Machine Vision Lens for Injection-Molded Plastic Part Inspection: How to Detect Flash, Short Shot, Sink Marks and Edge Defects

Injection-molded plastic inspection can look straightforward until the smallest rejectable defect is compared with the total size of the molded component. A part may be 100 mm wide while the flash that must be detected extends only a fraction of a millimetre beyond the nominal edge. A short shot may remove material from only one corner, a sink mark may create a shallow local contour change rather than a strong edge, and parting-line damage may appear as a narrow irregularity along an otherwise acceptable profile. Selecting the right machine vision lens for injection-molded plastic part inspection therefore requires more than fitting the complete component inside the camera image. The optical system must allocate enough usable image detail to the smallest flash, missing-material region, surface depression or edge defect that determines whether the molded part passes or fails.

Buyers searching for machine vision lens for plastic part inspection, camera lens for injection molding defect detection, machine vision flash detection, short shot inspection camera, sink mark inspection machine vision, or lens for molded plastic edge inspection are generally dealing with the same design problem: how can the required product area remain inside the FOV while small molding defects still occupy enough pixels for reliable inspection? The answer depends on physical part size, number of cavities or components inspected in one image, sensor resolution, focal length, working distance, surface finish, part height and the minimum defect specification.

Kyptec Automation® provides a broad Machine Vision Lens portfolio covering multiple focal lengths, image formats and optical resolution classes. The current collection includes 5 MP and 10 MP lenses for 2/3" systems, 10 MP options for 1" cameras and a larger-format 25 MP family across several focal lengths. This allows OEM machine builders and system integrators to choose the optical configuration around molded-part size and defect resolution instead of relying on one general-purpose lens for every injection-molding inspection station.

Start With the Plastic Defect That Actually Causes Rejection

The phrase “plastic part inspection” covers very different inspection requirements. One production line may need only presence, orientation and gross shape verification. Another may reject a component for a thin flash extending from a parting line, a slightly incomplete corner, a small edge chip or a shallow visible sink area.

These requirements should not share the same optical acceptance criterion.

A Machine Vision Lens selected simply because the complete molded component looks sharp can still be unsuitable for micro-flash or local contour inspection. Lens selection should begin with the smallest physical molding defect that must be detected consistently, followed by the total area that must remain visible.

Why Flash Detection Is Primarily an Edge-Resolution Problem

Flash is unwanted excess plastic that commonly extends from a parting line, edge or other molding interface. Depending on the process and defect tolerance, it can be extremely narrow.

From a machine vision perspective, the important question is how far the flash extends beyond the expected good-part boundary and how many sensor pixels represent that extension.

If a 0.15 mm flash occupies only two or three poorly defined pixels, detection can become unstable. If the optical system provides substantially greater sampling, the difference between the nominal part edge and the protruding material becomes much easier to classify.

For machine vision flash inspection, the field should therefore be no wider than necessary for the part and its legitimate positioning tolerance.

Calculate Pixels per Millimetre From the Final FOV

A practical starting calculation is:

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

Suppose the sensor provides 4,000 pixels horizontally and the molded-part inspection FOV is 100 mm wide. The system provides approximately 40 pixels/mm.

A 0.25 mm edge defect would then correspond to approximately 10 pixels under simplified geometry.

If the same camera is used with a 200 mm FOV, sampling falls to approximately 20 pixels/mm and the same physical defect occupies only about 5 pixels.

This is why a lens that makes setup convenient by capturing a very broad surrounding area can reduce the inspection sensitivity that the application actually needs.

Short Shot Inspection Requires Detecting Missing Geometry

A short shot occurs when a molded region is not completely formed. In machine vision, this often appears as a missing corner, shortened rib, incomplete wall, reduced projection or absent portion of the expected silhouette.

Large short shots are relatively easy to detect. Small incomplete regions can be far more demanding.

The Machine Vision Lens needs enough image scale that the difference between the correct CAD-like profile and the incomplete molded contour is represented clearly.

The smallest incomplete feature, not the overall part size, should determine the required optical sampling.

Edge-Based Short Shot Detection Benefits From Controlled FOV

If the defect changes the outside silhouette of the molded part, a controlled inspection field can make the missing geometry easier to measure.

