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jimboshieldo1-Visitor
1-Visitor
January 18, 2011
Question

one model for casting and machining

  • January 18, 2011
  • 7 replies
  • 2731 views

Is there a way to have one part used to create a casting and machining part?

I thought Simplified Reps would do it, but it has been some time since I have done this.

Thanks,

Jim Shields

DRS C3 and Aviation Co.

Horsham, Pa. 19044


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7 replies

B
BrentDrysdale12-Amethyst
12-Amethyst
January 18, 2011
Hi Jim,
This one comes up quite frequently.

Yes you can use Family Tables to do this though I would not use this
approach unless your models and especially the machining were very simple.

The way that seems best to me is to make an original model of either the
cast or the machined part then use this as an "Inheritance Model" to do the
other option. I would probably make the cast model the original then make
the machined part using the casting as the "Inheritance" part. This would
allow you to have several stand alone machinings using the original casting.
Note that you can make the solid part with external surfaces of an
alternate colour so that you can see which surfaces have been machined.

It would also be possible to make the machined model as the original and add
material for the casting as this is the reality of how the design is done.
However this would limit machining variation so unless there was a very
good reason I would not use this.

If you want I can send a small set of part files and a PowerPoint that shows
this "Inheritance" process which I made using WF2 but is still valid.

There was a presentation at the 2007 conference by Craig Iverson and Kevin
Alexander of Fluidmaster that covered Inheritance Features compared to
Family Tables quite nicely. If you want I can send that too.

Hope this helps.


Regards, Brent Drysdale
Senior Mechanical Designer
Tait Radio Communications
New Zealand
DDI +64 3 358 1093
www.taitradio.com


On 18 January 2011 13:59, jim shields <shields@drs-c3a.com> wrote:

> Is there a way to have one part used to create a casting and machining
> part?
>
> I thought Simplified Reps would do it, but it has been some time since I
> have done this.
>
> Thanks,
>
> Jim Shields
>
> DRS C3 and Aviation Co.
>
> Horsham, Pa. 19044
>
H
HugoHermans12-Amethyst
12-Amethyst
January 18, 2011
Consider using Publisch/Copy as alternative to Inheritance, since
Publish/Copy reduces the file size over the transfer from rough to
finished. Inheritance doesn't.

Consider also to have a 'design intent' part to start from. Rough
castings are prone for feature failure because of the drafts and rounds.
It would be a pitty if also your finished part goes into resolve when
you are investigating design alternatives. In this case, your 'design
intent' part would be very stable and follow you.

Regards, Hugo.

H
HugoHermans12-Amethyst
12-Amethyst
January 18, 2011
Hey Daniel,

This design intent part is basically a part just as all the other parts.
You may implement it as a skeleton part as well, but this is not
essential in the concept. The concept is that you seperate the driving
geometry from the details. Driven geometry has to be rock stable. I
think you do not want your driven geometry (the actual design intent) to
go into resolve mode when you make a rather small change in your design
concept. So, the design intent part is a part as all other parts, but
only contains the essential features of your part.
Another consideration. When you succeed to limit the complexity of your
design intent parts, and you have rather complex assemblies, you will be
able to play with your assemblies and consequently regenerate all driven
design intent parts within a reasonable amount of time.

Drafts and rounds are most of the time not essential (if technology
would allow, we would cast without drafts, isn't?), and are heavy to
regenerate. So, keep them out of your design intent parts, but add then
to the third stage, the rough parts. The second stage parts are parts
where you add material allowance to your design intents. The fourth
stage are the finished parts, where you publish/copy and solidify the
rough geometry into, and publish/copy but not solidify the design intent
into. This second publish/copy is ment as reference for the finishing
(because you do not want your finishing to go into resolve when some
silly round fails).

We add the design intent and the finished parts to our assemblies. The
other parts stay out of it. When you implement your design intents as
skeletons, the mass properties of your assemblies will disregard the
design intents, and stay correct. And with simplified reps, you can
easily switch from design intent assemblies to full detailed assemblies.

OK?

Regards, Hugo.
(I think I explained the above earlier, so if you search the exploder,
you should find it in other words ...)

