The PREFORMER™ inspection machine, with associated handling equipment, is a total preform quality control system that can be operated off-line or closely coupled to an injection molding station.
The PREFORMER™ is capable of inspecting a large quantity of preforms for a variety of common defects, effectively separating defective and acceptable preforms.
The PREFORMER™ is able to sort and check the quality of up to 22,000 preforms per hours for seal surface, sidewall, and base defects, as well as leaks.
The design of PREFORMER™ is the result of more than 20 years of operational experience in injection moulding of PET preforms for the world market.
Preform Handling
As preforms enter the PREFORMER™ Inspection Module, they are picked from a dispensing wheel and individually gripped by the chain-driven handling system.
We also design and manufacture special rotary joints and connectors for gases and liquids, in accordance to the customer's requirements.
They are then transported first into the camera inspection area where they are inspected for visual defects and then to the vacuum test area where preforms are checked for leaks.
Preforms that do not meet the minimum pre-defined quality standards are scrapped and sent to the reject outlet gate via a pneumatic reject system. "Passed" preforms are discharged to a second gate, permitting both lots to be accumulated in palletized, standard boxes next to the PREFORMER™.
Inspections
The PREFORMER™ incorporates two inspection stations within the unit:
- a camera-based inspection that detects sidewall and base defects;
- and a leak detection system, a gas connector, a joint connector that checks for seal integrity and leaks caused by holes or insufficient material.
Visual Defect Inspections
The PREFORMER™’s electro-optical inspection station performs comprehensive inspection of the preform sidewall and base region for cosmetic and structural defects. Three cameras are oriented to provide inspection coverage over the entire preform sidewall. A separate camera oriented above the preform inspects for base defects.
The special illumination system and high-resolution CCD cameras on the PREFORMER™ provide accurate and reliable detection of a wide variety of common defects inherent to the preform production process.
Defects as small as 0.35 mm can be reliably detected.
In addition to basic defect detection, the PREFORMER™ also incorporates advanced vision analysis algorithms for detecting chromatic defects (color variations) over the body of preforms.
Light intensities on each preform are compared to those transmitted by a reference preform that is observed during the system calibration phase. Preforms exhibiting variations from the standard are rejected.
Leak Detection
The PREFORMER™ incorporates a vacuum test module for verifying the integrity of the inner sealing surface and identifying leakers regardless of cause.
The vacuum test module consists of a rotating wheel assembly equipped with 10 spherical probes that are vertically activated by a mechanical cam and pneumatically connected to a vacuum pump that is assisted by specific pressure instrumentation.
During the test, each preform entering the system is subjected to a specified vacuum level. Preforms that do not maintain this vacuum level through the full rotation of the wheel will be rejected. Preforms with seal surface defects, pinholes or out-of-round finishes can easily be detected by this method.
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