Poison test for quality inspectors in manufacturing industry

What is a Poison Test:

A poison test is a process of checking the competence of quality inspectors. It is done by providing a small mixed lot of OK and defective parts for inspection within the defined takt time. It is a periodic practical process of taking tests of inspectors. Poison tests should be taken on all inspectors with visual defects.

Poison Test Work Instruction:

Below are the steps to conduct a poison test:

  • First of all, mix the OK and Defect parts according to the Poison test sheet. (Take the OK part at least 50 and the defective part takes 10%). Before mixing, mark the defective parts as not visible to the inspector.
  • Then give the bin to the final inspector to check.
  • Give the inspector a specific time ( Takt time ) to check the parts.
  • Recheck inspector checked parts and keep OK and defective parts separately.
  • Check all the defective parts of the Final Inspector with your noted paper.
  • If the final inspector separates the parts with defect marking, then he is working correctly and is fully aware of his work.
  • If the final inspector cannot separate the marked parts, he does not have full knowledge of his work. Stop inspection by that inspector until he qualifies in the poison test.
  • Hold the previously checked parts by the inspector and recheck those parts by any qualified inspector.
  • Then provide him training for all the defects of that part.
  • Again take his test to do his work correctly & completely.

Process-wise defect list:

1. Stamping:

Example: Burr, Dent, Scratch, Blank Short, Bending out, Wrinkles, Punching out, Rust etc.

2. Welding:

Example: Porosity, Blow holes, Bead offset, spatter etc

3. Machining:

Example: Unclean, Chamfer out, Burr, Dent, Scratch etc

1StampingBurr, Dent, Scratch, Blank short, Wrinkles, Punching out, Rust
2WeldingPorosity, Blow holes, Bead offset, Spatter
3MachiningUnclean, Chamfer out, Burr, Dent, Scratch

Poison Test Benefits:

  • Reduction in customer complaints
  • Reduction in house complaints
  • Improvement in inspector skill level
  • Improved customer satisfaction
  • Reduction in Cost of poor quality as defects captured in the house.
  • Multi-skilled inspector
  • Improved confidence in inspection activity
  • The final inspector’s productivity improves

Key requirements for poison test:

  • An actual poison test should be done & not prepare a fake report
  • All defects should be covered in the poison test
  • The frequency of the poison test should be adequate. For the new inspector, it should be more.

Poison Test Plan:

A poison test plan is a month-wise testing plan for inspectors. The testing frequency should be a monthly base. The poison test frequency should be in decreasing order. When an inspector joins a company, frequency should be weekly for the first 3 months then reduced to monthly. If an inspector is fully skilled then it can be quarterly based.

Poison test plan

Poison Test Format:

Poison Test Format

Poison Test Format for inspectors in Excel:

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