Five Things To Consider When Purchasing Product Inspection Equipment

Choosing the correct product inspection system to detect foreign materials in your production line is vital for protecting your brand, much like safeguarding a family name.  

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The choice to install a new product inspection system or upgrade an existing one usually stems from two main factors: either you possess strong corporate backing and financial resources for acquiring the best inspection system tailored to your specific product, or you are required to do so to comply with certain regulatory requirements, faced with financial limitations that may restrict your options. Regardless of the reason behind your exploration of product inspection tools, consider the following suggestions before making any decisions.

Assess the 'True' Cost of Ownership

It is advisable to choose a single vendor capable of providing magnetic, metal detection, x-ray, and check-weigh systems while also demonstrating a thorough commitment to food safety and customer service. Your aim should not only be to purchase the least expensive system that meets your needs, but rather to evaluate it as a long-term investment.

Initial costs and installation - The initial purchase and installation often represent just a small portion of your total investment in electronic inspection equipment, especially compared to other contaminant removal systems like magnets.

Usability and adaptability of the equipment - Consider factors such as the cost of ‘false’ positive readings or rejected products, ongoing maintenance and equipment validation costs, as well as how adaptable your selected system will be in the future. Understanding the level of support provided by your vendor as software updates become available is crucial for keeping your equipment technologically up-to-date; otherwise, it may become obsolete.

Technical support - Inquire whether your vendor offers an annual technical support subscription that may include discounted rates for software upgrades, parts, and service, along with necessary third-party re-certifications.

Employee training - Factor in the ongoing costs of training new hires. High employee turnover is common in the industry and is frequently at the root of errors and recalls. The price of a product recall due to a ‘false’ positive from employee mistakes can damage your brand reputation as severely as actual contamination events. Once a recall occurs, it cannot be reversed; the damage is permanent and your brand could be compromised.

Understand Food Safety and Product Inspection Limitations

Your vendor should clarify what their equipment can and cannot do. For instance, properly sized and installed magnets are very effective at capturing ferrous and weakly magnetic non-ferrous metals. At times, magnets can outperform many metal detection and X-ray systems. However, be aware that non-ferrous metals, such as aluminum, cannot be removed by magnetic systems, making metal detectors or X-ray systems necessary.

Metal Detectors - The technology behind metal detectors relies on the product's conductivity. Highly conductive products like meats and baby food may prove challenging for detecting smaller, specific metal types, typically leading to a more generalized detection approach to maintain quality standards and avoid expensive ‘false’ positive rejections.

X-ray - This technology is based on a product's density. Some products are easier to inspect than others, while some cannot be assessed by X-ray technology at all. If the unwanted materials have densities similar to the products being inspected, for instance, non-calcified bones in chicken, X-ray detection may fail.

Take the time to engage with multiple vendors to ensure that your chosen partner not only understands but can effectively communicate the technical limitations of their equipment. The vendor should explain the physics behind particulate detection in simple terms, enabling you to leave the meeting with a newfound understanding and confidence in the potential decision you are about to make.

Invest In Ongoing Education

Selecting a vendor who partners with your organization to provide service packages which include education, training, and routine retraining for employees is essential. Industries continuously evolve, improving foreign material detection in food products. On average, 20 to 25 percent of recalls stem from detectable foreign objects such as bone, plastic, glass, or metal ending up in the consumer's meal. It is crucial for those monitoring and maintaining detection equipment to have comprehensive knowledge on its operation and upkeep. Changes in recipes or mixtures may necessitate system recalibrations and reprogramming, indicating that one size does not satisfy every requirement in electronic inspection.

Ensure Technical Support Is Easily Accessible

Experiencing issues after purchasing a product while struggling to receive necessary technical support can be frustrating. Common obstacles to obtaining support are language barriers and geographic distance. You may find that a U.S.-based company is usually more willing and capable of providing adequate support resources. Ideally, select a vendor that provides service for the products they sell, even if this may require paying a higher price. Proper technical support encompasses a thorough understanding of your system beyond mere installation. This includes system validation, programming, preventive maintenance, and regulatory compliance reporting. Accessibility to support is key, as delays could result in significant revenue loss. Prioritize asking challenging questions and seek documented responses.

Choose a User-Friendly Sanitized Design

The FDA's increasing emphasis on food safety means choosing a sanitary design is a prudent choice. Look for equipment designed to minimize the need for disassembly during cleaning and, when disassembly is necessary, it should be quick, preferably requiring no tools. Food processing can be a messy endeavor, as both wet and dry food residues can accumulate in the tiniest of areas, fostering growth for potentially hazardous pathogens. Nuts, bolts, screws, and even disassembly tools can also harbor microorganisms. Routine cleaning is essential and included in any comprehensive HACCP plan—unfortunately, this chore often becomes neglected. Thus, investing in durable, smartly designed sanitary equipment can yield long-term savings.

