Machine Vision Lens for Metal Stamping and Pressed Part Inspection: How to Detect Burrs, Edge Cracks, Holes and Forming Defects

Metal stamping and pressed-part inspection is a demanding machine vision application because a single component can contain several types of quality features at very different physical scales. The inspection system may need to confirm the complete stamped profile, measure punched-hole position and diameter, detect a thin burr along a cut edge, identify a small crack near a bend or corner, verify formed tabs and flanges, and find incomplete or distorted features caused by the pressing process. A machine vision lens that easily captures the complete component may still provide insufficient detail for a 0.2 mm burr or narrow edge crack. Selecting the right machine vision lens for metal stamping inspection therefore requires balancing field of view, focal length, working distance, sensor format and optical resolution around the smallest defect that must be detected.

Buyers searching for machine vision lens for pressed part inspection, industrial camera lens for metal stamping inspection, machine vision burr detection, camera lens for punched hole inspection, edge crack detection machine vision, or machine vision for sheet metal forming defects are essentially trying to answer two questions: how much of the stamped component must fit inside one image, and how many usable pixels must represent the smallest burr, crack, hole variation or forming defect? The correct lens should solve both requirements simultaneously rather than being selected only because the complete part is visible.

Kyptec Automation® provides a broad Machine Vision Lens portfolio covering several focal lengths, image formats and resolution classes. The current collection includes multiple 5 MP, 10 MP and 25 MP Machine Vision Lens configurations across 2/3", 1" and larger-format product families, giving OEM machine builders and system integrators flexibility to design optics around stamped-part size and required defect resolution.

Start Lens Selection With the Smallest Stamping Defect

“Stamped part inspection” can range from simple presence confirmation to detailed quality control.

One application may need only to confirm that all holes and tabs exist. Another may reject a component for a fine burr, a small crack originating from a formed edge, a slight hole deformation or an incorrectly formed flange.

These tasks require very different optical resolution.

The first design input should therefore be the smallest physical defect or dimensional variation that must reliably trigger rejection. Once this is known, the engineer can calculate required pixels per millimetre and then choose the Machine Vision Lens that provides the necessary FOV from the available camera position.

Why Burr Detection Requires High Edge Resolution

Burrs are particularly important in stamped and punched components because they often extend only a small distance beyond the intended sheet-metal boundary.

A large burr may be visually obvious, while a small rejectable burr can occupy only a few image pixels if the part is viewed through an excessively wide FOV.

From the lens-selection perspective, the critical number is the physical burr height or width relative to the final image scale.

If a 0.2 mm burr must be detected reliably, the camera-lens system should provide enough sampling that this extension becomes a repeatable geometric feature rather than a one- or two-pixel irregularity.

Calculate Pixels per Millimetre Before Choosing Focal Length

A useful starting calculation is:

Pixels per millimetre = number of sensor pixels across the inspection direction ÷ physical FOV in millimetres

If a camera provides 4,000 horizontal pixels and the Machine Vision Lens produces a 200 mm horizontal FOV, the system provides approximately 20 pixels/mm.

A 0.5 mm defect would then occupy roughly 10 pixels in that direction under simplified geometry.

If the FOV increases to 400 mm with the same camera, available sampling falls to approximately 10 pixels/mm and the same defect occupies only around 5 pixels.

This is why selecting the widest possible lens can work against small burr and edge-defect inspection.

Use Only the FOV the Stamped Part Actually Needs

The inspection field should include the maximum component dimensions plus the expected product-position tolerance.

It should not include large unused areas merely because the optical system can see them.

A 150 mm pressed component located accurately inside a fixture may require only modest additional margin. Capturing a 300 mm field would spread sensor resolution across twice the necessary physical width.

Controlled FOV is therefore one of the simplest ways to improve small-defect resolution without changing the camera.

Punched Hole Inspection Has Several Different Requirements

A punched hole may need inspection for presence, diameter, roundness, edge quality, location or partial blockage.

