AirSprayTech Academy

Finishing Quality—From Spec to Sign-Off | Article 04 of 28

Incoming Materials and Receiving Inspection

How to inspect substrates, coatings, powders, chemicals, and supporting materials before they become part of the finishing process.

Bad Material Does Not Improve in the Booth.

Receiving inspection is the front gate of the finishing process. If the wrong, damaged, contaminated, expired, or undocumented material passes through that gate, the rest of the line may spend the day turning an incoming problem into finished scrap.

A finishing department depends on many incoming materials. The obvious ones are paint, powder, thinner, catalyst, cleaners, and pretreatment chemicals. But quality can also be affected by the substrate, masking materials, filters, compressed-air components, abrasives, packaging, and even the condition of the containers in which materials arrive.

Receiving inspection does not mean performing every possible laboratory test on every shipment. It means confirming that the correct material arrived, that it is suitable for use, that required documentation is present, and that anything questionable is controlled before it reaches production.

Receiving Is the First Process Control

Incoming inspection is sometimes treated as a warehouse activity. In a finishing operation, it is part of process control.

A mislabeled coating, damaged bag of powder, rusted substrate, expired catalyst, contaminated chemical, or incorrect masking material can affect:

• Adhesion
• Color and gloss
• Film thickness
• Surface appearance
• Cure
• Corrosion resistance
• Chemical resistance
• Process stability
• Customer approval

Once material enters the finishing line, identifying the original cause of a defect becomes more difficult. The best time to catch an incoming problem is before the container is opened or the part is processed.

What Should Be Inspected?

The inspection plan should be based on product risk, customer requirements, supplier performance, material sensitivity, and the ability to detect problems later in the process.

Seven Steps in Receiving Inspection

1. Verify the purchase order.
   Confirm that the shipment matches the approved purchase order, including manufacturer, product identification, quantity, revision, and required documentation.
2. Inspect the shipment before opening it.
   Look for damaged containers, broken seals, water exposure, crushed packaging, leaks, punctures, corrosion, or evidence of improper handling.
3. Confirm the material identity.
   Compare labels, part numbers, colors, product codes, batch numbers, and other identification with the approved requirements.
4. Check shelf life and storage history.
   Confirm expiration dates and determine whether the material may have been exposed to damaging temperatures, moisture, freezing, or excessive heat.
5. Review required documents.
   Verify that certificates, test reports, technical information, and other required records are complete and match the shipment.
6. Perform required inspection or testing.
   Conduct the checks identified by the receiving-inspection plan before the material is released.
7. Accept, conditionally hold, or reject the material.
   Clearly identify its status and prevent questionable material from reaching production.

Inspect the Container Before the Material

The container often provides the first evidence that something may be wrong.

Look for:

• Broken or missing seals
• Dents, punctures, splits, or crushed corners
• Leaks or dried material around closures
• Water stains or moisture-damaged packaging
• Corrosion on cans, drums, or closures
• Powder escaping from bags or boxes
• Missing, damaged, or unreadable labels
• Evidence that the container was previously opened
• Cold, frozen, overheated, or otherwise unusual container condition

A damaged container does not automatically prove that the material inside is unusable. It does mean the material deserves closer inspection and should not be released without an informed decision.

Verify Identity—Do Not Trust Color Alone

Two containers can look nearly identical while holding materials with very different properties. Similar product names can also create confusion.

Verify information such as:

• Manufacturer’s name
• Complete product or material number
• Color code and color name
• Gloss or texture designation
• Component designation for multicomponent coatings
• Batch or lot number
• Manufacturing date
• Expiration or retest date
• Container quantity or weight
• Storage and handling requirements

Certificates Are Useful—but They Must Match

A certificate of analysis, certificate of conformance, material certification, or supplier test report may be required by the customer or purchase order.

Receiving personnel should verify that the document actually applies to the material received.

• Does the supplier name match?
• Does the product or material number match?
• Does the batch, lot, or heat number match?
• Does the quantity or shipment information make sense?
• Are the required test results included?
• Are the results inside the required limits?
• Is the document signed or approved when required?
• Is the certification legible and complete?

A certificate with the wrong batch number is not evidence for the material sitting on the receiving dock.

