Installation of hydraulic cropping machine

The task

Removing flash and excess metal (fettling) from nodular iron castings.

The problem

At one foundry, cast exhaust manifolds used to be fettled by two groups of five workers using hand tools. In this process, one worker knocks off the larger pieces with a lump hammer and then puts the castings onto a conveyor. The casting is carried to three others who in turn operate a large pedestal grinder, a chipping hammer and a straight grinder. Finally a fifth person inspects the castings for any defects. The chipper and straight grinder used are types which can produce vibration magnitudes as high as 12 m/s2 and 6 m/s2 respectively. The pedestal grinder is of the type which can expose operators to magnitudes of around 10 m/s2. The exposure times were such that each operator was exposed above the exposure action value.

The solution

The company installed a hydraulic cropping machine, in which the castings are held in a fixture and the bulk of the flash is removed with a single blow from a specially made tool, pushed by a hydraulic press. Some work still has to be done with the grinders, although much less than before. The lump hammer is no longer used at all. With the new machine, a single, rotating group of six people fettle marginally more castings in a day than the two old groups together. Vibration exposure is now below the exposure action value.

Casting before fettling

Casting before fettling


Casting after fettling

Casting after fettling


Cropping machine showing castings in fixtures

Cropping machine showing castings in fixtures

The result

  • Daily vibration exposure for the operators has reduced.
  • The machine has improved quality, and produces a more consistent and neat finish.
  • Productivity has improved by about 80%.

