SOP for Handling Punches and Dies

The purpose of this standard Operating Procedure (SOP) is to lay down a procedure for handling and control of punches and dies, used during compression.

This procedure is applicable for procurement, usage, cleaning, maintenance and disposal of all the punch sets (i.e. new and in use) and related testing kits, i.e. punch height checking kit and punch polishing kit used in Tablet department at manufacturing facility of Pharmaceutical Industry.

  • PROCEDURE:
    • ORDERING NEW PUNCHES AND DIES:
      • ORDERING OF NEW SET OF PUNCHES AND DIES OR ORDERING OF EXISTING PUNCH SET WITH NEW PARTY.
        • Drawing’ for Upper punch, Lower punch and Die should be prepared by the manufacturer as per the specifications given or as per sample punch set. 
        • After primary approval of the drawing, sample punch set (1Upper punch, 1 lower punch and 1 die) will be received from the supplier.
        • Department Head will approve ‘Sample punch set’ after taking a trial on the machine.
        • Standard specification of punch set for respective product is prepared after successful trial and approval of sample  write down in appropriate Annexure.
        • After approval of the ‘Sample punch set’, Purchase order for the full set of punches and dies will be initiated by the Purchase Department Head, and authorized by the Unit Head, giving following details:-
          • The total number of punches and dies required for Compression machine will be as follows.
          • Example :-  For 26 station m/c: 31 sets, For 32 station m/c: 37 sets, For 55 station m/c: 60 sets
          • Type of Tooling required e.g. D/B type.
          • Material of construction to be used (High Carbon High Chromium (HCHC) /Oil Hardened Not Shrinkable (OHNS)).
          • Engraving/laser etching of following details on individual punch
            • Serial number.
            • Name of the manufacturer (Short form) e.g. GMI for General Mechanical   Industries.
            • Date of Manufacturing (Month and Year).
            • Punch size in millimeter.
            • Any other Specifications/Special requirements like embossing, central break line,      beveled edge, chrome plating, groove on upper punches for rubber cups etc.
        • After receiving the consignment, punches and dies will be checked as per standard specification / sample punch set of respective punch set. Along with the following additional checks:-

Appearance (finishing of Punch set)

Damages (cracks/chips)

Height of punches (Working length)

Proper fitting of punches and dies on the machine

  • Record the observations in the  appropriate Annexure
    • Supplier should provide following documents with punch set :-

Drawing

Certificate of material of construction

Inspection report

  • ORDERING OF EXISTING PUNCH SET FROM SAME SUPPLIER:
    • Place the order to the manufacturer who had supplied earlier punch set   for the particular product.
    • Give one set to the manufacturer as a sample and repeat the step no. as above mentioned.
    • CHECKING OF PUNCHES AND DIES:
      • Each punch and die should be checked individually using the standard specification.
      • Check the details engraved on individual punch and die as above mentioned.  
      • For new punch set if supplier has provided all test documents then it should be taken for use after verification and QA approval based on in-house verification.
      • Checks for Punches:
        • Tip Dimension. Check individually UP and LP by vernier calliper.
        • Tip surface Check visually for scratches, damages, surface finish, cracks, pits, and spots and chrome plating (if applicable).
        • Body surface Check visually for scratches, damages, surface finish, cracks, pits, spot and chrome plating (if applicable)
        • Chamfer Check visually for angle, uniformity
        • Tips edge: Check visually for damages, cracks, sharpness and burr
        • Embossing

Check visually for letters, flattening of letters, burr, roughness, cracks and deep score.

  • Central Break Line

Check visually for position, flattening, roughness, cracks, deep score

  • Checks for Punches:Inner dimensions- Inner dimension of bore with help of vernier calliper and by inserting lower punch in it.   Inner surface, Check visually for scratches, damages, surface finish, cracks, pits, spots    and chrome plating (if applicable).Body surface, Check visually for surface finish, level uniformity, edges (both upper and lower surfaces)

NOTE: Check individual die by inserting upper and lower punch in it and check for its freeness

  • Frequency Of Checking The Punch SetWhen the punch set is new, Quality Assurance should certify the punch set. (Annexure V).   Visual checking of Punch set should be done after every batch and at the time of fixing or removing the punch set from machine.
    • PUNCH HEIGHT CHECKING:
      • Take the punch set from the punch set cabinet.
      • Clean all the upper and lower punches as per SOP and arrange them in sequence with the help of their serial numbers.
      • Assemble the punch height variation checking equipment.
      • Clean the platform of punch height checking equipment.
      • Place the Calibrated Standard Hobb (supplied along with equipment) on platform and adjust it below the dial knob.
      • Set dial indicator to ‘zero’ by rotating the dial of equipment. Recheck the ‘zero’ setting of dial indicator with standard Hob and check the height of punches as per following instructions.
      • Check the ‘Variation Working Length’ for deciding the suitability of the punch In all types of punches viz. Concave, Flat Beveled Edge etc.
      • Keep the punch in ‘Head DOWN and Tip UP’ position while checking the punch height i.e. Critical Working Length and find out the constant minimum reading on the dial by moving the tip-surface of punch against the pointer (actuator) of the dial gauge.
        • Check and record the variation in height of all punches in Annexure I Discard the punch if the difference is more than + 0.003 inch  (in case of round shaped) and +0.005 inch (in case of other than round shaped  than the standard height 133.600 mm).
        • Clean the platform and dismantle the equipment. Keep the equipment parts, dial and standard punch in the respective drawer.
        • Frequency of punch height checking is as per following table.
Punch set typePunch set lifeHeight-checking frequency
Circular4 million tabs/set2 million tabs/set
Other than circular2 million tabs/set1 million tabs/set
Double layered (circular)2 million tabs/set1 million tabs/set
Double layered (noncircular)1 million tabs/set0.5 million tabs/set