Hole-presence inspection is relatively easy because the difference between a complete hole and no hole is large.

Detecting a small burr around the hole perimeter or a slight deformation in its edge requires substantially more resolution.

The Machine Vision Lens should therefore be selected around the smallest hole-edge variation rather than only the nominal hole diameter.

Hole Position Measurement Requires Stable Full-Part Geometry

If the system measures hole location relative to other stamped features, both the hole and the reference geometry must remain inside the valid FOV.

A very tight localized image may provide excellent hole detail but omit the datum feature needed for positional measurement.

The optical design must therefore balance local edge sampling with sufficient overall component coverage.

This distinction is important when selecting a machine vision lens for punched hole measurement rather than simple hole-presence inspection.

Edge Cracks Can Be Much Smaller Than the Component

Cracks near a stamped edge, corner, slot or bend can be difficult because they may be extremely narrow relative to the total part dimensions.

A component might be hundreds of millimetres wide while the critical crack is only a fraction of a millimetre.

Whole-part visibility therefore says very little about crack-detection capability.

The smallest required crack width and length should be evaluated at the final FOV before the Machine Vision Lens is approved.

A 25 MM 10 MP Lens Can Provide Controlled Framing

For compatible 2/3" camera systems, the Kyptec Automation® KL-1228 25 MM Machine Vision Lens With 10 MegaPixel & 2/3" Format Lens provides a moderate focal-length option. Kyptec Automation® specifies this model as 25 mm focal length, 10 MP resolution, 2/3" image format, C-mount and F2.8–16 aperture range.

A 25 mm focal length can be useful where a medium-size stamped component or localized critical area needs controlled framing without an unnecessarily wide field.

Final suitability should still be determined from sensor dimensions, part size, working distance and minimum defect.

Forming Defects Are Different From Cutting Defects

Stamped components can fail because of more than cutting or punching.

The forming stage can create bent flanges, incomplete forms, distorted ribs, wrinkling, local deformation or features that do not reach the expected final shape.

These defects may change contour, height or local profile rather than creating a simple missing edge.

A Machine Vision Lens used for pressed metal forming inspection therefore needs enough FOV to include the relevant formed geometry and enough image detail to distinguish acceptable contour variation from a rejectable shape.

Flange Inspection Often Requires Both Position and Shape Information

A formed flange can be present but still incorrectly angled, incomplete or dimensionally displaced.

If the inspection observes the flange from a fixed view, the Machine Vision Lens should provide enough image scale to resolve the relevant boundary while maintaining enough surrounding geometry to establish the flange's position relative to the parent component.

This is different from simple component presence inspection.

The FOV should therefore be designed around the relationship between the formed feature and its reference edges.

Tabs and Small Projections Can Require More Resolution Than the Main Part

Pressed parts frequently include locating tabs, clips, lugs or narrow projections.

A partially formed or broken tab may occupy only a small fraction of the full component image.

The lens should be selected so that the smallest critical tab dimension receives sufficient pixels even when the complete component remains visible.

If these features become too small in a whole-part view, a tighter inspection field may be more appropriate.

A High-Resolution Larger-Format Lens Helps When Large Coverage and Small Defects Must Coexist

Some stamped components are physically large but still require detection of small burrs, cracks or hole-edge defects.

In these cases the FOV cannot simply be reduced because the complete geometry must remain visible.

A higher-resolution larger-format camera-lens architecture can provide more total image information across that necessary area.

For compatible larger-format systems, the Kyptec Automation® KL-1238 16 MM Machine Vision Lens With 25 MegaPixel & 1.1" Format Lens provides a 16 mm, 25 MP, C-mount configuration with an F2.8–16 aperture range. The official product title identifies it as part of Kyptec Automation®'s 1.1" Machine Vision Lens family.

This configuration can be evaluated where broad stamped-part coverage must be combined with high total image resolution.

Higher Megapixels Should Not Be Used to Justify Excessive FOV

A high-resolution camera does not mean the optical system should capture unnecessary surrounding space.

