Packing materials

We are in a manufacturing company, of fruit juices. We have purchased a bottling machine, and from the item of Preforms, we are manufactuting different size Pet bottles, for our packing of finished products. Please let me clarify, whether , the manufacuturing of Pet bottles, from Preforms, for inhouse requirement, is attractive of Central Excise duty? or pls clarify , the process  or system  to be followed in those cases.

v.p.chandra sekar,Salem

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