       1 set = 1 upper punch + 1 lower punch + 1 die

NOTE:

  • Punch height shall be checked as per height checking frequency or one year, whichever is earlier.
    • Always consider the minimum reading on the dial indicator, which shows the deepest point on the punch tip surface.
    • In case of embossed punch tip with break line the reading should be taken by adjusting the pointer on plain surface at the same location on each punch.
    • POLISHING OF PUNCHES AND DIES:
      • PUNCH SHOULD BE POLISHED WHEN.
        • There is burr or claw on punch tip.
        • Punch tip turns black.
        • Roughness on the tip is observed.
        • Sticking/picking problem is observed.
        • Appearance of tablet becomes dull.
      • DIE SHOULD BE POLISHED WHEN.
        • There is ring formation inside the die-bore.
        • Die-bore surface becomes black.
        • Corrosion is observed inside die-bore.
        • Wear or drag is observed in die-bore
      • POLISHING OF PUNCHES AND DIES.
Tooling typePolishing toolPolishing material
PunchesNylon brushesEmery paste
DiesFelt bobEmery paste
  • FREQUENCY OF POLISHING THE PUNCHES AND DIES:As and when required (Whenever the above problems are observed)Use the equipment for polishing of punches and dies and recommended polishing compounds as per SOP.
    • ISSUE AND RECEIPT OF PUNCHSETS:
      • ISSUING A PUNCH SET.
        • Depending on the product and the compression machine, select a punch set for issuing it to the required machine.
        • Take the punch set from Punch storage cabinet and clean the punches and dies as per SOP .
        • After cleaning, check:
          • Total number of punches and dies in the punch set.
          • Suitability for their use by checking the tip surface, body surface embossing etc. of the individual punch and die.
          • Issue the exact quantity of punches and dies for setting on the machine and store the spare/remaining punches and dies back into the respective drawer. Make the entry in punch Stock Card in  appropriate Annexure NO

Note: For uniform wear and tear of the Punches and Dies, use the tooling in rotation of 5 sets during product to product changeover or every week whichever is earlier.

E.g. For first time from 1 to 26 and next time from 6 to 31 and so on…. (Use every punch set in rotation).

  • RECEIVING A PUNCH SET FROM THE MACHINE.
    • After completion of the compression of a batch or the production plan, dismantle the punches and dies from the machine.
    • Clean the punches and dies as per SOP and check all the punches and dies individually and store them into the respective drawer of cabinet or the box by applying a thin smear of non-toxic food grade oil (as per Standards).
    • Record the number of punches and dies received in Punch Stock Card in appropriate Annexure
    • CLEANING OF PUNCHES AND DIES AND DUST CAPS:
      • CLEANING OF PUNCHES AND DIES :
        • Cleaning of the punch set shall be performed as per the SOP for cleaning of Punch & Dies
        • In case of campaign manufacturing, the punch and die set shall be cleaned after 5 batches or 3 days, whichever is earlier.
      • CLEANING OF DUST CAPS :
        • Carry the dust caps in a virgin polybag to the washing area.
        • Keep all the dust caps fully immersed in water for half hour. Scrub the dust caps, if required.
        • Clean with approx 2 kg of filtered potable water & finally rinse with purified water.
        • Dry the dust caps using filtered compressed air.
    • DISPOSAL OF PUNCH SETS:
      • Punch set to be disposed when whichever of the following is earlier.
        • Punch set should be disposed when the set becomes incomplete due to reduction in the number of upper punches/ lower punches or dies because of rejection during the usage of punch set.
        • A full set (upper punch/lower punch/die) should be disposed when it becomes unusable due to damage to the tip/head/body of the punch or die during handling and usage of the punch set or due to corrosion.
      • Procedure of disposal:
        • Collect all the defective upper punches/lower punches and dies along with incomplete punch sets, which are to be disposed..
        • Record the details of all these defective punches and dies and in Annexure III and prepare a ‘Scrap Transfer Note of all these punches and dies.
        • Deface the punches and dies with the help of grinder and transfer the punches and dies to the scrap yard and dispose them.
        • Disposal activity should be done only after approval by the Head- production/ Head – QA and Unit Head and by taking all the necessary safety precautions.
NOTE:
  • Punch trolley should be used to carry the punches and dies from storage area to compression area and back.
    • Punches should be stored in plastic sleeves.
    • Dial gauge and Standard Hobb should be calibrated at every year.
  • TRAINING:
    • As per SOP For Employee Training
  • DISTRIBUTION:
    • As per SOP ON SOP
  • ANNEXURE:

Annexure I   : Punch Height Checking Record.

Annexure II : Punch Stock Card

Annexure III  : Punches / Dies (Punch set) DestructionRecord.

Annexure IV : Standard Specification

Annexure V: Punch and Dies Certification

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