Drop Tower Machines

MPM manufactures drop tower test machines for a wide variety of impact tests. The MPM drop tower systems can be configured to satisfy several ASTM standards including: ASTM E23, E208, E436, D3763, D256, D2444, and D6110. In addition to the above listed ASTM standards, MPM drop towers can be constructed to meet API standards such as the API recommended practice 5L3. The MPM basic tower design is easily modified to accommodate special impact testing needs. Recent examples include towers for circuit board testing and a tower that was designed for testing explosive materials.

The drop tower shown in Figure 1 is configured for the ASTM D3763 puncture test. This machine includes the automatic drop height control system, an instrumented striker, a velocity measurement transducer, a pneumatic specimen clamp (see photograph under "Test Configuration"), an initial velocity launcher, and a safety enclosure. In Figure 2, the tower shown is a combination drop tower which includes hail impact simulation and high velocity The drop tower shown in Figure 3 is for the study of explosive materials and is also equipped with an instrumented striker and the automatic drop height control system.

System Features

If requested, the MPM drop tower test machines can be provided with instrumented strikers. An instrumented striker option is used in applications that require measurement of absorbed energy. However, some of the standards listed in the introduction, such as ASTM E436 and API 5L3, are focused on dynamic tear measurement and do not require the use of an instrumented striker. Some important features of the MPM drop tower are listed below:

Rigid frame construction and precision bearings minimize transverse play of the rail cart
The test machine can be provided with an electrically driven motor for raising the rail cart to the desired drop height
The test machine can set the drop height automatically under computer control and the machine is also equipped with a digital readout and hand control to accurately set the drop height manually
The test machine is equipped with a computer-controlled rail cart release and also includes a push button pneumatic release for manual control
The base of the test machine is enclosed inside a six-foot tall polycarbonate enclosure with an interlocked door for safety during testing. The door is designed to permit easy access to the test machine specimen support
The test machine includes a pneumatically controlled safety plate to protect the operator while working around the test machine base
Test machines that satisfy ASTM E208 and E436 are provided with excess test capacity with energy levels of up to 4,000 ft-lbs
Test machines that are equipped with an instrumented striker have the following additional features:
- Up to 1,000,000 data points per test
- Data acquisition ranges from microseconds up to 100 milliseconds (longer acquisition times available)
- User friendly software controls acquisition and data analysis
- High speed, 12-bit acquisition board
- Strain gage amplifier
- Instrumented striker
- Hardware/Software manual
- Software

Please refer to our Instrumented Impact Testing and In-Situ Heating & Cooling web pages for further information.

Test Configuration

The MPM drop tower test machine design can accommodate various test geometries such as dynamic tensile, Charpy, Izod, and impact penetration. The test machine base is a solid plate with an attachment connection that enables the various test specimen configurations to be quickly and easily set up. The striker tip is a threaded connection to the rail cart and can be quickly and easily attached. The rail cart allows for easy addition and removal of weights for energy capacity adjustment.

In addition, special purpose configurations can be provided. MPM has recently built drop towers to study: printed circuit board component fracture, explosive material properties, seat belt buckle shock characteristics, and battery impact fracture resistance.

System Upgrades

Existing test machines can be upgraded by addition of the MPM state-of-the-art equipment including: instrumented striker systems; impact velocity measurement systems; in-situ heating and cooling systems; high velocity launchers; no second strike components; and automatic rail cart drop height positioning systems. MPM will assemble the system and provide a field installation and calibration if desired.

Please refer to our Refurbished Equipment web page for information on reconditioned equipment.