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| Specifications for the TTST Series of |
| Tension/Compression/Torsion Testing Machines |
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| Revised: April 17, 2000 |
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| Introduction |
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| The TTST Series comprise four different capacities of computer controlled table top mounted testing machines for performing rotational torsion testing and tension/compression testing. These were primarily designed for performing rotational torque rupture testing on circular cross section wire with the capability of maintaining a constant axial load on the wire as the rotations were applied. The Model TT-100 software used with these machines was designed for this specific application. The flexibility of the software control package also allows the TTST series of machines to be used for a wide variety of applications in Quality Control, Research and Development testing of other products and components, and for applications in Education demonstrations of mechanical properties of a wide variety of materials. Additional software packages are also available for performing uniaxial tension/compression tests, constant load creep tests, and low cyclic fatigue testing for fatigue cycling applications at testing frequencies < 1 Hz. |
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| CAUTION: Axial testing may be performed up to 25 kN (5,600 lb) with |
| tension/compression rated load cells. Depending upon the load |
| cells purchased with the machine, the tension/torsion/compression |
| load cells available may not be rated in tension to the maximum |
| axial capability of the particular machine. Please contact ATM |
| with information on your exact testing requirements for the TTST |
| series machines and we will recommend the proper load cell for |
| your testing purposes. |
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| The torsion loading of the TTST Series machines is provided by a DC servo electric motor with encoder feedback operating in a closed loop control mode for accurate speed control. The motor speed is mechanically reduced to drive the rotary output shaft which protrudes through the platen of the testing machine. Optional loading grips such as three jaw chuck types can be mounted on this shaft. The movement of the crosshead is controlled by a second mechanically speed reduced DC servo motor with encoder feedback. Figure 1 shows an overall view of the TTST-25KN testing machine complete with a computer control system. The TTST-25KN requires a 486DX or Pentium based IBM PC compatible type computer system for control. The system speed should be 25 MHz or faster for optimum response. A Microsoft DOS 5.0 or higher, Winclows95, or Windows98 operating system is required to run the ATM software. The software will not run under WindowsNT or Windows2000. |
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| Views of typical setups for the TTST-25KN for performing rotational torsion and tension tests are shown in Figure 2 and Figure 3 . Figure 2 shows an axial load cell mounted on the lower surface of the crosshead. The upper circular adapter plate (UCAP) is attached to the lower surface of the axial load cell to which the torsion load cell is attached. The upper optional three jaw rotary grip is connected to the lower surface of a torsion load cell using the lower circular adapter plate (LCAP). Figure 2 shows a circular specimen in place between the optional rotary grips. Figure 3 shows the suggested arrangement for performing tension tests. For tension testing, the upper rotary grip and the torsion load cell and the UCAP have been removed to mount the optional tensile grip. The upper tensile grip is mounted to the lower surface of the axial load cell using a short mounting stud. As shown in Figure 3 the lower rotary grip does not require removal for performing tensile testing. An axial loading structure consisting of four chrome plated steel posts are threaded onto the top surface of the platen. The axial loading plate is then mounted on top of the steel posts. The lower tensile grip is then mounted on the axial loading plate. |
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| In addition, other testing grips such as compression platens are also available for performing other types of tests. |
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| Mechanical Specifications |
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| The diagram and table in Figure 4 shows the major dimensions of the TTST |
| Series machines and the main part locations. A summary of the mechanical specifications are given as follows: |
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| 1. Rotational Test Speed Range: |
| 0.005 - 0.62 rad / s (0.05 - 6 RPM) at full capacity |
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| 2. Axial Loading Range: |
| Low Speed Clutch: 0.05 - 75 mm / rnin at rated capacity |
| (0.002 - 3.0 in / min at rated capcity) |
| TTST-65KN only: 0.05 - 50 mm / min at rated capacity |
| (0.002 - 2.0 in / min at rated capcity |
