Hygienic and lubrication-free bearings in UV cleaning device for smart phones

• What was needed: drylin® W Linear bearing technology
• Requirements: a particularly quiet linear bearing was needed; no lubricants were to be used in the application; a long service life of the product had to be guaranteed
• Industry: Medical technology
• Success for the customer: drylin® W linear guides are lubrication- and maintenance-free; because the bearings glide instead of rolling, the steriliser runs particularly quietly; in addition, the bearings are insensitive to dirt and dust and represent a cost-effective and particularly flexible solution

Ultraviolet light has been used as a disinfectant for more than 30 years. A new product now uses this technology to eliminate bacteria from mobile phones, tablets and other mobile devices in 20 seconds. It is already being used worldwide in healthcare facilities, biotechnological production plants and even in food processing. The CleanSlate steriliser eliminates 99.9998 percent of MRSA bacteria in seconds.
During the initial F&E phase, it was found that the CleanSlate's UV lamps need to be switched on and warm to achieve effective sterilisation in 20 seconds. As UV light poses a risk to skin and eyes, a movable chamber had to be developed that transports the device in a movable sliding chamber into a second UV chamber for sterilisation.
Particular emphasis was placed on a quiet linear bearing to avoid disturbing patients and staff with additional noise, especially at night. In addition, no lubricants were to be used in the application, as the system is used in hospitals and food processing plants. Finally, another project planning objective was to guarantee the longest possible service life for the product, which the linear bearing should also be able to fulfil without any problems.

Initially, the project managers tried out stainless steel roller bearings. However, the contact between the metal ball bearing and the guidance resulted in noise on the carriage that exceeded the acceptable limits in hospital facilities. Furthermore, the friction caused by the movement placed additional strain on the motor and therefore the entire system. In addition, the steel bearings also failed the service life tests and only achieved 10-20 per cent of the expected service life of the product. 
Therefore, the engineers finally decided to mount and move the devices into the UV chamber with our drylin® W linear guides, which are completely lubrication- and maintenance-free. This is achieved thanks to the solid lubricants incorporated in the sliding elements. This not only fulfils the requirement to operate without lubricants. This also ensured the continued reduction of noise in the cleaning device: thanks to the use of lubrication-free sliding foils, but also because the bearings glide instead of rolling, the steriliser now runs particularly quietly.
The use of drylin® linear systems has also resulted in two further advantages: Not only are they insensitive to dirt and dust, they are also a cost-effective and particularly flexible solution.