Exercise critical thinking prior to making a purchase. Understand what foreign materials pose risks to your product line and find a vendor capable of addressing these concerns. Recognize that meeting optimal detection might require several pieces of equipment, and be open to exploring multiple options. This approach will likely ease ownership costs and instill greater trust and confidence in your product inspection system.

 

 

Magnetic Products, Inc. (MPI) is a family-owned US-based company established in . They provide comprehensive metal contamination control with a wide array of products, including magnetic and non-magnetic material separation and handling technology, metal detectors, check-weighers, and X-ray inspection equipment. MPI President, Keith Rhodes, credits the company's consistent market success to its ability to adapt and often deliver custom integrated solutions to meet specific customer aspirations. Rhodes takes pride in the firm's legacy devoted to enhancing product performance alongside an ever-growing series of metal-control systems.

 

When Do You Need to Perform Magnetic Particle Testing?

What is Magnetic Particle Testing Used For?

Table of Contents

1.

What is Magnetic Particle Testing (MPT)?

1.1.

How Does Magnetic Particle Testing (MPT) Work?

2.

What is Magnetic Particle Testing Used For?

2.1.

Common Application of Magnetic Particle Testing

2.2.

When Do You Need to Perform Magnetic Particle Testing?

3.

Magnetic Particle Inspection Process Overview

3.1.

Wet Suspension Inspection

3.2.

Dry Particle Testing

3.3.

Final Inspection Steps

4.

Pros and Cons of Magnetic Particle Testing

5.

Magnetic Particle Testing Equipment

5.1.

Contour Magnetic Probes

5.2.

Magnetic Particles

5.3.

Lights

5.4.

Other Accessories

6.

Alternatives to Magnetic Particle Testing

For more Brinell Hardness Tester Suppliers information, please contact us. We will provide professional answers.

While invisible, magnetic fields reveal much about our environment. Birds have evolved specialized iron-based receptors that allow them to sense Earth's magnetism for navigation.

It took us decades of experimentation and substantial equipment resources to harness magnetic field capabilities. Initially, we devised an artificial 'magnetic receptor,' or compass, for global navigation. Later, William Hoke introduced a new inspection strategy to identify minute defects.

In the s, Hoke observed metal shavings accumulating around vehicle fractures. This keen observation inspired Hoke's research, eventually leading to the patent for magnetic particle testing, an innovative method capable of locating subsurface defects in materials at nearly microscopic levels.

What is Magnetic Particle Testing (MPT)?

Magnetic Particle Testing (MPT) is a non-destructive testing (NDT) technique utilizing magnetizing force to identify surface and subsurface defects.

MPT is effective only for assets made of ferromagnetic metals like iron, cobalt, and nickel, as these materials are highly responsive to magnetic forces and can maintain magnetic properties even after being removed from an external source.

This technique is visual in nature, enabling inspectors to detect tiny, often microscopic cracks, voids, and irregularities otherwise overlooked during regular checks. Moreover, MPT generates swift results, providing real-time insight into the defect's location, size, and severity.

The surface defects become highly visible when exposed to magnetic fields and UV light.

How Does Magnetic Particle Testing (MPT) Work?

The magnetic particle test consists of two primary components: a testing instrument with magnetic poles at each end, and a colored medium containing magnetic particles. The apparatus produces a magnetic field, directing magnetic flux through the test material, with two potential outcomes:

• No defects: The magnetic flux flows uniformly through the material, suggesting a consistent surface.

• Defect present: A defect causes the magnetic flux to alter its route, creating a separate flux leakage field with greater magnetic strength than defect-free zones.

The flaw isn't visible without applying colored magnetic particles across the test zone, as these particles gather around the flux leak, allowing us to visualize the crack, delamination, or other irregularities.

The figure illustrates how the magnetic flux disperses across tested regions with and without defects.

What is Magnetic Particle Testing Used For?

Magnetic particle testing serves as the primary inspection method for assets composed of iron, nickel, cobalt, and their alloys (particularly steel). It's commonly employed in NDT applications for welds, pipes, tubes, rails, and boiler assessments.

Since MPT necessitates direct visual observation and surface contact for particle application, it is best suited to more readily accessible assets.

Common Application of Magnetic Particle Testing

IndustriesDefect typesAssets 1. Aerospace
2. Automotive
3. Oil and gas
4. Petrochemical
5. Manufacturing
6. Power Generation
7. Railroad 1. Surface cracks
2. Subsurface cracks
3. Lack of fusion
4. Inclusions
5. Pores
6. Holes
7. Discontinuities
8. Laps 1. Welds
2. Pipelines
3. Boilers
4. Heat exchangers
5. Turbine blades
6. Gears and shafts
7. Automotive components

When Do You Need to Perform Magnetic Particle Testing?

