Uneven color, streaks or black specks: what to send your masterbatch supplier.
When a finished part or film looks different from the reference, the first useful step is a clear record. Show what happened, which materials and run were involved, and what comparison you made. An appearance issue alone does not establish its cause. This guide helps a buyer prepare evidence for a joint review; it does not diagnose the problem or prescribe machine adjustments.
Use specific, observable language.
Describe the visible issue and its location: uneven appearance across a part, a streak along a surface, or dark specks in a film. State whether it affects all checked samples or only some, and whether it was observed throughout the run or at a particular time. Separate what was directly seen from what another person reported.
Identify the expected reference and the exact difference being questioned. If a measurement was made, include the result, unit, method and conditions. Avoid replacing these details with a verdict such as “bad dispersion” unless the responsible technical review has actually established that conclusion.
Label photos and keep the physical samples.
Provide an overview of the part or film and a close-up of the area being discussed. Label each image with the sample ID, date and location. Show which sample is the reference and which is from the questioned run. Note relevant viewing conditions and any image editing, rather than presenting an edited image as the original record.
State whether the physical reference and affected samples are available for review. Agree any sample transfer with the supplier before sending it. Share only information and images you are authorized to disclose; crop out unrelated customer identifiers without hiding the observed issue.
Connect the issue to a specific run.
Record the masterbatch sample or grade and lot, base-resin grade and lot, process, finished application and trial date. List other materials included in that run, where known, and whether the recipe followed an agreed instruction. Keep requested carrier information separate from the resin used in the finished product.
If a detail is missing, mark it unknown. Do not copy information from a different order just to complete the form. A distributor can collect the processor's permitted trial record and make clear which details still need confirmation by the production team.
Explain when it appeared and what changed.
Provide the relevant production record available to you, including the operating procedure or recipe reference. Note the timing of the observation and any documented change in materials, equipment, recipe or production conditions. A timeline is more useful than a long list of possible explanations presented as facts.
If an existing production sample or another trial is used for comparison, state what was the same and what differed. Materials, handling, equipment and operating conditions may all need review. The available evidence should guide which questions to investigate; it should not be used to assign fault before the cause is established.
Ask a question the evidence can answer.
Send the issue worksheet with selected images and reference details. Ask what additional information is needed and who should review it. Record the agreed follow-up, its owner and the result. Keep any technical conclusion separate from the original observations.
Does a visible issue prove the masterbatch caused it?
No. The observation identifies something to investigate. The supplier and processor need the relevant materials and production evidence before reaching a conclusion about cause or corrective action.
Should I change machine settings to test an idea?
This guide does not recommend settings or adjustments. Any further trial should follow the responsible production team's approved procedure and equipment guidance. Record authorized changes and results so the next review has a clear comparison.
That is a useful starting point. Keep proposed explanations labeled as questions until the technical review supports a conclusion.