Critical defect detection in moulded glass
In today’s food packaging solutions, glass is an excellent material.
Glass is an inert material, transparent, strong, low cost and fully recyclable!
Besides these properties, glass can be shaped in nearly any form by moulding.
The production of moulded consumer glass products is done by inserting a ‘gob’ of molten glass in a mould.
While the glass cools, it accurately takes the shape of the mould and a product is formed.
This article highlights detection of critical defects in the sealing surface of moulded glass.
Glass-moulding offers wanted and unwanted features
In the forming process, all mould-details are taken over in the geometry of the product. This applies to the wanted features, but sometimes also leads to unwanted features.
Unwanted features negatively influence the product-quality or can even cause a reject.
One typical defect-mode which relates to moulding is called Line-Over-Finish (LOF).
A Line-Over-Finish defect is a physical imperfection on a surface and it is a problem when it occurs on a sealing surface, for example the edge of a jar where the lid has sealing contact.
Detection of most difficult defect on sealing surface
For moulded glass production-facilities, the LOF is an exceptionally nasty feature, since it is hard to prevent and most difficult to detect.
Existing LOF-inspection systems have a high False Reject-ratio, which leads to unnecessary rejects and reduced factory-output.
At the same time, the reliability of existing systems is below market-expectation and False Accepts still lead to customer-complaints.
Vimec’s Enceladus: moulded edge inspection system
After nearly three years of studies, tests and validation, Vimec has recently released Enceladus.
We look back on a project that was initiated as a LOF-inspection system and resulted in a powerful edge inspection system with unprecedented performance and reliability.
Like all our solutions, the inspection is established with machine-vision and specifically designed for reliable inspection of a defined feature.
The functionality has been designed in such a way that there are no compromises to the glass production process. There is only a physical add-on to the existing line, all parameters, speed and handling have remained unchanged.
What’s in a name….
You may have noticed that Vimec products are always named after a certain moon.
The LOF-inspection device is named Enceladus, a name which is particularly relevant for two reasons:
- Enceladus is the moon which was discovered after Mimas (which is the name of Vimec’s off-line moulded glass inspection system)
- Enceladus is the moon with the highest albedo (reflection of light), which is suitable given the enormously bright LED panel
How is the performance achieved?
The high performance is achieved with a line-scan camera which observes the sealing surface of a rotating jar. In order to meet the market-wishes and demands, the hardware resulted in an extreme set-up of ultra-fast linescan imaging, telecentric optics and a customized, enormously high-powered LED light setup.
To have real-time processing of the extreme data-capturing, a double CameraLink connection and dedicated algoritms have been implemented.
What is to be expected of the new inspection device?
Vimec is proud to announce that Enceladus will join the existing product-family of moulded glass inspection-tools.
- Defects on product edge
- Air bubbles
- Moulded glass
- In-line Cold End inspection
- Round diameter up to 96.5 mm
- System capability
- Resolution 11 micron
- Capacity 240 parts per minute @96.5 mm diameter
- Max capacity depends on edge-diameter
- System hardware properties
- Line-scan, framerate 250 kHz !
- Telecentric optics
- LED white light 1500 Watt
- Integrated cooling to maintain operating temperature to max 70 °C
- Sideways adjustable to adapt to product diameter
- Height adjustable to adapt to product height
More details coming up!
The formal datasheet will be released soon!
Feel free to contact our technical advisor to learn about the benefits Vimec has to offer you.
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