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The Ultimate Guide To Automated Product Inspection

March 14, 2019

Australian manufacturers today are under more pressure than ever to produce the highest quality goods. With increasingly tough competition at home and from overseas, there’s no room for error.

However, retailers and consumers are both demanding these high-quality products at lower prices. This leaves manufacturers with a challenge: how can you ensure exceptional quality while protecting your profit margin?

Traditionally, manufacturers have relied on the human eye to pick up errors. That was sufficient when line speeds were slower; however, today’s speeds mean human inspectors just can’t check every product on the line — and that’s simply not good enough to meet the increasingly stringent regulations of retailers and trade customers.

For many, the solution is automated product inspection.

In this guide

  • What is automated product inspection?
  • Benefits of automated product inspection
  • What can be inspected?
  • Inspection standards you need to know
  • Different types of inspection technology
  • Metal detection vs X-ray inspection
  • Summary

What is automated product inspection?

Automated product inspection systems help ensure that every product leaving your factory doors ticks all the boxes for consumers and retailers.

At the same time, inspection systems can substantially decrease operational expenses and optimise plant efficiency.

Automated product inspection systems include: metal detectors, checkweighers and x-ray systems.

Benefits of automated product inspection

Product integrity is a big issue for manufacturers. The high speeds at which products are processed, packaged and labelled today, along with short and varied production runs, results in a wide variety of possible defects. The second those defects leave the factory doors, they can damage the brand reputation and customer relationships.

Companies can spend a great deal of time, energy and money checking products manually. However, with complex processes and faster production lines, humans are unable to inspect for packaging errors, contamination and quality standards without impacting efficiency.

“Humans are animals that make mistakes.”
- Dr Shigeo Shingo, Japanese master of lean manufacturing

In a worst-case scenario, relying on human inspection means problems may only be found days after they first appear. However, hundreds or even thousands of contaminated products could have been produced before the issue was even detected.

Where human inspection is utilised as the main method of quality control, the first time you find out you have a problem is when a customer alerts you. That’s where brands run the risk of recalls, a damaged reputation and high costs.

This is where automating inspection has many benefits.

Benefits of automated inspection systems

  • Higher rate of accuracy Inspection systems have a higher average detection rate than humans, resulting in fewer errors. but they are also able to streamline processes and improve the line’s efficiency.
  • Drive continuous improvement in quality control By automating inspection, you can drive quality improvement through repeatable and reliable inspection. Automatic data capture helps measure reject rates and alert operators, which also provides the ability to ensure quality based on specific parameters.
  • Build trusting customer relationship Inspection systems make it possible to demonstrate that reliable QA processes are in place to satisfy your customers, such as the major supermarkets.
  • Stronger brand integrity High quality products and fewer errors strengthen brand integrity by keeping flawed products off the shelves.
  • Higher speeds Inspection systems can also operate at higher speeds where humans struggle.
  • Lower costs With fewer reworks and product recalls, production costs are lower. Inspection systems also provide cost savings by reducing waste and manual efforts.
  • Free up resources Without the need for a manual inspection team, employees can be redeployed to other areas of the production line, ultimately improving your bottom line.
  • Create one lean solution Some inspection systems can now be incorporated with other line technologies, so your automated solutions work as one. Any faulty products can be redirected or rejected if the error cannot be rectified. The whole process is streamlined. For businesses, this level of quality control is invaluable, as it prevents costly recalls for products that are not shelf-ready and yet still shipped.

What can be inspected?

  • Checkweighing
  • Metal detection
  • X-ray system
  • Compliance with regulations Ensuring products are legal and comply with measurement standards.
  • Trend control Can control the filling process to alter the amount of product being filled
  • Classify products Sort goods according to weight classes.
  • Check product weights Check food and non-food products to ensure weights are within specified limits and automatically remove any packs that aren’t. Can check packaged goods (from 10g to 60kg) as well as unpackaged food such as fish, poultry, minced meat, sausages, bakery products, milk and dairy products.
  • Missing item Find boxes / multipacks with items missing e.g. find / identify surgical kits which have items removed.
  • Inspect for contaminants Make sure that products leaving your factory door don’t have metal contaminants in them such as: nuts, bolts, washers, bars, swarf etc These could harm your customers, your reputation and your bottom line.
  • Inspect for inclusions Make sure every pack contains a specific item e.g. at least one foil sachet of salad dressing in a bag of salad mix.
  • Inspect for contaminants including glass, stone, bone, ceramic.
  • Check for voids such as missing items.
  • Inspecting packaging for things like open flaps on a box, items present, gross weight.
  • Type of products that can be inspected: Packed goods, loose free flowing goods, pumped products (meat, cheese, dough), liquids etc.

