Go to Post IRI ... no contest. It is borderline insane. - Paul Copioli [more]
Home
Go Back   Chief Delphi > ChiefDelphi.com Website > Extra Discussion
CD-Media   CD-Spy  
portal register members calendar search Today's Posts Mark Forums Read FAQ rules

 
Reply
 
Thread Tools Rate Thread Display Modes
  #1   Spotlight this post!  
Unread 11-05-2010, 19:05
Ty Tremblay's Avatar
Ty Tremblay Ty Tremblay is offline
Robotics Engineer
FRC #0319 (Big Bad Bob)
Team Role: Mentor
 
Join Date: Feb 2006
Rookie Year: 2004
Location: Alton NH
Posts: 822
Ty Tremblay has a reputation beyond reputeTy Tremblay has a reputation beyond reputeTy Tremblay has a reputation beyond reputeTy Tremblay has a reputation beyond reputeTy Tremblay has a reputation beyond reputeTy Tremblay has a reputation beyond reputeTy Tremblay has a reputation beyond reputeTy Tremblay has a reputation beyond reputeTy Tremblay has a reputation beyond reputeTy Tremblay has a reputation beyond reputeTy Tremblay has a reputation beyond repute
Re: pic: 3 Hour Chassis + 2 Hours

Quote:
Originally Posted by Jeff 801 View Post
From the looks of it the small sprocket on the toughbox looks to be about 16 tooth and the sprockets on the wheels look around 48 (Very ROUGH numbers) and assuming its a standard toughbox the overall reduction is 28.3:1 and those look to be 6" wheels so the top speed would be 3.05ft/s

Or on the back side of that wheel the sprocket is smaller than all the others and after looking at the AndyMark website the smallest sprocket (#25 I am assuming) is 32 tooth and the sprocket on the toughbox output shaft is still 16 that means the overall reduction is 25.5:1 and the top speed is 4.57ft/s

From what I know your average single speed robot is ~9ft/s which would cause me to thing there is some sort of difference in the toughbox or the extra chain reduction can be removed and supplemented with one of the many gearing options AndyMark has for sale.

After going back to the old thread I see that your wanting to get ~12ft/s which you can do by using the Toughbox with the optional 9.87:1 and direct drive which would give you ~11.82 ft/s
I've done no calculations regarding gear ratios, chain reductions, or overall speeds yet. I felt that there were more pressing structural concerns in my design that I needed to adress before conquering the gearing.

That 9.87:1 Toughbox seems interesting, but if we're going to buy more Toughboxes, we might as well just make our own (lighter) gearboxes. I just threw the Toughboxes in the CAD in the event that the team wanted to save money and use the Toughboxes we already have.
__________________
Reply With Quote
  #2   Spotlight this post!  
Unread 11-05-2010, 19:10
sgreco's Avatar
sgreco sgreco is offline
Registered User
AKA: Steven Greco
FRC #2079
Team Role: Mechanical
 
Join Date: Jan 2008
Rookie Year: 2007
Location: Millis
Posts: 1,031
sgreco has a reputation beyond reputesgreco has a reputation beyond reputesgreco has a reputation beyond reputesgreco has a reputation beyond reputesgreco has a reputation beyond reputesgreco has a reputation beyond reputesgreco has a reputation beyond reputesgreco has a reputation beyond reputesgreco has a reputation beyond reputesgreco has a reputation beyond reputesgreco has a reputation beyond repute
Re: pic: 3 Hour Chassis + 2 Hours

Quote:
Originally Posted by Ty Tremblay View Post
I've done no calculations regarding gear ratios, chain reductions, or overall speeds yet. I felt that there were more pressing structural concerns in my design that I needed to adress before conquering the gearing.

