Cleaning Procedure for Multi mill

1.0       OBJECTIVE

1.1       To lay down a cleaning procedure for Multimill.


  • Technical Assistant – To follow the SOP.
  • Executive – To comply the SOP.

3.0         PROCEDURE:

  3.1     TYPE “A” CLEANING ( Batch to Batch Changeover):

3.1.1    Ensure that status label is updated as “TO BE CLEANED”.

3.1.2    Switch off the mains before cleaning the multimill.

3.1.3    Remove labels, materials and containers of previous batch from the processing area.

3.1.4    Remove any adhering material from the outer surface of multimill using vacuum cleaner.

3.1.5    Wipe out the adhered material from outer surface of the multimill using dry lint free cloth.

3.1.6    Record the cleaning details in equipment log sheet.

3.1.7    Take the line clearance from QA department before starting the operation.

3.2 Frequency of Type A Cleaning:

  •    Shall be performed between batch-to batch changeovers.
  •    At the end of a particular operation in the batch.
  •     At the end of the day.
  •    Before type “C”cleaning.

3.3    TYPE “C” CLEANING (Product to Product Changeover) :

3.3.1    Update the status label as “TO BE CLEANED”.

3.3.2 Switch off the mains of the multimill and cover all the electrical points with polythene cover.

3.3.3 Remove any material, labels and containers of previous product from the processing area.

3.3.4    DISMANTLING OF THE MULTI MILL PARTS: Stop the dust extraction system. Remove the feeding hopper with sliding lid and gasket by rotating the wing nuts in anticlockwise direction. Remove the multimill chamber by unlocking the ring nuts and gasket. Remove the perforated sieve (screen) and screen holding plate by rotating the ring nuts of the studs in anticlockwise direction. Remove the rotor with the blades (16 nos knife/impact edged swinging type blades and two nos of scrapper blades) by unlocking the rotor-mounting bolt from the shaft. Remove the key and retaining pins holding the blades. Transfer all the dismantled parts to the washing area after affixing “TO BE CLEANED” label.

3.3.5 CLEANING OF MAIN BODY AND AREA: Remove any adhering material to the multimill body using vacuum cleaner. Wipe the body with lint free cloth dipped in Purified water until no adherent material is seen. Finally wipe the multimill body with lint free cloth dipped in 70% IPA. Remove the polythene cover fixed to the electrical points and wipe them with dry lint free cloth. Wipe the walls, ceiling, door and glass with dry lint free cloth and mop the area with disinfectant solution.


  • Wash the parts with about 50L of purified water using nylon scrubber until no adherent material is visible.
  • Rewash the parts with about 30L of purified water.
  • Rinse the parts with about 30L of purified water.
  • Clean the gasket with purified water and then wipe with 70% IPA.
  • Dry the SS parts of the multimill in the IR drier, record the drying details in the IR drier logbook. Finally wipe with 70%IPA.
  • Transfer the cleaned and dried parts to cleaned milling area after affixing “CLEANED” label.
  • Assemble the dismantled parts in the reverse order of dismantling and update the status label as “CLEANED”.
  • Record the cleaning details in the equipment log sheet.


1.   Store the cleaned screen in a clean polythene cover and close the cover with tag and label it as “CLEANED” mentioning all the details given in the cleaned label.

2. Do not store more than one screen in one polythene cover.

3. Check the integrity of the screen before and after cleaning.

FREQUENCY of Type C Cleaning:  

  • After product-to-product changeovers.
  •   After continuous production of 6 days of the same product.
  • Major break down of equipment.
  •   If the equipment is idle for more than 30 days.

4.0         ABBREVATIONS

4.1           SS    – Stainless Steel.

4.2           QA   – Quality Assurance.

4.3           QC   – Quality Control

4.4           IR    – Infra Red

4.5           IPA  – Isopropyl Alcohol

5.0        REFERENCES


6.0       ANNEXURES


7.0       Distribution

This SOP (Controlled Copy & Display copy) shall be distributed to Manufacturing  department.

8.0       SOP Revision History record

Revision No.Details for Revision(s) with Change Control No.Effective Date (Sign. / Date)

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