Machine vision applications -  Successful examples from many industries

MACHINE VISION APPLICATIONS

Successful examples from many industries

Improving the quality of pharmaceutical packaging components

Ensuring that rubber stoppers and plungers used in pharmaceutical vials and syringes are free from defects and contamination is of paramount importance. The iM series of modular, fully automated inspection machines manufactured by Simac Masic bv have been designed to meet that challenge.

Utilising multi-camera high-speed vision systems, developed in conjunction with STEMMER IMAGING, in combination with metal detection, they provide 100% inspection of these products and provide automatic rejection of out-of-specification product.

Huge quantities of rubber stoppers and plungers of different sizes are manufactured for the pharmaceutical industry each year using many different elastomer materials. The stoppers are used to seal drug products in a vial and are held in place by an aluminium cap. They feature a hollow central plug and in use, a syringe needle is inserted through the stopper.

When the vial is inverted, the medication flows into the hollow plug allowing it to be extracted through the needle. The plunger forms an airtight movable seal in the syringe body that allows the medication to be drawn into the syringe. The elastomer stoppers and plungers are potential sources of particulate contamination and since both come into contact with the drug product itself, this could lead to costly end of line product rejection or even compromise patient safety.

 
Potential particulate defects in the stoppers and plungers include loose and embedded particles, defects caused by trimming and moulding, hairs, fibres, grease and metal contamination from the moulding process.
Roberto Griguoli, Manager Engineering at Simac Masic

But it is not just those surfaces that will be in contact with the medication that need to be checked. Any loose contamination on any of the non-contact surfaces could move onto the contact surface while the product is being transported. This means that all of the surfaces on each and every stopper and plunger should be inspected to eliminate that possibility.”

Industry expertise meets the challenge

Simac has been involved in the design and production of rubber stopper inspection machines for around 25 years so has extensive experience in this field. Each new generation of their inspection machines is designed to address the increasing requirements of the industry.

Key considerations include:

  • The speed, accuracy and reproducibility of inspection
  • Imaging the internal bore of stoppers and plungers
  • High speed, high volume data handling
  • Mechanical handling to allow inspection of all surfaces
  • Mechanical handling of different size stoppers and plungers in the same machine
  • Meeting CFR21 Pt 11 and GAMP5 requirements
  • Ensuring the system can be used in an ISO Class 5 clean room environment

In addition, many stopper and plunger manufacturers also want to make dimensional measurements and check for the presence or absence of any inert elastomer coatings that have been applied, so the system needs to be able to meet these needs.

Self-contained system with modular design

The Simac iM series of inspection machines are compact, stand-alone QA systems for rubber stopper and plunger QC that are designed for use in an ISO Class 5 clean room environment. They have a modular construction that consists of a product feeder system, two vision inspection stations which include colour imaging, a metal detector, sample ejection mechanisms at two positions and the capability to add extra inspection modules such as dimensional measurement and coating inspection.

The products move continuously through the two vision stations and the metal detection station, with defective products automatically removed after the first inspection station or after the second inspection and metal detection stage if defects are detected. Stoppers or plungers are loaded into the machine at one end and are automatically sorted into pass, QA sample and fail bins at the other end. Either stoppers or plungers can be inspected in a single machine and feeder systems are supplied which can handle anything from 0.5 ml plungers up to 32 mm diameter stoppers.

Roberto Griguoli added: “Stoppers and plungers are manufactured in a number of different sizes and designs. The inspection process is recipe driven and recipes can be set up for the required shape and size of the product. It takes just 15 minutes to exchange the feeder system when changing to a different product design. The whole system has been designed so that no mechanical adjustment of any of the cameras is needed after product changeover.”

Vision inspection

A vibratory bowl feeder receives the parts from a hopper and then orients them onto an accumulation track. A rotating separation wheel collects the stoppers one by one from the accumulation track and transfers them to a rotating mechanical vacuum wheel which presents them to the first vision station. Here two high resolution cameras are used to inspect the top of the stopper and the steep internal sidewalls of the hollow plug for defects such as marks, cosmetic defects, inclusions, dents, particulate debris, fibres etc. Inspection of the cavity and inner walls of the stopper is particularly demanding, requiring precise positioning and careful attention to the lighting and lenses used.

A similar approach is used for the plungers, but as the cavities here are much smaller, a different camera with wide angle lensing is used. Since the stoppers and plungers can be made from a wide range of elastomer compounds, colour cameras are used to ensure that light coloured defects on light product compounds can be detected. A pneumatic ejector blows all components that fail these inspections off the wheel and into a reject bin.

Parts that pass the inspection remain on the rotating wheel and are then transferred onto a larger, uniquely designed rotating ring, which transports them through the second vision station and metal detector. They are given an identification key so that they can be tracked through this process.

