ISO 7285:1995

Overview - ISO 7285:1995 (Pneumatic cylinders for mechanized multiple spot welding)

ISO 7285:1995 specifies geometrical and mechanical requirements, manufacturing, delivery and test specifications for pneumatic cylinders used on mechanized multiple spot welding machines. The standard covers double‑acting cylinders with two piston stages for the working stroke and one stage for return, nominal forces and strokes, mounting methods, electrode‑holder attachment details, performance tests and marking/delivery requirements.

Key topics and technical requirements

• Nominal characteristics
  • Standardized nominal forces (kN) at 1 MPa (10 bar) - e.g. 2.19, 2.86, 3.61, 4.61, 5.92, 7.60, 9.74.
  • Standardized nominal strokes and outside dimensions (see annex C for dimension tables).
  • Bore diameters and tolerances referenced to ISO 4394‑1.
• Operating limits
  • Maximum supply pressure: 1.6 MPa (16 bar).
  • Nominal force specified at 1 MPa with +5% tolerance; return force ≥ 40% of nominal.
• Construction and mechanical requirements
  • Anti‑rotation device must resist 150 N·m torque.
  • Seals compatible with lubricants used; surfaces protected against corrosion.
  • Electrode‑holder attachment must be electrically insulated from the cylinder body (exceptions noted).
• Mounting methods
  • Annex A defines mounting methods (A–H) and annex C gives detailed mounting dimensions.
• Marking and delivery
  • Permanent identification (alphanumeric symbol), manufacturer name, reference to ISO 7285 and rating plate data.
  • Delivery in original packing, openings stopped, corrosion protection for long storage.
• Inspection and type tests
  • Visual and dimensional inspection; perpendicularity/parallelism checks.
  • Pressure test: water at 3.2 MPa (32 bar) for 1 min (see clause 10.4).
  • Leak test: air at 0.2 MPa and 1.0 MPa while immersed - no bubbles allowed.
  • Endurance (type) test: specified cycle counts by stroke length, welding current and test setup (air supply dry, oil‑free, 1 MPa with 40 µm filtration).
  • Post‑endurance leakage and play measurement (rotation ≤ 2° under specified torque).

Applications and who uses it

• Manufacturers of pneumatic cylinders for automated welding equipment.
• Machine builders and integrators of multiple spot welding systems (automotive, metal‑assembly lines).
• Quality, testing and R&D engineers specifying cylinder performance, mounting interfaces and electrical insulation for electrode holders.
• Purchasing and compliance teams ensuring components meet international welding‑equipment standards.

Related standards

• ISO 4394‑1 (Fluid power - cylinder barrels - requirements for steel tubes with specially finished bores) - referenced for tolerances and bore requirements.
• Prepared by ISO/TC 44 (Welding and allied processes), SC 6 (Resistance welding).

Keywords: ISO 7285:1995, pneumatic cylinders, multiple spot welding, nominal force, stroke, electrode holder attachment, mounting methods, pressure test, leak test, endurance test, ISO 4394.