Material
Compliance of the material used with established requirements.
Quality Control
Quality must be measurable.
OID controls the critical parameters of a product from the raw material to the final acceptance of the batch. Results are linked to the specific product, procedure, and shipment.
A bearing cannot be judged by appearance. Its performance is affected by the material, heat treatment, raceway and fit geometry, internal clearance, assembly quality, and the condition of the working surfaces.
That is why OID's inspection system is built as a chain of measurable parameters that accompanies the product from raw material to batch release.
The goal of the system is to detect a deviation before it carries over to the next production stage.
On this page
What exactly OID controls
Heat treatment
Hardness, structure, and applicable hardened-layer parameters.
Geometry
Mounting dimensions, shape, runout, and profile of the working surfaces.
Assembly
Internal clearance, preload — where applied, completeness, and rotation quality.
Functional condition
Vibration, noise, and other applicable characteristics of the finished product.
Batch and documentation
Identification, inspection results, final acceptance, and clearance for shipment.
Control is built into the process
- 01Incoming inspection
- 02In-process
- 03Heat treatment
- 04Geometry
- 05Functional testing
- 06Special methods
- 07Final acceptance
The transition between checkpoints occurs only after compliance with the requirements of the specific product or batch has been confirmed.
1. Incoming material inspection
We verify starting conditions before processing begins.
Incoming inspection is necessary to confirm that the material is cleared for production of the specific product.
May be checked
- material identification;
- chemical composition;
- hardness;
- structure;
- blank condition;
- accompanying documentation.
Outcome
Material cleared / not cleared for the production process.
2. In-process inspection
An error must be detected where it occurs.
After critical operations, the intermediate part is checked for compliance with the specified geometry and process requirements.
| Checked | Why |
|---|---|
| Dimensions | To prevent accumulation of dimensional error |
| Runout | To control the position of the working surfaces |
| Ovality and taper | To confirm the shape of fits and raceways |
| Profile | To confirm the geometry of the working surface |
| Surface condition | To detect damage before the next operation |
Final inspection should not compensate for a lack of control within the process.
3. Heat-treatment control
Hardness must match not only the specified value, but also the measurement location.
Control may include
- surface hardness;
- hardness at the designated zone;
- material structure;
- hardened-layer depth — where applicable;
- process-cycle results.
OID uses hardness measurement and metallographic methods for inspection; heat-treatment results are recorded by batch.
4. Geometric inspection
Microns determine load distribution.
A bearing can conform to its nominal d × D × B and still perform incorrectly if its shape or working surfaces deviate.
That is why the following are checked separately
| Parameter | What it determines |
|---|---|
| Mounting diameters | Interaction with the shaft and housing |
| Ovality | Uniformity of geometry around the circumference |
| Taper | Fit stability |
| Radial / axial runout | Rotational accuracy |
| Raceway profile | Distribution of contact load |
| Internal clearance | Operating condition of the assembled bearing |
5. Inspection of the assembled bearing
After assembly, what is checked is no longer a single part but the system.
Parameters applicable to the design are checked
- internal clearance;
- preload;
- smoothness of rotation;
- noise;
- vibration characteristics;
- seal condition;
- absence of interference;
- completeness.
Vibration testing
Rotation reveals what is not always visible in a static measurement.
Vibration testing helps assess the actual behavior of the assembled bearing and can reveal deviations related to
- raceway geometry;
- condition of the working surfaces;
- assembly;
- rolling elements;
- contamination;
- the product's internal condition.
For results to be meaningful, it is important to record the test method, speed, load, and the criterion used — not only the final class designation.
6. Non-destructive testing
For critical designs — additional methods.
Depending on the product and project requirements, special inspection methods may be applied
Ultrasonic testing
For detecting certain internal material discontinuities.
Magnetic particle testing
For detecting applicable surface and near-surface defects in ferromagnetic parts.
Eddy current testing
For evaluating applicable surface and near-surface irregularities.
Not a single test, but a body of evidence
| What is checked | Primary verification method |
|---|---|
| Material | Analysis and laboratory testing |
| Heat treatment | Hardness / metallography |
| Size | Metrological measurement |
| Shape | Geometric inspection |
| Surface | Condition / roughness inspection |
| Assembly | Clearance, rotation, functional check |
| Special risks | Applicable NDT methods |
| Batch | Final acceptance and recording |
Batch traceability
Not only the product is checked — the batch is controlled.
Inspection must link the result to a specific shipment.
- 01Product
- 02Designation
- 03Batch
- 04Inspection operations
- 05Results
- 06Final acceptance
- 07Shipment
What may be recorded
- designation;
- batch;
- inspection date;
- procedure applied;
- measured parameters;
- compliance status;
- responsible checkpoint;
- accompanying documentation.
What the customer receives
The scope of documentation is determined by the supply requirements.
For standard and project supply, the following may be issued
- supply documents;
- batch identification;
- results of agreed inspections;
- special test reports — where specified;
- material or analysis certificates — where required;
- inspection documents under an agreed program.
It is recommended to agree the set of documents and special checks before the order is started in production.
Independent inspection
Additional acceptance on request
For critical projects, participation of an independent inspection body can be agreed
- inspection of the product;
- review of documentation;
- witnessing of agreed operations;
- pre-shipment inspection;
- verification of results under an agreed program.
Quality begins with the technical specification
Before production of a critical product, it is advisable to agree
- standard;
- precision class;
- internal clearance;
- material;
- heat treatment;
- critical dimensions;
- vibration requirements;
- NDT — if required;
- special tests;
- report format;
- acceptance criteria.
Special tests and non-standard acceptance criteria must be defined before the batch is manufactured.
If a question arises about a product
Analysis begins with identifying the batch and the operating conditions.
For technical review, it is advisable to provide
- exact designation;
- batch number;
- supply documents;
- photos of the product and any damage;
- installation data;
- load and speed;
- temperature;
- lubrication;
- operating time;
- symptoms before the failure.