Technical cleanliness: writing a useful fastener requirement

Describe the contamination concern

Explain whether particles could block a passage, damage a contact surface or affect another assembly function. Identify internal bores, thread roots and other areas that matter. A generic clean-and-dry instruction does not communicate a particle limit or a verified extraction method.

Agree the method and acceptance criteria

If a recognized cleanliness framework is required, specify the applicable procedure and project criteria. State the surfaces, extraction approach, reporting and acceptance limits relevant to the part. A standard number by itself does not define all of these choices for a particular order.

Separate deburring from cleaning

Attached burrs and loose residue are different conditions. The manufacturing route should address edge condition before the agreed cleaning process. Inspection may need to evaluate both, especially at cross holes and internal intersections where visual access is limited.

Protect the result through handling

Define drying, handling and packaging appropriate to the requirement. Recontamination can occur after cleaning if the process and packing sequence are not coordinated. Include the expected condition at delivery and any restrictions on protective oil or other residues.

Specification example

For an adhesive-dispensing passage, provide the smallest relevant flow section and the contamination acceptance requirement. A cleaning process can then be reviewed against the actual passage rather than a general appearance target.

RFQ checklist

• Functional contamination concern
• Specified surfaces and passages
• Extraction and acceptance method
• Permitted residues and dryness
• Handling and packaging controls