plastic bottle and cap thread engagement

[revier]

i am in design of plastic bottles and cap for food container application.


i used spi neck finish spec to design the thread of botlte. but i dontknow how to design thread for cap which will engage the bottle thread. where can i get the specification for cap thread? and how should be the section of bottle and cap thread engagement at the fully closed condition?

 

[mgnt8]

http://www.cmadc.org/index2.tpl


[url]http://cmadc.firstcontactsuite.com/guestreg/WG/spec_drawings .tpl[/url]


As for what the thread engagement should look like, there are many variables involved that unfortunately make each case unique. Is it a plastic cap, and if so how are they molded? Is the mold stripped or unscrewing? What's the torque for closing the cap? Think through it and you may get to a point where you're in the ballpark, at least enough to start prototyping.