Blow molding solution required

[Soupcat]

Blow Molding is not my area of expertise and would like some advice. My customer has approached me to design a new device which has a blow molded bottle as an accessory. Their competitors product has a PP bottle. Am I correct in holding the opinion that for conventional blow-moulding, a parison is extruded, nipped top and bottom and blown between two dies. This process is suited to PE, PP (as per my customers competitor sample. For more rigid materials e.g. PC and PET, the final product is blown from an injection moulded pre-form? My customer requires a more rigid material which has more clarity. What process should I be looking towards?
Regards

Kieran

http://www.moulddesigner.com

 

[CoryPad]

You seem to have a good grasp on the details of this technique. Injection molded preforms are not necessarily for more rigid materials - they can be used to control properties in the final product (strength, permeability, etc.). I would investigate using blow molding in general and look for suppliers that are familiar with your material.

 

[Soupcat]

Thanks CoryPad, although at this stage a material hasn't been decided on. Could I rephrase the question possibly and ask, if I wanted to use a material having more clarity and rigidity than PP, what material choices are available to me and which of the two processes would have to be used to suit those choices?

Regards

Kieran

http://www.moulddesigner.com

 

[PrentP]

It sounds as if you want injection blow moulding of PET.
Regards,

Peter P

 

[insideman]

What you need is injection-blow molding. A preform with accurate thread and opening detail and a blob for the rest of the bottle is made, which is then immediately transferred to another station for blow molding the body of the bottle. The machinery for this is quite specialised. No names occur to me, but a search on "injection blow mold" should bring results.

 

[patprimmer]

Injection blow moulding is generally more expensive than extrusion, but does give a better thread and more control over final wallsection in all areas.
Most materials can be blow moulded either way. The limiting technical factor is melt strength or melt viscosity. With some materials, the extruded parison cannot support it's own weight, and it breaks and drops to the floor during processing Regards
pat