• Company
  • Certificates
  • News

Visual testing (VT)

VOGT NDT is your partner for visual inspections by experienced and highly trained inspectors.

State of the art

How powerful is the visual inspection (VT)?

Cracks, Impurities, Burr formation, Burn-in notches, Color changes, Surface roughness, Misbonding, Incomplete or faulty assembly

Cracks, Impurities, Burr formation, Burn-in notches, Color changes, Surface roughness, Misbonding, Incomplete or faulty assembly

Defects must be detectable by eye or by an aid such as a camera or magnifying glass (armed eye).

The component to be inspected must be accessible, if necessary with the aid of a camera.

Visually inspected

Visual inspection in the VOGT test center

The quality of a visual inspection depends on many influencing factors on site. These include: Light, camera systems, optical aids, cleanliness, quietness and much more. The VOGT test center offers an ideal environment for the inspection of components and small parts. Here it is possible to carry out a comprehensive and cost-effective visual inspection under the best conditions. Especially for small parts, such an inspection can account for a large part of the production costs. Therefore, our test center is designed to perform serial inspections quickly and reliably, thus keeping inspection costs in limits.

At your side

VOGT NDT visual inspection at your site

The requirements for visual inspections are numerous. VOGT NDT also uses various aids for visual inspection depending on the requirements.

Incoming goods inspection

In all industries, visual inspection is used for the evaluation of delivered goods during incoming goods inspection. Here, primarily the intactness, defects and qualities of the surfaces as well as the geometric shapes are tested.

In this application, VOGT NDT provides on-site support at the customer’s location to visually inspect delivered raw materials, preliminary products, components or even assemblies up to finished objects.

This starts with the accompanying documentation and continues with the design and finish of the components (defects, coloring, etc.) and includes dimensional checks, roughness tests and position checks.

Inspection of installed facilities

The regular inspections are mandatory for planning a cost-efficient maintenance. VOGT NDT is your partner when it comes to inspecting weld seams, steel beams, rivets, bolted joints and much more for damaged areas. Visual inspection is the fastest way to evaluate the condition of a facility. VOGT NDT creates detailed reports, which are used to efficiently apply further inspection procedures. Thereby we have possibilities of visual inspection with various tools.

With so-called camera pigs even the inspection of complex pipe systems is possible.

An inspection provides certainty and enables planning. Spare parts for maintenance can be ordered in advance and the maintenance itself can be carried out in a more structured and thus time-saving manner. This reduces downtime due to maintenance and preventive repairs and optimizes facility availability.

New construction of a facility

VOGT NDT regularly inspects larger complex or permanently installed components on site. The visual inspection of piping and welded joints as well as the evaluation of corrosion are part of our core competencies in visual testing. Before the first operation, many inspections with unarmed or even armed eye are necessary. Here, VOGT NDT is happy to assist you so that flawed welds and other imperfections can be detected and reworked before initial operation. VOGT NDT supports you so that your facility can start production on schedule.

We solve your inspection task

We provide single and serial testing of your components in our Test Center – automated and manual.

Error detection

What is a visual inspection?

Visual inspection (VT) is the oldest and most basic method of inspection. It involves checking a component for defects with the eye (unarmed eye) or with the aid of equipment (armed eye). Often, no instruments are required except the eye of a trained inspector.

Visual inspection can be used for internal and external surface inspection of a wide range of components, assemblies and equipment, including automotive components and assemblies, such as connecting rods, cylinders, plastic fixtures as well as aerospace seat rails, turbine disks, blades and vanes, and even storage tanks, pressure vessels and piping from the chemical and petrochemical industries.

Visual inspection is generally simple and less technologically advanced than other methods. Nevertheless, it has some advantages over high-tech methods. For example, it is much less expensive compared to other methods. This is due to the fact that it usually does not require any equipment. It is also one of the most reliable methods. A well-trained inspector can detect a comprehensive range of indications of damage.

Pro & Contra

Advantages of visual inspection

Limitations and disadvantages of this testing method include:

How efficient is a visual inspection?

A study on visual inspection of small integrated circuits showed that the duration of eye fixations of trained inspectors was about 200 ms. Whereby inspectors who perform visual inspections on a daily basis inspected the fastest and most reliably. Thus, it can be clearly concluded that practice and routine are an important part of performing high-quality and cost-effective inspections. For visual inspection, the false positive rate was 2% and the false negative rate was 23%.

How does a visual testing work?

There are two methods: Direct and indirect visual testing.

In direct inspection, the inspector looks at and assesses the component directly with his eye, if necessary with the aid of a magnifying glass, a microscope, a light source, a visual scope or a mirror.  Profile gauges are also an aid to visual inspection, if necessary.