If increasing sensor resolution is followed by substantially increasing the physical FOV, the expected improvement in pixels per millimetre can disappear.

The efficient approach is to define the smallest legitimate FOV first and then use additional optical resolution to improve feature sampling within that field.

This is especially important for burr and micro-crack inspection.

A 25 MM 25 MP Lens Can Balance Coverage and Fine Detail

For compatible high-resolution larger-format systems, the Kyptec Automation® KL-1240 25 MM Machine Vision Lens With 25 MegaPixel & 1.1" Format Lens provides a 25 mm, 25 MP, C-mount configuration with an F2.8–22 aperture range.

This type of Machine Vision Lens can be evaluated for medium-to-large pressed components where full-part or multi-feature coverage is required but small punched-hole irregularities, edge defects or forming deviations must still be preserved with substantial image detail.

Edge Quality Should Be Verified Across the Entire Sensor Region Used

Stamped-part inspection frequently places critical edges close to the outer image field.

If the component occupies most of the sensor, a hole, notch or corner defect may appear far from the center.

The Machine Vision Lens should therefore be qualified using representative defects at the center, edges and corners of the actual inspection region.

A system that detects a small burr only when it appears near the center is not robust enough if production parts can move that feature elsewhere.

Pressed-Part Position Tolerance Consumes Resolution

If the component position varies significantly inside the fixture or on the conveyor, the FOV must expand to ensure that the complete part remains visible.

That additional area directly reduces pixels per millimetre.

Mechanical positioning accuracy and optical resolution are therefore connected.

Improving part location can allow a tighter FOV and consequently increase effective defect resolution without increasing camera megapixels.

Surface Reflection Can Change Crack and Burr Visibility

Stamped metal frequently has a reflective or semi-reflective finish.

A burr or crack can appear with strong contrast at one surface orientation and weak contrast at another.

The Machine Vision Lens must preserve the available image information, but sufficient optical contrast must also exist at the defect.

The inspection should therefore be qualified using representative production surface conditions rather than only a single ideal sample.

Oil Films Can Change Edge Appearance

Pressed and stamped components may carry lubricant or processing residue.

An oil film can change local reflections around holes, cut edges or stamped surfaces and may make a small defect appear differently from a clean laboratory part.

The optical system should therefore be validated against the realistic condition of parts arriving at the inspection station.

This helps distinguish true defect-resolution limits from changes caused by production surface condition.

Formed Parts Can Contain Several Object Heights

A flat stamped blank is relatively simple to keep in focus.

A fully formed pressed component may contain raised bosses, recessed sections, bent flanges and stepped surfaces.

These features occupy different working distances.

If the inspection must evaluate defects across several heights, focus and aperture should provide sufficient usable depth tolerance.

The Machine Vision Lens should be qualified at the nearest and farthest inspection-critical surfaces rather than only at one nominal plane.

Aperture Should Balance Depth of Field and Edge Detail

Stopping the lens down can improve focus tolerance across formed features.

However, excessively small apertures can reduce the contrast of very fine details because of diffraction.

For stamped-part inspection, the final aperture should be tested using the smallest real burr or crack while also ensuring that all required formed heights remain acceptably focused.

The best setting is the one that satisfies both requirements.

A 35 MM 25 MP Lens Can Support Tighter High-Resolution Inspection

Where the application requires more stand-off or a smaller high-detail inspection area, the Kyptec Automation® KL-1242 35 MM Machine Vision Lens With 25 MegaPixel & 1.1" Format Lens provides a 35 mm, 25 MP C-mount configuration with an F2.8–16 aperture range.

This focal-length class can be evaluated for critical stamped regions such as punched-hole groups, formed tabs, precision slots or localized edge zones where higher image scale is more important than capturing a very wide surrounding area.

Long Focal Lengths Can Be Useful for Localized Burr and Crack Inspection

Not every stamping inspection must capture the complete component in one image.

If one particularly critical edge or punched region requires much higher defect sensitivity, a localized view may be better.

