A Sacmi Group company and a leading designer of machines and complete plants for the tableware sector, German firm Sama Machinenbau has supplied Chinese company Dalian – one of the biggest local producers of ceramic insulators – with a high-tech. automated, efficient, high performance machine designed to execute bending tests on large-size high voltage insulators.
These tests employ Sama-developed testing technology to ensure the items have a bending strength that complies with established standards. This testing solution has several advantages. Firstly, there is a high degree of automation, with fully automatic insulator loading/unloading. Another advantage is that the insulator is attached to the test machine by way of automatic clamps that fix the insulator in the wedges.
What really makes the difference is the test software, which start automatically as soon as the insulator is gripped. The machine, designed to test items up to a maximum length of 3 m and a maximum weight of 300 kg, can bend, during testing, diameter areas of up to 400 mm and exert a force of 150 kNm.
More specifically, the machine process consists of exerting a bending force on both extremities of the insulator by way of a hydraulic cylinder. This stage gives significant advantages in terms of flexibility, as both the rate of force application and bending strength can be personalised according to the customer’s specific needs. The same “bending leverage” can easily be adjusted manually in compliance with specific standards.
Different bending strengths can also be set for each side of the insulator: when the machine reaches the maximum pre-set bending strength, the process stops, the clamps open automatically and the item is rotated 5° (or multiples thereof) around the median axis. The test is repeated on each segment and ends when the insulator has completed a full rotation around its own axis.
The result? A comprehensive, multi-parameter analytical report that can be enclosed with the insulator itself to certify quality. Note also that insulator unloading is fully automatic, thus optimising the quantity of insulators that can be tested by the machine per unit of time and minimising labour requirements.