Capturing excessive space around the part decreases pixels per millimetre and gives no corresponding defect-detection benefit.

A useful FOV should cover the complete maximum component size plus fixture or conveyor position tolerance.

Anything substantially beyond that area should be justified by another inspection requirement.

Sink Marks Are Different From Missing-Edge Defects

Sink marks create a different optical challenge because they may not alter the outside silhouette at all.

A shallow depression can exist inside a broad molded surface while the external edge remains perfect.

For this reason, the lens requirement is not simply edge sharpness. The system also needs enough spatial resolution to preserve the local surface variation that identifies the sink region.

A shallow sink may occupy many pixels in area but produce only subtle visible structure. Resolution and surface contrast must therefore work together.

A Higher-Resolution Lens Cannot Create Contrast That Is Not Present

A fine optical system can preserve small visible differences, but it cannot make an optically invisible depression become automatically obvious.

If a sink mark produces almost no measurable image difference under the selected viewing condition, simply increasing megapixels may provide limited improvement.

Once the sink region produces sufficient optical contrast, however, a higher-resolution Machine Vision Lens can represent its local boundaries and texture more accurately.

This distinction is important when buyers evaluate high-resolution lenses for plastic surface defect inspection.

Parting-Line Inspection Needs Consistent Edge Detail

Parting lines frequently create narrow visual structures along molded components. Excess material, mismatch or irregularity may occur locally along this line.

The lens should therefore preserve sufficient detail across the entire parting-line region where rejection decisions are made.

If the line passes close to the image edge, outer-field image quality becomes relevant. A setup should not be qualified only with the defect centered in the sensor.

Minimum-size defects should be tested wherever the parting line can validly appear.

A 16 MM 1-Inch Lens Can Support Broader Molded-Part Coverage

Where a larger molded component or several features need to fit inside one image on a compatible 1" camera, the Kyptec Automation® KL-1214 16 MM Machine Vision Lens With 10 MegaPixel & 1" Format Lens provides a broader-field 16 mm option. The official product page specifies 10 MP resolution, 1" image format, C-mount and an F1.4–16 aperture range.

This focal-length class can be evaluated where complete-part coverage is important but the lens still needs to preserve sufficient object sampling for edge defects, missing molded regions and dimensional features.

The final suitability should be based on calculated FOV rather than focal length alone.

A 25 MM Lens Can Provide More Controlled Framing

For compatible 2/3" systems, the Kyptec Automation® KL-1228 25 MM Machine Vision Lens With 10 MegaPixel & 2/3" Format Lens is specified with 25 mm focal length, 10 MP resolution, 2/3" image format, C-mount and an F2.8–16 aperture range.

A 25 mm configuration can be useful where the molded component does not require an extremely wide field and preserving edge scale is more valuable than capturing large amounts of background.

Applications involving flash, gate-area defects, incomplete corners or localized edge damage can particularly benefit from using as much of the sensor as practical on the actual component.

Part Size and Position Tolerance Must Be Separated

A 70 mm part does not automatically require a 100 mm FOV.

The correct field depends on actual positioning variation.

If the component is mechanically located within ±1 mm, a relatively small margin may be adequate. If it can shift ±10 mm, more FOV is necessary.

The important point is to measure this variation rather than adding an arbitrary large safety margin.

Every unnecessary millimetre of FOV reduces the sensor sampling available to detect molding defects.

Multi-Cavity Molding Can Create a Different Lens Requirement

Some inspection stations evaluate several molded components or multiple cavity outputs simultaneously.

The total FOV may therefore become much larger than the dimensions of one part.

This creates a trade-off: inspecting more parts in one image increases throughput efficiency but gives fewer pixels to each individual component.

The smallest defect in the smallest part should therefore be calculated against the full multi-part FOV, not against the dimensions of one component alone.

Cavity-to-Cavity Consistency Can Be Evaluated Optically

Injection molds with multiple cavities can produce components that are nominally identical but show slightly different edge, flash or surface behavior.

Machine vision can compare these products effectively only when each component is imaged at sufficient scale and under comparable optical geometry.

If parts from different cavity positions land at different image locations, the lens should maintain adequate image quality over every valid region.

