Design approach help

I need to design a solid model for an elastomeric keypad. With most of the
2D design work now done in AutoCAD it is time to move it to SW. I am
looking for recommendations as far as the best approach to attack this.
Here are some areas of concern:

First, I've had trouble trying to import even single DXF layers into SW as
the basis for a sketch. Within ACAD each button type is a multi-layer
block. I only need one of the layers for SW sketch purposes. The touble is
that SW only seems to want to bring in one of the instances of each blocks
rather than the whole 50-some button keypad at once. I've resorted to
turning off all layers except for the one I want prior to saving a DXF, to
no avail. Next I'll try to explode all entities before DXF output to see
what happens. Any recommendations on this front?


The design has about fifty buttons of four different types. Ideally, I
would create solid models of the five buttons and then bring as many as I
need of each into an assembly. There are two possible variables:

(1) The height of the buttons is dependant on the thickness of the panel
that they will protrude through. This is not yet known but assumed to be
0.125in. at the moment. This may very well be half that by the time it is
actually made.

How do I create a part and/or assembly that can take the panel thickess as a
parameter for extruding the buttons? The formula would be something like
"height = panel_thickenss + button_protrusion". The "button_protrusion"
parameter will be different for various buttons and might range from 0.000in
to 0.100in.

(2) Each button will have a different legend or graphic laser cut onto the
top.

How do I design a part that I can then replicate many times within an
assembly yet change the legend sketch during assembly creation time?


As I get into the assembly there are other considerations. One is that the
buttons are joined at the bottom by a silicon rubber matt about 0.050in
thick. The easiest way to model this is a simple 0.050in rectangular
extrusion. However, each button has an underlying structure that cannot be
filled in by this matt. My thinking is that the model for each button will
be designed with a small square section of matt, enough to allow for the
underlying structure and also to aid in mating. How do I get the button to
cut a hole in the solid matt when placed into the overall assembly?

Simarly, I would like to have each button cut a suitable hole in the front
panel based on a given clearance, say 0.010in. What's the best way to
approach this?


I've been reading a lot on the archives about issues with incontext mates
and related assembly matters. As a new user (about two months) some of this
is confusing/daunting in that there's great fear of making assemblies that
self-destruct (I've already had that happen). The worst of it is not
knowing whether it is a "free SW feature" or an aspect of the approach taken
in building either the parts or the assembly. I've taken the one-week "SW
Essentials" course and will probably follow-up with the Advanced version
after I get about six months' experience. For now, I could use a shove in
the right direction.

Thanks,

-Martin

 

Martin,

I have a reccomendation,,,,,, STOP !!!!!!!!!!!!! back away from the
computer! Take a deep breath,,,,,,, ahhhh, that's better.

First off, Solidworks doesn't work anything like ACAD. Importing sketches
from ACAD is a mistake, and will cause you nothing but problems. It's much
better to start from scratch in SW, and do it the SW way.

To this end, I suggest you go through some of the online tutorials. Pay
special attention to sketching and linear "feature" arrays (not the sketch
array variety).

Take two aspirin

Call me in the mornin

Regards

Mark

 

Martin,

To me, it sounds like you have the Acad to SW order mixed up. If anything,
you should start in SW. I'm kind of curious how you can do the 2D design
in Acad and now get ready for more design in 3D.

DXF layers... you can explode layers in SW if you just import the whole
dxf, but take Mark's advice and learn to work in SW and try to forget Acad.
There are several ways of getting Acad data into SW sketches, but none of
them is really something I'm fond of. Be careful of the imported 2D data,
make sure it's really what it seems. Add relations and dimensions to it to
fully define the sketch.

As for getting an offset cut outs around your buttons, there are lots of
ways of doing this, but I would use intersection curve or might even try
the new Indent function. Other possibilities include cavity, join or
convert entities. Look the functions up in the help, and it should become
clear to you whether it will help you get where you need or not. Most of
these functions will depend on whether you are doing all of this in a part
or in an assembly.

Use equations for the variable heights, or check out global variables or
even link values.

It's good that you're taking training to get things figured out. Sounds
like you want information faster than they can give it to you, though.

Good luck,

matt

 

"First off, Solidworks doesn't work anything like ACAD. Importing sketches
from ACAD is a mistake, and will cause you nothing but problems. It's much
better to start from scratch in SW, and do it the SW way."

