Fully Integrated Sheet and Strip Metal Testing Autogrid System Model 142-20
Electro-hydraulic sheet metal testing with automatic strain analysis based on grid patterns
This Testing Machine can be used not only to perform effortlessly, quickly and accurately all important and known deep drawing tests for ferrous and non-ferrous metals, but it is also designed for a large number of additional technological investigations. The Testing Machine is driven electro-hydraulically. The test sequence can be controlled automatically or manually, as desired.
A programme logic control is used to control the functions of the machine. Drawing force and blankholder force as well as the drawing punch stroke are displayed digitally. The triple-acting hydraulic system in conjunction with the general design results in the following cost saving simplifications. In this Sheet and Strip Metal Testing Machine the sheet holder force control is realised in proportional valve technology with differential pressure measurement. The drawing speed is also regulated through proportional valve technology. Therefore allowing a much finer and more stable adjustment of the parameters. The Sheet and Strip Metal Testing Machine, Model 142, was developed not only for testing as a means for continuous production control, using standardised and other established methods, but also for research into all aspects of testing of sheet metal for deep drawing, due to the precise data acquisiton of all parameters during testing.
We provide the AutoGrid® system solution for strain analysis in sheet metal industry. Based upon the automatic evaluation of grid patterns that consist of printed or electrochemically- marked orthogonal lines spaced at 1 to 5 mm, the system is able to determine a field of strain values on specimens or components very rapidly. Strains of more than 100 % can be measured with high accuracy and reliability (up to 0.1%).
The AutoGrid® solution uses four CCD cameras that are mounted in a fixed position on the measuring jig. All four cameras observing the specimen from different perspective views are exactly synchronized and the image sequences are recorded with a rate of up to 30 x 4 frames per second. Electronic shuttering is combined with the progressive scanning mode of the cameras to avoid any blur or disturbance due to the object motion. In addition, the corresponding data of the testing machine (force, path, pressure) are also recorded and related to the image sequence. In case of the testing velocity of 1-2 mm/sec, a punch depth resolution of less than 0.05 mm can be achieved. Recording can be started automatically by thresholds in time, machine force or punch displacement, respectively.
This approach allows the time-resolved analysis of forming processes whenever the area of interest is optically accessable. In particular the determination of forming limit curves (FLC) takes advantage of this operation mode providing significant benefit both in time and costs. Directly connected to the testing machine, the systems gives precise access to the maximum strain value just before necking and subsequent cracking occurs. Comfortable software allows to create FLC's from a set of specimens very effectively. The in-process capability of AutoGrid® can of course also be used e.g. for bulge or tensile tests.
The AutoGrid® solution is unique with respect to the fact that it solves two tasks with exactly the same instrumentation: measuring material's properties and analysing formed parts. Thus, quality assurance requirements are fulfilled that call for unified measuring solutions.
|Technical Specifications for Fully Integrated Sheet and Strip Metal Testing Autogrid - Model 142-20|
|Drawing force||200 kN|
|Blanking force||265 kN|
|Blankholder force||up to 100 kN|
|Drawing punch stroke||approx. 80 mm|
|Blankholder stroke||approx. 38 mm|
|Drawing punch dia.||up to 50 mm|
|Drawing punch dia. (FLC)||up to 100 mm|
|Blank dia.||up to 120 mm|
|Drawing speed||approx. 1.100 mm/min|
|Digital displays / resolution|
|Drawing punch stroke||0.1 mm (on request 0.01 mm)|
|Drawing force||0.1 kN|
|Blankholder force||0.1 kN|