Amcor Rigid Plastics and plastics machinery manufacturer Sacmi have teamed up for the commercialization of the industry's first compression blowforming (CBF) machine for the production of rigid HDPE pharmaceutical bottles.

Calling it a "highly viable alternative to traditional injection blowmolding" for rigid pharmaceutical bottles, Amcor and Sacmi made the announcement at a May 1 press conference during the Interphex 2012 Exhibition and Conference at the Javits Center in New York City.

The process, which combines compression molding and blowmolding, was originally developed by Sacmi Imola S.C. Amcor collaborated with Sacmi in a 14-month development project to adapt the unique technology for pharmaceutical packaging.

Laurel Spencer, VP of marketing for Amcor Rigid Plastics North America, told PlasticsToday this new technology delivers significant advantages over conventional processes.

"There are three main benefits: the first is enhanced quality, the second is the faster processing, and the third is the sustainability benefits," she said. "In addition, there is also the potential for lightweighting."

Amcor has an exclusive arrangement with Sacmi to utilize the technology in select market segments and global regions.

The company has already commissioned a 12-cavity platform (CBF-12), and is producing HDPE packer (over-the-counter and prescription) bottles at its Youngsville, NC facility. Three additional machines are on order and will be in production by the end of the year.

In addition to the 12-cavity unit already in production, Amcor has committed to additional CBF systems, including a 20-cavity unit, which will be in production by the end of 2012. New-generation equipment will have capability for production of HDPE, PP, and PET pharmaceutical containers.

Bob Israni, Amcor's technical manager for the pharmaceutical market, said that in the past, plastic bottle manufacturers have relied on injection blowmolding as the primary technology for pharmaceutical containers.

However, drawbacks in the areas of quality, process control, cycle time, and sustainability have limited the process and new alternative manufacturing technology has been slow to emerge over the years.

The compression blowforming process

In the compression blowforming process, material is extruded, cut, and transferred into the compression cavity. A preform is produced and a pre-blow and full-blow process is completed in the same mold station with no transfer of the preform.

Compression blowforming has no manifold for melt distribution to individual, separate cavities, which results in no temperature differences and less chance of resin burn and degradation.

The pre-blow process allows for effective separation of plastic from the compression core, which reduces the chance of plastic sticking to the metal core rod, resulting in more uniform wall thickness distribution.

The weight of the resin shot is controlled for all cavities with a servo-controlled melt pump, resulting in more accurate part weight distribution across all mold cavities.

The process also operates at lower temperatures (30ºF cooler), which results in lower residual stress in the end product and cycle times, which are reduced.

In the CBF continuous rotary process, the plastic preform undergoes compression forming through the use of a neck ring, core, and compression cavity. The neck ring carries the plastic preform through the continuous rotary motion with the entire mold assembly (compression and blow), moving in synchronization in a circular 360-degree process.

Compression blowforming's continuous rotary motion eliminates station-to-station indexing time, thus optimizing idle (non-process) time. Secondary cooling on the exit conveyors allows bottles to be removed hotter from the machine.

Sustainability  

Key sustainability advantages include a significant energy reduction through lower process temperatures and application of updated machine process improvements, the companies said. The process achieves thermodynamic stability quicker and makes production bottles within 10 minutes from machine start-up.

Inspection system

One unique aspect of the CBF process is an inline quality inspection system that is fully integrated into the machine control. An infrared vision system detects dimensional variations and contamination (including any embedded opaque or metal particles).

Additionally, a fully integrated plasma surface treatment system is available for full wrap label and finish induction seal application.

And with CBF, leak testing validated to 0.3-mm minimum hole diameter is performed before the bottle leaves the machine immediately after each bottle is blown.

Other market potential

Along with pharmaceutical packaging, Amcor and Sacmi see strong potential for CBF in other markets, including single-serve dairy packaging made of HDPE for applications such as liquid yogurt and probiotics.

The commercialization of the new technology gives Sacmi entry into a new market segment and increases brand awareness, according to Luca Nanetti, sales and marketing manager for closures and containers for Sacmi.

"Pharma is a good fit for us, and dairy is also something we are very interested in," he said.