Monthly beauty: Porsche 911 Carrera S
Source: - the quality management portal launched! Check out our Knowledge Base, News, Company Database and more...
Everything about quality management, quality products and quality companies.
Events / News
Quality knowledge base - article QA-0036
Updated on 05-01-2017

Limit Sample

Limit samples – also referred to as border samples – are used as frame of reference. These parts are the ones that can be correlated to the actually produced parts in order to make decisions.
TEST ADVERTISEMENT (for temporary testing purposes, source:
Key Features
Border samples are pre-selected parts of which have given characteristics on (or very near) to the specification limit. These samples are most commonly used if the given characteristic is not, or hardly measurable.
Examples of use:
Limit sample for visual inspection: An aesthetic product is being checked by human eye. The customer requirement – based on the specification - allows one visual failure with the maximum size of 0,2 mm. The human eye is incapable to measure, so the supplier uses a limit sample that can be correlated to the checked part. If the visual defect of the actual part is bigger, than the one on the limit sample, the part must be rejected by the technician / operator. Note: this kind of inspection is unreliable, so try to use automatic system whenever it is possible.
Quality Management
Limit sample for visual inspection (Source:
Limit sample for test system verification: The length of a component is checked by a camera system, combined with a software. The engineer uses different limit samples to teach and frequently verify the measuring capability of the system. This method is also called "Check the checker". The specification for the length is 50 +/- 0,5 mm. The engineers have pre-selected parts in the specification range, and also parts out of it.
Quality Management
Limit sample for test system verification (Source:
Many limit samples are used continuously, with various frequencies. Those of used for visual inspection can wear out earlier, that the ones used for system verification. Anyway, you need the take care of your limit samples frequently:
  • Revalidate your limit sample with the needed frequency (e.g. daily in case of visual inspection, weekly in case of test system verification).
  • If it’s possible, prepare your limit samples in the way to keep them in good condition with conservation (supporting materials, glues, resins, etc.).
  • Limit samples must be marked perceptibly to avoid any part mixing with the serial production.
  • If your limit sample is not a usable any more, scrap it immediately.
Important: the limit sample is not equal to the golden / master sample!
  • Limit samples are production parts that are used as a frame of reference.
  • Limit sample are also referred to as border samples.
  • You can use limit samples for visual inspection, but also for test system verification.
  • Limit samples need special care, from pre-selection through revalidation, to conservation and scrapping.
  • The limit sample is not equal to the golden sample!
Relevant Topics
Process Control and Analysis
Gage Repeatability and Reproducibility (GR&R)
Process Control and Analysis
Attribute Agreement Analysis (AAA)
Process Control and Analysis
Incoming Quality Inspection
Process Control and Analysis
Controlled Shipping Level (CSL)
Process Control and Analysis
Golden Sample
Fact sheet
Information about limit samples.

Topic / Article: Limit Sample
Term Category: Process Control and Analysis
Business Sector: All
Timing: In serial production
Files, Attachments: None
Term Up-to-date
Scroll to Top