Replacement gears withstand high loads in use

• What was needed: Special load-bearing gears for the repair of servomotors in the roof turrets of large airport fire engines
• Manufacturing process: Laser sintering
• Requirements: cost-effective, highly resilient
• Material: iglidur® i3
• Industry: Commercial vehicles
• Success through co-operation: The gears withstand the high load trade show and were used for the repair of other vehicles. The company was thus able to avoid the cost-intensive replacement of the entire servomotors.

The Fraport AG plant fire brigade provides fire protection at Frankfurt am Main Airport. Its large airport fire engines are equipped with roof turrets that change the angle of the spray nozzle via a servomotor. As this change in height also takes place while water is being discharged, the servomotor is subject to a high load. After ten years of use, the gears installed in them are worn out, which is why the roof turrets need to be repaired.

Roof turrets of large airport fire engines have to withstand intense loads while discharging water

Frankfurt Airport is Germany's largest commercial airport. It is also one of the leading international airports in Europe in terms of passenger and cargo traffic. With almost 81,000 employees in around 450 companies, it is the largest local workplace in Germany and an attractive centre of attraction for other companies in the economically important Rhine-Main region. With the high density of aircraft, commercial and private vehicles, the airport fire service is always busy. In order to comply with the legally prescribed response times, the fire service must be able to reach any location on the apron within three minutes. The personnel and technical equipment of the three fire stations located on the airport site is correspondingly important.

The more than 115 fire engines on the airport site include fourteen large airport fire engines. With their roof turrets, they can throw at least 5,300 litres of water more than 80 metres in just one minute. The load on the actuators of these roof turrets is correspondingly high, as they control the height of the water jet by changing the angle.

Printed gears made of iglidur® i3: Successfully in use in large airport fire engines

Two special gears made of robust plastic are installed in the servomotor. After ten years in use, these were worn, which made maintenance of the roof turrets necessary. The vehicle manufacturer advised the maintenance technicians to replace the entire servomotor - but this was associated with high costs. Instead of replacing the complete and otherwise fully functional servomotor, the design engineers decided to explore new avenues: after researching the Internet, they discovered the possibility of manufacturing durable gears using 3D printing at igus® and decided to test the wear-resistant plastic iglidur® i3. The gear was designed using the freely available online CAD configurator for gear, which can be used to quickly and easily design templates for 3D printing gear.

The SLS manufacturing process took less than 3 days, so the fire brigade was able to quickly move on to testing the new gear. The tests showed that the iglidur® i3 gears were up to the high load. Accordingly, the maintenance technicians were able to reorder gear for further vehicles. Enthusiastic about the quality of the materials and the fast and uncomplicated service, they immediately had another component printed and tested that controls the pneumatic doors of the large airport fire engines - with success. This printed application also met the requirements and is now in use in the fire service fleet at Frankfurt Airport.

Why print gears from iglidur® i3?

The iglidur® plastic specially developed for the production of moving machine parts is characterised by a particularly high abrasion resistance and the incorporated solid lubricants. They are used for the production of components by means of injection moulding, additive manufacturing and mechanical machining of bar stock. iglidur ® i3 was developed as a plastic powder for production in laser sintering and is characterised by high wear resistance and strength. It is not without reason that this material is the undisputed bestseller among the 3D printing materials from igus®.

Thanks to its mechanical specification, iglidur® i3 is particularly suitable for spur and bevel gears as well as for all other types of gear moulds. iglidur ® i6 is only recommended for 3D-jerked worm gears, as this plastic was developed for increased sliding properties. How long a printed gear made of iglidur ® i3 will last under the given application parameters can be determined quickly and easily online in the gear-service life calculator. The particularly high service life of gears made of iglidur ® i3 compared to conventional plastic gears was undefined.

One of the biggest advantages of manufacturing gears in 3D printing is the flexibility with regard to the tooth root geometry. The tooth root radius can be optimised, thus improving the service life of the gear. In mechanical production, such optimisation is generally not possible due to the tool size. To design gears directly with the optimised tooth root radius, we recommend using our free CAD configurator.