Hybrid Zinc and Polymer Worm Gears for Industrial Automation

igus has released the Apiro HD, a hybrid gear unit designed to provide lubrication-free operation and high mechanical stability in food and beverage format changeover applications. The system utilizes a combination of advanced polymers and metal alloys to optimize industrial automation systems operating in demanding physical environments.

Resolving Impact Vulnerabilities in Polymer Drive Systems
In material handling and format changeover applications, traditional metal gearboxes often prove oversized, heavy, and reliant on continuous lubrication. While switching to high-performance plastic worm gears reduces both component weight and maintenance costs, engineering teams have historically been reluctant to deploy all-polymer solutions in environments where physical impacts from transported goods or mechanical stress could fracture the housing.

To bridge the gap between metal and plastic components, the Apiro HD utilizes a modular hybrid architecture. The internal worm gear is manufactured from self-lubricating tribopolymers, eliminating the need for applied grease or oil. Simultaneously, the external housing is constructed from a zinc-based die-cast alloy, which shields the internal polymer mechanisms from external blunt force and operational impacts.

Load Capacity and Manufacturing Tolerances
The integration of a rigid zinc alloy housing significantly increases the overall load capacity of the gear unit. The Apiro HD supports a static load of up to 70 kilograms and a dynamic load of up to 25 kilograms. Despite the metal enclosure, the internal plastic worm gear operates at a 4:1 ratio completely dry, eliminating ongoing maintenance requirements.

Giulio Ferrante, Country Manager of igus Italia, noted that the zinc die-cast enclosure was developed specifically because system designers feared that pure polymer gears could be damaged by impacts in highly demanding applications.

Furthermore, utilizing zinc for the housing provides specific manufacturing advantages over aluminum or steel. Zinc-based alloys possess a lower melting point, which reduces the energy required during the casting process and allows for highly precise, dimensionally accurate production with minimal post-machining. The resulting material maintains high mechanical strength and inherent corrosion resistance, making it suitable for the washdown environments typical of the food and beverage industry.

Additional Context
This section details technical specifications and competitive benchmarking not included in the original news release.

In the power transmission and motion control sector, standard compact worm gearboxes for food and beverage applications are typically manufactured entirely from stainless steel or aluminum with bronze and steel internal gearing (offered by manufacturers such as SEW-Eurodrive and Bonfiglioli). These traditional units require food-grade (H1) lubricants and routine maintenance to prevent gear galling and thermal wear. Conversely, pure acetal or nylon gearboxes eliminate lubrication requirements but possess significantly lower torque ratings and are susceptible to brittle fractures under shock loads.

The zinc-polymer hybrid approach of the Apiro HD competes directly with lightweight aluminum gearboxes by matching their external impact resistance. However, by retaining the self-lubricating tribopolymer internal gear, the hybrid unit eliminates the need for oil seals and H1 grease. This removes the risk of lubricant leakage onto packaging lines—a critical compliance metric in food-safe industrial automation—while substantially reducing lifecycle maintenance costs compared to equivalent all-metal gearboxes.

Edited by Aishwarya Mambet, Induportals Editor, with AI assistance.

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