The second vision station consists of a compact camera aisle on which multiple cameras are mounted. Four of these cameras are arranged around the component to provide a full view of the entire side surfaces of the component. One of these cameras looks down to image the bottom surface of the top of the stopper. These inspections are triggered simultaneously. There is also space on this camera aisle to mount optional cameras for dimensional measurements and inert surface coating inspection.

The component then passes through a metal detector to check for embedded metal particulates that may have come from the moulding process. On completion of this inspection, the components pass to another pneumatic ejector system. Failed components are blown into a reject bin, while good parts are blown into either an acceptance bin or a QA sampling bin for subsequent manual inspection. The proportion of good components that are sampled for QA is specified by the manufacturer and set up in the inspection recipe. The system is capable of inspecting 700 components or more per minute, depending on the design of the components.

System performance

The high sample throughput places high demands on image acquisition, processing and data processing and storage. The high resolution imaging system captures high contrast images with low geometrical distortion to detect small defects and the individual lights used for each camera are run in pulsed overdrive mode, which both freezes the motion of the components to prevent image blur and delivers sufficient light intensity for the short shutter times used in the high speed inspections. Cameras are linked to high performance Windows 10-based industrial PCs running the image processing software in which the vision applications are developed.

All systems are fully calibrated before they leave the factory. With 7 or more images being acquired for component in a standard system, huge data processing rates are required. Data for every component inspected is securely saved and archived. The data recorded includes details such as time stamping to make it possible to conduct a full inspection audit trail for every component, in accordance with CFR21 Part 11 requirements. Images can also be viewed off-line on a laptop if required.

Enhanced productivity

A touch screen interface provides access to all machine functions and any changes and adjustments are displayed in ‘real-time’. Batch information can be entered and recipes can be selected for the particular components being inspected. The operator can follow statistics, processing results and operationally-check the current product run. A separate vision terminal shows images and vision inspection results.

Roberto Griguoli concludes: “Key factors that characterise our machines are performance and the potential to go further. In the current generation of machines we have increased the speed, the reliability of error detection and the accuracy of detection.

Defect detection levels are >99% and the current inspection speeds are limited by the mechanical feeder system – the imaging system could handle a faster inspection rate. We can also offer additional inspection modules but we are always happy to speak to manufacturers about their specific needs and carry out additional customisation if needed. We provide comprehensive customer support including remote access to monitor machine status if needed.”

Simac’s latest iM range of rubber stopper and plunger inspection machines enable top-of-the-range pharmaceutical component suppliers to deliver products that have been automatically 100% verified to be free of specified defects and contamination. Designed, engineered and manufactured in house according to GAMP standards, these new machines precisely meet the needs of the industry.

Pushing machine vision to the limits

Simac have been integrating machine vision systems into its products since the 1990s. After market research and extensive in-house testing, a number of preferred brands of machine vision components have been selected. STEMMER IMAGING was the supplier for a large number of these brands and the two companies have worked closely to ensure that the vision systems in the Simac products are of the highest quality and deliver the best possible performance.

Roberto Griguoli observes: We push STEMMER IMAGING and their suppliers to the limit. We make sure that we keep fully up to date with the exact performance levels of the components available. In some cases, for example with some of the lights used in our current system, we get the manufacturers to make us something special to meet our needs.

We exchange ideas with STEMMER IMAGING and we have worked together on feasibility studies carried out on site at their offices in The Netherlands. They are also always happy to let us borrow components for evaluation in our laboratories, so all cameras, lenses and lighting are fully tested in our laboratory before being used on a machine.”

“Of course we also use machine vision in many of our other products both in the pharmaceutical sector and in other industries,” he continued.

 
The relationship with STEMMER IMAGING is very much a collaboration. Through many years of vision integration in different industries in multiple markets we have become a true knowledge centre and we would always be happy to recommend STEMMER IMAGING to others who need machine vision support.

About Simac Masic bv

Simac Techniek N.V. was founded in 1971. Operating as a family business across Benelux and Central Europe, it supplies and supports high-quality technology solutions for improving the business processes of large and medium-sized organisations. The Simac operating companies offer a wide range of solutions, products and services in the ICT infrastructure, ICT applications and Industrial Electronics & Automation business sectors.

Simac Masic bv is part of the “Smart Solutions” group of companies within Simac and a global supplier of machine vision systems to a number of industries including pharmaceutical, medical, food, electronics, and packaging. Since the delivery of its first vision system in the 1990s, the company not only provides complete turnkey solutions, but also supplies integration pathways for existing production lines. The last few years they focus mainly on medical and pharmaceutical applications to provide true technology leadership within these industries.