The inspection should not assume that a defect will always occur close to the sensor center.

Small Gate Vestige or Gate-Area Defects Need Local Detail

The location where material enters the molded component can leave a small gate-related feature after separation.

If inspection needs to confirm acceptable gate trimming or detect an abnormal projection, the required image scale may be substantially higher than for overall part presence.

A localized FOV can therefore be more suitable than whole-part imaging when this feature is the critical quality characteristic.

The Machine Vision Lens should be selected around the smallest permitted projection or missing region at the gate area.

Rib and Boss Inspection Requires Enough Resolution for Narrow Features

Molded components often contain ribs, bosses, tabs and narrow projections.

A short shot in one of these features may remove only its end portion while the main body remains correct.

If the complete component occupies too little of the sensor, these narrow features can become poorly represented.

The smallest rib width or boss-edge defect should be included in the optical-resolution calculation before the final lens is selected.

High-Resolution Larger-Format Lenses Can Help When Coverage and Fine Defects Must Coexist

Some molded components are physically large yet contain small rejectable edge or surface defects. In that case, simply tightening the FOV may not be possible because the whole product must remain visible.

A higher-resolution larger-format optical configuration can provide more total image information across that necessary field.

For compatible larger-format systems, the Kyptec Automation® KL-1238 16 MM Machine Vision Lens With 25 MegaPixel & 1.1" Format Lens is listed as a 16 mm, 25 MP C-mount Machine Vision Lens with an F2.8–16 aperture range in Kyptec Automation®'s larger-format family.

This type of configuration can be evaluated where broad molded-part coverage and fine-detail inspection need to be combined.

Fine Flash Can Justify a Higher-Resolution Optical Class

When the reject criterion is extremely small flash, the defect may consume only a small number of pixels even after the FOV has been optimized.

At that point, increasing total sensor resolution can provide additional sampling, provided the lens can deliver corresponding optical detail.

Kyptec Automation®'s 25 MP Machine Vision Lens family provides multiple focal-length choices for compatible high-resolution camera systems, allowing engineers to maintain the resolution class while changing the physical FOV according to machine geometry.

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

When a higher-resolution system needs more controlled framing or greater working distance, 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 option with an F2.8–16 aperture range according to the official Kyptec Automation® page.

A focal length in this range can be considered for localized high-detail inspection of molded edges, gate regions, tabs or other critical areas where the complete product does not need an extremely broad field.

Working Distance Changes the Defect Scale

Focal length should never be considered without working distance.

The same Machine Vision Lens produces different physical FOVs when the camera is moved closer to or farther from the part.

Moving farther away usually increases the visible area and decreases object magnification. Moving closer generally increases magnification and makes defects larger on the sensor.

The correct design therefore starts from available machine stand-off and then determines which focal length produces the required field.

Plastic Part Height Variation Can Affect Focus

Injection-molded components are rarely perfectly flat.

Raised bosses, ribs, walls and recessed regions can occupy several object depths.

If the inspection requires defects across all of these planes, the lens should maintain enough usable depth tolerance that critical regions remain acceptably focused.

Focus should not be qualified only on the tallest central surface when flash may occur at a lower peripheral parting line.

Aperture Must Balance Depth Tolerance and Small-Defect Detail

Stopping down the aperture can increase depth-of-field tolerance and help keep multiple molded heights in focus.

However, excessively small apertures can reduce fine image detail because of diffraction.

The final aperture should therefore be selected using the smallest flash, edge irregularity or surface feature rather than by maximizing depth of field alone.

A practical inspection system needs sufficient focus tolerance and sufficient fine-detail preservation.

Glossy and Matte Plastic Can Produce Different Inspection Images

Injection-molded plastics can range from matte textured surfaces to highly glossy finishes.

The same physical sink mark or edge defect can therefore produce very different contrast depending on material finish.

A system developed using only one ideal sample may perform differently when surface gloss varies during production.

The Machine Vision Lens should be evaluated with representative production parts covering the expected appearance range.

Dark Plastic Does Not Automatically Require a Different Focal Length

Part color can influence exposure and contrast, but it does not independently determine focal length.

Focal length should still be selected from sensor size, working distance and FOV.