What a massive waste of time !!!!

The SolidWorks way means you have to redraw everything from scratch because
SolidWorks is a program that hates non-native imported geometry.

Lets compare starting from scratch with SolidWorks to VX :

In VX you import the Autocad wireframe (dxf or dwg) and use it ! It doesn't
even import into the skectcher... comes right into the model / assembly
environment.

All you do in VX is extrude the wireframe AutoCAD geometry to a solid. If
you need to rotate a section of the wireframe geometry to do a revolve no
problem, etc....

Why use a program that hates non-native geometry ????

Forget the asprin:

Dump SolidWorks and get a program that doesn't treat non-native
geometry like some sort of illegal alien.


jon

 

To me it sounds like just another case of how SolidWorks can't cope
with real world conditions / data from other modelers.

Why use a CAD/CAM product that is so limited in it's approach ?


jon

 

Mark Mossberg wrote;

OK. Done.

I've been using ACAD since version 1.2 (can you say 8in floppies and CP/M
system?). So, I am used to using it as a thinking tool. In this particular
case I've simply used it to play with layouts, 2D clearances and general
ideas. Sort of like paper and pencil. Now, with that out of the way, I
need to graduate the design to s solid model to submit to the fabricator.
This is simple enough that starting from scratch with SW is not a problem
whatsoever.

I am sort of taking this as a learning opportunity as well, and so, I wanted
to figure out if it makes sense to, at the very least, import button
outlines (front view) via DXF/DWG. Of course, the first thing that happens
is that the sketch comes in with no constraints or relationships whatsoever.
With more complex sketches there would be a non-trivial amount of work in
constraining the sketch.

Unless I'm missing something, the simple rounded rectangles and circles for
my particular excercise do not suffer from being imported and
hand-constrained this way vs. being created from scratch within SW.
Correct?

To address your first statement, yes, absolutely, SW does not work anything
like ACAD and one shouldn't even think the ACAD way when using it. I'm
progressively getting better at this and the questions I asked (and those
that I will undoubtedly ask in the near future) are a reflection of the fact
that I am trying to better understand how to do it the SW way.

I'll lookup feature arrays. Not sure I remember that. I've done all the
online tutorials as well as going to the class and going through most of the
sheetmetal coursebook. Now I have information overload. The new mission is
about connecting the dots and making it work under fire without taking
rounds.

Thanks for the pointers,

-Martin

 

Don't hand constrain all the unconstrained imported Acad data. Use Tools,
Relations, Constrain All. This will only work if there are no relations in
the sketch. It may be advantageous to delete any existing relations, and
use this to recreate them all automatically.

 

See my prior post regarding this. It's about being a nearly 20-year ACAD
user two months into a new tool. I can run ACAD without thinking about the
mechanics of the program. As is evidenced by my questions, I'm not there
yet with SW (only a couple of months on it) and so, it is much easier for me
to doodle in ACAD than in SW.

BTW, I've read through most of your site. Thanks for taking the time to
post such useful material.

I'll look these up. I'm looking for the solution that will have the
assembly and related parts automatically adjust to design changes. For
example, if my vendor tells me that the buttons need to be 0.010in wider, I
want the holes cut in bezel to change when I change the part and do so
according to the clearance rule I specified.

I just have to get work done. I can't be in learn-and-no-work mode forever.
I'm willing to accept making mistakes as I go. Make enough of them and you
become an expert!

One of the problems with the SW training (all manufacturer training, for
that matter) is that the folks who teach are not always accomplished
practitioners. Sometimes they are not even good teachers. I've seen the
worst and the best. The SW class I took was good, but not the best by a
longshot. The material is there, in the book, but the instructor would have
been better positioned in front of a kindergarden class.

That's real life, I guess.

Thanks again,

-Martin

 

Jon,

While I appreciate your comments, I don't --and I say this with the utmost
respect-- have any use for them. Engineers have to learn to live in a
non-idea world. If I had it my way, I'd be off on a dive boat in the
Caribean and someone else would be duking it out with whatever CAD system to
get this design done over a weekend.

When I first started to use ACAD nearly twenty years ago you had to load and
unload modules from memory; convert DWG's to DXF and edit them with WordStar
just to get the damn thing to be usable for real-world designs. We made it
work and it served its purpose. Now, for me, it's about adding a new tool
to the arsenal: SW. It matters not that it might be the best or the worst
out there, it's what I have to work with.

