Overview
EN ISO 2818:2019 - Plastics: Preparation of test specimens by machining (ISO 2818:2018) establishes general principles and procedures for machining and notching test specimens from plastics. The standard applies to specimens taken from compression‑moulded and injection‑moulded parts, extruded sheets and plates, and partially or wholly finished products. It defines a common basis for reproducible machining conditions so that mechanical test results are comparable and representative.
Key topics and requirements
- Scope and intent: Defines agreed machining practices when specific material or test-method standards do not prescribe procedures.
- Terminology and definitions: Standardized terms for machining operations (milling, sawing, slicing, broaching, stamping, lathing, planing), and key parameters such as tool radius (R), cutting speed (vc), feed speed (vf), feed path (λ) and cutting depth (a).
- Machinery and tools: Guidance on choice and characteristics of milling cutters, circular/band saws, abrasive discs, tubular cutters, lathes, planing machines, stamping and broaching tools.
- Specimen shapes and states: Recommendations for preparing dumb‑bell, rectangular, disc‑shaped and other specimen geometries by appropriate cutting or stamping.
- Notching procedures: Methods for producing notches in finished specimens (e.g., milling, broaching) to ensure consistent stress concentrators for fracture or impact testing.
- Procedure and reproducibility: Emphasis on controlling machining variables and documenting conditions to ensure reproducible surface finish and internal structure that can affect test results.
- Test reporting: Information to be recorded in test reports to capture machining conditions and tool parameters.
Applications and users
EN ISO 2818:2019 is used wherever machined plastic specimens are required for mechanical testing:
- Test laboratories and quality control labs preparing tensile, impact, flexural or fracture specimens.
- Plastics manufacturers and processors (injection moulding, extrusion, compression moulding) establishing in‑house test protocols.
- Material developers and R&D teams evaluating additives, grades or new formulations.
- Standards writers and conformity assessors who need consistent specimen preparation rules.
The standard helps ensure that surface finish and machining-induced changes do not invalidate comparative mechanical test results.
Related standards
- ISO 2818:2018 (identical international text)
- ISO 3002‑1 and ISO 3855 (machining terminology and tool geometry references cited)
- ISO 21950 and ISO 6104 (abrasive products and disc guidance referenced)
- EN adoption: CEN endorsement as EN ISO 2818:2019, superseding earlier editions
Keywords: EN ISO 2818:2019, plastics specimen preparation, machining, milling, sawing, notching, injection‑moulded plastics, extrusion, test specimen reproducibility, surface finish.