This distinction helps prevent a common mistake where optical framing decisions become mixed with brightness problems.

First establish the correct geometry. Then optimize the image acquisition conditions around the actual molded material.

Transparent Plastic Requires a Different Defect Strategy

Clear molded plastic can introduce multiple visible surfaces and refractive effects that are not present on ordinary opaque components.

If the inspection is specifically aimed at transparent walls or internal features, the Machine Vision Lens still needs the correct FOV and resolution, but the visibility of the targeted plane must also be considered.

For ordinary opaque injection-molded-part inspection, by contrast, the primary lens-selection problem is often the balance between complete shape coverage and fine edge or surface detail.

Edge Chips and Broken Tabs Can Be Easier Than Sink Marks

Not every molding defect has the same optical difficulty.

A missing tab or broken edge creates a strong geometric difference from the expected silhouette and may be easy to detect.

A shallow sink mark may not change the silhouette at all and can require much stronger local image quality.

When specifying lens resolution, the easiest defect should never be used as the benchmark for the complete inspection station.

The most difficult required defect should drive optical qualification.

A 50 MM Lens Can Be Useful for Localized Inspection From Greater Stand-Off

When a critical molded feature occupies only a small region and the machine permits greater camera distance, a longer focal length can provide tighter framing.

For compatible 1" systems, the Kyptec Automation® KL-1220 50 MM Machine Vision Lens With 10 MegaPixel & 1" Format Lens provides a 50 mm, 10 MP C-mount configuration with an F2.5–22 aperture range.

This lens can be evaluated where a local molded edge, gate region, clip or feature needs stronger image scale while the camera remains farther from the product.

Digital Zoom Cannot Recover Flash Resolution Lost Optically

A software crop may make a small flash look larger on a monitor, but it does not create additional physical image information.

If the defect was represented by only three sensor pixels, enlarging the image does not turn it into a genuinely higher-resolution ten-pixel feature.

The real solution is to increase physical sampling by reducing FOV, improving sensor utilization or selecting a higher-resolution compatible lens-camera configuration.

This is a critical principle in machine vision inspection of small plastic defects.

Part Rotation Can Hide Edge Defects

An edge defect may be clearly visible when the component is correctly oriented but become foreshortened or hidden when the part rotates.

Inspection qualification should therefore include the full permitted angular positioning tolerance.

If rotation can vary substantially, the FOV and mechanical presentation should be controlled so critical edges remain visible to the Machine Vision Lens.

Resolution cannot detect a feature that is physically occluded from the camera.

Sink Mark Inspection Should Cover the Actual Surface Zone

A sink mark often appears in predictable areas associated with thicker molded sections, ribs or bosses.

If the production process identifies these zones as particularly important, it may be better to dedicate more sensor area to them rather than imaging a very large portion of the part.

A controlled local FOV can improve the pixel representation of shallow surface variations.

This is often a better optical strategy than maximizing the amount of component visible in one image.

Molded Edge Measurement Requires Stable Magnification

If the system measures molded dimensions rather than only detecting defects, working distance must remain stable.

Changing product height changes magnification, which changes the relationship between image pixels and physical dimensions.

After the Machine Vision Lens and camera geometry are finalized, dimensional calibration should be performed at the actual production plane.

The system should then be verified over the expected component-height tolerance.

Qualification Should Use Real Minimum-Acceptance Samples

A large obvious flash or completely missing tab is useful for initial setup but not for final qualification.

The decisive samples should represent the smallest defect that production actually requires the system to reject.

For injection molding, this can include minimum flash height, smallest incomplete corner, shallow acceptable-versus-rejectable sink variation and smallest edge break.

These samples should be tested at several valid positions across the FOV.

Why Kyptec Automation® Is a Practical Choice for Injection-Molded Plastic Inspection

Kyptec Automation® provides a broad Machine Vision Lens portfolio spanning multiple focal lengths, optical resolution classes and industrial image formats. The current collection includes 5 MP, 10 MP and 25 MP Machine Vision Lens families, giving inspection engineers flexibility to match optical coverage to molded-part size while preserving the resolution needed for small defects.