Inspection standards you need to know

Which standards apply to your manufacturing facility?

First, let’s look at measurement standards.

Trade measurement laws apply to all retail and wholesale transactions where measurement determines price.

As a manufacturer, you must comply with Australia’s trade measurement laws if you sell goods by measurement (e.g. selling meat by weight) or manufacture, pack, import or sell pre-packaged goods.

In Australia, the National Measurement Institute (NMI) regulates all trade transactions involving measurement.

They employ trade measurement inspectors who can visit your business in response to a complaint or enquiry from a consumer, or as part of a trade measurement compliance program.

Coles and Woolworths have previously been prosecuted and fined for significant breaches of trade measurement law. For example, a birthday cake by Woolworths was found to be seriously underweight.

88% of fines imposed by the NMI in 2013–14 were related to prepacked goods that were underweight.
Expert Tip: In Australia, NMI certification of weighing equipment only applies to catch weighers, not checkweighers. There is no NMI certification for checkweighers in Australia.

Australian manufacturers can choose from two key standards of measurement for their goods:

1. Uniform Trade Measurement Legislation (UTML)

The UTML is the longstanding international system. It states that one package in 12 can be less than the stated weight, but the average content in a sample of 12 prepacked items of the same measurement cannot be less than the stated quantity. No items can have a shortfall of more than 5%.

There are exceptions, such as mushrooms and soap, where a greater maximum deficiency is allowed as a result of moisture loss.

2. Average Quantity System (AQS)

The AQS is designed to assist packaging companies to make it easier to meet the average net content requirements. The AQS standard is especially good for large production runs, helps minimise waste and re-work and is globally recognised. This is the “e” mark on a product.

Under this system, the average net content in a pre-packed sample from the production run cannot be less than the quantity marked on packs. An allowance is made for a small number of packs that exceed the tolerable deficiency. However, none can have more than twice the tolerable deficiency.

The AQS provides a 97.5% assurance that goods are within the prescribed tolerances (source).

Another essential inspection standard to know is Retailer QA programs.

Woolworths, Coles and other major retailers manage their own quality standards for suppliers.

Let’s look at the Woolworths Supplier Excellence Program.

There are separate Codes of Practice for:

  • Weight, Volume and Count
  • Metal Detection and X-Ray Systems

For example, the Weight, Volume and Count code requires suppliers to have a “clear documented policy and procedure for the management of weight, volume and count for each product manufactured which conforms to the legal requirements of the country of manufacture and the country of intended sale”.

For inspection, Woolworths asks suppliers to carry out a risk assessment to determine the requirement for metal detection/X-Ray and the format it should take.

The code also details the types of metal detector and X-ray systems to be implemented. For example, a metal detector must have an automatic rejection device or an alarmed belt-stop system.

These are just a couple of examples of the supplier code of practice. If you are considering supplying to Woolworths, Coles and other major supermarkets, you must become familiar with their standards

Types of Inspection Technology

  • Checkweigh
  • Metal detection
  • X-ray inspection
What does it inspect?

Checkweigh systems are used to precision weigh products to ensure they are suitable for sale at that weight. They typically sit at the end of the line, where they are the policeman of the production line, keeping an eye on the weight and checking it remains legal. They can support weight compliance for two standards: AQS and non-AQS (UTML)

Checkweighing is essential if you supply to leading retailers. They often have their own compliance requirements which recommend checkweighing.

Checkweighers typically sit at the end of the line, where they can precision weigh at required line speeds.

If a product is overweight or underweight, the checkweigher will instantly remove it from the line (reject the product) and alert the operator immediately, so you can address the problem before you produce thousands of out-of-spec products.

