Printed from Kezuriba (kezuriba.net/en/maintenance/press/lubrication/)

Press lubrication

Where to lubricate, oil types and viscosity (ISO VG), and replacement guide. Inspection intervals, acceptance values, and oil types follow the press manufacturer's manual and the nameplates on the machine and safety devices first. The specified self-inspection is done by a qualified person or a registered inspection company. Mounting and adjusting safety devices is work that requires special training. The legal points here were checked on 2026-10-06 against public materials from e-Gov and the Ministry of Health, Labour and Welfare (MHLW), so watch for amendments

⛽Lubrication points and oils

Location	Machine	Oil (example)	Interval guideline
Oil for wet-type friction clutches and disc brakes	Mechanical press	Oil specified by the manufacturerAcceptance criteria: no oil leaks and the oil quantity is right. The oil drawn off has no foreign matter, foaming, emulsification, discoloration, or heavy contamination	Check oil quantity, oil leaks, and oil condition at the specified self-inspection (annual)^[2](1 source, for reference)
Friction surfaces of dry-type brakes (where oil must not be applied)	Mechanical press	None (do not apply oil or grease)Article 24 of the Structural Standard for Power Presses requires a structure that keeps oil and grease off the brake surfaces (except wet brakes). The Specified Self-Inspection Standard also uses no oil on the lining as an acceptance criterion. Oil on the surface reduces braking force	Take care every time you lubricate^[3][2](1 source, for reference)
Hydraulic fluid tank (reservoir) of hydraulic presses and hydraulic press brakes	Hydraulic press	Hydraulic fluid specified by the hydraulic equipment manufacturerMoisture in the air condenses and water collects in the tank, so drain the water from the drain port when the machine is shut down (Yuken Kogyo). The Specified Self-Inspection Standard checks that the hydraulic fluid drawn off has no foreign matter, foaming, emulsification, discoloration, or heavy contamination	Watch the oil level at all times. Fluid property tests every 3 months for the first half year, then every 6 months (example of a Yuken Kogyo hydraulic unit). Drain water about once a month^[5][2]
Bearings, guides (gibs), gears (lubrication of the machine body)	Common	The oil specified in the manual. Presses use it at many points, such as bearings, guides, and gears, so general-purpose multi-purpose lubricating oil is often used (AIDA)There are cases where oil of the same viscosity grade caused trouble because of different additives, and failures from unspecified oil are not covered by warranty (AIDA). The Specified Self-Inspection Standard uses "the lubrication system functions normally and lubrication is reliable" as an acceptance criterion	Lubrication follows the model's lubrication method (centralized lubrication, etc.). Replace the oil periodically^[1][2]
Oil mist lubricator (lubricator) of pneumatic equipment	Common	Lubricator oil specified by the equipment manufacturerItems in the pre-work inspection and periodic inspection of the Guideline for Management of Press Safety Devices, and in the Specified Self-Inspection Standard (pneumatic system)	Check whether there is oil before work; check oil quantity, cloudiness, and drip rate in the periodic inspection^[4][2](1 source, for reference)

🛢Oil types and how to choose

General-purpose multi-purpose lubricating oilExpressed as ISO VG (median kinematic viscosity at 40 °C in mm²/s). The larger the number, the thicker the oil

One oil covers many points such as bearings, guides, and gears. Many are enhanced with additives. Lubricating oil degrades from sludge due to foreign matter and wear particles, water contamination, oxidation, and additive depletion, so periodic replacement is needed (AIDA)^[1](1 source, for reference)

Oil specified by the manufacturer (designated oil)

The manufacturer decides the oil type and viscosity for each press model and for each use of peripheral equipment. JFMA treats lubricating oil as one of the replacement parts and asks that it always be replaced with the manufacturer-specified oil^[1][6]

Hydraulic fluid (petroleum-based)

Transmits power in hydraulic presses and hydraulic press brakes. Example of Yuken Kogyo's oil change criteria: change when kinematic viscosity at 40 °C changes by ±10 %, total acid number changes by 0.5–1.0 mgKOH/g, or water content is 0.2 vol% or more. Contamination within NAS class 10 (ISO/DIS 4406 18/15), and a filter of 25 µm or finer in the return line is recommended. Flush thoroughly when changing brands^[5](1 source, for reference)

Oil change criteria for petroleum-based hydraulic fluid (Yuken Kogyo example)
Item	Replacement guide
Change in kinematic viscosity (40 °C)	±10 %
Change in total acid number	0.5〜1.0 mgKOH/g
Water content	0.2 vol% or more

📚Sources

Items without a mark are those on which two or more materials from different publishers agree. Values and intervals are governed by each machine's specifications. The text is summarized in Kezuriba's own words.