For compatible 1" systems requiring broader part coverage, Kyptec Automation® KL-1214 16 MM Machine Vision Lens With 10 MegaPixel & 1" Format Lens provides a 16 mm option. For compatible 2/3" systems requiring more controlled framing, Kyptec Automation® KL-1228 25 MM Machine Vision Lens With 10 MegaPixel & 2/3" Format Lens provides a 25 mm configuration.

For applications combining larger physical coverage with small-defect requirements, Kyptec Automation® KL-1238 16 MM Machine Vision Lens With 25 MegaPixel & 1.1" Format Lens provides a higher-resolution broader-field option, while Kyptec Automation® KL-1242 35 MM Machine Vision Lens With 25 MegaPixel & 1.1" Format Lens can be evaluated for tighter high-resolution framing on compatible larger-format camera systems.

This range gives OEM machine builders and system integrators the ability to select Kyptec Automation® Machine Vision Lens configurations according to the actual molded-part geometry, sensor format, stand-off and defect size rather than treating every injection-molding inspection as the same optical problem.

Frequently Asked Questions About Machine Vision Lenses for Injection-Molded Plastic Part Inspection

1. What is the best Machine Vision Lens for injection-molded plastic inspection?

The correct lens depends on part dimensions, sensor format, working distance, minimum defect and whether the inspection covers the whole component or a localized critical region. For whole-part inspection, choose a focal length that fits the component with only the required positioning margin. For very small flash, gate defects or edge damage, a tighter FOV may provide better object sampling.

2. How much resolution is needed to detect plastic flash with machine vision?

Resolution should be calculated from the smallest rejectable flash dimension. Determine pixels per millimetre from the final FOV and sensor pixel count, then calculate how many pixels represent that flash. A system that easily detects 1 mm excess material may still be unsuitable when the rejection threshold is only 0.1 or 0.2 mm.

3. Can machine vision detect a short shot on an injection-molded part?

Yes, when the missing material creates a sufficiently visible change and the Machine Vision Lens provides enough spatial sampling. Large incomplete sections are relatively easy, while small missing corners, ribs or tabs require more image detail. The optical system should be qualified using the smallest incomplete feature that must trigger rejection.

4. Can machine vision detect sink marks on plastic components?

It can when the sink mark produces enough visible surface variation under the final inspection geometry. Because sink marks may not alter the outside silhouette, they can be more difficult than missing-edge defects. The lens must preserve sufficient local detail, but surface contrast is also necessary; resolution alone cannot make an optically invisible depression detectable.

5. Which Kyptec Automation® lens can be considered for a broader plastic-part inspection on a 1-inch camera?

For a compatible 1" system requiring 16 mm focal length, Kyptec Automation® KL-1214 16 MM Machine Vision Lens With 10 MegaPixel & 1" Format Lens provides a 10 MP C-mount configuration with an F1.4–16 aperture range. Final suitability should be determined from actual component size, working distance and smallest defect.

6. Is a 25 mm Machine Vision Lens suitable for flash and edge-defect inspection?

It can be when the resulting FOV matches the molded component. Kyptec Automation® KL-1228 25 MM Machine Vision Lens With 10 MegaPixel & 2/3" Format Lens provides a 25 mm, 10 MP, 2/3" C-mount configuration with an F2.8–16 aperture range. A moderate focal length can be useful when tighter framing is preferred over excessive surrounding FOV.

7. Why can my camera detect a missing tab but not thin flash?

A missing tab creates a large geometric difference, whereas thin flash may extend only a fraction of a millimetre beyond the nominal boundary. The flash therefore needs substantially higher pixels per millimetre. A tighter FOV or higher-resolution compatible optical system may be required even though large defects are already easy to detect.

8. Should the complete molded part fill most of the image?

Generally, using the sensor efficiently improves the number of pixels available for defects. The complete product should occupy a large portion of the valid inspection area while still leaving enough margin for normal position variation. Large unused background regions reduce object sampling without improving inspection performance.

9. Is a 25 MP Machine Vision Lens useful for injection-molding defect inspection?

It can be particularly valuable when a relatively large molded component must remain fully visible while small flash, edge defects or fine features still require substantial image sampling. Kyptec Automation® offers multiple 25 MP Machine Vision Lens focal lengths for compatible larger-format systems, allowing FOV to be adjusted without leaving the high-resolution optical family.

