Safety in Gear Cutting Machine Maintenance Work

⚠What laws and standards require

• Ordinance on Industrial Safety and Health (Japan), Articles 107 and 108 (Stopping operation when cleaning, and when cleaning the cutting part)

  For cleaning, lubricating, inspecting, repairing or adjusting a machine, and for cleaning, inspecting, repairing, replacing or adjusting the cutting part, stop the machine when there is danger, and lock the starting device and attach a sign so that no one but the worker can operate it. When clearing chips from a running cutting part or applying cutting fluid, have workers use a tool such as a brush

  Hob and cutter changes, arbor centering, clearing chips from flutes, and cleaning tanks and mist collectors are done only after stopping and locking and tagging out (lockout/tagout). Release the residual pressure of hydraulic clamping and anti-backlash devices. When several people work, each person applies their own lock (MHLW material, OSHA)^[1][2][3]

• Ordinance on Industrial Safety and Health (Japan), Articles 110 and 111 (Wearing work caps; prohibition of gloves)

  Where hair or clothing could be caught in a power-driven machine, workers must wear work caps and work clothes. Where a rotating cutter could catch a hand, workers must not wear gloves

  The examples in the text are drilling machines and chamfering machines. The same idea applies to work near a rotating hob or cutter^[1](1 source, for reference)

• Ordinance on Industrial Safety and Health (Japan), Articles 28 and 29 (Keeping safety devices effective)

  The employer inspects and maintains covers and safety devices and keeps them effective. Workers must not remove safety devices or disable them. When one is removed temporarily, permission is needed, and it is restored immediately after the work

  DGUV likewise requires using the protective measures (protective devices) the builder specifies and not disabling them, and not using the machine if a safety-related defect is found^[1][4]

• Ordinance on Industrial Safety and Health (Japan), Articles 105 and 106 (Preventing danger from flying workpieces and chips)

  Where fragments of the workpiece or chips could fly and create danger, provide covers or enclosures on the machine. Where the nature of the work makes that difficult, have workers use protective equipment

  The covers and doors of a gear cutting machine also serve to stop chips from scattering and mist from leaking^[1](1 source, for reference)

• JMTBA, “Fire Safety Guidelines for Machine Tools (for Users)” (Technical Document 60-2014)

  Use water-soluble cutting fluid wherever possible (except for easily ignited metals such as magnesium). If oil-based fluid is used, recognize the higher fire risk, monitor periodically even during unattended operation, and provide an automatic fire extinguishing system together with fire detection, alarm and extinguishing equipment at the installation site. When switching from water-soluble to oil-based fluid, always contact the machine builder and take measures such as a larger-capacity pump, a mist collector, an automatic fire extinguishing system and checking the safety data sheet

  DGUV also calls for fire prevention first, before extinguishing systems (low-emission fluids, labyrinth seals on doors, exhaust). The DGUV 2024 document lists safety functions such as keeping the door locked once a fire is detected, stopping the cutting fluid supply, stopping or isolating the exhaust, and stopping machining and the chip conveyor^[5][4][6]

• Fire Service Act (Japan) Articles 9-4 and 10, and Cabinet Order on Control of Hazardous Materials Appended Tables 3 and 4 (classification of cutting fluids as hazardous materials)

  The class of a water-insoluble cutting oil is set by its flash point: Class 3 Petroleums (flash point 70℃ to under 200℃, designated quantity 2,000 L for water-insoluble), Class 4 Petroleums (200℃ to under 250℃, 6,000 L), and flash point 250℃ or higher is a designated combustible, combustible liquids (2 m³ or more). Hazardous materials at or above the designated quantity may not be stored or handled anywhere other than a licensed storage or handling facility. Standards for storing and handling hazardous materials below the designated quantity and designated combustibles are set by municipal ordinances

  When handling hazardous materials of different names or designated quantities in the same place, if the sum of each quantity divided by its designated quantity is 1 or more, it is treated as at or above the designated quantity (Fire Service Act Article 10). JMTBA asks that the Fire Service Act, fire prevention ordinances and the guidance of the local fire department be followed in preference to its guidelines. Lubricant makers' product material states the Fire Service Act class (example: ENEOS's high-flash-point type is Class 4 Petroleums)^[7][8][5][9]

• Ordinance on Industrial Safety and Health (Japan), Article 289 (Fire extinguishing equipment) and Article 288 (Restricted entry, etc.)

  In places that handle hazardous materials, or flammable oils and other items that could cause a fire even if not hazardous materials, provide fire extinguishing equipment suited to the scale and the materials at suitable locations. In places with fire or explosion risk, display a prohibition on the use of open flame

  JMTBA also asks for fire detection, alarm devices and extinguishing equipment where the machine is installed, in case the automatic fire extinguishing system fails to put out a fire^[1][5]

• Inspection and operation of the automatic fire extinguishing system

  At delivery, attend the extinguishing system's start-up test and the release of the discharge-stop function after the test, and confirm that it is in the normal monitoring state. Teach operators the daily inspection and emergency procedures. Have the maker carry out periodic inspections within the interval it recommends (JMTBA)

  Under German regulations, the function of the extinguishing system is checked at least once a year, an expert inspection is done at least every 2 years, and records are kept for at least 4 years (DGUV). Optical fire sensors also react to flashing light (lighters, welding), so avoid using these nearby (DGUV)^[5][4]

• What to do when a fire occurs

  Flames can suddenly burst out through openings such as door gaps. Opening the door before the machine has cooled lets in air and causes explosive re-ignition. CO2 extinguishing gas risks suffocation in a small, poorly ventilated room. Oil-soaked work clothes burn easily. After a fire, the metal parts of the machine are hot, and burnt cables risk electric shock (DGUV)

  JMTBA asks that when a fire occurs, however small the damage, you contact the local fire department and follow its instructions, leave the machine untouched and photograph the scene until the cause is known, and report to the machine builder and the extinguishing system maker^[4][6][5]

• ISO 19353:2019 Safety of machinery: Fire prevention and protection

  Specifies how to identify fire hazards arising from machinery and carry out risk assessment, and the approach to prevention and protection measures at the design and manufacturing stages. A guide to reducing fire risk through machine design, risk assessment and instructions to users

  DGUV says fire prevention measures for machine tools are given in Annex E of this standard (choice of fluid, labyrinth seals on doors, exhaust and extinguishing systems)^[10][6]

The legal provisions are summarized in Kezuriba's own words. Check the exact wording against the original text in e-Gov Law Search.