For compatible larger-format systems, the Kyptec Automation® KL-1244 50 MM Machine Vision Lens With 25 MegaPixel & 1.1" Format Lens provides a 50 mm, 25 MP C-mount configuration with an F2.8–22 aperture range.

A 50 mm focal length can be considered where sufficient stand-off is available and the inspection should concentrate sensor resolution on a small critical metal feature.

Hole Groups Should Be Checked for Both Presence and Geometry

A stamped component can contain many punched holes or slots.

An inspection system may need to verify not only that each opening exists but that its edge shape and relative position are correct.

A Machine Vision Lens should provide enough complete-part coverage to compare the hole group while preserving sufficient local edge detail for the smallest acceptable deviation.

This is another situation where FOV and defect resolution must be designed together.

Slot and Notch Defects Can Be Directional

A narrow slot may have adequate resolution across its length but poor sampling across its width, depending on image orientation.

Inspection designers should therefore calculate image sampling in both sensor directions.

For narrow stamped features, the most restrictive dimension should determine the required optical scale.

Simply quoting total camera megapixels does not reveal whether a narrow notch or slot edge is represented adequately.

Deformed Holes Require More Than Hole-Presence Detection

A punched opening can be present but still be elongated, partially collapsed or irregular around one edge.

Presence detection may pass such a component even though the geometry is unacceptable.

For machine vision hole quality inspection, the lens must provide enough pixels around the complete perimeter so shape differences can be measured or compared consistently.

This requirement can be substantially more demanding than detecting whether the hole exists.

Progressive Stamping Can Create Repeating Inspection Features

In progressive stamping, components may move through several forming and punching stages.

Different stations can create holes, trims, bends and other features.

From an optical perspective, the final inspection may therefore contain many feature classes within one component.

The lens should be selected based on the smallest required feature among them—not the average feature size.

A tiny burr from one operation can set a higher resolution requirement than a much larger formed flange created elsewhere.

Digital Zoom Does Not Recover Missing Burr Detail

Software can enlarge a region of interest after the image is captured, but enlargement does not create physical optical resolution.

If a burr occupies three recorded sensor pixels, zooming the image cannot turn it into a genuine fifteen-pixel defect.

The correct solution is to increase object sampling through a tighter FOV, more suitable focal length, higher camera resolution, or a matched higher-resolution Machine Vision Lens.

Dimensional Inspection Requires Calibration After Optical Geometry Is Fixed

If the system measures hole diameter, edge spacing or stamped-part dimensions, calibration should be performed only after focal length, camera location, focus and working distance have been finalized.

Changing any of these can alter image scale.

A measurement system should also keep part height and camera stand-off repeatable during production.

The Machine Vision Lens provides the imaging foundation, while stable geometry ensures that pixel measurements remain physically meaningful.

Why Kyptec Automation® Is a Practical Choice for Metal Stamping and Pressed-Part Inspection

Kyptec Automation® offers a broad Machine Vision Lens range covering multiple focal lengths, sensor formats and resolution classes. The portfolio currently includes multiple 5 MP, 10 MP and 25 MP configurations, allowing inspection engineers to choose between wider complete-part coverage and tighter high-resolution views according to the specific stamped-metal application.

For compatible 2/3" systems, Kyptec Automation® KL-1228 25 MM Machine Vision Lens With 10 MegaPixel & 2/3" Format Lens provides a practical moderate focal-length configuration for applications where controlled part framing is needed. For compatible high-resolution larger-format systems, Kyptec Automation® KL-1238 16 MM Machine Vision Lens With 25 MegaPixel & 1.1" Format Lens can be evaluated where broader coverage is required, while Kyptec Automation® KL-1240 25 MM Machine Vision Lens With 25 MegaPixel & 1.1" Format Lens and Kyptec Automation® KL-1242 35 MM Machine Vision Lens With 25 MegaPixel & 1.1" Format Lens provide progressively tighter high-resolution options.