E
eslotty1-Visitor
1-Visitor
January 18, 2011
I'm not a huge fan of family tables for cast/machine applications,
however keep in mind:

1) Generally, you want the final machined item as the generic... This
precludes the issues encountered when working with instances; layers can
be changed, deleted featured are actually deleted and not suppressed,
etc.....
2) Organize the database so all the cast model features are up front and
are separated from the machine features using an feature to mark the
end. I use a point called "Last_Cast".
3) Use a yes/no parameter such as "machined" and pro/program to toggle
the machined features on or off. This way the family table has one
parameter controlling many features in addition to the appropriate model
parameters. If you are working in the casting, be disciplined to use
"insert mode" to get behind the "last cast" feature.

It takes a little getting used to, but a robust clean model can be
maintained. Personally, I prefer the inheritance or publish geometry
paradigm.

Good luck!

GO PACKERS

GE Healthcare Technologies
Clinical Systems
Monitoring Solutions
Eric R. Slotty
Mechanical Designer
8200 W. Tower Avenue
Milwaukee, WI 53223
B
BrentDrysdale12-Amethyst
12-Amethyst
January 18, 2011
Hi Folks,
Quite a few replies to my reply. Some people requested files from me so I
sent those.

However the big thing to realise is that there are usually several ways in
ProE of achieving the final part geometry. In this case the discussion is
on castings which are going to be machined. For this aspect as for others
there is no best way! The best way for each person/company is what works
for them and even there it depends on what you want your original premise to
be.

I would argue that purist logic says that the final part is what you want to
use in your assembly so that should be the master for whatever system you
use. Having said that designing parts without a decent understanding of the
manufacturing process to produce these is the cause of much angst. In our
company we prize people with good overall knowledge of design and
manufacturing techniques so that we can minimise the design cycle by doing
once and doing it right. We still have to have in depth reviews to ensure
this and even then no system is perfect. Personally due to my toolmaking
background I always think of how parts are going to be made and this is
usually an advantage though it can preclude some ideas which may be valuable
and can be implemented in some other way.

So to round up what I saw on this Casting to Machined part topic you can use
(not in any order of preference):

- Family Tables (either cast first and material removed, or machined part
first and casting detail added)
- Inheritance parts either cast first and material removed, or machined
part first and casting detail added). Probably best used if you have a
really stable base model and several variations of machining.
- Merge model. Again you can start with the cast or final part
- Master model with PUBGEOM surfaces and COPYGEOM and SOLIDIFY in the sub
model. Again you can start with the cast or final part
- As for the Previous method but using the Skeleton part as the master
(Surface and Datum Features only). This method requires an assembly.
- Cast part in an assembly and assembly cuts to make the finished part.

Maybe there are more methods but these are what I have come across in 15
years with ProE.
Specifically I have not seen or tried using Simplified Reps to work on
parts; I have used this with assemblies only.

What I like to see is a really robust models that do what you want still do
this when you and to make changes as you invariably do. Can the next person
to work on the model understand it and change it? Possibly best captured by
Hugo Hermans but also in other replies.

Nice as always to see the number of viewpoints in the emails.

Happy 2011 to you all.

Regards, Brent Drysdale
Senior Mechanical Designer
Tait Radio Communications
New Zealand
DDI +64 3 358 1093
www.taitradio.com


U
uavron1-Visitor
1-Visitor
January 19, 2011
If you MUST have a single object, I would think about controlled suppressing
of Features using Layers, but frankly, my preferred method is using the
traditional Inheritance Feature. From the stability and upscalability point
of view, nothing beats it.

All the best

Uriel Avron
harmonic Systems Ltd.

On Tue, Jan 18, 2011 at 2:59 AM, jim shields <shields@drs-c3a.com> wrote:

> Is there a way to have one part used to create a casting and machining
> part?
>
> I thought Simplified Reps would do it, but it has been some time since I
> have done this.
>
> Thanks,
>
> Jim Shields
>
> DRS C3 and Aviation Co.
>
> Horsham, Pa. 19044
>
H
HugoHermans12-Amethyst
12-Amethyst
January 29, 2011

I've uploaded some demo models to http://communities.ptc.com/docs/DOC-1642, to illustrate our approach. Feel free to comment or to add additional content to the models.
Regards, Hugo.

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