Plastic Products and Mold Design

please talk about this topic

i think experience persons can help us.....

Look at DIN16901. This is the condensed experience of generation of german engineers. The default tolerances table shows how much the part dimensions differ one from another during a mold "session". By session I mean one production period - 1000s or 100s of injected part or few hours(injected in the same nest in a multi-nest mold). Let take an simple example: You have to produce on plastic case with two holes on the bottom separated by a distance of 100mm. DIN16901 says that, if the hole making elements in the tool are at 100mm, the holes in the part will be at 100±0,51mm (i am ignoring the shrinkage). This means that in the tool we do not need restrictions like 100±0,005, 100±0,02 is enough. You have to care about this, designing your products, containing plastic parts.

this is German standard whether Indian's also fallow the same standard....?

I have no idea about the good practices in India. May be there the physics of the molds are the same ;-)

okay thank you