In indirect inspection, the component is viewed using visual aids, e.g. flexible and rigid industrial endoscopes, fiberscopes with cameras, camera systems and even crawler devices.  Digital images or videos are often created, which are then digitally processed, measured, evaluated, stored and made globally available.

The regulations

Which standards are relevant for visual inspection?

Standards and specifications for visual testing exist in extremely wide range for very different sectors and industries. The standards listed here are strongly limited to technology and the metal industry.

A little theory

Comparison of direct and indirect visual testing

Direct visual testing

Using direct visual testing, the component to be tested is checked by an inspector. Testing, analysis and evaluation are performed by one person. Direct visual testing can be carried out with aids such as magnifying glasses, endoscopes, etc.

Advantages of direct visual testing

Disadvantages

Indirect visual testing

For an indirect visual inspection, the area to be inspected is captured by a camera and displayed on a monitor. The inspection image can be processed in further steps. For example, the image can be enlarged, digitally enhanced and details can be visually highlighted for analysis purposes. The image can be saved for documentation purposes. By displaying it on a screen, several people can evaluate. Comparisons with previous inspections by comparing the images or videos can thus be easily and reliably realized. In this way, even the smallest changes can be detected.

The trend is moving to indirect visual testing, as the use of camera technology offers more possibilities and leads to a more efficient interruption of the production process. Indirect visual inspection is performed, for example, with the help of videoscopes or stationary camera recordings. In industries with high quality requirements, inspection solutions are used that provide high-resolution images.

We solve your inspection task

We provide single and serial testing of your components in our Test Center – automated and manual.

The procedure

How is a visual testing effectively performed?

According to the British Institute of Non-Destructive Testing (BINDT), many defects are on the surface and can be detected by careful direct visual testing. In some cases, quality assurance inspectors may come to inconsistent visual inspection results because they either do not fully understand the defect specifications or do not have references for comparison.

Because it is one of the simplest and most cost-effective quality assurance methods, visual testing procedures vary by industry. In general, there are 5 simple steps to effectively perform visual inspections:

Critical to the quality of the visual inspection are the viewing conditions and lighting. Best possible contrast must be achieved to detect defects. The color spectrum of the component and the defect as well as the light conditions also have an impact. The viewing angle on the surface to be inspected is also essential for good results. 

Clear definition of defect criteria

Key stakeholders, such as quality engineers, production personnel and customers, should reach consensus on defect specifications. Clearly defined defect criteria enable inspectors to make accurate pass/fail decisions. Defects are documented with sample photos and technical descriptions for daily visual inspection in production.

Schritt 01
Schritt 02

Standardization of inspection performance

Identify how consistent the decisions made by inspectors are with the established defect criteria to standardize visual inspection performance across the organization. Occasionally, inspectors misinterpret the standard when visual displays of the defects are not available to them during visual inspection.

 

Step #2

 

Analysis of visual defects

If the decisions made by inspectors on the same product are inconsistent across different visual inspections, the most important visual defects must be analyzed. By frequency and number of defects, evaluate the cost of quality to determine which defect type has the greatest impact on daily operations. Quality managers must also consider cost, time to repair, and importance to the customer to create and implement effective action plans.

 
 
 

Analysis of visual defects

If the decisions made by inspectors on the same product are inconsistent across different visual inspections, the most important visual defects must be analyzed. By frequency and number of defects, evaluate the cost of quality to determine which defect type has the greatest impact on daily operations. Quality managers must also consider cost, time to repair, and importance to the customer to create and implement effective action plans.

Schritt 03
Schritt 04

Communication of actions for improvement

After resolving issues with specific visual detected defects, inspection performance is re-evaluated to confirm consistency between inspector decisions and established standards. The results are communicated objectively to all safety and quality personnel to ensure a continuous improvement process.

 

Step #4

 

Use mobile-enabled checklist

Most often, checklists are used for visual testing. If inspectors can access defect criteria anytime, anywhere, and if video and photo evidence of visual defects is captured, the accuracy of pass/fail decisions can be radically improved.

 
 

Use mobile-enabled checklist

Most often, checklists are used for visual testing. If inspectors can access defect criteria anytime, anywhere, and if video and photo evidence of visual defects is captured, the accuracy of pass/fail decisions can be radically improved.

Schritt 05

We solve your inspection task

We provide single and serial testing of your components in our Test Center – automated and manual.

FAQ

Frequently asked questions about visual inspection

Visual testing is one of the oldest and most proven non-destructive testing methods for evaluating the condition of a facility or component as part of the production and overall maintenance process.

The task of a visual testing is to detect defects and flaws in materials as well as dimensional inaccuracies of components and materials within the scope of quality assurance.

Surface quality deviations, cracks, impurities, burr forming and penetration notches in welds, color changes, surface roughness, corrosion and erosion, incomplete or faulty assembly, geometric deviations.

WordPress Cookie Notice by Real Cookie Banner