Help - How should one deal with components requiring flexibility?

I will describe my problem with a simple example. An air cylinder
consists of
2 basic components - the cylinder and the rod. The easiest way to
model the
cylinder so that it can move properly would be to have an assembly
containing 2
parts - the cylinder and the rod. Now I have the freedom to slide the
rod in and out of the cylinder. Following are some of the problems
that arise:

1. If I save the assembly using my companies part number for the
cylinder as
the file name, what should I name the cylinder and rod parts?

2. When I use the air cylinder assembly in another assembly, how can I
allow it
to move? I dont want to solve it as flexible because multiple
flexible
instances are not allowed in one assembly. I dont want to dissolve the
subassembly because then my feature manager tree no longer matches my
desired
BOM. I dont want to use configurations of the subassembly because I
could
quickly end up with many configurations.

How have you guys dealt with some of these issues? Any advice would
be greatly appreciated.

David

 

What I would do is Have a rigid and a flexible configuration in the main
assembly, and 3 configs in the subassembly.

The subassembly would have a config with both the cylinder and the rod in a
defined state "Default", and a config with only the cylinder shown
"Cylinder", and a config with only the rod shown "Rod".

In the Main assembly you would have 2 or 3 instances of the cylinder. In
the rigid config you have the Cylinder in its "Default" config this is for
drawing purposes so your BOM is correct.

In the flexible config you would have 2 instances of the Cylinder one is the
"Cylinder" The other is the "Rod" mate these apropriately and you have a
flexible configuration for checking movement and clearance.

Note that you would have any unused instances of the cylinder suppressed in
the configuration you use to create your BOM so that your quantities are
correct.

Regards
Corey Scheich

 

As much as I try to avoid in-context, this may be a case for it. Make the
cylinder a part. Set the clevis on the end of the rod to be coincident to
the end of a sketch line in the cylinder part. Set the dimension of the rod
length by an in-context relationship in the upper assy. After you move
stuff in the assy, a rebuild will update the cylinder.

The problem with using flexible assy's is that, as you point out, you can
only have one instance. However, you can create more than one config of the
assy, and then make one of them flexible. However, flexible assy's
sometimes don't play nicely.

WT

 

Use "dash" numbers for sub-components. Say main assy is "12345.sldasm",
Cylinder would be "12345-1.sldprt" & Rod would be "12345-2.sldprt".

Multiple flexible assemblies are allowed. I use them all the time. All you
need to do is create multiple configs in your assembly & use a different one
for each instance in the same assy.

Matt B.

 

This is a good use for derived configurations.

Simply make as many derived configs as you will have need of the assembly
and number them 1 to N. Each one can be set to flexible in the main
assembly. Since the configs are derived any changes to the parent will be
applied to the children.

For part numbering the dash number approach seems reasonable. The
alternative would be to use the same part for both cylinder and piston. Now
that we have multibodies you can model both in the same part and have a
single part number that covers both parts in your assembly and the assembly
negating the need for any part number magic. Since both are revolved parts
you can even use a contour sketch for both bodies.

David Didelot wrote:
....snip

 

Hi David,

On the part numbering topic, we use the "standard" company part number
and then a suffix like PARTUMBER_01, _02, _03 and alternately
PARTNUMBER_Motor, _Shaft, etc. This works very well for us. When I
have seen this go awry is when your numbering system pattern is
infringed upon by these suffixes.

For example if you have a system that has a base number NNNN-NN, these
"slots" in the pattern should never be populated with anything other
than the company part number. Suffix as you wish, which will
generally not harm anything and the NNNN-NN portion will always "lead"
the other data and keep it grouped.

For your flexible assemblies, how ever many instances your model
needs, regardless of nested sub-assys, that's how many unique configs
you need for a given assy model. I consider this to be ultra lame
thing to have to do, particularly with the emergence of PDM which
generally locks your model at the point of release, of course with
nobody knowing that 2 years from now, you do not have enough configs
to support a given assy without errors . . .

But that's another discussion for another day.

Flexible assemblies are great, but the one-for-one instance/config
roadblock is a real limitation that keeps this from being the great
feature that it hopefully aspires to be.

Regards,

SMA