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Recommended Book for graduate Design Engineer?
3

Recommended Book for graduate Design Engineer?

Recommended Book for graduate Design Engineer?

(OP)
Hello all,

I am a fresh graduate in my first job and I'm in need of help. I am looking for a book to help with me standard tolerances for different machining processes and materials. Essentially I need to teach myself how to tolerance my designs ( I have an idea on what features are critical to my designs but have no idea how fine a tolerance I can put within reason) I also need to learn the best way to dimension certain features and further reading on geometric tolerances is also a plus.

Does anyone have any experience with books that could be a help? One I have been looking at is

Design for Manufacturability Handbook (McGraw-Hill Handbooks)

[http://www.amazon.co.uk/Design-Manufacturability-Handbook-McGraw-Hill-Handbooks/dp/007007139X/ref=sr_1_6?s=books&ie=UTF8&qid=1305052899&sr=1-6]

I would appreciate any advice from design engineers out there.

RE: Recommended Book for graduate Design Engineer?

Machineries handbook has a small relevant section but it's not got much detail.

There have been some relevant threads on this site - see if you can see them.  I think I started one and Ctopher started another.

Posting guidelines FAQ731-376: Eng-Tips.com Forum Policies http://eng-tips.com/market.cfm? (probably not aimed specifically at you)
What is Engineering anyway: FAQ1088-1484: In layman terms, what is "engineering"?

RE: Recommended Book for graduate Design Engineer?

OK, mad panic over.

There are multiple aspects to your questions.

1.  Knowing what tolerances you need functionally.

2.  Knowing how to specify those tolerances on your drawing/MBD correctly.

3.  Verifying that those tolerances can be met at reasonable cost by available processes.


For #1 & #2, I'm pretty sure there have been threads over in forum1103: Drafting Standards, GD&T & Tolerance Analysis relating to this.  In any case, that's a really good place to ask questions related to that.  Sadly a lot of GD&T training classes seem to focus more on how to apply the correct symbols etc. than on calculating the tolerances you need.  For hole patterns it's actually very simple and is in appendix B of ASME Y14.5M-1994.  I would definitely recommend getting a copy of whatever drawing standard you work to - each author of GD&T books or training material has their own personal preferences etc. - I always try to go back to the source.

On #3There really have been lots of relevant threads so try and search for some forum281: Machines & Machining engineering might be a good place to look too, though I know the search isn't fantastic - yet.

Here are a few to get you started.

http://procnc.com/resources/newsletters (from thread404-278305: More Machining/Design Tips)

thread1103-197339: Machining tips

thread281-128667: CNC positional tolerances

There really aren't simple answers to 'what typical tolerances can process X achieve'.   

Posting guidelines FAQ731-376: Eng-Tips.com Forum Policies http://eng-tips.com/market.cfm? (probably not aimed specifically at you)
What is Engineering anyway: FAQ1088-1484: In layman terms, what is "engineering"?

RE: Recommended Book for graduate Design Engineer?

Well, wherever you work, you probably won't be creating things from scratch; you'll be improving old designs. Look at the tolerances on similar parts as a starting point.

What's probably going to be more of a challenge for you is learning the proper application of GD&T. I had essentially no training in GD&T in college, and I assume many schools are similar in that regard. The standard, ASME Y14.5, is well written and a worthwhile investment. If you are interested in training, I know some people who've taken classes and got their ASME certification. They seemed to think it was worthwhile. Apart from being a eye-catcher on your resume, you'll probably have to learn something about GD&T to get the certification. Good luck.

RE: Recommended Book for graduate Design Engineer?

Here is a link to a graphic similar to the one that is in machinery handbook.  Basically a rough order of magnitude on the levels of tolerance that are available for various processes.

http://adcats.et.byu.edu/Publication/87-5/WAM2.html

-Dustin
Professional Engineer
Pretty good with SolidWorks

RE: Recommended Book for graduate Design Engineer?

Just did some Googling and BYU/ADCATS has a lot of reports relating to tolerance optimization for cost on the web.

The appendix, especially Table A1 of this report may be particularly interesting as it gives some idea not just of capability of processes but cost.  However, the source data is a little old - certainly pre CNC so if it's quite as valid today I'm not sure.  Therein lies one of the problems with the question of cost V toleranc.  The 'state of the art' changes and so information often becomes out of date - let alone the effect of inflation & currency fluctuation if you use actual cost values rather than relative.  

BYU-ADCATS-REPORT

Here's another simple presentation from ohio state which has a nice graph of cost V tolerance on slide 6.

Ohio-state-presentation

I suggest you do some of your own searches to find more.

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What is Engineering anyway: FAQ1088-1484: In layman terms, what is "engineering"?

RE: Recommended Book for graduate Design Engineer?

(OP)
Thank you all for the advice I will spend time trawling through the forums when I can an I'll choose a book from the suggestions as well for when I'm in work.

Regards

RE: Recommended Book for graduate Design Engineer?

If anyone says "Atlas Shrugged" I'm gonna hurl so hard it ruins your computer.

RE: Recommended Book for graduate Design Engineer?

What happened to your engineering, design, and math textbooks?  Believe it or not there could be valuable information in them.

RE: Recommended Book for graduate Design Engineer?

I've still got all of my engineering textbooks, and even though they are 40+ years old (I'm attending my 40th reunion this summer at my Alma Mater back in Michigan), most of them are still relevant particularly the Mechanical Engineering series by Shigley as well as the various handbooks, such as Marks and Hicks, and the smaller volumes of tables and formulas by Roark and Rinehart.  After all, the principles have not changed, just some of the tools used to get the job done.

John R. Baker, P.E.
Product 'Evangelist'
Product Design Solutions
Siemens PLM Software Inc.
Industry Sector
Cypress, CA
http://www.siemens.com/plm
http://www.plmworld.org/museum/

To an Engineer, the glass is twice as big as it needs to be.
 

RE: Recommended Book for graduate Design Engineer?

It would help to know exactly what you will be manufacturing.  Small parts, large parts, which industries are you supplying.  Almost all of us in the design field over tolerance and overspec in our early years.  The guys in the shop will be a great help too so communication there is very important.
The tighter the tolerances, the higher the costs in most cases.  A good book on metallurgy would be of help too if you are designing for long life.

RE: Recommended Book for graduate Design Engineer?

Aren't you using GD&T?

RE: Recommended Book for graduate Design Engineer?

You ask a heavily loaded question.  The tolerances that are appropriate for your work depend on the material of manufacture, method of manufacture, surface finish, part / feature size, mass production vs. small-run, etc.  The best answers tend to come from existing designs.

While there may be books that discuss the subject, it will either present you with details and you'll need to determine which details actually apply to your work, or it will be too generic to be accurate for your needs.

If you have a machine shop in your building you have potentially the best resource imaginable.  Likewise, a good inspection department (with CMM especially), they can probably talk about the tolerances they see achieved with various machining processes.

Industry standards can sometimes be helpful too.  If your designs include parts like commercial bearings or couplings, these manufacturers will provide manufacturing tolerances where the components will interface with the assembly.

Above all I hope you have a mentor available to discuss these things because it's a lot to learn and it's much better to start with a good recommendation from someone with the right experience.  Then the production and commercial issues will help you tweak and revise.

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