A checkweigher can also be used for trend control. It can control the filling process to alter the amount of product being filled. For example, if a box of flour is supposed to be 1kg and the weight starts to trend upwards, the checkweigher will send a signal to the filling machine to reduce the amount.

Expert Tip: Checkweighers can also supply data. Using a software reporting package, they can tell you how many packs have been produced, the weight of each pack, and the weight of the total batch.

Why invest?

Checkweighers are most often associated with compliance to regulations. They can also boost your bottom line by reducing waste, tightening tolerances and ensuring more consistent products.

By improving weighing precision, checkweighers are proven to provide an immediate contribution to productivity and profits. The more accurate your checkweigher, the more money you can save. So even with a packet of nuts, saving the tiniest amount of overfill could add up to massive savings over time.

Because checkweigh technology can help manufacturers detect issues with product overfill (or underfill), you are able to correct the problem fast and save costs.

What does it inspect?

Metal detection systems only inspect products for metal. They are ideal for inspecting dry products (think flour, coffee powder, sugar) and frozen products, and give very good results on a wide range of other products.

Metal detection systems sit towards the end of the line in most cases and check the “final product”.

Why invest?

One of the biggest culprits for food contamination today is metal and (in-particular) non-magnetic stainless steel. This is where metal detection technology is extremely effective.

Metal detection systems can be affected by electrical interference, vibration, salt, moisture and high or changing product temperature. That said, advanced metal detection systems today can be configured to detect contaminants even in products with high moisture content.

Systems can have a greatly reduced sensitivity when inspection products in aluminium packaging such as foil pouches or metalised film – an increasingly common packaging type in the food industry. If aluminium or foil packaging is being used, look to X-ray metal detection technology.

Metal detector can also be used in reverse. For example, a packet wraps should include a sachet of metal filings for oxygen absorption. The metal detector can be used to check that every pack has an oxygen absorber. If there is no oxygen absorber, the product is rejected.

What does it inspect?

Glass, stone and ceramic are the main culprits for contamination. By evaluating density through the product and packaging, X-ray inspection equipment can identify these foreign bodies.

Advanced X-ray inspection systems can perform in-line quality checks to:

  • Detect physical defects
  • Measure product mass
  • Identify missing or broken products
  • Check metallic closures are present for packaging seals
  • Can check for oxygen absorbers
Why invest?

Unlike metal detection, X-ray inspection is ideal for a wide range of packaging, especially in bottles, cans, jars, pouches, boxes, trays and foils as well as many products that metal detectors typically struggle with, such as high moisture, high salt or high temperature products.

It can also detect contaminants embedded right in the product and tell the operator where in the product the contaminant sits.

Over recent years, X-ray equipment has become a lot faster and easier to use, making it ideal for high-speed production lines. This makes it a worthy investment for those processors who want to reduce contamination and protect against recalls.

Metal detection vs X-ray inspection

Which one will provide the best performance for your facility?

There are essential boxes any inspection system must tick. For food and beverage applications, both metal detectors and X-ray systems must be:

  • Extremely sensitive
  • Easy to use
  • Fast
  • Fully automatic
  • Robust
  • Reliable
  • Cost effective

Bottom line – the system often needs to be able to pick up the smallest contaminants from thousands of products in challenging processing environments.

So which inspection technology should food and beverage processors invest in to ensure the safety and quality of their products — metal detection or X-ray?

Consider these questions:

How is performance measured?
Detectable contaminant types

There are lots of contaminant types, including glass, ceramic, bones, plastic, pieces of metal and so on. Often, the real challenge isn’t finding the contaminant, but ignoring the packaging, product and environment. False detections can quickly add up in terms of time and costs.

Minimum contaminant size

This depends on the system design and technology as well as the “product effect”. This is the degree to which the food looks like a contaminant to the detection system.

Probability of detection

What is the chance of the system missing a contaminant in real production, with real products running at real speeds? As a general rule, the larger the contaminant, the higher the probability of detection. However, you also need to build in a margin for error, with periodic audits and preventative maintenance.

What contaminants do you want to detect?

