis example

Quote:

Originally Posted by philso There was a mostly wood robot in the Tesla Division that exhibited better workmanship and looked more professional than 80% of the other robots in Tesla.

24-05-2015 02:14

PAR_WIG1350

Re: pic: GBX-123 chassis example

Quote:

Originally Posted by highlander I have to address a pet peeve here: anecdotal evidence. Stating a random example doesn't prove or disprove anything. Has anyone actually performed a statistical test on how wooden robots perform vs how metal robots do? I don't know or suspect an answer, it just would be interesting to know.

24-05-2015 02:57

asid61

Re: pic: GBX-123 chassis example

Quote:

Originally Posted by highlander I have to address a pet peeve here: anecdotal evidence. Stating a random example doesn't prove or disprove anything. Has anyone actually performed a statistical test on how wooden robots perform vs how metal robots do? I don't know or suspect an answer, it just would be interesting to know.

24-05-2015 12:09

MichaelBick

Re: pic: GBX-123 chassis example

Quote:

Originally Posted by highlander I have to address a pet peeve here: anecdotal evidence. Stating a random example doesn't prove or disprove anything. Has anyone actually performed a statistical test on how wooden robots perform vs how metal robots do? I don't know or suspect an answer, it just would be interesting to know.

24-05-2015 12:16

Jared

Re: pic: GBX-123 chassis example

Quote:

Originally Posted by highlander I have to address a pet peeve here: anecdotal evidence. Stating a random example doesn't prove or disprove anything. Has anyone actually performed a statistical test on how wooden robots perform vs how metal robots do? I don't know or suspect an answer, it just would be interesting to know.

26-05-2015 15:15

AdamHeard

Re: pic: GBX-123 chassis example

A plywood bellypan is easily rattle-canned black, and no one would ever know it's wood.

The wood we use is a 5 ply baltic birch at 6mm thick. It's density is .025 lb/in^3.

For a structural bellypan two things are happening load wise.

1) Shear loads are being transferred corner to corner.
2) frame torsionally loads are reacted.

Most reasonable materials easily satisfy #1 if attached properly. The second is harder, and is one of the advantages of the plywood (over the garolite) due to stiffness. The increase in stiffness mainly comes from the much greater thickness.

We like the wood because it's so easy to work with, and meets the performance specs we need. The garolite works, but is much harder to get cut how we need and costs far more.

12-07-2015 10:18

evanperryg

Re: pic: GBX-123 chassis example

We use perforated aluminum sheet like this stuff. It's surprisingly strong, and offers plenty of pre-made spots for zipties and other cable management hardware. It's not particularly heavy, either. The one thing I hate about it is that the holes don't line up with component holes, but some precision drilling can make up for that.

Anyway, cool gearboxes. I couldn't tell what you meant by a dropped swerve until I saw the modules in a base.

12-07-2015 14:44

asid61

Re: pic: GBX-123 chassis example

Quote:

Originally Posted by evanperryg We use perforated aluminum sheet like this stuff. It's surprisingly strong, and offers plenty of pre-made spots for zipties and other cable management hardware. It's not particularly heavy, either. The one thing I hate about it is that the holes don't line up with component holes, but some precision drilling can make up for that. Anyway, cool gearboxes. I couldn't tell what you meant by a dropped swerve until I saw the modules in a base.