Large Assembly Advice

I have now ventured into the world of large incontext assemblies. i.e. My
current assembly is over 11,000 parts and 2400 assemblies. Since my largest
assemblies prior to this were in the neighborhood of 1800 to 2200 parts and
assemblies, I need to get some helpful pointers from people doing large
assemblies. I know that several of you do assemblies that make this seem
trivial. However, this is the first of many and and it is still growing.

Please send me any advice which (don't assume that I know it already!) that
you think would be helpful. That includes hadling large assemblies and
drawings.

I don't do curvy stuff.

How do you handle the drawings. I change specific items in a design table
(this resizes the entire system) then need to print an entire set of
drawings for the customer and for mfg. I need all drawings to update
properly. Today I printed a master assembly and found that it was out of
date.

I leave that feature checked so that I know if the drawing have updated
properly. If you use lightweight drawings do you have to open each drawing
and have it set lightweight to resolved prior to printing or is there a
setting that will make sure the drawings are up to date?

Also, I made a mistake and asked for a section view today of the assembly.
I don't think I'll do that again any time soon.

I don't know what you guys are finding, but I'm impressed with the speed of
SW2004. My old assemblies use to give me problems (2000 parts)and with 2004
my problems are just starting (13000+).

Tom Chasteen
remove deleteme from email address

 

Jeez Louise, 11,000 parts in 2400 subassemblies and a lot of in-context
stuff? My heart goes out to you. In-context relationships even in
relatively small assemblies can slow SolidWorks to a crawl in rebuilds,
or even with simple things like editing a mate. I expect that removing
the in-context stuff seems out of the question right now, but I think
you might be driven to it anyway before you see light at the end of the
rebuild tunnel. My advice (seldom followed) is to use in-context
relationships (including InPlace mates) ONLY where absolutely necessary
to maintain design parameters and ONLY before a design is proven out.
All or at least almost all should be entirely removed by the time a
design is released for production. If you need help with a logical
procedure for doing that I can help you, but it'd be more than a couple
of sentences long. Unless you're sorely tempted to do it I don't want
to waste the keystrokes, but I've recently gone to the extreme of
destroying ALL mates and starting over on a POS assembly somebody else
created. After recreating all the mates (takes less time than you might
think since you can start from a more logical beginning and proceed very
quickly and logically) the asssembly went from about 25 or 30 seconds
just to edit a mate to almost instantaneous for the same thing, and from
45 seconds or more for a Ctrl-Q down to about 2 or 3 seconds. And the
assembly was much easier to work with (not just faster). Good luck.

'Spork'

 

Tom,

I feel your pain. I've been working with 2 large assemblies for over a year
and lets simply say I've been less than enlightened. Fortunately, I'm soon
going to a company that makes a much smaller product.

But, here's how I've been managing...
Multi-sheet drawings must be split up so that each sheet is in a separate
file. Child views lying on another sheet are the exception. Sometimes I
would make another parent view and hide it.
My parts are all imported, so I made sure that all like parts are instanced.
Lightweight mode and more lightweight mode. When mating parts get loaded
into memory. I made it a habit to 'set resolved parts to lightweight' as
often as every minute.
In 2004, lightweight assemblies in drawings is a great idea, but there are
pros and cons. For detached drawings there are obvious advatages to opening
the drawing without the model loaded, but you can't open the assembly
lightweight in the detached drawing. For non-detached drawings you can load
the model lightweight through the open dialog box and switch back and forth
between lightweight and resolved after the drawing is opened. I'm currently
having a resource exceeded error message problem with cropping a large
assembly view and am tempted to save the drawing as non-detached, load the
assembly lightweight and try cropping again. Otherwise, SolidWorks just
can't crop the view and I'll have to go back to my cut and paste .jpeg's
drawings. I don't like 'rigging' drawing like that, but it's the only
workaround I could come up with.
Fortunately, after I get all my parts mated in place, I delete the mates and
fix them. This is because the design is actually modelled in AutoCAD and
documented in SolidWorks.... don't ask, long story.
I'd also suggest using the /3GB switch that they talk about in the whats new
manual. You may want to talk to your VAR since the MS site seems to be
explaining how to set it up on your server or how to implement it into you
C++ code.
Other than that have fun with all the spare time watching the hourglass. I
actually added a second monitor to do some surfing while the views
regenerate.
-Jeff

 

Here are my "wild" suggestions. Some of these are off the top of my
head and may not make sense but maybe I might spawn a good idea so
here it goes:

One I would use configurations and have every part have a
configuration named simple. This way I could load by that
configuration. I am sure you know this one but if you can dumb down a
part as much as possible the better off you will be.

I would also possibly use configurations to seperate out the assembly
into "zones". Maybe by the way it might be assembled if done in
steps. For example if I was modeling a car I might have one
configuration that in the engine compartment only and one that is
dashboard only.

As for drawings I would use as much of the technology SolidWorks has
to speed things up as possible. hide parts and rapid draft will
probably be a must if you have any timeline at all.

I hope I helped a little

Ken

 

Tom,

The advice from Jeff N. covers good ground. I usually try to get 7-10
drawing sheets per file and have found you can generally break a project
down to these increments quite sensibly. Also, after you get the whole
assy onto sh.1, you can then use subassy's and detail parts for the
model and convert to detached drawing, fomerly rapidraft. Like Jeff, I
frequently use a parent view that is kept off the sheet to get a better
view with less baggage the using part of an unwieldy assy.