10. Which Kyptec Automation® high-resolution lens can be considered for a wider molded-part FOV?

For a compatible larger-format system, 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 broader coverage and fine defect detail need to coexist.

11. Can a 35 mm high-resolution lens help inspect localized molded features?

Yes. 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 class can be evaluated for tighter inspection of gate regions, clips, tabs, edge details or other localized features.

12. Can a 50 mm Machine Vision Lens be used for small plastic features?

Yes, where sufficient working distance is available and only a localized region requires inspection. Kyptec Automation® KL-1220 50 MM Machine Vision Lens With 10 MegaPixel & 1" Format Lens provides a 50 mm, 10 MP C-mount configuration with an F2.5–22 aperture range for compatible 1" systems. Tighter framing can allocate more sensor pixels to small molded features.

13. How does part height affect Machine Vision Lens selection for molded components?

Raised ribs, bosses and walls can sit at different working distances from recessed regions and peripheral edges. If defects must be inspected across these different heights, the final focus and aperture should provide adequate depth tolerance. The lens should be tested using the actual tallest and lowest critical features.

14. Can the same Machine Vision Lens inspect parts from multiple mold cavities?

Potentially, provided all cavity outputs fit inside the required FOV and the smallest defect still receives sufficient sampling. If several components are inspected simultaneously, calculate pixels per millimetre using the complete multi-component FOV, not one individual part. Outer-field image quality should also be qualified because different cavity outputs may appear at different sensor positions.

15. Why do sink marks sometimes appear clearly on one plastic color or finish but poorly on another?

Sink-mark visibility depends on the optical contrast created by the surface geometry and finish. Glossy, matte, textured and differently colored plastics can produce different image responses even when the physical depression is similar. The Machine Vision Lens should therefore be qualified with representative production materials rather than one ideal sample.

16. What information should I provide before buying a Machine Vision Lens for injection-molded plastic inspection?

Provide maximum part width and height, sensor format and camera resolution, available working distance, smallest flash or edge defect, minimum short-shot feature, critical sink-mark area, part-height variation, position tolerance and whether one or multiple parts need to fit in the image. These parameters allow a Kyptec Automation® Machine Vision Lens to be selected around the actual inspection geometry rather than focal length alone.

17. Where can I compare Kyptec Automation® Machine Vision Lenses for molded plastic inspection?

The Kyptec Automation® Machine Vision Lens collection includes multiple focal lengths across 5 MP, 10 MP and 25 MP optical classes and several industrial sensor formats. Buyers can define the required molded-part FOV, working distance and minimum defect first, then compare Kyptec Automation® focal-length and resolution options that provide enough coverage without unnecessarily sacrificing defect sampling.

Design Injection-Molded Plastic Inspection Around the Smallest Rejectable Defect

Reliable injection-molded plastic inspection depends on understanding that full-part visibility and defect visibility are not the same requirement. A camera may display the complete molded component sharply while a thin flash, shallow sink mark, small incomplete rib or local edge defect remains below the useful resolution of the inspection system. The Machine Vision Lens must therefore be selected according to the smallest required quality feature as well as the overall component dimensions.

The strongest optical design begins with the maximum part dimensions, position tolerance and smallest flash, short-shot feature, sink region or edge defect. These values establish the physical FOV and required pixels per millimetre. Sensor format and optical resolution can then be selected, followed by focal length and working distance that use the available sensor area efficiently. Focus and aperture should be qualified across actual molded-part height variation, and minimum defects should be tested at the center and outer valid image positions rather than only under ideal conditions.

Kyptec Automation® provides a comprehensive Machine Vision Lens portfolio spanning multiple focal lengths, sensor formats and optical resolution classes, giving OEM machine builders and system integrators practical flexibility for both whole-part inspection and localized high-detail defect detection. By matching the appropriate Kyptec Automation® Machine Vision Lens to molded-part dimensions, smallest defect, sensor format, working distance and required FOV, industrial inspection systems can create a stronger optical foundation for reliable flash detection, short-shot identification, sink-mark inspection, parting-line analysis and molded-edge quality control.