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| High Speed Clutch: 0.50 - 500 mm/min at 20% rated capacity |
| (0.020 - 20 in /min at 20% rated capacity) |
| TTST-65KN only: 0.05 - 305 mm / min at 20% rated capacity |
| (0.002 - 12 in / min at 20% rated capcity) |
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| 3. 76 cm (30 in) maximum specimen length. Note that this length can vary |
| depending upon the arrangement of grips and load cells used with the |
| testing machine. |
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| 4. Torsion loading is provided by a a speed reduced output shaft from a gearbox |
| protruding through the platen. The optional lower torsion loading rotary grip is |
| mounted on this shaft. A DC servo motor is used to drive the input shaft of |
| the gearbox. The loading mechanism of the crosshead consists of two ball |
| screws protruding through the platen of the test machine whi.ch drives two |
| linear ball nuts mounted on the lower surface of the crosshead.The crosshead |
| moves vertically between the ball screws. The lower ends of the ball screws |
| are mechanically coupled to a DC servo motor |
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| 5. The two drive motors are DC servo motors with rear shaft mounted encoders. |
| The encoders are used for output shaft angular position and angular speed |
| calculations for the rotary shaft and for calculating the crosshead position and |
| linear speed calculations for axial loading. Power Requirements: 110-120 VAC, |
| 60 Hz, 1 phase. |
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| Note: All Specifications and Dimensions are Subject to |
| Modifications without prior Notice |
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| Motor Control System |
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| The motor control system requires an IBM compatible 486DX or Pentium type PC system with a color VGA monitor, hard drive, 3.5 inch 1.44 MB high density floppy drive, and minimum 1 MB RAM. Two unused XT type expansion slots on the mother board are required for the control and data acquisition cards. For report printouts, a Hewlett Packard Series 600 Deskjet printer (ie. Model 692C, 695C, 697C, etc.) or Panasonic 24 pin dot matrix printer (ie. Model KX-P2023) is required. A 386DX type IBM compatible PC may also be used but data acquisition speed will be considerably reduced. The ATM software requires Microsoft DOS Version 5.0 or higher, Windows95, or Windows98 as the operating system. The ATM software will not function under WindowsNT or Windows2000. The software packages run under DOS and should be run under the Real DOS mode if using Windows95 or Windows98. The motor control hardware consists of two XT type expansion boards, a motor control electronics system, and a combined DC and AC conditioners system. The two XT expansion boards consists of a 12 bits resolution A/D / D/A / I/0 board and a two channel servo motor controller board. The servo motor controller board uses the encoder feedback signals from the two DC servo motors and software commands to produce the motor control system command signals. The motor control system consists of two separate DC power supplies for powering the two servo amplifiers which provide the motor control current to the two DC servo motor. |
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| Manual rotational control of the output rotary shaft and positioning of the crosshead is provided by use of two toggle switches mounted on the Base Unit front panel as shown in the diagram of Figure 4. The left toggle switch labelled Up/Forward and Down/Reverse is used to move the crosshead up or down or to move the rotary output in either the forward or reverse direction. The right toggle switch is used for selecting Fast or Slow speed during the manual position movement. The speeds corresponding to Fast and Slow are set independently in the software for both the rotary output and the crosshead speed. |
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| Computer data acquisition is performed using a 12 bit A/D D/A I/0 expansion board. This board mounts in one of the PC bus XT type card slots. There is provision on the board for changing the board address location by means of a DIP switch. If this is required, a data file in the software must be modified for the new address location. The female DB subminiature type 25 contact connector on the rear of the data acquisition board connects using a "Straight Thru" style cable directly to the AC/DC conditioner board mounted in the base of the testing machine. The data acquisition board supplies the +15 VDC and +5 VDC power required for operation of the AC/DC conditioner circuit board. The A/D input and D/A output ranges are set at -/+10 VDC. Two D/A outputs and an I/0 signal are available via BNC connections on the TTST Series Base Unit's rear panel. These are not used in the standard ATM software packages but are intended for use in customized versions of the ATM software and for future applications. The amplified outputs of the AC/DC conditioner board are connected to the data acquisition card through the main cable. |
