Molding Plastic - Can This Thing Be Done?

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SUMMARY

The discussion centers on the feasibility of molding plastic bottles and jars with re-entrant screw threads using conventional plastic molding techniques. Participants conclude that traditional molding methods are impractical due to the inability to remove the molded product without damaging the mold. Alternative design suggestions include snap fits and interference fits as more viable solutions for achieving similar functionality without the complications posed by screw threads.

PREREQUISITES
  • Understanding of plastic molding techniques
  • Knowledge of re-entrant screw thread design
  • Familiarity with alternative fastening methods such as snap fits
  • Basic principles of mold design and manufacturing
NEXT STEPS
  • Research conventional plastic molding methods for bottles and jars
  • Explore the mechanics of re-entrant screw threads in design
  • Investigate snap fit and interference fit design principles
  • Study case studies on alternative designs for functional plastic containers
USEFUL FOR

Product designers, mold engineers, and anyone involved in the development of plastic packaging solutions will benefit from this discussion.

Blokle
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Hi,

1) Can this thing be molded using methods and materials that are used to mold conventional plastic
1.1) bottles?
1.2) jars?

2) How much more expensive will it be (percentage and/or absolutely ) compared to 1.1/1.2?

3) In a case that it is impossible or much more expensive than conventional bottles/jars - do you have ideas for alternative design to achieve the same functionality?

Thanks
 

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I think this is pretty much mpossible, because of the re-entrant (or internal) screw threads. Once you have filled the mold, the only way to get the bottle out would be to break the mold. That would be OK for casting with a sand mold that is only used once, but you can't "unscrew" a re-useable mold from the bottle.

Apart from that, I don't understand quite how your "mid height" connectors are meant to work. How can you insert the "bottle top" and then turn it without using tools, since you will finish up with no free space between the bottles except the thickness of the "nut" between the two opposite-direction threads? And if the two threads don't engage at the same time on both bottles, one side is going to be fully screwed in before the other.
 
How about snap fits? might be much easier to make. Or an interferrence fit.
 

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