Taxonomy for mechanical design structural elements

jason_29

Is there a universal (i.e. ISO) glossary or taxonomy for mechanical design elements?  They would include things like: gusset, bracket, strut, frustum, mounting plate, etc...  From my observation, it appears as though there might be such a taxonomy for common mechanical hardware (piston, shock, spring, damper, socket head cap screw, bearing, etc...), but not the structural elements a mechanical engineer commits to designing.  What's more, is that every industry appears to invent its own, and every engineer does as much before encountering better nomenclature from other engineers.  I'm wondering if someone has observed this before and done something about it.

So, community of OS; are you aware of such a taxonomy, or have you developed a good and extensible one yourself?

Warmest, 

Jason

traveler_hauptman

This is a great question. It's my experience that 'naming' is a key aspect and potential stumbling block in designing complex assemblies.

The problems I see are when people don't name things at all, or when they waste time trying to find the perfect name.

I tend to use generic descriptive names at the beginning of a design and for any key elements with uniqueness or important functionality, do a little bit of research into an appropriate name (one that helps newcomers quickly understand what the thing is) later as it becomes clear that this design will stick around.

When I was starting out in engineering there were times I wished there was a picture dictionary available with all the terms...

pete_yodis

I don't know of a universal source of descriptive definitions.

You'll probably find there are just as many thoughts about descriptions as there are about part numbering systems.  Over time companies tend to settle on a set of agreed upon lingo.  When I started my current day job, it took quite a while to learn the lingo so that I could be useful searching for things within the ERP system.  If you can't speak the lingo, it's awfully tough to find things in text based searches.  I really am a fan of finding things in a visual exploded BOM type of manner with pictures of the items letting me know what they are as I explore.  I know I'm looking for a part in such and such a product, I'll manually browse that in our WorkGroup PDM or EPDM vault and then find it visually as I explore subassemblies.  I am often a lot faster that way than thinking of what something might be named and then searching on it.  Once I have found that item, I can then look at the text description and find more by running a search and casting a wider net.  We have 83,000+ drawings (and far more entries in the ERP system), so this technique may work here but not elsewhere.  Regardless, if you are trying to standardize on a naming scheme - then you might just want to create a document to put down what you want.  At some point you will have overlap where items will be characterized in more than one way.  That's where it gets interesting.  The rules always seem to break down at some point, you just have to be flexible and adaptable.

pete_yodis

I should add... do not put where used information in the descriptions.  I have run across that numerous times. 

brucebartlett

Naming can be a real art and when multiple people of differing opinions are involved can become messy. I try to keep things simple, some argue I don't give enough description.  When it comes to structural welded components I use, plate, tube, boss, panel, gusset, strut (never used frustrum but may have to in future, but sure it will just confuse people). When it comes to mechanical assembly components I would use spacer, washer, nut, bolt, packer, shim etc. I will try a stick to what has been done in the past at the certain company or follow the description of the component supplier. 

Like Pete I am very visual and like to scan through thumb nails in directory's to find what I looking for rather than a search the ERP system. I am looking forward to an in depth search and filters on the Onshape home screen to drill into meta properties and bring up thumb nail views of parts, now that would be powerful.

Jason it would be nice to have some kind of glossary with visual guides. I think I may have seen something in a standards book once but not an overall guide or dictionary. 

andrew_troup

I'm not aware of a concise taxonomy, and agree that it would be a great thing. Young engineers often struggle with spelling and have limited appreciation of semantics, no matter how gifted they are (in fact, often it seems there's a negative correlation) and guidelines would be a fine thing. In heavy press design, for instance, I have seen "Platen" mis-spelled and mis-used in dozens of highly creative ways...

Here's a super-set of what's being suggested, and it might form a useful resource in spite of (and sometimes because of) the broader scope:

http://homepages.cae.wisc.edu/~me349/resources/engineering_terms.pdf

ON EDIT: I guess it's not quite a "superset" - for instance, it doesn't attempt to demonstrate the difference between a web and a flange, or a bracket and a lug....
But it's a good start, I think, and the examples are mostly interesting and informative.

I think it's a bit of a shame that the conventional distinction between fillets and rounds has been blurred by the decision (in early, entry-level 3D CAD, perhaps) to adopt a single term to cover both. 

peter_paul

My two cents:

To my knowledge there is no taxonomy for parts or assemblies. IMO I don't think this will be very helpful either. Depending on the domain knowledge of the user most names will have different meaning. Also language plays a part. The always "fun" bolt versus screw discussion. 

At our company we have the following policy for naming:

Standard parts covered by Norms. We use the norm name with size and material for example a hexagon socket head cap screw is named.

DIN912 M4x10 A4 70 --> The name fully describes the part. Size, material, strength. We omit descriptions to keep item list readable.

For custom parts we have the following requirements.

1. We add a numbered prefix to guarantee uniqueness. For example. 0007150702001 The benefit of this is that engineers don't have to be to creative about names. We generate this number by combining employee number, date and instance information.

2. The name should descriptive. However structure information is forbidden. It should be describe the function of the part.

3. We also add a suffix to the name to indicate version/revision  vXX-YY

For example a bracket that carries a senor in the stage module is named.

0007150702001 Sensor Bracket v02-03

Underlying idea is that part names are unique and human readable.

You can get alot of sensor brackets in company but they are all unique.

andrew_troup

From another current thread, "saddle" is a good example of a useful descriptor. Patchface is another which springs to mind (for a machined recess which is round-cornered, rather than simply round like a spotface)

Young engineers are not born knowing this stuff, (nobody is) but the experienced guys often seem to forget this, so are not as helpful as they might be.