| A circuit board containing two DC and two AC conditioners is located in the Base Unit. All of the input connections from the rear panel and front mounted Manual Control switches are made to this board through connectors. The DC conditioners can be used for excitation and amplification of the ATM line of full Wheatstone bridge type of load cells or extensometers. The AC conditioners are used for excitation and amplification of LVDT (linearly variable displacement transducer) and RVDT (rotary variable displacement transducer) type devices including certain types of extensometers and other position feedback transducers. The 15 turn potentiometers accessible through a slot in the Base Unit right side panel are used for the 2 DC conditioners for electrical adjustment of the Gain, Input Offset (In OS), and Output Offset (Out OS) adjust. The AC conditioners have potentiometers for adjustment of the + Offset (+OS), - Offset (-OS), and Gain. In addition, the DC conditioners have a push button Calibration Check (Cal Chk) switch for a quick check of correct DC conditioner calibration. In the typical setup of the TTST Series machines, the DC conditioner 1 is used for the axial load cell signal and the DC conditioner 2 is used for the torsion load cell signal. In systems supplied with an extensometer for use with the Model TC-100 Tension/Compression software package, the DC conditioner 2 is also used for amplification of the extensometer signal. |
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| Computer Software Descrilption |
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| The TT-100 software package included with the TTST Series machines is used for performing torsion/constant axial load testing. This software features a user friendly control environment for setup and control of the machine. A brief description of the software is given as follows. |
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| Figure 5 is a sample Main screen of the TT-100 software and shows the current data set displayed on an X-Y graph. When the software is started, the current system configuration and data set displayed are that which were current at the previous software shutdown. This configuration and data set are stored in the TESTBAK.000 file. The maximum and minimum values of the current data set are displayed in the Present Data box located in the upper left hand corner of the screen. The Limits Status Box located beneath the Present Data box will indicate if the axial or torsion load or other limits are currently being exceeded. The Current Test box consists of a series of screens of data which shows test parameters such as test speed, sampling rate, static axial load to be applied, and specimen material type and dimensions. The different screens for the Current Test box are accessed in the Main Screen configuration using the < UP > arrow key. The lower right portion of the screen displays the command descriptions of the keyboard function keys Fl to F8 and the < RIGHT > arrow key. The < RIGHT > arrow key is used to select a second set of command descriptions for the Fl to F8 keys. The clutch speed for the crosshead speed range is selected with the < F12 > function key. Its current setting is shown in a small box above the function keys box to the right of the screen. |
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| The design of the system software allows maximum flexibility for making changes to the testing configuration. The Operator can make changes to the display screen with the < F7 > Change Setup key with minimum disruption of the background display. |
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| Up to 100 data sets can be stored in the directory which contains the software. The data file TESTS.NAM contains a listing of the data sets that are available for display. The test results are stored in a filename which is either manually entered by the Operator or automatically generated by the software. The resulting files are stored for future use by the software for performing data analysis. The Operator may load and erase stored data files from within the program. Performing replicate tests is easily accomplished with a minimal amount of Operator adjustments. The system features the software selectable F2 Zero Offsets command for removing any offset axial load or torsion load represented by changes in the test grips or test setup. An Automatic Return at end of test teature,may be selected which automatically or on Operator input returns the crosshead and rotary output shaft to their positions at the start of the test. |
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| During a test, the results are displayed in Real-Time to the monitor on an X-Y plot. The current value of the individual point being displayed is updated during the test in the Present Data box. The test is stopped at a preselected end point determined by such parameters as maximum time limit, rotations limit, detection of specimen breakage, % axial load drop, or by the operator pressing the <Esc> key. The maximum torsion load, rotations at maximum load, and time are displayed at the end of the test. At test completion, after the test data has been stored to a data file, the Operator may scroll through the individual data points using the F5 Trace Test Curve function with the < LEFT > and < RIGHT > arrow keys. Also, the data may be replotted by changing the axes scales or with different Engineering Units and the resultant data stored under a different filename. The F8 Data Functions key may be used to display multiple data sets for comparison, storing data sets, or erasing stored data sets. |
