Mold Locked Design..Multiple Side Action/Collapsible Core? 2

[CPosner]

I've got a design that is currently Mold locked. It consists of two mating parts. The issue is with the Female part. I know by opening the bottom, it can be made and by eliminating that undercut.

I'm looking for some suggestions on how to make this design work. The design can change, but the intent is a "twist-fit" connection that must be removable, multiple times. Must be a Robust connection.

Thanks in advance.
Chad

 

[Pud]

You might investigate the lost metal technique to produce your internal bayonet forms:

http://www.coretechsys.com/metal.html

as an example...


Cheers


Harry

 

[patprimmer]

Branson is the leading supplier of ultrasonic welders, but there are others who I cannot recall at this time.

There are some minor design considerations to designing a part to be ultrasonically welded, but the equipment suppliers can supply this, as can the plastics raw materials suppliers.

A moderate proportion of injection moulders have in house ultrasonic welding. Some companies also do welding only on a contract basis. The equipment is not prohibitively expensive, and purchase may be justified on a large project.

Regards

eng-tips, by professional engineers for professional engineers
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.

 

[CPosner]

Based on previous discussion, One of the cores would look something like this:

and the resulting part would then look like:

I think I like this approach. Its seems reasonable and then I need to cap/seal the bottom off with another part...

 

[MikeHalloran]

A soft circular gasket nestled in the cup shown should seal off the full circular end face of the part not shown. Four lugs on the gasket rim could retain it. No need to seal off the slots left by the core; they're outside the pressure boundary.







Mike Halloran
Pembroke Pines, FL, USA

 

[CPosner]

Unless I am not fully understanding your suggestion..If there is a gasket in the cup(shown)..there is direct contact with water in the cup(shown). Since the outside diameter and bottom surface are fully captured, the slots left from the core are exposed to a capturing surface which is permeable. The back side can be sealed with a welded on disk. I need a positive seal from the remaining slots. I'll post another of the underside.

 

[CPosner]

So I'm at the point where I've tried to create uniform wall thickness by adding pockets in the part on the underside...making the bottom core slightly more detailed.

I think I'll still need the external features requiring some multiple side action. So right now I visualize the mold in 4 parts basically. the two parts along the cylindrical axis and two parts for the side actions for the radial/wing features.

Thanks everyone for tips and great ideas so far!

 

[mtpi]

Question: I don't see in any one of the postings that ask the question of what is your volume? Is this a low volume requirement or high volume? That will determine just how the tool will be built, or if a tool should be built. If this is low volume, you may consider machining from bar stock of which there are suppliers that can take your CAD file and program their equipment within aprox. 20-30 minutes and be makeing your parts.

Regards,

mtpi.us

 

[patprimmer]

The OP comes across as intelligent, competent and professional and he mentions tooling cost several times which indicates he is aware of their magnitude and is therefore able to asses viability of the project.

Regards

eng-tips, by professional engineers for professional engineers
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.

 

[CPosner]

mtpi,

For prototyping and testing purposes, machining might be feasible, but I don't think the geometry and nature of the design lends to efficient machining. Maybe if the parts are machined in pieces for easy machining/setup will make that method more effective. I am currently I am at the phase where the design is fairly locked down, and design changes can be adjusted with mold inserts on the cores/cavities. When it does go to production, tooling will be set up already and quantities will be high enough to justify the tooling.