That 9.87:1 Toughbox seems interesting, but if we're going to buy more Toughboxes, we might as well just make our own (lighter) gearboxes. I just threw the Toughboxes in the CAD in the event that the team wanted to save money and use the Toughboxes we already have.
If you like the gearing in the Toughbox, there are lot of weighs to reduce weight. You can mill out some of the material in the side plates, get aluminum gears instead of steel, or just cut out material in the gear sand sprockets like this http://www.chiefdelphi.com/media/photos/30614

I'm all for custom gearboxes, but if you want to keep it simple, you have a lot of options.
Reply With Quote
  #3   Spotlight this post!  
Unread 11-05-2010, 19:41
Chris is me's Avatar
Chris is me Chris is me is offline
no bag, vex only, final destination
AKA: Pinecone
FRC #0228 (GUS Robotics); FRC #2170 (Titanium Tomahawks)
Team Role: Mentor
 
Join Date: Dec 2008
Rookie Year: 2006
Location: Glastonbury, CT
Posts: 7,621
Chris is me has a reputation beyond reputeChris is me has a reputation beyond reputeChris is me has a reputation beyond reputeChris is me has a reputation beyond reputeChris is me has a reputation beyond reputeChris is me has a reputation beyond reputeChris is me has a reputation beyond reputeChris is me has a reputation beyond reputeChris is me has a reputation beyond reputeChris is me has a reputation beyond reputeChris is me has a reputation beyond repute
Send a message via AIM to Chris is me
Re: pic: 3 Hour Chassis + 2 Hours

Quote:
Originally Posted by Jeff 801 View Post
After going back to the old thread I see that your wanting to get ~12ft/s which you can do by using the Toughbox with the optional 9.87:1 and direct drive which would give you ~11.82 ft/s
Running 12fps without shifting and using roughtop tread will lead to a lot of current issues as well as iffy acceleration.
__________________
Mentor / Drive Coach: 228 (2016-?)
...2016 Waterbury SFs (with 3314, 3719), RIDE #2 Seed / Winners (with 1058, 6153), Carver QFs (with 503, 359, 4607)
Mentor / Consultant Person: 2170 (2017-?)
---
College Mentor: 2791 (2010-2015)
...2015 TVR Motorola Quality, FLR GM Industrial Design
...2014 FLR Motorola Quality / SFs (with 341, 4930)
...2013 BAE Motorola Quality, WPI Regional #1 Seed / Delphi Excellence in Engineering / Finalists (with 20, 3182)
...2012 BAE Imagery / Finalists (with 1519, 885), CT Xerox Creativity / SFs (with 2168, 118)
Student: 1714 (2009) - 2009 Minnesota 10,000 Lakes Regional Winners (with 2826, 2470)
2791 Build Season Photo Gallery - Look here for mechanism photos My Robotics Blog (Updated April 11 2014)
Reply With Quote
  #4   Spotlight this post!  
Unread 11-05-2010, 15:32
Ty Tremblay's Avatar
Ty Tremblay Ty Tremblay is offline
Robotics Engineer
FRC #0319 (Big Bad Bob)
Team Role: Mentor
 
Join Date: Feb 2006
Rookie Year: 2004
Location: Alton NH
Posts: 822
Ty Tremblay has a reputation beyond reputeTy Tremblay has a reputation beyond reputeTy Tremblay has a reputation beyond reputeTy Tremblay has a reputation beyond reputeTy Tremblay has a reputation beyond reputeTy Tremblay has a reputation beyond reputeTy Tremblay has a reputation beyond reputeTy Tremblay has a reputation beyond reputeTy Tremblay has a reputation beyond reputeTy Tremblay has a reputation beyond reputeTy Tremblay has a reputation beyond repute
Re: pic: 3 Hour Chassis + 2 Hours

Quote:
Originally Posted by 548swimmer View Post

The tubes should have material underneath them. There's no constraint tool in real life, so spacers have a hard time just hanging there. Think about the assembly process when you're designing robots, that helps me the most. You can usually just pound them through with a gentle persuasion tool if the hole is a tad small.
I intend to weld the cross beams to the inner plates. Our team has a CNC mill, but it doesn't have a coolant system built in, thus milling operations can be quite cumbersome. By designing it this way, the only CNC operation necessary is the drilling of the holes so everything lines up square. The rest of the dimensions are more or less non-critical and can be cut with some careful band sawing.
__________________
Reply With Quote
  #5   Spotlight this post!  
Unread 11-05-2010, 16:12
JamesCH95's Avatar
JamesCH95 JamesCH95 is offline
Hardcore Dork
AKA: JCH
FRC #0095 (The Grasshoppers)
Team Role: Engineer
 