Following this method permits assemblies of virtually unlimited size
with the possible exception of getting the whole assy on sheet 1 for the
ISO view.

Regards,

Dennis

 

Wherever possible use driving sketches for as much of your incontext stuff
as you can - I normally make a master driving part that only contains a
bunch of sketches (eg. plan, & 2 elevations) and a heap of planes & axis
hung off the sketches - you can then drop this driving part into many of
your major sub assemblies. Driving sketches will also allow you to keep
most of your incontext references at the top level, otherwise you can end up
with incontext references buried many levels down in the assembly (this will
take longer to re-build and some of the really deep references may not
update unless you hit ctrl Q a few times.

If you have to hang sketches off other parts use the underlying feature
sketch rather than faces/edges/vertices etc. - nothing worse that constantly
hunting down 'cherries' when you make a minor change that eliminates a
face/edge/etc.

Instead of using section views in drawing of large assemblies you may be
better off creating an assembly cut in the model (new configuration of
course) and then using this in the drawing - it's heaps quicker.

Beware of cropped views with large assemblies - they can cause major slow
down.

Set your SW options wisely (i.e. no auto saves, shadows, etc) - this can all
help to speed up the system.

Try to eliminate all 'cherries' otherwise you will find the the entire model
re-building every time you hit save (and you must save often).

Note that large assemblies have a bad habit of blowing a fixed price quote
because of the huge additional time just waiting for something to happen
(drawings, models, renders, etc).

Merry

 

Merry's method works well - I've used it on the last two models I've worked
on (not a huge number of parts, but lots of splines and intersections
through surfaces that gunk up SW) and it has saved a heap of time. Once you
have got the hang of what to add to the driving sketches it is pretty
intuitive. The other pearl I was given by more than one person on this NG is
"Sub assemblies, sub assemblies, sub assemblies......." - couldn't agree
more.
Another one I use is to use an E-drawing to plan what views I want and which
bits to kill to get what I am aiming for - it's also quite handy to use as a
reference alongside the drawing - no hopping back and forwards to figure out
how one bit relates to the other. Also keeps the customer off your back
while you get on with the real drawings!
I seem to remember being pointed at Mike Wilson's site ?? which has a load
of "collected thoughts" and a good run down on what affects what.
Unfortunately I left the copies of the replies at my last place of work.
Best of luck
Deri

 

You're probably thinking of Matt Lombard's site.
< http://www.frontiernet.net/~mlombard/ >
He has "Large Assemblies" under his "Rules of Thumb" . You might also want
to look at "In-context relationships" and "Tools/Options settings".

Jerry Steiger
Tripod Data Systems

 

Thank you everyone for your comments and ideas.

I don't know if I mentioned it, but the incontext stuff is required. I have
to (in the end) be able to edit a design table and generate all required
drawing and BOMs to manufacture a similar system with different heights,
widths, and length of the total system.

That seems to dictate that I can't detach the drawings (part dimensions,
hole location, etc. change). However, I will look at detaching drawings for
all items which remain constant.

Also, I set up an assembly with a set of planes and one sketch to define all
of the variables which I would need to change in the assembly. Something
similar to what Merry recommended. I then imported all of the variables
into a design table prior to inserting the first assembly. It gave me peace
of mind to know that I had control of the environment before having to worry
about controlling all of the components.

I then designed and assembled my subassemblies. I would take a
sub-subassembly and insert it into the master assembly and work out the
incontext mates that were required to get the proper changes. I would then
delete the sub-subassembly and continue building the subassembly.

I mate the major subassemblies to planes and then change the appropriate
parts to extrude up to or offset from the appropriate plan (sometimes in
both directions).

Also, when making the first set of parts, I carefully set up all features
(i.e. slots, holes, etc) so that the ones which would not move in relation
to some feature or each other were dimensioned so that I could keep their
relationships in tact when stretching or shrinking things later.

It took me three tries to really get going.


I'm loading a 15000 parts (12000+ parts & 3000 assemblies) in 90 seconds
lightweight.

I mirrored one part and won't do that again. It is a real PITA!

I take the lowest sub assembly that is to be inserted a lot of times and
make a fastener assembly (bolt nut and washers) as required to mount the sub
assembly and insert the fasteners into the appropriate holes. This allows
me to assemble the system with all fasteners included without having to go
backwards and insert them in each hole. There are thousands.

Thanks for the cut the assembly idea. I tried one section view and was
forced to pull the plug.

I've been doing this with only a gig of ram, but next week I'll be bumped up
to 2 gigs. Only the master assembly print (2 pages) with parts bom force
the processor to page. I've seen 1.3 gigs commited.

I'll take a look at Matt's site for his tip list. I forgot about that. He
always has good advice.

Also, I going to try the 10 drawing limit idea. I may be able to have
details, weldments, sub assemblies and major assemblies. I know that with
the total assemly on a sheet, I won't be adding many more sheets to that
file.

Thanks again to all,

Tom





Tom Chasteen

 

How do you insert quantites or item numbers on detail drawings for large
assemblies?? (Manually???) How do you guys handle that?

Thanks again,

Tom