MPT is frequently employed post-manufacturing to assess whether produced items comply with quality and safety specifications. Moreover, it finds applications in industrial asset inspections as part of maintenance programs.

For planned inspections, the National Board Inspection Code (NBIC) outlines the following scenarios for magnetic particle testing usage:

• Internal and external surface tests of boilers and pressure vessels
• Inspection of vessels subject to liquid ammonia service for stress corrosion
• Evaluation of fire-damaged components to determine retained strength
• Detection of cracks in locomotive and steam boiler plates
• Identification of cracks during baffle clip welding in pipes, valves, and manholes
• Defect localization within welded joints and adjacent heat-affected zones

According to ISO standards, magnetic particle tests are also utilized to identify:

• Inhomogeneities in coolant circuit components for light water reactors (ISO -2:)
• Discontinuities in railway rolling stock materials (ISO :)
• Imperfections in seamless and welded steel tubes (ISO -5:)
• Defects in welds (ISO :)
• Discontinuities in steel and iron castings (ISO :)
• Surface imperfections on steel tubes' bodies and end/bevel faces (ISO -5:)

Magnetic Particle Inspection Process Overview

While magnetic particle inspection can appear straightforward, it necessitates thorough prep work. Asset owners should engage a qualified inspector (in line with ISO standards).

The inspector will select the appropriate test tool (like a portable yoke or stationary bench) and the method of magnetic particle inspection (dry or wet). They must also choose a magnetic substance that meets the necessary specifications (color, particle size, and operating temperature).

The accuracy of results relies on ensuring parallel alignment between the test object and the magnetic field (a range of 45-90 degrees) and adequately lighting the test area (with a lamp or UV light). Removing items with ferromagnetic properties from the test area is necessary to avoid interference.

Prior to testing, the area must be cleaned of grease, oil, and rust, while paint coatings shouldn't exceed 0.05 millimeters to maintain test sensitivity.

The inspector must then choose the appropriate magnetic flux density (minimum 1T) and strength (between 30 and 60 gauss) to proceed with inspection. The subsequent steps will vary according to the method of magnetic particle inspection employed.

Wet Suspension Inspection

This technique involves dispersing water-based magnetic particles over the test region. Wet inspections excel at discovering even the smallest defects for two key reasons: the tiny size of wet state magnetic particles (0. mm) allows for even distribution in a flowing medium.

Wet suspension testing steps:

1. Spread the suspension across the tested area
2. Apply an even magnetic field in short bursts (1/2 second)
3. Identify locations with concentrated magnetic particles
4. Demagnetize and clean the inspected area

Dry Particle Testing

This technique involves sprinkling magnetic powder across the test surface. Typically, portable probes generate pulsating magnetic fields, enhancing the adhesion of particles to defects. This method is ideal for examining irregular surfaces, inclusions, welding discontinuities, and subsurface defects.

Dry particle testing steps:

1. Apply the magnetic field evenly
2. Disperse a thin layer of powder over the tested area
3. Gently blow away excess powder
4. Remove the magnetic field
5. Examine areas with concentrated magnetic particles
6. Demagnetize and clean the inspected surface

Final Inspection Steps

The MPT inspector will compile a defect map along with detailed descriptions and severity ratings. For external validations, the technician is required to document the complete procedure (tested surface, magnetization approach, equipment employed, testing materials, results, and actions taken following testing).

Pros and Cons of Magnetic Particle Testing

A variety of MPT devices enable assessments in labs, factories, and field scenarios. This method yields immediate results and a clear depiction of existing defects.

However, MPT is not comprehensive as a NDT method for all applications due to its dependency on ferromagnetic materials and its inability to detect subsurface defects beyond 2 mm.

Benefits of magnetic particle testing include:

• Low-cost equipment and inspection expenses. Magnetic probes are generally less expensive than ultrasonic or radiography devices.

• Tests yield accurate results on both smooth and rough surfaces.

• Quickly visualizes the size, location, and quantity of defects facilitating fast remediation.

• Identifies both surface and near-surface defects using various probes.

• Detects even microscopic surface cracks, enabling early analysis of wear and corrosion.

• Highly portable probes can connect easily to battery supplies for field evaluations.

Drawbacks of magnetic particle testing include:

• Limited applicability: Only effective with ferromagnetic materials; does not expose deeper material defects.

• Preparation can be extensive (lighting, setup, protective wear, cleaning, and rust removal).

• Removing coatings may be necessary; excessive thickness can impede accuracy and requires demagnetization post-testing.

• Can result in a messy workspace; liquid particles can splash around and stain the surface.

• Some particle suspensions and powders can pose hazards or be flammable in unventilated areas.

