Reliable in extreme heat and dirt: linear guide in the dental casting unit

The Heracast EC inductive casting unit is a laboratory unit for casting all precious metal and almost all non-precious metal and model casting dental alloys for dental applications with a liquidus point of 500 °C to over 1600 °C.
To minimise the risk of injury to the device used in dental laboratories, the moving components have been moved to the interior, where a vacuum prevails. A durable and reliable mechanism was required to open and close the pressurised chamber in which the vacuum is created. However, the special nature of the application posed various challenges. For example, the tooth alloys that are cast in the device are several hundred degrees hot, so the mechanism must be able to withstand high temperatures permanently. There is also a high level of contamination in the application. Finally, the customer was also looking for a solution that would permanently reduce the maintenance effort in order to make handling the device as easy as possible.

The design engineers at Heraeus Kulzer opted for linear rails and linear housings from our drylin® W-programme. The linear movement when opening and closing the vacuum pressure vessel significantly minimises wear on the safety-relevant closure system. In addition, this measure has enabled the rotational movement of the entire chamber to be decoupled and shifted to the interior, thus minimising the risk of injury.

Unlike conventional linear guides with recirculating ball bearings, drylin® linear bearings glide on tribologically optimised sliding foils. Thanks to the solid lubricants integrated into the plastic , no external lubricants are required that could become clogged with dust and dirt. This eliminates the associated faster wear of the bearing and the need for maintenance. The linear bearings also run particularly quietly and have high wear resistance. They are unaffected by moisture and high ambient temperatures.