Testing machines and systems for building materials - Zwick

Catalogue Testing machines and systems for building materials

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Zw/ck # Roell

Drives

Electro-mechanical drive systems

The basis of all electro-mechanical drive systems are backlash-free and low-friction ball screws and digitally controlled drive systems. They are used with load frames for test loads of up to 600 kN. Together with the digital measurement and control system they have the following advantages:

• Extremely high, stepless speed range

• Very low speeds adjustable (from about 0.5 um/min on)

• High-precision and exactly reproducible positions and speeds

The testing machines designed with single-column load frames (zwicki and BasicLine) are equipped with low-cost d.c. drives, all the others with particularly low-inertia, brushless three-phase drives.

Hydraulic drive systems

This drive unit is located centrally on the upper fixed crosshead. Thus, the test area lying beneath is easily accessible. A servo or proportional valve regulates the oil flow between the hydraulic unit and the differential cylinder. The oil cushion in the

upper pressure area avoids the "piston jump" the rams are known for after the specimen break. The resolution of the piston travel transducer is 1.25 um (less than 1/400,000 of the max. test travel). The hydraulic drive unit is the most economic solution particularly for large test loads.

Hybrid drive systems

In this patented drive unit, the advantages of the electromechanical drive (high precision) are combined with those of the hydraulic drive (high force density). The result is that even cylinders with high forces and long travels can be driven and positioned with an utmost accuracy. According to this principle 2 parallel synchronous cylinders coupled with the moving crosshead can regardless of the load applied be displaced exactly synchronously by following precisely and practically instantaneously the preselected position of an electronic pilot drive unit. The special features of this drive are the following:

• Large test stroke (no adjustment of the fixed crosshead required).

• Comparatively low height of the load frame.

Materials testing machine Z400E

Load frames and drive systems of the BasicLine


Series	Z0.5	Z005	Z010	Z020
• Type	table top	table top	table top	table top
• Max. load, kN	0.5	5	10	20
• Working area, max.
* Height, mm	596	561/1,061	1,041	1,041
* Width, mm	no limit	420	420	420
* Depth, mm	99.5	no limit	no limit	no limit
• Max. crosshead speed, mm/min	1,500	500	1,000	500
• Crosshead travel resolution, um	0.226	0.05	0.09	0.045
• Max. power consumption, kVA	0.4	0.6	0.6	0.6

Materials testing machine Z1200H