Traditionally, metal detection systems were used to detect metal (including aluminium and wires), while X-ray inspection detects all metals, as well as many other solid contaminants (glass, ceramic, etc).

However, today’s technology means metal detection systems can also detect non-ferrous metals. See what the Bizerba Varicon can do.

X-ray inspection systems can typically find smaller contaminants than metal detectors and can check a wider range of materials, including large packaged products, cases, cans and bottles.

Challenges exist for both systems. Metal detection systems can find it difficult to ignore wet and salty products, as they are conductive. While X-ray inspection systems have limited success when it comes to dense products with lots of texture.

That said, there are examples of advanced systems that can overcome both of these issues.

What is the packaging type?

In the food and beverage industry, many brand owners are switching to metallised film or foil-based packaging to enhance products’ appearance or shelf life.

This effectively rules out metal detectors, because you have to reduce their sensitivity in order to cope with the packaging. This means the size of the metal piece that is able to be detected is vastly increased and therefore the risk of having a metal contaminant pass through in a product without being detected is vastly increased.

X-ray inspection systems can see right through into foil-based packaging to detect extremely small foreign objects.

EXPERT TIP: Take into account how you might change your packaging down the track, as this will determine the best investment for your inspection processes.

What’s the optimum detection point?

The optimum detection point is the stage in your processing line that has the most chance of finding contaminants. This influences which technology should be employed for the best performance.

Metal detectors can be installed almost anywhere along the line, but their success largely depends on the size of the opening in the metal detector that the product passes through. As a result, they tend to work best for products in small packages and bulk conveyed products.

By contrast, X-ray systems have greater sensitivity with large products. In both cases, processors and packers can often derive the best value by placing the unit at the end of the line, examining finished (i.e. packaged) products.

What’s the speed of application?

One of the biggest challenges for manufacturers and processors is finding a system that will perform at rapid speeds. This is where many X-ray systems come up short. Because of the scanning rate, their speed range may be limited.

X-ray systems also need a constant, known speed to construct images, so they cannot be used in gravity-flow, blown or vacuum applications.

Metal detection systems can be used almost anywhere in the process.

What else can the technology do?

When investing in any technology, it’s worth thinking about how you can get the most value for your business. In this case, you want to look at what the systems can perform in addition to detecting contaminants.

For example, X-ray inspection systems can also:

  • see inside a container to detect missing products in a pack — something that’s not possible with a metal detector.
  • inspect a product by measuring the shape, counting objects or using the density of the image to estimate weight.

Each of these processes helps to ensure that only the highest quality products are leaving your factory doors.

What’s the total cost of ownership (TCO)?

As with all processing equipment, it’s worth weighing up the upfront cost against the total cost of ownership over its lifetime – this is known as the “TCO”. It includes training, maintenance, repair, parts and so on.

In general, X-ray systems are more expensive up front than metal detection systems. Metal detectors also last up to four times longer.

If you only need to examine small, dry products the extra functions of an X-ray system won’t add any value to your business, so opt for a metal detector. But if you need to go beyond the basics, the X-ray system could prove a worthy investment over the long term.

The Verdict

One solution doesn’t fit all. There are many factors that affect performance so the best way to choose your ideal inspection system is to look at your exact application, product and industry needs.

Contact Matthews Australasia to speak to a specialist about your application needs.

Summary

There’s no doubt that automating quality processes is the key to delivering the highest quality products. And in today’s environment, that is a huge competitive advantage. But there’s also a push from the major Australian food and grocery retailers to embrace this technology to enhance product quality and reduce the risk of errors.

We’re not saying that inspection systems are the magic bullet – there are other processes and checks that can help. But they are proven to vastly improve processes and reduce the risk of recalls due to packaging and labelling faults. And that can only be a good thing for any manufacturer.

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Related Case Studies

Strawberry Springs is an Australian-owned strawberry farm and seller located in the Yarra Valley, Victoria. They approached Matthews in wake of the pins found in Strawberry crisis, to find an inspection solution to help safeguard their business.

 
 
 

Tasmania's Westhaven Dairy is a Australian-owned business located in Invermay, Tasmania. Westhaven approached Matthews to assist in providing date coding and inspection equipment onto their production line.