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:
Example: Burr, Dent, Scratch, Blank Short, Bending out, Wrinkles, Punching out, Rust etc.
Example: Porosity, Blow holes, Bead offset, spatter etc
Example: Unclean, Chamfer out, Burr, Dent, Scratch etc
|1||Stamping||Burr, Dent, Scratch, Blank short, Wrinkles, Punching out, Rust|
|2||Welding||Porosity, Blow holes, Bead offset, Spatter|
|3||Machining||Unclean, 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.