Mold Design

Hello again good folks,

I'm continuing my exploration of Solidworks. As a product design
package I'm pretty impressed so far. Have completed my first design,
and it went well. Nothing too complicated -a case with various
electronics in it and some rubber end caps. Built the front and rear
case from one part -using different configurations for the different
features (when editing a part as part of an assembly can you
automatically edit only one configuration? -I seemed to need to go
into the part and supress the feature I'd added in the other
configuration all the time). It is with the SLA people now, and I
should have some parts in my hand later this week. Once it is
approved it will get tooled up for injection moulding -which brings me
on to the title of this rather rambling post. Do people use
Solidworks for mold design? I have had a quick run through the
tutorials, and was not at all impressed. To put this in context I'm a
tool designer by profession, and the move into solids is to cope with
an increasing amount of product design (to make tools for later on).
I have always designed tools with a surface modeler, and find this
many times faster than Solidworks looks like it could ever be. From
getting an IGES file to the drawings hitting the shop floor is, on
average, half a day at the moment for an average part (with a complex
3D split line and not too many undercut features). This seems so much
easier with surfaces. Even the simple example supplied by Solidworks
(the telephone handpiece) slowed my PC down to a crawl -I went to get
a cup of tea while it did some functions!! Compared to most of the
stuff we see that was an incredibly simple part -it all fell into line
of draw, had draft on most of it, and there were no undercuts -I'd
kill to see parts like that all the time <G>

I'm not bothered by this, as I only intend to use Solidworks for
product design, not tool design. I just wondered how people who did
use Solidworks for tool design got on with it (perhaps, having been so
negative, I should duck now).

Regards

Kevin

 

Generally, I don't like to mix in-context and configurations. There are
too many limitations and too many ways to get yourself in trouble. I
would do one of two things:

1) Design the assembly as a single part and then split it into two to
do the detail design.

2) Design the second part as a separate part in context.

Anyway, after your experience, I think if you see a new way of doing it,
you won't try the other way again.

As far as molds in SW, yes, several people do them. Probably one or two
will answer your post here. I'm a product guy that gets involved on the
tooling side sometimes, but I agree that the SW mold tools are not
incredibly useful. There are many types of parts where they just won't
do it. Any SW mold demo I've seen has always done most if not all of
the work manually, not even using the "mold tools" functions. The one
exception is the "core" tool, which is actually very useful, and not
just for molds.

When I have to do cavity/core work, I use a partner software called
SplitWorks, which does a much better job than the SW tools, plus it
doesn't create all the cavity/core geometry in the same file as the
plastic part, which (I think) is a really bad idea.

As far as using solids vs surfaces, SW has a lot of surfacing tools in
it, enough to do most types of mold work. Some of the functions are a
bit iffy, though, like the radiate and ruled surfaces, but most work
acceptably.


Anyway, good luck.

Matt

 

Yes, I think that in retrospect I should have designed the front/rear
case without the individual features, then copied it and had seperate
front and rear case parts. I was trying to be too clever for my own
good (I'd done the "hinge" tutorial and got carried away). Most of
the work on the parts was done as individual parts, but there were
some final details that needed to be done as part of the assembly
-where they interacted with other parts. The time it saved me having
two configurations of one part was probably lost in switching to the
other configuration to supress features I had added.

But it was a good experience, and taught me a lot about the strengths
(and weaknesses) of the package. Overall I'm still impressed, but
probably not for mould tool design. It is all about the right tool
for the job though -the reaon for looking at Solidworks was that the
surface modelling package I use is designed for mould tool work, and
has serious weaknesses as a product design tool. If one CAD package
was great at everything there wouldn't be any others!

The surfacing in Solidworks is average for a solid modeler, but realy
doesn't cut it compared to a surface modeler -but that is a rather
unfair comparison. And I believe it has been improved in SW2006.

Regards

Kevin

 

Kevin

Been designing molds in SW for about 7 years. I have my own ways of doing
things that have nothing to do with the mold tools.

Just the ablility to change a hundred different things with one command
makes it overwhemingly superior to surfaces all by itself.

I'd never go back to using a surfacing system.


Regards

Mark

 

Kevin,

I too have been designing mold with SW for about 8-9 years. It has come a
long, long way over the years.

I had developed my own methods and techniques over the years, none of which
include the SW mold tools (they are fairly useless). They basically
included base parts and tons of in-context relations. They worked pretty
good for the most part unless I got into a fairly complex part. Then it
would bring SW to its knees.

Recently, we hired a new designer here that has shown me some new techniques
that are, how should I say,,,, the bomb. I still use base parts similar to
the way I had always done it. However, instead of tons of in-context
relations, I now use derived sketches. We create assembly sketches of the
entire assembly (as few as possible), and derive these sketches into our
parts. The derived sketches is the only in-context feature in the entire
part. You then open each of the parts in their own window and use the
derived sketches to create your features. Everything is parametric, and
there is little overhead on your system, even with complex designs.

I thought I had figured out the best way to design molds in SW over the
years. But the new guy proved me wrong. His methods ROCK!

 

Seth,

Sounds very interesting.

can you send me a simple example ???

Mark

 

I don't do molds, but I would also be interested in looking at a simple
example. Please??

WT

 

Kevin, you noted " (when editing a part as part of an assembly can you
automatically edit only one configuration? -I seemed to need to go
into the part and supress the feature I'd added in the other
configuration all the time)."

Indeed you do have to go into the "Properties" of a part in an assembly
or of a feature in a part and click on the appropriate options to
suppress added features in other configurations, if you haven't seen
that yet.

I sometimes think there is a bug in the saving of configuration states,
however, as when I go back to an earlier config. after changes to
several others I often find some other features turned back "ON"
mysteriously, and they were ones I hadn't even modified in the mean
time.

Anyone else see these buggy configuration issues?

Thanks - Bo

 

The problem is that I don't readily have a "simple" example that would be
relatively small in size. I have been meaning to create a simple example to
use as a reference, but just have not had the time, until now perhaps. I am
kind-of slow at the moment (won't last long probably), so tomorrow I will
try to create an example and get it to you.

 

Seth,

Thanks a bunch, I appreciate it

Regards

Mark

 

That would be great. It would be even better if Wayne could host it on the
Kansas City SWUG site!

Jerry Steiger
Tripod Data Systems
"take the garbage out, dear"

 

I believe I've seen these problems as well, but they have never been
repeatable and I'm not absolutely positive that there isn't some kind of
pilot error involved.

Jerry Steiger
Tripod Data Systems
"take the garbage out, dear"

 

Sure - no problem.

WT

 

I agree on not being repeatable, but that speaks to a bug, as we are
pretty good creatures of habit.

What makes me think it is a bug, is features get flipped which I was
NOT working on, and which were in other untouched configs.

Bo

 

Let us know when it's up, I'd like to see it too. It's good to learn
from others with a practical use behind them.

Regards

John Layne