Current state of Model Based Definition 1

[KENAT]

There have been several threads both here and in other forums on use of MBD (Model Based Dimensioning). When I'd previously looked at it I'd decided it would be more effort than it would be worth for most of our stuff, however, have implemented it on some castings and moldings.

We're being pushed to decrease development time cycles and my boss wants to look at MBD as a way of achieving this.

So how many people are doing MBD and have any major developments in this field come along since it was last discussed in depth?

I'm especially interested in those out side of the 'managed supply chain' of Aerospace/Defense and Automotive where it seems to have been achieved largely by the OEM's dictating what CAD system will be used and using their leverage to enforce this on their suppliers.

We are a smaller/independent player in the technology field who outsource all our machining etc. with only assembly done in house (even some of this is outsourced) and I'm wondering how other smaller players have dealt with it. Do you:

1. Only deal with suppliers with the same (or at least compatible) CAD/CAM system(s) so that tolerances etc. in the model are carried across?
2. Use a lightweight format and does it correctly handle MBD.?
3. Use hybrid drawing/model and if so how do you handle Tolerancing of features not explicitly defined on the drawing?
4. Have extensive "rules of use" in addition to/in place of the above or just rely on ASME Y14.41 or equivalent?

I have a copy of 14.41 and looked through it a while back but I’m not completely familiar with it.

thread1103-182896
thread730-184173
thread1103-182500
thread730-221206

Are all more or less relevant.

Thanks.



KENAT,

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[KENAT]

Thanks all. While I've gained some usefull information it seems that most of my original opinions/impressions were fairly accurate.

I spent some time last night looking at ASME Y14.41-2003 and it does seem like much (most?) of it is more about setting the standard for what the CAD packages should be able to do than with what the individiual designer should be doing.

I don't think our current primary CAD system does anywhere near all of the stuff it requires, though I'm not overly familiar with it's capabilities.

KENAT,

Have you reminded yourself of faq731-376 recently, or taken a look at posting policies:

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[SDETERS]

What Cad Format DO you use. I think Catia and I-Deas is the closest 3D modeling software that comes anywhere close to meeting the needs of ASME Y14.41-2003. They both still have down falls But it is getting there. I-Deas is going to NX or What was Unigraphics so hopefully in the near future there will be a 3D modeling package that will be capable of meeting these needs.

 

[KENAT]

Our primary CAD system is the other Siemens/UGS offering - Solid Edge. It has some 'PMI'(Product Manufacturing Information) functionality with our current version (19) I'm not sure yet how much it introduces with the newer versions.

If I understand the standard, then in many cases if you 'query' a FCF in the model, then the surface or feature it applies to is meant to 'hi-light' and vice versa. I don't think it does this and there were a few other things I wasnt sure about.

KENAT,

Have you reminded yourself of faq731-376 recently, or taken a look at posting policies:

http://eng-tips.com/market.cfm?

 

[KENAT]

Hey fcsuper, did I get you thinking;-)

http://www.fcsuper.com/swblog/?p=175

KENAT,

Have you reminded yourself of faq731-376 recently, or taken a look at posting policies:

http://eng-tips.com/market.cfm?

 

[fcsuper]

Yes, KENAT, yes you did. If I find myself writing some detailed response to a question, I'll often leverage my work by turning it into an article on my blog.

Matt Lorono
CAD Engineer/ECN Analyst
Silicon Valley, CA
Lorono's SolidWorks Resources
Co-moderator of Solidworks Yahoo! Group
and Mechnical.Engineering Yahoo! Group

 

[KENAT]

I'm currently putting together a presentation on MBD to try and share my limited knowledge with management. My attempts at verbal communication have met with no success, I'm hoping they can understand some pretty pictures and bright coloured bullet points!

On the bright side, both my boss and his boss seem to have realized we'd probably need some kind of PLM/PDM.

On the bad side my boss is already talking to potential vendors without seeming to know what MBD really means.

KENAT,

Have you reminded yourself of faq731-376 recently, or taken a look at posting policies:

http://eng-tips.com/market.cfm?

 

[fcsuper]

Best of luck!

Matt Lorono
CAD Engineer/ECN Analyst
Silicon Valley, CA
Lorono's SolidWorks Resources
Co-moderator of Solidworks Yahoo! Group
and Mechnical.Engineering Yahoo! Group

 

[KENAT]

Thanks, I'll need it!

By the way, your blog came up as the first result when I googled solidworks MBD. Good as it is I was a bit surprised there wasn't more from SW themselves.

KENAT,

Have you reminded yourself of faq731-376 recently, or taken a look at posting policies:

http://eng-tips.com/market.cfm?