For localized high-detail inspection from greater stand-off, Kyptec Automation® KL-1244 50 MM Machine Vision Lens With 25 MegaPixel & 1.1" Format Lens provides a longer focal-length alternative. This range gives OEMs and system integrators useful flexibility to select a Kyptec Automation® Machine Vision Lens according to component dimensions, stamped-feature size, camera format, available working distance and minimum defect rather than relying on one general lens for every pressed-metal application.

Frequently Asked Questions About Machine Vision Lenses for Metal Stamping and Pressed-Part Inspection

1. What is the best Machine Vision Lens for metal stamping inspection?

The correct lens depends on stamped-part dimensions, minimum burr or crack size, camera sensor format, available working distance and whether the complete part or only a localized region must be inspected. The strongest approach is to determine the minimum required FOV first, calculate pixels per millimetre, and then select a Kyptec Automation® Machine Vision Lens that provides sufficient resolution at the available stand-off.

2. How much resolution is required to detect burrs on stamped metal parts?

Resolution should be calculated from the smallest rejectable burr dimension. If the burr extends only 0.2 mm beyond the intended edge, it must occupy enough sensor pixels to be distinguished consistently from normal edge variation. A wide FOV that produces only a few pixels on the burr may be unsuitable even though the complete component appears sharp.

3. Can machine vision detect edge cracks in stamped parts?

Yes, when the crack is visible from the selected camera direction and receives enough optical and sensor sampling. Fine cracks are usually much more demanding than whole-part presence inspection. The system should be qualified using the smallest real rejectable crack at several valid image positions rather than only a large obvious defect near the center.

4. Can machine vision inspect punched hole diameter and shape?

Yes. The Machine Vision Lens should provide enough pixels around the hole perimeter to define the edge consistently. Measuring diameter or detecting deformation requires more resolution than simply verifying hole presence. Stable camera geometry and calibration are also important when physical dimensions are calculated from the image.

5. Is a 25 mm Machine Vision Lens suitable for stamped-part inspection?

It can be when the resulting FOV matches the component dimensions. For compatible 2/3" systems, Kyptec Automation® KL-1228 25 MM Machine Vision Lens With 10 MegaPixel & 2/3" Format Lens provides a 25 mm, 10 MP, C-mount configuration with an F2.8–16 aperture range. It can be considered where moderate framing provides enough part coverage while preserving edge detail.

6. Why can my camera detect a punched hole but not a burr around it?

The hole itself is a large feature, whereas a burr may extend only a fraction of a millimetre beyond the perimeter. Hole presence can therefore be obvious while the burr receives too few pixels. Tighter optical framing or a higher-resolution matched lens-camera configuration may be required.

7. How should FOV be selected for a pressed metal component?

FOV should cover the maximum part dimensions plus real positioning tolerance and any surrounding reference geometry required for measurement. Excessive unused background should be avoided because it reduces pixels per millimetre on stamped features. The optimum FOV is the smallest practical field that reliably contains every required inspection feature.

8. Is a 25 MP Machine Vision Lens useful for stamped-metal defect detection?

Yes, particularly when a relatively large component must remain visible while small edge cracks, hole irregularities or burrs still require substantial image sampling. Kyptec Automation® currently provides multiple 25 MP Machine Vision Lens focal lengths for compatible larger-format camera systems. Higher optical resolution should still be combined with an appropriately controlled FOV.

9. Which Kyptec Automation® lens can be considered for broader high-resolution pressed-part inspection?

For compatible larger-format systems, Kyptec Automation® KL-1238 16 MM Machine Vision Lens With 25 MegaPixel & 1.1" Format Lens provides a 16 mm, 25 MP, C-mount configuration with an F2.8–16 aperture range. It can be evaluated where broad component coverage and small-defect resolution need to coexist.

10. Which Machine Vision Lens can provide tighter high-resolution framing for stamped features?

For compatible larger-format systems, Kyptec Automation® KL-1242 35 MM Machine Vision Lens With 25 MegaPixel & 1.1" Format Lens provides a 35 mm, 25 MP, C-mount configuration with an F2.8–16 aperture range. This focal length can be evaluated for localized punched-hole groups, tabs, slots or high-detail edge regions.

