Plastics manufacturing can leave fines behind probes and colour at a common outlet even after pellets have discharged. The product owner decides whether recovered regrind is reusable or quarantined; the cleaning record identifies its source. The shift record should also note any purge material and where it was held.
Residue may remain in feeders, filters and transfer lines. Identify which areas are included in the cleaning request and which will be handled by the site.
Clean the route used by both grades
Follow pellets, powders and fines through the retention points shared by the outgoing and incoming products.
Follow pellets and powder into the outlet: The site records resin, filler or additive history and any heat or moisture event. The contractor maps ledges, cone surfaces and discharge equipment. Recovered material remains tied to the correct product and silo reference.
Pellets, regrind, additives and fine powder
Plastic raw materials vary from free-flowing pellets to dusty regrind and fine additives. Product shape, static, moisture and repeated grade changes can affect where residue collects. Send the material grade, colour, previous contents and the specific contamination or flow problem.
Internal probes, filters, air systems and liners create predictable blind spots for direct cleaning. Drawings and earlier photographs help identify those positions. If the concern is a colour or polymer change, the included walls, cone and connected transfer points need to be named. The grade, colour and presence of regrind or additives decide where material removed from the wall can go. The product owner chooses whether it can return to stock or must be quarantined, and the cleaning record identifies the source of each recovered stream.
Read about powder silo cleaning and use planning around product changeovers when contamination between grades is the main concern.
The site should provide its existing controls for static, fine dust and hazardous areas where relevant. Cleaning equipment is reviewed against those conditions and the actual product form. A method used for pellets should not be assumed suitable for a fine additive powder.
Include the filling connection, extraction and discharge route on the drawing. These components may introduce old material after the wall is cleaned unless their condition and responsibility are addressed in the grade-change plan.
The product owner decides whether recovered pellets stay separated by grade or go into quarantine. The receiving containers and labels should be ready before cleaning releases mixed or uncertain material.
The quality check should say whether the next grade can accept residual colour or fines, and identify the site’s separate sampling or approval check before refilling.
Pellets and powders may need different equipment because particle size, dust, static, compaction and the required grade-change finish all affect the method.
Which plastic grades should appear in the enquiry. List the grade currently in the silo, the previous grade where relevant and the material intended next, including whether each is pellet, regrind or powder.
Product information, dust controls, isolation and the site’s return-to-service process must be confirmed before work begins.