Join Date: Dec 2004
Rookie Year: 2001
Location: Enfield, NH
Posts: 1,811
JamesCH95 has a reputation beyond reputeJamesCH95 has a reputation beyond reputeJamesCH95 has a reputation beyond reputeJamesCH95 has a reputation beyond reputeJamesCH95 has a reputation beyond reputeJamesCH95 has a reputation beyond reputeJamesCH95 has a reputation beyond reputeJamesCH95 has a reputation beyond reputeJamesCH95 has a reputation beyond reputeJamesCH95 has a reputation beyond reputeJamesCH95 has a reputation beyond repute
Re: pic: 3 Hour Chassis + 2 Hours

Quote:
Originally Posted by Ty Tremblay View Post
I intend to weld the cross beams to the inner plates. Our team has a CNC mill, but it doesn't have a coolant system built in, thus milling operations can be quite cumbersome. By designing it this way, the only CNC operation necessary is the drilling of the holes so everything lines up square. The rest of the dimensions are more or less non-critical and can be cut with some careful band sawing.
I do a fair amount of aluminum machining dry without too much argument... what sort of tooling are you using? Are you making nice aggressive cuts to keep heat in the chip?

I've had good luck with carbide tooling and heavy feeds on 6, 2, and 7 series alloys.

I assume because you're planning on welding it you're going to use a 5 series alloy, which has a "poor" machinability rating, which may well be your problem.
__________________
Theory is a nice place, I'd like to go there one day, I hear everything works there.

Maturity is knowing you were an idiot, common sense is trying to not be an idiot, wisdom is knowing that you will still be an idiot.
Reply With Quote
  #6   Spotlight this post!  
Unread 11-05-2010, 16:34
Ty Tremblay's Avatar
Ty Tremblay Ty Tremblay is offline
Robotics Engineer
FRC #0319 (Big Bad Bob)
Team Role: Mentor
 
Join Date: Feb 2006
Rookie Year: 2004
Location: Alton NH
Posts: 822
Ty Tremblay has a reputation beyond reputeTy Tremblay has a reputation beyond reputeTy Tremblay has a reputation beyond reputeTy Tremblay has a reputation beyond reputeTy Tremblay has a reputation beyond reputeTy Tremblay has a reputation beyond reputeTy Tremblay has a reputation beyond reputeTy Tremblay has a reputation beyond reputeTy Tremblay has a reputation beyond reputeTy Tremblay has a reputation beyond reputeTy Tremblay has a reputation beyond repute
Re: pic: 3 Hour Chassis + 2 Hours

Quote:
Originally Posted by JamesCH95 View Post
I do a fair amount of aluminum machining dry without too much argument... what sort of tooling are you using? Are you making nice aggressive cuts to keep heat in the chip?

I've had good luck with carbide tooling and heavy feeds on 6, 2, and 7 series alloys.

I assume because you're planning on welding it you're going to use a 5 series alloy, which has a "poor" machinability rating, which may well be your problem.
I'm also on 190, which has plenty of Haas CNC mills for me to do my worst with. My alma mater team, 319, has the CNC I've mentioned, but I've never seen it run. I was intending to use 6061, but should I choose something else due to my intention to weld? Also, is it difficult to weld two different alloys together?
__________________
Reply With Quote
  #7   Spotlight this post!  
Unread 11-05-2010, 17:16
JamesCH95's Avatar
JamesCH95 JamesCH95 is offline
Hardcore Dork
AKA: JCH
FRC #0095 (The Grasshoppers)
Team Role: Engineer
 
Join Date: Dec 2004
Rookie Year: 2001
Location: Enfield, NH
Posts: 1,811
JamesCH95 has a reputation beyond reputeJamesCH95 has a reputation beyond reputeJamesCH95 has a reputation beyond reputeJamesCH95 has a reputation beyond reputeJamesCH95 has a reputation beyond reputeJamesCH95 has a reputation beyond reputeJamesCH95 has a reputation beyond reputeJamesCH95 has a reputation beyond reputeJamesCH95 has a reputation beyond reputeJamesCH95 has a reputation beyond reputeJamesCH95 has a reputation beyond repute
Re: pic: 3 Hour Chassis + 2 Hours

6061 loses its temper when it's welded, so your 6061T6 becomes 6061T0, which according to wikipedia is an 80% loss in strength, which is what I've noticed/experienced with the welding and mechanical testing I've done.