Control Shelf Life

Shelf life affects more than old cans of paint. Coatings, catalysts, sealers, adhesives, masking materials, cleaners, and pretreatment chemicals may all have useful-life limitations.

Shelf-life control should address:

• Date received
• Manufacturing date
• Expiration or retest date
• Required storage temperature
• Protection from moisture, sunlight, or freezing
• First-in, first-out inventory rotation
• Opened-container life when applicable
• Authorization required for any shelf-life extension

Do not change an expiration date because the material looks acceptable. Any extension should be supported and authorized by the appropriate manufacturer, customer, or approved quality procedure.

Incoming Substrates Need Attention Too

The coating department may receive fabricated parts that already contain defects capable of causing finishing failure.

Inspect substrates for conditions such as:

• Rust, corrosion, oxidation, or white rust
• Heavy oil, grease, drawing compound, or shop dirt
• Silicone, adhesive, marker, or unknown contamination
• Weld spatter, slag, soot, or heat scale
• Sharp edges, burrs, and difficult-to-coat recesses
• Mixed metals or unexpected substrate changes
• Water trapped in seams, tubes, or cavities
• Improperly completed grinding or fabrication
• Dents, scratches, distortion, or handling damage

The finishing line should not be expected to hide fabrication defects. Some conditions may require rework before cleaning and pretreatment can begin.

Sampling: How Much Should Be Inspected?

The inspection level should be defined rather than left to whoever happens to unload the truck.

Depending on risk and requirements, the shop may use:

• Inspection of every container or item
• A defined sample from each shipment
• A defined sample from every batch, lot, or heat
• Reduced inspection for a proven supplier
• Increased inspection after a supplier problem
• Independent laboratory testing for critical materials

Sampling plans should consider the consequences of accepting a bad lot and the possibility that a small sample may not represent the whole shipment.

Use an Approved Supplier Program

Incoming quality begins before the truck arrives. Purchasing should obtain critical materials from suppliers capable of consistently meeting the requirements.

Supplier performance may be evaluated using:

• Delivery performance
• Correct product and quantity
• Container and packaging condition
• Certificate accuracy
• Incoming rejection rate
• Production problems linked to incoming material
• Responsiveness to corrective-action requests
• Consistency from batch to batch

A supplier’s history can help determine the appropriate inspection level, but good history should not eliminate required verification.

Quarantine Questionable Material

Material that has not been accepted should be clearly identified and separated from usable inventory.

A quarantine or hold system should prevent the material from being issued accidentally while the shop investigates the problem.

The hold record should identify:

• The material and quantity
• Supplier and purchase order
• Batch, lot, or heat number
• The reason for the hold
• The person who placed it on hold
• The date of the hold
• The required review or testing
• The final disposition and authorization

Accept, Reject, Return, or Conditionally Release

Incoming material should receive a documented disposition.

Accept

The material meets the applicable requirements and is released for normal storage and use.

Reject or Return

The material does not meet requirements and will not be used. It should be controlled until returned, replaced, or disposed of properly.

Conditional Release

In unusual cases, material may be released for restricted use while a question is resolved. Conditional release should require authorization, defined limitations, traceability, and a plan for controlling affected product.

Production pressure should never become automatic approval for questionable material.

Receiving-Inspection Records

A receiving-inspection record should be detailed enough to show what was inspected and why it was accepted or rejected.

• Supplier name
• Purchase-order number
• Material or product identification
• Quantity received
• Batch, lot, heat, or serial number
• Manufacturing and expiration dates when applicable
• Container and shipment condition
• Required certificate status
• Inspection or test results
• Acceptance, rejection, or hold status
• Inspector’s name or identification
• Date of inspection
• Location of related certifications or reports

The Bottom Line

A finishing process cannot consistently produce acceptable work from materials that are unknown, incorrect, damaged, contaminated, expired, or poorly controlled.

Receiving inspection provides the first opportunity to protect the process. It verifies the material, checks its condition, confirms its documentation, establishes traceability, and prevents questionable items from reaching production.

Catching a problem at the receiving dock may require a few minutes. Discovering the same problem after cleaning, coating, curing, inspecting, stripping, recoating, and delaying an order costs considerably more.