By all means, if you have anything to contribute that could help understand
(me and others) how to approach SW at my level I'll humbly listen and learn.

Thanks,

-Martin

 

The sketch where I tested this is a simple rounded rectangle. 0.210in to
the side and 0.03125in radiuses on all corners.

I displayed all relations and deleted all my hand-applied relations.
Then I used the "Constrain All" function.

This just added tangent, vertical and horizontal relations. The sketch
remained under-defined. In order to fully define it I still have to add
dimensions and a relationship to the origin.

Which brings-up another question:

To fully define the sketch dimensions and additional relations are needed:

- The you dimension one arc and tell the other arcs that they are equal to
the first.

- Horizontal and vertical relations from one vertical and one horizontal
side to the origin.

When it comes to the sides, you can dimension this sketch three ways (maybe
more):

1- Length of each linear segment
2- Inside distance from side to side
3- Inside distance from the intersection of an arc and a line to the same
point on the opposite side

My gut feeling is that [2] might be the most appropriate (whatever that
means) way of doing this. Correct?


-Martin

 

Understand that driving SolidWorks can be like showing up for Indy 500
on a moped and expecting to be competitive. It doesn't matter how good
you are, without the right tool sometimes one can't be productive.

The FACT is that what SolidWorks makes you go through by having to
start all over again by drawing everything from scratch is an insane
limitation.

VX can easily work with imported wireframe. SolidWorks can't.
Start asking yourself why SolidWorks should not be able to work
with imported wireframe. Does this severe limitation of SolidWorks
make ANY sense ??? How can this limitation be justified ???

Throw SolidWorks in the garbage and get a real CAD/CAM tool.

Or :

Stop accepting the massive limitations of SolidWorks and demand more
from a CAD/CAM product. This is a typical real world problem that
SolidWorks falls apart on.

VX handles this kind of thing with ease.

jon

 

I apologize for my ignorance, what's "VX"?

-Martin

 

<snirk, sniffle>
Esk im for the drawin and sho im how good it wurks jon. Then yu kin stert
tha secund thred on the new VX forum. Or maybe yu already been banned.

 

Martin,

www.vx.com

Take a good look at the videos posted showing how VX works with imported
wireframe data and easily turns that imported wireframe data into a
parametric solid.

It's very important to understand what SolidWorks should be able to do but
can't.

Take it another step and download VX and try doing it yourself. VX makes
it very easy.

jon

 

That clueless wants to hump your leg <G>

 

It's the buzzword of the day.

HTH

 

You don't use ANY CAD system at all, clueless.
Probably never have.

Still driving a truck?
"Parametric" way over your pointed little head?
"History" as well?

 

Clueless idiot.

 

No IGES, ParaSolid, DXF/DWG, STEP, SAT, VDA/VDAFS, PRT, ASM, XPR,
XAS, etc. importing, huh?

Your wisdom on & knowledge of these subjects is just astounding,
as usual.

 

I have done some of these sorts of things and some other experienced
SWks users are on track.

It sounds like you have not really gone through the SWks Tutorial or
taken an introductory class that covers that material as a first step.
Once you go through those basic operations in the tutorial, which was
maybe 80 pages when I did it, you will get your mindset for how
SolidWorks functions for basic things. That is essential, but easy.

The logic of certain design methods will start to become apparent as
you start designing with draft, versus adding draft later, and there is
no "Right" way to do this. The nature of the part and the way the
tooling HAS to be built often determines which way is best or required.

Other construction details can likewise be done several ways, and this
initial openminded experiment and learning phase of a few days to a
week will set you in good stead for quickly determining the methods to
try in your project.

For me, I must admit, I sometimes make 3-4 designs of a particularly
complicated part, with sometimes 2 different initial starting points.

Some parts just have no chance of parallel walls, so "Shell" doesn't
work, or can work only in a limited area, which gets drawn first or
drawn as a separate solid and shelled and then connected to the rest of
the part design. I've actually cut out a part of a solid as a separate
piece to accomplish this once.

Some part constructions are totally determinined by the need for
specific locations of parting lines, so that I can't just "Loft a cut"
through an area where 2 cores split.

In the "old days" this sort of expertise was called "having time on the
board", meaning the drafting table. Now its similar in "screentime in
Solidworks". Shouldn't take you too long to fly.

Bo