11. Can a 50 mm Machine Vision Lens help inspect very small burrs or cracks?

Yes, if sufficient working distance is available and the inspection can focus on a smaller region. Kyptec Automation® KL-1244 50 MM Machine Vision Lens With 25 MegaPixel & 1.1" Format Lens provides a 50 mm, 25 MP C-mount option for compatible larger-format systems. Tighter framing can allocate more sensor pixels to a critical stamped edge.

12. Can machine vision inspect bent flanges and forming defects?

Yes, provided the relevant contour remains visible to the camera and falls within the lens's usable focus range. Forming defects may alter height, angle or local shape rather than simply creating a missing edge. The optical system should therefore be qualified with real acceptable and rejectable formed parts.

13. Does oil on stamped metal affect defect inspection?

It can alter the brightness and reflections around cut edges, holes and stamped surfaces. A system developed only on clean parts may perform differently on production components carrying normal process lubricant. Lens qualification should therefore include the actual surface condition expected at the inspection station.

14. Can the same Machine Vision Lens inspect multiple punched holes in one part?

Yes, if the complete hole pattern fits inside the FOV and the smallest hole-edge defect still receives adequate image sampling. If several holes span most of the sensor, outer-field edge quality should also be validated rather than testing only the central opening.

15. Why are forming defects sometimes harder to detect than missing holes?

A missing hole creates a large binary geometry change, while a forming defect may involve only a subtle local contour or height difference. These defects can therefore require higher image detail and carefully controlled viewing geometry even though the complete component is easily visible.

16. What specifications should I provide before buying a Machine Vision Lens for metal stamping inspection?

Provide maximum component dimensions, smallest burr or crack size, minimum punched-hole diameter and permitted hole variation, camera sensor format and resolution, available working distance, product-position tolerance, part-height variation and whether inspection includes dimensional measurement, formed features or localized defects. These parameters allow a Kyptec Automation® Machine Vision Lens to be selected around the actual production requirement.

17. Where can I compare Kyptec Automation® Machine Vision Lenses for stamped and pressed metal inspection?

The Kyptec Automation® Machine Vision Lens collection includes multiple focal lengths across 5 MP, 10 MP and 25 MP resolution classes and several industrial image formats. Buyers can first calculate the required part FOV and minimum pixels per millimetre, then compare Kyptec Automation® focal-length options according to complete-part coverage, localized defect size and available stand-off.

Design Metal Stamping Inspection Around the Smallest Critical Edge or Formed Feature

Reliable stamped and pressed metal inspection requires more than fitting the component into the camera frame. The full part may appear clearly visible while a thin burr, narrow crack, slightly deformed hole or small forming error receives too little image detail to be identified consistently. This is why Machine Vision Lens selection should start with the smallest rejectable feature rather than the largest component dimension alone.

The strongest optical design begins by documenting part width and height, actual position tolerance, punched-hole requirements, minimum burr and crack dimensions, formed-feature geometry and the areas requiring measurement. The minimum practical FOV can then be established, followed by calculation of pixels per millimetre. Camera resolution and sensor format are selected next, and focal length and working distance are chosen so the part uses the available sensor efficiently. Focus and aperture should then be validated across actual component-height variation, while the smallest defects are tested at the center and outer valid image regions.

Kyptec Automation® provides a comprehensive Machine Vision Lens portfolio spanning multiple focal lengths, sensor formats and optical resolution classes for industrial vision inspection and dimensional-analysis applications. By matching the appropriate Kyptec Automation® Machine Vision Lens to stamped-part dimensions, smallest defect, required FOV, camera format and working distance, OEM machine builders and system integrators can create a stronger optical foundation for reliable burr detection, punched-hole inspection, edge-crack identification, formed-feature verification and automated quality control of pressed metal components.