Upright Manufacturing

[Conor]

I was just curious as to how most teams manufacture their uprights. We're a first year team and we have our design made in ProE, but we're not sure if we want to send the work out to a shop or try and do it ourselves. We're probably going to make them out of machined aluminum so if anybody has any good advice or some things we might need to know, it would be greatly appreciated. Thanks.

[Conor]

I was just curious as to how most teams manufacture their uprights. We're a first year team and we have our design made in ProE, but we're not sure if we want to send the work out to a shop or try and do it ourselves. We're probably going to make them out of machined aluminum so if anybody has any good advice or some things we might need to know, it would be greatly appreciated. Thanks.

[Igor]

Laser sintering, CNC, welding, carbon layup.
Please use the search function, this subject has been beaten to death.

Igor

[Jersey Tom]

Get some quotes from some job shops, see what it will cost you to outsource.

What kind of machine shop facilities do you have at your school (machine tools, tooling, free time..)? How many students on your team are good CNC machinists? (~500-750 hrs experience minimum).

I'm machining ours.

And yes, this has been covered mannnny times.

[Chris Boyden]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">(~500-750 hrs experience minimum </div></BLOCKQUOTE>

That seems excessive. I wouldn't consider that a hard and fast requirement.

[Jersey Tom]

I dont think 500 hours is much. Buying a $100-150 block of 7075 for an upright you don't want to scrap parts.

Gotta know how to do custom fixturing, gotta know how to clamp parts without them moving with a half inch or bigger tool plowing into it, what tooling to choose, what the highest feeds and speeds are that you can push given your setup and machine tool, what kind of runout you'll have at your tool and how sharp it is/how well its ground, how to write time-efficient toolpaths, how to hear and fix tool chatter and part vibration, metrology, thinking through your whole toolpath so you don't crash into things..

All ties into how many hours you've got in. Machined uprights are typically time-intensive, with a couple setups, and like I said you don't want to scrap em. But you don't want to spend forever making em. So I'd put the best guy on it.

[Denny Trimble]

As I made more parts, I learned more (especially during the CNC class I took one year ago this quarter). My productivity probably tripled in the shop, for all the reasons Tom mentioned.

But, if you don't have any machinists with more than 500 hours experience, don't let that stop you from making cool stuff. Just be prepared to spend more time, and to make mistakes. We're students, we should take this opportunity to learn what we want to. And if that's CNC uprights, so be it!

[Jersey Tom]

Yea don't get me wrong, feel free to do the machining yourselves. But for a first year team, if you want to get the car done on time you might really want to look at oursourcing if you don't have a good machinist or two.

For example, two years ago here at CU..

New design for the uprights, which was designed to be functional but not the most friendly CNC part. Took 4 setups, custom fixture, and a bunch of tools. Add to this when the student who designed it went to machine it, it was his first CNC project. Because of that, it took something like 50-60 hours for ONE upright. And that's outrageous. They actually wound up breaking one of them right as they were getting done.

By contrast, my goal this year with a ground-up redesign is an hour per upright.

[Denny Trimble]

Wow... one hour isn't very long. I guess it's longer than 3 minutes (the Haas video). How long do you expect to spend programming and making fixtures? Will your four uprights be common parts, or will each be unique?

I probably had 8 hours into FEA on the my latest wheel centers, and 8 hours each (including cutting the stock out of 12" x 12" x 5" solid, squaring it up, making fixtures, programming, and running). This is on low-powered, non-enclosed machines with mist coolant or dry.

I've just updated my cnc gallery with pics of that:
http://students.washington.edu/dennyt/fsae/cnc/

[James Waltman]

If you count toolpath generation, setup, running, and sitting in front of the machine I could probably say that I have over 1000 hours of CNC experience. I never kept track though and that includes a lot of learning time. I would consider myself a "Competent Novice"�.
I could have made simple uprights early on in my learning experience. I could pull off some really complicated ones now but I know better than that.

I had little incentive to make super efficient tool paths because I never did a run of more than about a dozen parts. Mostly it was prototyping so I could afford some laziness with tool paths. Machine time was always free for us and material usually was too.

I broke my fair share of tools learning. I also scrapped my fair share of parts. The worst was a $600 block of aluminum after about 15 hours of machining. I gouged the hell out of it the day before I was supposed to deliver it.

I'm still impressed by how fast a real CNC shop can make parts. Getting some advice from a shop might save you a lot of time if you don't have much experience yourselves.

If you want to machine them yourselves I would say go for it. But be prepared to break some tools and scrap some parts. No worries though, this is a learning experience. I also recommend using the rule of π for time estimates. Take your most conservative estimate for how long it will take and multiply that by 3.14.

Test bores in a spare block is a good way to figure out what you need to do for accurate bearing bores.

Edit:
Denny snuck one in while I was typing.
For our wheel centers I spent an evening on setup (fixture plate). I could make each one in less than an hour (machine time and setup change). I thought that was painfully slow. Mine weren't as complex as Denny's though.
http://dot.etec.wwu.edu/fsae/HostedPics/Viking38/Wheels...Centers/DSC09069.JPG (http://dot.etec.wwu.edu/fsae/HostedPics/Viking38/Wheels/Wheel_Centers/DSC09069.JPG)

[Jersey Tom]

Those are some nice centers, Denny.

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Wow... one hour isn't very long. I guess it's longer than 3 minutes (the Haas video). How long do you expect to spend programming and making fixtures? Will your four uprights be common parts, or will each be unique? </div></BLOCKQUOTE>

Yea I don't have the spindle speed to be pushing 150+ipm like the VF2SS, and my design involves a couple things that will require some minimal clamp moving. Actually that video is deceiving. From everything I've heard, you run a Haas that fast all day and it just wears out. Ain't a Mori...

Programming, I dunno. Couple hours. Fairly straightforward design. 1 or 2 tools will be doing the vast majority of metal removal, so I will spend a while dialing those in to the right overhang, speed, feed, radial and axial DOCs so its all smooth no-chatter operation. One of the tools will be a half inch flat EM, probably running 80-ish ipm. Maybe up near 100. The total stock required for each entire upright, should be like 65ci.

Actually first process will be the bandsaw.

No fixtures. Just the machine table which already has a big subplate drilled and tapped 1/4-20 and 1/2-13, and a vice. Should be all I need. The upright is a universal design, the base piece is the same for each wheel (other than drilling another hole or two). Then there's a couple simple bolt-on pieces.

http://ucsu.colorado.edu/~szelag/fadal.jpg

[Conor]

I just want to thank everyone who responded to this thread. As a first year team, we learn something new every time we step in the shop and we usually have more questions than what we started with by the time we turn the lights off. If you're a new member on a team it's one thing, but when your entire team has to figure something out, it's an entirely different story. I know this is kicking a dead horse for some, but for me it's very very helpful. So thanks to everyone who didn't say "This topic has been beaten to death", because a lot of people use this forum to learn, not just to brag about their car.

[Conor]

P.S. Those are effin sweet rims you machined man!

[kozak]

yeah i wish i had crazy awesome CNC skillz. or a crazy awesome cnc at my disposal.