Working molds in reverse

I know how to get a cavity from a part file. BUt is there a way to work in
reverse with out creatign a new part file and say do an extrusion using "up
to surface"? Like how basically you create the part and insert the mold body
around it and then get the cavity. I would like to be able to then take the
mold body and say tewak it out a little in the left and right halves
(assuming that there are only two halves of the mold) and then bring that
back to together into an assembly and say press "mold" and get what would
come out if I cast directly to that mold???

I figure that i could always start a new part file and work top down, but
maybe guys might know something.

Thanks in advance

 

Arthur,

Do you mean you want to create a virtual molded part from the mold assy.
with all the runners and gates attached ?

I do this all the time just to check for parting line alignment, ejector pin
witness lines, etc..
As far as I know, there is no quick and easy way to do this. What I usually
do is create an in-place rectangular block that extends beyond the part
boundaries in all directions, and subtract all of the mold parts from it.
Then you can scale it by the reciprocal of the original shrink scale, and
compare it with the driving part.

A little involved, but doesn't really take very long

Regards

Mark

 

ummmm...well more like this...imagine that you create a cube. Put the mold
block around that cube in a assembly and then get the cavity. you can then
go back to the mold block part file, use a line for a cut extrusion and get
the left and right halves of the mold. Add keys and what not.

Here is where my question starts. Imagine that I make some change to the
molds interiors. And now I want to put the two halves together in an
assembly and in much the same way that I got the cavity, I would like to get
what the positive of what the mold would create.

As I posted before, top down could work in this instance, but is that the
only way?

 

Arthur,

OK.. are you trying to create standard inserts or something for a MUD type
base, without having to actually model them ? You can do what you describe.
I'm just not sure what it will buy you in the larger scheme of things.

What you should be concerned about (maybe) is having to many cavity features
in an assembly. Or creating circular referances in the process. This can
really slow things down, or even cause the system to hang

Please excuse my confusion and ignorance. I have my own custom mold base
format, and don't use off the shelf sets very often.

Regards

Mark