For nearly one century, the ANSI B11 standards have minimized the inherent risks of machinery that come with processing materials. In doing so, these machine guarding standards have helped reduce the accidental misdirection of released energy during production, maintenance, commissioning, and de-commissioning. A new standard in the ANSI B11 series continues this trend: ANSI B11.27-2020: Safety Requirements For Electro Discharge Machines.
About ANSI B11.27-2020
Where traditional machine techniques are too difficult (for example, with hard metals), electro discharge machine (EDM) equipment (also known as electrical discharge machining) is used. EDM can cut intricate contours or cavities in pre-hardened steel and alloys (eg. titanium, hastelloy, kovar, and Inconel) without the need for heat treatment to soften and re-harden the material. As this nonconventional form of machining incorporates the removal of material within a dielectric fluid by electro-discharges to obtain a desired shape, it requires unique safety considerations to minimize the risks associated with its use.
In meeting this need, ANSI B11.27-2020 specifies safety requirements and/or risk reduction measures for EDM equipment and EDM systems. It is applicable to manually controlled die sinking and drilling machines and numerically controlled die sinking, drilling machines, and wire cutting machines. For these systems and equipment, the standard addresses hazardous conditions during the use and foreseeable misuse in normal environments and non-explosive atmospheres. It also covers associated machine tasks, including transportation, installation, maintenance, repair, and dismantling for removal or disposal.
This standard is also applicable to auxiliary devices essential for EDM processing, and it features some important information to be provided by the supplier to the user. Please note, however, that ANSI B11.27-2020 is not applicable to arc eroding and electro-chemical machining equipment.
Relationship Between ANSI B11.27-2020 and ISO 28881
Those who work with electro discharge machines are likely already familiar with the international standard ISO 28881:2022 – Machine Tools – Safety – Electro-Discharge Machines and might want to know more about the relationship with existing document and the new American National Standard ANSI B11.27-2020.
The reasoning behind creating a U.S. safety standard for EDMS is that while these machines are not currently manufactured in the U.S., they remain in wide use throughout the nation. With this in mind, the B11 Standards Developing Committee (B11 SDC) began developing a Type-C standard for EDMs, using ISO 28881 as a template document.
As mentioned in the Foreword of ANSI B11.27-2020, two very important distinctions exist between it and ISO 28881:
“ISO standards only address manufacturer (supplier) requirements whereas ANSI B11 standards address both supplier AND user requirements
ISO standards only address machines made after the approval date of the standard whereas ANSI B11 standards address both new machines AND existing ‘legacy’ machines.”
Furthermore, it is stated that:
“while compliance with ANSI B11.27 would automatically confer compliance with ISO 28881, however, compliance with ISO 28881 requirements would fall short of meeting the additional requirements for the North American market and that are contained in ANSI B11.27 since there are no ‘user requirements’ in ISO 28881.”
About the ANSI B11 Standards
As the newest B11 standard, ANSI B11.27-2020 joins another 30+ documents, which began with the publication of the safety requirements for power presses in 1922. Since then, B11 Standards, Inc., an ANSI-accredited standards developing organization (SDO), has administered the process to develop this series of American National Standards, along with several technical reports, and, as the requirements have expanded, as has the relationship between the various documents, which adhere to the ISO Type A-B-C structure for machinery standards.
In fact, ANSI B11.27-2020, which is a type-C standard, was developed to integrate with the broader B11.0 (type-A) standard on general safety/risk assessment and the B11.19 (type-B) standard on risk reduction measures.
ANSI B11.27-2020 and the other ANSI B11 standards were written and developed to eliminate or minimize risks through appropriate machine design, by restricting personnel or other individuals’ access to hazard zones, and by devising work procedures to minimize personnel exposure to hazardous situations.
ANSI B11.27-2020: Safety Requirements For Electro Discharge Machines and the other ANSI B11 standards are available on the ANSI Webstore. Users in need of all these documents can get them together with a 50% discount as the ANSI B11. Machine Tools Safety Package.
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