RAILWAY WHEELS Machining AND CONTROL LINE
1.0 PURPOSE OF SUPPLY
A railway wheel machining and control line was designed to meet the following operations:
- a) ultrasonic test execution
- b) hardness test execution
- c) balancing test execution
- e) marking execution
In the line it was necessary to insert a railway wheel tilting station.
The equipment for the ultrasonic test, for the hardness test and for the balancing test are supplied by the Customer and have been mechanically and electrically integrated to the supplied line.
In addition to the wheel transfer system, it was necessary to design and implement the railway wheel tilting device, the drilling machine and the marking head handling robot.
The system design meets the following objectives:
- satisfy an intensive production through the automation of the whole process
- provide a simple and robust system, suitable for the environment and reliable over time
- prepare the system to be integrated into a wider automation system
2.0 PROJECT DATA
The study has considered the manipulation of the following railway wheels:
Wheel diameter 650 -1.350 mm
Wheel weight 150 – 750 Kg
3.0 DESCRIPTION OF THE SUPPLY
For logistical reasons the plant has been separated into 2 lines:
- Test table that includes the ultrasound control station and the hardness control station
- Machining table that includes the balancing station, the marking station and the drilling station.
3.1 Test table
It consists of an electro-welded structure that forms the base on which the system for moving the railway wheel is located, the wagon for positioning the hardness test station and the 90 ° tilting device for unloading the wheel from the table.
The wheel is deposited on the guides of the wheel movement system by the 90 ° tilting device of the ultrasound control station.
Wheel movement takes place in 3 sequential moments; vertical lifting, longitudinal displacement, vertical descent.
In this way the wheel is translated from the loading position to the position for the hardness test; during the descent, the wheel is guided in the correct position by references with V-shaped guidelines that ensure correct positioning. These guidelines are manually positioned during the set-up phase of the line.
At the end of the hardness test, the movement system takes another step to move the wheel to the unloading position where the 90° tilting device unloads the wheel, taking it from the vertical axis position to the horizontal axis position.
The length of the table covers the positioning of 3 wheels. The 90° loading and unloading tilting device will act simultaneously in masked time. The duration of the cycle depends on the duration of the ultrasound test.
3.2 Maching table
It consists of an electro-welded structure which forms the base on which the railway wheel movement system, the balancing station, the marking station, the system of 180 ° tilting of the wheel, the drilling station and the 90° loading and unloading tilting devices at the beginning and end of the line are placed.
The wheel is deposited on the guide of the wheel movement system from the 90° loading titling device. The same movement system takes one step to move the wheel from the loading position to the balancing station.
At the end of the balancing operation, if the wheel is not discarded, a subsequent step of the movement system transfers the wheel to the marking station and 180° tilting device. The tipper will rotate the wheel at 180° to prepare it (if necessary) for both marking and drilling. The correct positioning and locking of the wheel for marking is done by means of a self-centring spindle. A controlled 3-axis robot, one of which rotating, will carry the marking head.
A 4th axis will rotate the railway wheel.
A subsequent step of the movement system transfers the wheel to the pitch of the drilling machine. The wheel is correctly positioned and locked by a self-centring spindle. A special CNC controlled three-axis drilling machine carrying a 6-spindle revolver head performs the lamatura, the ladder hole and tapping. The controlled rotation R will guarantee the orientation of the drilling head, while the sinking is guaranteed by the controlled stroke Z. A subsequent step of the movement system transfers the wheel to the unloading position where the 90° tilting device provides for the unloading. The 90° loading tilting device is equipped with a hydraulic centring system on the wheel hub.
The length of the table covers the positioning of 5 wheels. The 90° loading and unloading tilting device will operate in masked time. The duration of the cycle depends on the duration of the drilling operation
4.0 DESCRIPTION OF STATIONS
4.1 Tilting device
The tilting devices are moved by a hydraulic cylinder. The machining table loading tilting device is equipped with hydraulically driven centring clamps. On the tilting devices, the wheel will not come into contact with metal parts that damage its surface.
4.2 Transfer device
The movement system is lift and move transfer type.
The system consists of:
– a lifting system with a vertical travel of 400mm
– a longitudinal translation system with a travel of 2,000mm.
On the movement system the wheel will not come into contact with metal parts that damage its surface.
4.3 Wagon for positioning of the hardness test station
The durometer column is fixed on the wagon. The wagon runs on the guides of the base with a travel of 1350mm.
4.4 Wheel tilting and marking station
The 180° tilting device is placed in front of the marking robot.
The tilting device consists of a portal structure anchored to the base and the gripping element has a travel of 450mm per grip as to cover the entire range of the railway wheels. The clamps take place on the wheel collar
The marking is performed by a 3-axis robot that will carry the single-punch mark. A 4th controlled axis will rotate the railway wheel. The software for controlling the writing axis is provided by SIEMENS. The travel of the horizontal X axis and the vertical lift is dimensioned to leave the overall dimensions to allow the 180° rotation and the lifting of the transfer.
4.5 Drilling station
A special CNC controlled three-axis drilling machine carrying a 6-spindle revolver head performs the fining, the pitched hole and the tapping.
The revolver head will be equipped with gear speed change gearbox for the passage from the pitched hole to the tapping.
A laser photocell system detects any breakage of the drilling bits.
A motor pump allows the circulation of the cooling liquid.
5.0 COMMAND AND CONTROL UNITS
The proposed system is equipped with 2 command and control units specific for drilling and marking plus 2 steering units for managing the functions of the individual banks. The electromechanical components are supplied by SIEMENS. The unit contains interfaces for external units – ultrasonic control, durometer and balancing machine. The supply of the communication cards only sets the tablees to be interfaced to remote stations with connection via Ethernet / Profibus.