Spring Presence/Absence Inspection
Judges whether compression springs, tension springs and spring plates are properly installed, for inline verification at assembly process steps and pre-packaging checks.
inspection Overview
Spring presence/absence inspection: determines whether compression springs, extension springs, spring plates, and similar parts are installed in place; suitable for in-line verification at the assembly process step and for pre-packaging checks. The judgement usually does not check details such as threads or dimensions, but rather Whether the visual feature at that position exists and matches expectations, output OK / NG and interlock with the production line.
Judge whether compression springs, extension springs, spring plates and similar parts are properly installed; suitable for in-line verification at assembly process steps and pre-packaging checks.
The feasibility of "spring presence/absence inspection" depends on Whether the visual features of the object are stable and distinguishable, as well as the on-site optical and tooling conditions. Each item is expanded below in the order commonly used in inspection engineering.
Object Characteristics
How the object appears in the image
- Slender or thin-sheet structures appear as fine dense texture in the image
- Metallic material, prone to specular highlights
- After assembly the part sits in a hole or groove with limited visibility
- States such as not fully inserted, tilted or wrong model may exist
inspection Challenges
Where Problems Really Occur on Site
- Fine coil textures easily blur together at small sizes
- Metal reflection makes the spring contour blend into the background
- Only a small part is exposed after insertion into the hole
- A compressed spring looks very different from a spring in its free state
Vision Judgement method
How acceptance criteria are set and why
The common criterion is Whether a regular stripe texture exists in the region (coil feature) or Whether there is a specular structure clearly different from the hole bottom.
If the spring is small and highly reflective, the "statistical features of the regional texture" can be used instead of precise contour matching, which is usually more robust.
Applicable algorithm
Choose by the Form of the Acceptance Criteria, Not by Complexity
Texture Statistics
Judges whether the spring is present by the regularity of the region texture
template matching
When the pose is stable, use standard spring template matching
Optical Precautions
Imaging conditions set the upper limit of feasibility
- Low-angle light creates alternating light and dark bands on the coil texture and reveals the spring structure more easily than frontal light
- If the spring is inside a deep hole, a dedicated light source (such as built-in coaxial light or a light guide) is needed to illuminate the bottom of the hole
- When reflection is too strong, add a polarizer to reduce specular reflection
OK / NG Output
How results are judged and passed to the production line
| Inspection Status | judgement | Interlocking Action |
|---|---|---|
| Spring feature detected | OK | release |
| No spring feature detected | NG | Block as missing part |
| Spring clearly tilted / not seated | NG | Handle as an assembly defect |
Applicable Industry
This type of inspection is common in the following industries
Common Question
The most common questions about this object
Can a small spring inside a deep hole be detected?
Yes, but the illumination problem must be solved — ordinary external light sources cannot shine into deep holes. Coaxial light, ring light guides or dedicated in-hole illumination are usually needed. A physical test is mandatory before implementation.
Are missing springs and crooked springs inspected the same way?
The criteria are different. A missing part is judged by presence/absence, while a crooked part is judged by pose (angular or positional deviation). If both must be managed, set separate acceptance criteria so that the site can tell where the problem comes from.
What are the acceptance criteria for this object?
A common acceptance criterion is whether a regular striped texture (coil pattern) exists in the area, or whether a highlight structure clearly different from the hole bottom is present.
What are the illumination requirements for this type of object?
Low-angle light makes the coil texture alternate light and dark, which reveals the spring structure more easily than frontal light. If the spring is inside a deep hole, a dedicated light source (such as built-in coaxial light or a light guide) is needed to illuminate the bottom of the hole
What Are the Inspection Accuracy and Minimum Detectable Size?
It depends on the combination of field of view and camera resolution, and is affected by the lens, illumination and algorithm. To be added — the configuration must be derived from your minimum defect size, subject to the results of a measured sample trial.
How Do We Verify That Our Product Can Be Detected?
Please provide samples with the spring installed, samples with the spring missing, and photos of the spring's position in the assembly.
Submit sample testing
Please provide samples with the spring installed, samples with the spring missing, and photos of the spring's position in the assembly.
Submitted successfully
We have received your sample testing request. A solution engineer will contact you within 1 business day via contact you.
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Send Us Your Workpiece and We Will Show You the Measured Results
Provide several OK and NG samples, and the solution engineer will run actual imaging and judgement tests on the equipment, then give inspection configuration recommendations that can be implemented, rather than just reading a specification table.