Modular safety guarding for flexible installation

The injection molding machine manufacturer ENGEL is improving employee safety in plastics processing with its safety guarding according to EN ISO 14120. Its modular concept supports straightforward configuration and installation. Thanks to the extensive selection of safety panels and functional elements such as control cabinets, cable ducts, and swivel and sliding doors, individual layouts can also be realized at reasonable cost.

A machine operator trips while walking through the production hall and falls against the safety guarding of a production cell. This scenario is simulated according to the EN ISO 14120 standard by a defined pendulum test with a 90 kg sandbag. Naturally the safety guarding has to withstand this test without being breached. This standard replaces the old EN 953.

EN 953 merely prescribed a “certain mechanical strength” but did not define this further. The new standard on the other hand provides concrete information on the load capacity from the outside to the inside, and defines both the test procedures and the conformity criteria. This makes it possible to compare the information from different safety guarding manufacturers.

In developing the safety guarding, ENGEL Austria GmbH set the goal of not only meeting the requirements of the new standard reliably but also improving flexibility for the user. As a provider of system solutions including injection molding machines and automation, ENGEL considers the free-standing safety guarding an essential component of the production cell. That is why the existing version of the safety guarding is being replaced by an easy to install modular solution. With the modular structure, the solution also meets future requirements arising from increasing process integration and automation.

Consistent Functional Design

The modular system is a flexible solution for the operation of individual injection molding machines with a conveyor and also for integrated and automated production cells. Individually adapted apertures with a safety tunnel make it possible to safely remove or supply any parts in the production process. The standard viewing fields consist of polycarbonate panels to ensure good visibility of the automation process. Optionally, the fields are also available with wire mesh or a combination of wire mesh and polycarbonate.

ENGEL injection molding machines and robots have a consistent, functional design. In the course of adaptation to the new standard, the machine manufacturer has also designed its own safety guarding. The experience accumulated by ENGEL over years with the previous version of the safety guarding was incorporated in development. Thus, the guarding can be installed quickly and in many cases by just one person. Connection points are provided on the injection molding machines to reliably install the safety modules.

Simplified Maintenance and Upkeep

In addition to the protective function, the design meets a variety of customer requirements. Even the standard version of the protective enclosure is easy to clean, since the ENGEL experts paid special attention to avoiding edges and slits. In combination with a corresponding options package, the safety guarding therefore meets the requirements of medical device manufacturing in general and clean room production in particular.

The recommendations of the standard for coloring were followed exactly. Thus, the dark color of the grating surfaces in the wire mesh version prevents reflections from negatively affecting the view. Stayers and door frames can also be matched to the injection molding machine or the user’s corporate design in the wire mesh version.

Thanks to its modular structure, the safety guarding is easy to expand and adapt to new requirements. The electrical engineering was optimized as well. The electronics of the safety doors are no longer installed in the door frames, but in easily accessible door connection boxes. That simplifies maintenance and upkeep.

Concealed system cable ducts on the walls of the safety guarding can be easily clipped in at the top and bottom as needed. A control cabinet with variable positioning simplifies the electrical installation. The safety guarding is easy to connect to the injection molding machine control unit with plug & play.

Voluntary Technical Testing

Having protective devices tested is not required. But ENGEL did so voluntarily. The safety guarding has been tested and approved by TÜV Austria (a technical testing organization). It is the ENGEL standard.

The Test Procedures

The EN ISO 14120 standard “Safety of machinery – Guards – General requirements for the design and construction of fixed and movable guards”, which came into effect on 1 June 2016, establishes requirements for the design and construction of protective devices intended primarily to protect people against mechanical hazards. Two test procedures take center stage. The first is a projectile test for strength against impacts at high speed from inside the hazard area, in particular for machines with rotating components that could potentially be ejected.

The second test procedure used for safety guarding of injection molding cells is a pendulum test to verify the strength against impacts from inside and outside the hazard area for soft and hard pendulums at low speed. For example, the impacts from outside the hazard area simulate a human body with a weight of 90 kg and a speed of at least 1.6 m/s. The impacts from inside the protected hazard area are simulated depending on the expected impact, using a cylindrical or spherical test specimen made of a rigid material such as steel with a corresponding mass.