Assembly Drawings vs MPI's

[dans95]

The company I currently work for has been doing fully exploded assembly drawings for years. All assembly information is contained in the drawing. At my previous job it was detailed MPI's with lots of pictures and NO assembly drawings. Other engineers I know do mostly assembly drawings that are not exploded, assembly shown complete from different views with some cross section views.

What does your company do?
1) Fully exploded assembly drawings.
2) Picture based Manufacturing Process Instructions.
3) Unexploded assembly drawings.

 

[CorBlimeyLimey]

Mainly unexploded assy drawings, but exploded where needed, cross-sections and details to suit.

Photo's or CAD images used only in manuals.

 

[ctopher]

I agree with CBL.

Chris
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[SnowCrash]

I do exploded assemblies with a BOM. These are for the shop (one guy) to know what parts to make as designated by the engineer (one guy) Parts are detailed with only one sheet, but he can look at the parts with eDrawings.
YMMV

--
Hardie "Crashj" Johnson
SW 2009 SP 2.1
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[smcadman]

We use both orthogonal views (front, right, top or most descriptive views) and exploded views on the same drawing if possible. This helps the shop in differentiating parts and sub-assemblies quicker. Sometimes we use the exploded view on assembly instruction sheets so the customers of our clients can assemble the product.

The industry you are in may dictate how you make your assembly drawings.

Flores

 

[macduff]

I'm old school and like the "Unexploded assembly drawings", but our company uses "Fully exploded assembly drawings" and can't stand it. I takes way more time to detail a drawing, and could possibly miss something in your design like a screw bottoming out in a blind tapped hole. Full cross sections tells the whole story about your design. Fully exploded looks really cool, but I believe it's for non-technical folks who are building bookcases from WalMart

Colin Fitzpatrick (aka Macduff)
Mechanical Designer
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[fcsuper]

The pendulum swings. I've seen shifts from completely relying on work instructions (and photos) to almost exclusive reliance on assemlby drawings and then back again.

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

 

[cpretty]

I think it totally depends on your circumstances.

I have had the privelege of working in two different companies with quite different production methodology.

1) Plastic parts assembled into complex sub assemblies in reasonable quantities with jigs etc to help, and semi-skilled labour

In this situation work instructions of pictures and words is critical for assembly. The relationships between parts, tolerances, and fits has all been created in the design phase and checked in pre-production. Defining drawings are created for parts, but these are used for tooling and checking (QA), not manufacturing.

2) Complex mechanical assemblies from fabricated parts, as one-offs with skilled labour

In this situation assembly drawings are used for fabricated parts, so that the final product dimensions and relationships are defined. Exploded assemblies are used for dissassemblable assemblies of standard parts ie bearings and bushes. Part drawings are created for standalone parts that fit into these assemblies.

You probably have to decide which of these situations suits you, or blend the two.

 

[gwubs]

I tend to agree with macduff.

 

[trsbrown]

Exploded views for presentations. Unexploded assembly drawings broken down into sub-assemblies for machining prints.

I always thought MPIs were for work instructions on assembly lines. The only time I messed with those were in my manufacturing engineering days so I haven't had to make any in a while...thank goodness.

 

[GRF]

We have a two step process. The design engineer creates an exploded view drawing, usually multiple pages showing the step by step assembly process as he/she envisions. The manufacturing engineer references this when he/she creates the word and photo assembly instructions used on the line. I know it does not make too much sense as a lot of work is duplicated except that some of our manufacturing facilities are in different countries and I am not going to translate. Also the exploded view drawing is an official tracked document where the assembly floor words and pictures are not.