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Plasma-SealTight technology used for lock

13 October 2019

The Schmersal Group is using an innovative Plasma-SealTight technology process for the first time in a pilot project to produce its AZM300 solenoid lock.

Plasmatreat has developed a process for hybrid injection-moulded parts in cooperation with the plastic compound manufacturer AKRO-PLASTIC. This new process is said to provide a significant improvement to bonding in hybrid plastic-metal components and can be integrated into series production lines.

Used on safety doors, Schmersal Group's interlock features a metal bracket integrated into a plastic actuator. The bracket engages with an interlock cross-head to ensure that safety doors are securely closed. 

A reliable, firm bond is crucial during the joining process to produce a high-quality, resistant joint between the dissimilar materials plastic and metal. In a plastic-metal bond, interfaces without a special seal represent a constant contact surface where water, air or other media ingress. The Plasma-SealTight plasma seal process developed by Plasmatreat and AKRO-PLASTIC offers a completely new approach to providing a highly bonding, media-resistant hybrid joint. In this new industrial solution, the plastic compound formula, the process parameters, and the composition of a plasma-polymer seal layer created under atmospheric pressure were matched to one another in such a way that they would create a durable, media-tight bond in the component.

The new process is said to achieve better product quality and a reliable, reproducible, cost-efficient production process, with the added bonus of respecting the environment. Thanks to the Plasma-SealTight technology, there is no need to apply cost-intensive, environmentally harmful chemicals to metal surfaces. Such chemicals are often used to create a firm bond with the help of solvent-based adhesion promoters. 

The AZM 300 safety interlock is used in many sectors of industry. Features include a new patented operating principle with a hub and cross-head. It brings the advantage that the safety door is pulled into its end position when closed and is securely locked free of almost any clearance. The solenoid interlock operates as an integrated guard catch, hence removing the need to fit a separate catch. An RFID sensor is used to identify the actuator reliably, thus providing three different code levels and, consequently, protection against manipulation.

If the new process proves to be successful after completion of a pilot phase,  Schmersal intends to use it in both new and existing products to enhance production efficiency.