Sensor-Based PET Stretch-Blowing Controls and Bottle QC Instruments

Advances in automated stretch-blow molder control, precision bottle measurement and laboratory automation are being highlighted by Agr International at NPE2024. The focal point of the booth is one of its newest systems, Process Pilot+ (introduced at K 2022), an enhanced version of its Process Pilot automated management system for two-stage stretch-blow molders. Like the original version, it uses wall-thickness measurements from Agr’s Pilot Profiler inline QC instrument to continuously measure material distribution on every bottle and adjust machine settings to compensate for changes in the operating environment (temperature, humidity), preform quality or the material — especially variations due to the presence of rPET — in order to maintain optimal material distribution. The new version incorporates multiple control loops that regulate slow-response processes like oven temperatures separately from very fast-acting processes like blow pressure and timing. The multiple control loops reportedly can correct process drift as much as 40% faster and enable startups to reach on-spec bottle production up to 65% faster.

In addition, a new Value Performance feature answers the question, “How do I make the best bottle for the lowest cost?” This option enables users to specify a less-than-perfect level of wall-thickness distribution that is acceptable in return for reducing compressed-air usage or energy consumption, or using lower quality preforms.

Agr International is also showing its Pilot Vision+ system for quality management of PET bottles, including those with high percentages of rPET. This system (introduced at K 2019) offers modular defect detection with up to six cameras inside the blow molder to spot randomly occurring defects and color variations.

Agr’s newest handheld QC device for bottles or flat sheets is the ThicknessPen, a dual-mode unit (also introduced at K 2022) for use on a variety of plastic materials. One measurement mode is magnetic, using a target ball on the opposite side of the plastic object from the sensor. The other mode is capacitance based, which enables single-sided measurement without a target ball. This mode offers a quick “touch-and-go” approach for use on large containers or other parts, as well as sheets or panels.

Agr is also featuring the Gawis 4D automated laboratory measurement system (introduced in 2021). It can create complex job setups in seconds to combine several dimensional or thickness measurements into a single operation. When paired with a robotic handling system, it can measure up to 128 bottles (PET, PP or PE) or preforms fully automatically.