 

[ewh]

Uh-oh... Our IT dept did the same thing, and sent down and edict that we were to use Sharepoint for all of our file control. "Hey, we have it, so use it" was their thinking.
Of course, that went over like a lead brick when the CAD administrator (me) heard about it. We still don't have a PDM system in place, though it is supposed to be in the 2010 budget. This, after it had already been in the budget for 2007 and 2008. Go figure...
At least make sure that your boss understands what is required to control relational databases before he signs off on anything.

"Good to know you got shoes to wear when you find the floor." - [small]Robert Hunter[/small]

 

[KENAT]

Does that mean first I have to learn "what is required to control relational databases";-)?

We spent a bunch of time looking at PDM/PLM in 05-07 and got no where. An aborted 'INSIGHT' implementation, which is a 'free' SE PDM that piggy backs on sharepoint, took place in late 05. We spent much of 06 looking at what it would take to make that work or what other options were needed. We then looked more generally at what our requirement was etc but that went real slow and we got told to pick our best guess. Picked Teamcenter, got a quote etc. and then got told we had no money for it at end of 07.

(How'd I get a star on my own question?)

KENAT,

Have you reminded yourself of faq731-376 recently, or taken a look at posting policies:

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[ewh]

Because it is a good question of general interest would be my guess.

By a program that can handle "relational databases" I am refering to one that, when a part file is changed, it knows enough to report all of the files that the change affects.

"Good to know you got shoes to wear when you find the floor." - [small]Robert Hunter[/small]

 

[KENAT]

I figured as much, I think I've heard it referred to as 'maintaining associativity'.

KENAT,

Have you reminded yourself of faq731-376 recently, or taken a look at posting policies:

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[ewh]

Right.
TeamCenter is out choice so far as well.

"Good to know you got shoes to wear when you find the floor." - [small]Robert Hunter[/small]

 

[SDETERS]

We are currently going from Our I-Deas TDM to the teamcenter Engineering.

 

[ewh]

Isn't MBD solely to replace drawings, not to be used for CAM?

We have been using it for just the opposite; neutral model files for CAM and CMM use, and reduced dimension drawings for tolerancing and other annotations. While we have the ability to annotate the models, it is fairly useless when few of our vendors can read them.

"Good to know you got shoes to wear when you find the floor." - [small]Robert Hunter[/small]

 

[ajack1]

KENAT as far as I am aware only Catia offers what you are asking for and that is still dependant on everyone in the supply chain working with it, there maybe other systems that do this but I am not aware of them. Again as far as I am aware no dumb solids can do this.

We design tooling mostly for the automotive industry, complex press tooling and moulds and have been working almost exclusively with only 3D models for a good few years. We operate a mid priced CAD/CAM system design for this market and so do most of our customers.

This type of work is fairly unique in two ways. Firstly all of our customers do their own manufacturing and understand what they are manufacturing and secondly whilst there are many complex surfaces only key areas are really tied up, for example guide pillars to guide bushes, punches to dies, dowel pins etc. Within our software there is a feature recognition system so you can apply tolerance and fit to certain items and this is recognised at the CAM stage, whilst this works well for this type of work it might not for other types.

Other “get arounds” include the use of face colour to denote certain operations or fudging sizes to denote certain criteria, the list is too long to try and explain on here. So I guess from your original post this would fall in the extensive rules of use category.

This does have plusses and minuses, you need to work very closely with chosen suppliers and have a very good working relationship with them, but it allows huge savings in terms of time and cost in getting to the market place and makes both parties “valuable” to each other.

If your bosses want to just throw quotes around the world and quote standard blah blah and pick up the cheapest, I would say they are bound to fail. If however they want to work closely with suppliers and try to solve the many problems that will arise, you can gain a significant advantage over the competition.

 

[KENAT]

Thanks ewh & ajack.

I think I may have run out of enthusiasm for the presentation, but maybe it'll come back later.

KENAT,

Have you reminded yourself of faq731-376 recently, or taken a look at posting policies:

http://eng-tips.com/market.cfm?

 

[KENAT]

Well, my boss had his conversation with the vendor and apparantly they reckon Inventor has the most capability at the moment in terms of being able to pull the annotation from the CAD model into the CAM and work with it.

I'd seen mostly bad press, or at least not particularly encouraging, for inventor so was a bit surprised. Anyone care to comment?

Also found out our director doesn't know the difference between a CAD model and a CAD drawing. Awesome.

KENAT,

Have you reminded yourself of faq731-376 recently, or taken a look at posting policies:

http://eng-tips.com/market.cfm?

 

[ewh]

Hey, at least your still working, and it seems like you'll have a lot more to do to keep you busy. ;-)

"Good to know you got shoes to wear when you find the floor." - [small]Robert Hunter[/small]

 

[SDETERS]

I think The Cam package they are pulling the inventor file into is GIBBS? Is this correct or is it a different cad Package?