Welding two aluminum alloy's together hasn't been an issue for me. Most, if not all, aluminum alloys will weld fine with the same filler material, so there shouldn't be much of an issue welding different alloys.

Haas CNCs are pretty good machines, I used one in college. Tooling, though, shouldn't be confused with the mill itself. You could have the best CNC on the planet, but if a low-quality HSS endmill is chucked up it'll run like crap. Look into solid carbide tooling, if you're CNC'ing plates you could easily get away with a 1/4" end mill, or maybe smaller. McMaster: 8829A19 about $24 for an end mill that will make you many a robot frame. If you have good compressed air for chip clearing you could get a 4-flute which is even less expensive.

IMHO, if you want to weld the chassis together (which I heartily approve of) you should CNC your side plates from 5052 (which has no temper and won't lose strength when welded) and then use AndyMark/KOP extrusions for your cross-bracing. It'll be a little less expensive, and you'll get tons of 1/4" mounting holes. My team's most recent chassis was made from CNC'ed and bent 5052 TIG welded to the KOP frame. I did the welding and found the 1/8" 5052 to be a very forgiving material to TIG. We dropped 3-4lbs in fasteners IIRC.
__________________
Theory is a nice place, I'd like to go there one day, I hear everything works there.

Maturity is knowing you were an idiot, common sense is trying to not be an idiot, wisdom is knowing that you will still be an idiot.
Reply With Quote
  #8   Spotlight this post!  
Unread 11-05-2010, 17:03
548swimmer's Avatar
548swimmer 548swimmer is offline
CAD Leader
AKA: Alec Wagner
FRC #0548 (Robostangs)
Team Role: CAD
 
Join Date: Apr 2010
Rookie Year: 2005
Location: Michigan
Posts: 299
548swimmer has much to be proud of548swimmer has much to be proud of548swimmer has much to be proud of548swimmer has much to be proud of548swimmer has much to be proud of548swimmer has much to be proud of548swimmer has much to be proud of548swimmer has much to be proud of
Re: pic: 3 Hour Chassis + 2 Hours

Quote:
Originally Posted by Ty Tremblay View Post
I intend to weld the cross beams to the inner plates. Our team has a CNC mill, but it doesn't have a coolant system built in, thus milling operations can be quite cumbersome. By designing it this way, the only CNC operation necessary is the drilling of the holes so everything lines up square. The rest of the dimensions are more or less non-critical and can be cut with some careful band sawing.
Could you use a smallish size end mill and cut like this:

______
|xxxxxx|
|xxxxxx|
|_____|

so the center piece falls out.

If you can use a 1/16 or 1/4 bit you can cut past the needed length/width just enough so that you end up with squared corners.
__________________
My religion is physics, it can explain everything.

WINNER -- 2011 Waterford District
District Chairman's -- 2011 Waterford District
Finalist -- 2011 Ann Arbor District
State Chairman's -- 2011 Michigan State Championship
Quarter-finalist -- 2011 Galileo
2011 Championship -- Highest Ranking Score
Reply With Quote
Reply


Thread Tools
Display Modes Rate This Thread
Rate This Thread:

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

vB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
pic: 3 Hour Drivetrain Ty Tremblay Extra Discussion 8 11-05-2010 16:47
pic: How many hours at robotics to get to this point? samir13k Extra Discussion 8 26-02-2009 08:50
pic: Spam Drive Team After Hours GateRunner Extra Discussion 19 08-04-2005 17:11
pic: 11 hours from ship (1002) Jonz0r Robot Showcase 4 24-02-2005 18:35
One hour Chassis? Josh Hambright Technical Discussion 23 07-02-2003 10:08


All times are GMT -5. The time now is 18:01.

The Chief Delphi Forums are sponsored by Innovation First International, Inc.


Powered by vBulletin® Version 3.6.4
Copyright ©2000 - 2017, Jelsoft Enterprises Ltd.
Copyright © Chief Delphi