How 3D printing is transforming the development of plastic packaging: Rapid tooling for plastic blow moulding and vacuum forming

Manufacturers of bottles, canisters, jars and moulded containers currently typically wait 4 to 8 weeks for their first metal prototype mould and pay between approximately 2,000 and 100,000 USD for it, depending on its complexity and the number of cavities. It takes a month or more for a company to determine whether a new shape, wall thickness or bottle neck works in production, and that is even before a decision is made on the final production mould. 3D-printed rapid tooling offers the same validation in a matter of days, at a significantly lower cost.

How plastic blow moulding and vacuum forming work

Plasticblow moulding works in a similar way to inflating a balloon inside a box – a heated plastic tube or preform (parison; in the case of PET bottles, a preform) is placed into a mould and inflated with air, so that the part precisely replicates the mould’s shape. Vacuum forming (thermoforming) works in the opposite way. A heated plastic sheet is ‘sucked’ onto the shape of the mould using a vacuum. It is mainly used for packaging, covers, crates and bespoke, non-standard parts. Conventional mould production using aluminium or steel typically takes weeks, and any change to the design then unnecessarily increases the cost of the entire project.

Where the conventional process slows down packaging development

Without rapid tooling, it is difficult to test multiple design variants and verify the actual material, transparency or wall thickness within a short timeframe. This unnecessarily prolongs both design approval and time-to-market.

The problem arises in three areas:

• in packaging development, where the geometry of the bottle or cap is modified,
• in the tool shop, which decides on the prototype mould,
• in process engineering, where blow-moulding parameters, wall thickness or part behaviour on the production line are validated.

Solution: a printed mould instead of a milled one

Instead of milling from metal, the mould is printed on an industrial 3D printer using a material that can withstand the temperature and pressure of the blow-moulding or vacuum-forming process. For smaller applications requiring high levels of detail, typically PET bottles, the Origin Two platform is used – for blow moulds, P3 Deflect 110 resin has proven effective, as it is designed for the rigidity, heat resistance and dimensional stability required by the repeated stress on the mould. For larger parts and longer production runs, Stratasys FDM printers are suitable; the high-temperature PC (polycarbonate) filament has proven effective for blow-moulding tooling. This is because it can withstand repeated exposure to the temperature and pressure of the process with only minimal modification to the standard mould design.

Rapid tooling does not replace the supplier of the final production mould – it simply precedes them in the design validation phase, before the company orders an expensive precision mould.

What do the figures show?

• Blow moulds (DLP Origin/resin): Anaverage reduction in mould production time of 85–95% and cost savings of 75–95%. This facilitates easier design revisions and enables the production of prototypes from real materials (PP, LDPE, HDPE), including transparent bottles.
• Extrusion blow moulding (FDM): The lead time for prototype parts is reduced from weeks to less than five days, whilst tooling costs amount to between a third and a half of the price of a prototype aluminium mould. One manufacturer produced 800 PET bottles using this method without any wear, deformation or dimensional changes to the mould.
• Pilot runs and consumer testing: For one client, it was possible to produce 200 units of each of four designs within a single month.
• Vacuum forming: The moulds are suitable for functional prototypes, pilot production and smaller custom runs, typically ranging from tens to hundreds of units.

Where are the limits of the technology

Rapid tooling is not suited to large-scale production. As a rough guide, it can handle hundreds to a few thousand units per mould, depending on the material and application. It is therefore ideal for prototypes, pilot runs and smaller or frequently changing orders. From our experience with completed development projects, we know that the mould ‘runs in’ after the first few cycles and remains stable thereafter without any obvious signs of wear.

Who can benefit from rapid tooling

It is most suitable for manufacturers of PET/PE bottles and blow-moulded packaging, tooling companies offering bespoke blow moulds, firms specialising in vacuum forming of plastics, and FMCG or beverage brands with in-house packaging development. It is typically suitable where a company is addressing eco-design, reducing packaging weight or switching to recycled materials, and needs to verify a new shape, wall thickness or bottle neck in a real-world process before investing in the final mould.

Do you want to test a new bottle or packaging shape before ordering the final mould?

We’d be happy to show you a real-world sample of a 3D-printed blow mould or vacuum mould and discuss your specific application with 3Dees’ technical experts. Get in touch, and together we’ll assess whether rapid tooling makes sense for your production too. You can find further inspiration in our case studies.

Photo source: 3Dees Industries