Magnetic Particle Testing Equipment

Magnetic particle testing tools fall into two categories: stationary and portable.

Stationary machinery (like a magnetic wet bench) is suited for lab evaluations requiring specific spaces, artificial lighting, and grounding surfaces. Tests on stationary systems often utilize wet fluorescent particles for optimal defect detection.

However, stationary MPT equipment tends to lack mobility, making it less viable for on-site assets. Let's shift our attention to portable options.

Contour Magnetic Probes

Contour probes, or yokes, are portable devices generating a magnetic field between two poles. They feature two operational modes (AC with alternating currents and DC with direct currents), allowing for both surface and near-surface defect detection.

Contour magnetic probes come in various configurations, including:

• Prods: Manual handheld electrodes pressed against both sides of the test object. This method creates a circular magnetic field, improving detection of lengthwise cracks. The prod pulses on and off during operation.

• Coils and conductive cables: Ideal for spherical objects, these items when wrapped around create a parallel magnetic field to reveal longitudinal cracks. Coils often work alongside magnetic wet benches.

• Electromagnets: Devices that generate strong magnetic fields through electric current by wrapping a coil around soft steel.

Magnetic Particles

Magnetic particles are nano-sized ferromagnetic materials that attract flux leaks, allowing defects to be identified. These particles consist of two forms: dry and wet.

Dry Particles

Composed of milled magnetic powders blended with color pigments, dry particles vary in characteristics based on manufacturing:

• Particle size: between 0.05 - 0.15 mm
• SAE sensitivity: 6-8
• Operating temperature: 0° - 427° C
• Available colors: black, red, grey, yellow, brown, or fluorescent green.

Dry particles are best suited for inspecting irregularly shaped rough surfaces.

Wet Particles

Wet particles reside in a water-based medium mixed with color pigments. These particles can be acquired as liquids, gels, sprays, or inks.

Manufacturing characteristics may include:

• Size: as small as 0. mm
• SAE sensitivity: 6-7
• Operating temperature: -10° - 80° C
• Available colors: black, white, fluorescent green or yellow.

Wet particles are optimal for detecting minuscule, nearly microscopic fissures.

Lights

Appropriate lighting is essential for executing magnetic particle testing. Configuration will depend on the type of inspection.

For traditional wet and dry inspection, utilize a lamp operating at a color temperature between and K (per ISO ). For fluorescent evaluations, mercury discharge, halogen, xenon, or LED arrays are necessary to generate UV light, known as blacklight. Ensure the UV light intensity does not exceed 365 nm (per ISO ).

Other Accessories

To enable efficient and rapid inspections, you may require additional tools:

• Cleaning agents: to eliminate dirt, grease, or oil from test surfaces.
• Wire brushes: for rust removal from test areas.
• Solvents: to strip paint coatings.
• Power bulbs or powder blowers: for clearing powder from the test surface.
• Demagnetizing equipment: to magnetically neutralize the test area.

Alternatives to Magnetic Particle Testing

The ease and cost-effectiveness of MPT make it an appealing option for assessing ferromagnetic materials, but it can fall short for other asset types. Moreover, MPT cannot identify defects deeper than 2 mm.

Alternative non-destructive inspection techniques, such as ultrasonic or eddy current testing, provide enhanced accuracy, adaptability, sensitivity, and detection depth.

Ultrasonic testing (UT) exhibits remarkable penetrative capacity, capable of identifying flaws within large items like storage tanks and wind turbines. This technique is viable for nearly all materials, including metals, polymers, plastics, ceramics, fiberglass, and glass. Furthermore, UT reveals not merely defect size and location but also their orientation. The MPT technician must adapt the magnetic field application from alternative angles (possibly adjusting the mounting layout).

EMAT testing combines UT with magnetic fields. As opposed to magnetic particle testing, EMAT delivers precise defect detection beneath the surface while avoiding contact with the test object. It's an optimal choice for assessments in constrained spaces, high-temperature areas, and hazardous conditions.

Eddy current testing (ECT) offers advantages when inspecting large structures promptly. Not requiring surface contact, it penetrates deeper into materials (up to 40 mm). Contrary to MPT, ECT utilizes no hazardous chemical particles, making it safer for workers. Additionally, ECT can evaluate both ferromagnetic and nonferrous materials.

To further enhance speed and flexibility within any of these methods, consider utilizing drone-mounted UT, ECT, and EMAT probes.

Designed for inspections, Voliro's omnidirectional drone facilitates asset evaluations of any shape, height, and size with increased efficiency. No scaffolding or lifts are necessary, allowing inspectors to remain safely grounded while capturing high-quality data for analysis. With interchangeable probes, the Voliro T adapts easily for various inspection tasks, rendering it an all-in-one solution for most non-destructive testing requirements.