Link URLs in this page

  1. Vibrationhttps://www.hse.gov.uk/vIBRAtIon/index.htm
  2. Hand arm vibrationhttps://www.hse.gov.uk/vIBRAtIon/hav/index.htm
  3. About this websitehttps://www.hse.gov.uk/vIBRAtIon/hav/about.htm
  4. Key messageshttps://www.hse.gov.uk/vIBRAtIon/hav/keymessages.htm
  5. Worried about your handshttps://www.hse.gov.uk/vIBRAtIon/hav/yourhands.htm
  6. Overview - Advice for employershttps://www.hse.gov.uk/vIBRAtIon/hav/advicetoemployers/index.htm
  7. Employers responsibilitieshttps://www.hse.gov.uk/vIBRAtIon/hav/advicetoemployers/responsibilities.htm
  8. Assess riskhttps://www.hse.gov.uk/vIBRAtIon/hav/advicetoemployers/assessrisks.htm
  9. Overview - How to protect workershttps://www.hse.gov.uk/vIBRAtIon/hav/advicetoemployers/protect.htm
  10. Control riskhttps://www.hse.gov.uk/vIBRAtIon/hav/advicetoemployers/controlrisks.htm
  11. Information and traininghttps://www.hse.gov.uk/vIBRAtIon/hav/advicetoemployers/information.htm
  12. Health surveillancehttps://www.hse.gov.uk/vIBRAtIon/hav/advicetoemployers/healthsurveillance.htm
  13. Overview - Good practicehttps://www.hse.gov.uk/vIBRAtIon/hav/campaign/index.htm
  14. Overview - Foundrieshttps://www.hse.gov.uk/vIBRAtIon/hav/campaign/foundries/index.htm
  15. Eliminate fettling by improving casting qualityhttps://www.hse.gov.uk/vIBRAtIon/hav/campaign/foundries/fettlingelimination.htm
  16. Machining as a substitute for fettlinghttps://www.hse.gov.uk/vIBRAtIon/hav/campaign/foundries/machining.htm
  17. Automatic fettlinghttps://www.hse.gov.uk/vIBRAtIon/hav/campaign/foundries/automaticfettling.htm
  18. Jig-mounting of grindershttps://www.hse.gov.uk/vIBRAtIon/hav/campaign/foundries/jigmounting.htm
  19. Semi-automatic cut off machinehttps://www.hse.gov.uk/vIBRAtIon/hav/campaign/foundries/cutoffmachine.htm
  20. Isolated casting cut offhttps://www.hse.gov.uk/vIBRAtIon/hav/campaign/foundries/isolatedcasting.htm
  21. Installation of hydraulic cropping machinehttps://www.hse.gov.uk/vIBRAtIon/hav/campaign/foundries/hydrauliccropping.htm
  22. Shell knockout 1https://www.hse.gov.uk/vIBRAtIon/hav/campaign/foundries/castingshell.htm
  23. Shell knockout 2https://www.hse.gov.uk/vIBRAtIon/hav/campaign/foundries/contactcastingshell.htm
  24. Hydraulic pushouthttps://www.hse.gov.uk/vIBRAtIon/hav/campaign/foundries/furnaceliningremoval.htm
  25. Ladle slag chippinghttps://www.hse.gov.uk/vIBRAtIon/hav/campaign/foundries/chippingslag.htm
  26. Overview - Constructionhttps://www.hse.gov.uk/vIBRAtIon/hav/campaign/construction/index.htm
  27. Preparing a code of practicehttps://www.hse.gov.uk/vIBRAtIon/hav/campaign/construction/tunnelling.htm
  28. Construction Industry Council guidancehttps://www.hse.gov.uk/vIBRAtIon/hav/campaign/construction/cicguidance.htm
  29. Mounted breakerhttps://www.hse.gov.uk/vIBRAtIon/hav/campaign/construction/mountedroadbreaker.htm
  30. Directional drillinghttps://www.hse.gov.uk/vIBRAtIon/hav/campaign/construction/directionaldrilling.htm
  31. Crushing concretehttps://www.hse.gov.uk/vIBRAtIon/hav/campaign/construction/crushingconcrete.htm
  32. Bursting concretehttps://www.hse.gov.uk/vIBRAtIon/hav/campaign/construction/burstingconcrete.htm
  33. Diamond wire cuttinghttps://www.hse.gov.uk/vIBRAtIon/hav/campaign/construction/diamondwire.htm
  34. Water jettinghttps://www.hse.gov.uk/vIBRAtIon/hav/campaign/construction/waterjetting.htm
  35. Codes of Practice from the Water Jetting Associationhttps://www.hse.gov.uk/vIBRAtIon/hav/campaign/construction/codeofpractice.htm
  36. Grit blastinghttps://www.hse.gov.uk/vIBRAtIon/hav/campaign/construction/gritblasting.htm
  37. Paint-on retarderhttps://www.hse.gov.uk/vIBRAtIon/hav/campaign/construction/paintonmaterial.htm
  38. Special formworkhttps://www.hse.gov.uk/vIBRAtIon/hav/campaign/construction/specialformwork.htm
  39. Overview - Steel fabricationhttps://www.hse.gov.uk/vIBRAtIon/hav/campaign/fabrication/index.htm
  40. Machininghttps://www.hse.gov.uk/vIBRAtIon/hav/campaign/fabrication/cncmachining.htm
  41. Laser cuttinghttps://www.hse.gov.uk/vIBRAtIon/hav/campaign/fabrication/lasercutter.htm
  42. Plasma cuttinghttps://www.hse.gov.uk/vIBRAtIon/hav/campaign/fabrication/plasmacutting.htm
  43. Noise reduction in the ship repair industry – research report 1992https://www.hse.gov.uk/vIBRAtIon/hav/campaign/fabrication/noisereduction.htm
  44. Abrasive blastershttps://www.hse.gov.uk/vIBRAtIon/hav/campaign/fabrication/abrasiveblasters.htm
  45. Overview - Regulationshttps://www.hse.gov.uk/vIBRAtIon/hav/regulations.htm
  46. Inspector briefinghttps://www.hse.gov.uk/vIBRAtIon/hav/inspectorbriefing.htm
  47. Overview - Resourceshttps://www.hse.gov.uk/vIBRAtIon/hav/information.htm
  48. Publicationshttps://www.hse.gov.uk/vIBRAtIon/hav/publications.htm
  49. Researchhttps://www.hse.gov.uk/vIBRAtIon/hav/research.htm
  50. Statisticshttps://www.hse.gov.uk/vIBRAtIon/hav/statistics.htm
  51. Useful linkshttps://www.hse.gov.uk/vIBRAtIon/hav/links.htm
  52. Vibration calculatorhttps://www.hse.gov.uk/vIBRAtIon/hav/calculator-guide.htm
  53. Overview - Case studieshttps://www.hse.gov.uk/vIBRAtIon/hav/casestudies/index.htm
  54. (HAVS) in two motor companieshttps://www.hse.gov.uk/vIBRAtIon/hav/casestudies/enforceex.htm
  55. Monitoring exposure to Hand-Arm Vibrationhttps://www.hse.gov.uk/vIBRAtIon/hav/casestudies/mhav-carlwest.htm
  56. Overview - Supply project eventshttps://www.hse.gov.uk/vIBRAtIon/hav/project-events.htm
  57. Controlling vibrationhttps://www.hse.gov.uk/vIBRAtIon/hav/controlling-vibration.htm
  58. Q & A on hand toolshttps://www.hse.gov.uk/vIBRAtIon/hav/hand-tools-qa.htm
  59. Q & A on using a vibration consultanthttps://www.hse.gov.uk/vIBRAtIon/hav/qa-consultant.htm
  60. Q & A on health surveillancehttps://www.hse.gov.uk/vIBRAtIon/hav/qa-surveillance.htm

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Updated: 2021-05-20