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| For testing ease, the Operator may also store up to 100 test setups by use of the F6 Test Setups key. When a test setup is loaded, the current data on the screen is automatically reconfigured to the new test axes and Engineering Units in the test setup. |
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| Other software features include the capability of printing one page summary test reports on a Hewlett Packard 600 or 800 Series DeskJet printer (ie. Model 692C, 695C, 697C, 832C, etc.) or a Panasonic 24 pin dot matrix printer (ie. Model KX- P2023). Figure 6 shows a sample test report. The Operator may change the axes scales of the graph and view the results on the monitor before printout. The test report contains information such as the material type, date and time of test, Test Operator identification, number of test points, applied axial load, maximum test torque, etc. The test report can also be configured to exclude the X-Y plot of the test data. |
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| Optional Features |
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| Additional features may be supplied with the TTST Series of machines to enhance their capabilities. Some of these are listed as follows: |
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| a) Safety Shields for Front and Rear (Option TTSTxxxx.SAF) |
| The TTST series machines may be supplied with clear safety shields for the front and/or rear working area of the systems. The safety shield package consists of two side panels and two front hinged panels of 3/8 in (9.5 mm) thick clear polycarbonate sheet. The shield design ensures a large enclosed working distance for specialized setups. The side panels are approximately 4 in (10 cm) wide and do not open. The hinged doors are secured in place by sliding bolts. |
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| The safety shield package includes two hinged door panels, two side panels, and mounting hardware. A complete package is used to enclose each of the front and rear working areas of the system. Price of each package includes factory installation of the safety shields on the machine when ordered with the TTST Series machine. |
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| b) Bellows Covers on Ball Screws (Option TTSTxxxx.BSC) |
| The standard TTST series machines include an upright sheet metal protective panel around three surfaces of the ball screws. For dusty environments, ATM can supply the TTST machines with bellows over the ball screws to prevent dust from coating the ball screws which may cause premature wear. This option is a factory installed modification and should be ordered with the system. |
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| In addition to the listed options, ATM can provide additional modifications to the standard machines to accommodate specific requirements. Some of these options included safety door mounted limit switches to shut off the motor, increased working distance between the ball screws, longer travel length, very low speed range for ultra low speed control applications, and others. Please contact us with your additional requirements. |
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| Accessories |
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| A wide range of accessories such as test grips and fixtures can be provided by ATM to allow testing of many different sample types or customer products. The following lists some of the items that are available from ATM. |
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| a) Extensometers |
| ATM can provide linear, diametral, biaxial, non contact laser type,and rotary type extensometers for room temperature and elevated temperature testing conditions. They are available in a wide range of deflections for use with the ATM line of software and test equipment. Please contact ATM for your specific requirements for extensometry equipment. |
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| b) Material Testing Grips |
| An extensive line of material testing grips such as rotary grips with 3, 4, and 6 jaw chucks, wedge loading tensile grips, clevis grips, compression plates, 3 and 4 point bending fixtures, and others can be provided. Special high temperature grips for ceramics testing are also available. ATM can also custom design test grips or test fixtures to test component parts. Please contact ATM for all your test fixture requirements. |
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| c) High Temperature Test Ovens |
| ATM can supply split tubular or box type testing ovens in a range of temperatures up to 1200 F and a very high temperature line for materials testing up to a maximum temperature capability of 2800 F. These models mount on swing arms which will attach directly to an upright post mounted on a TTST Series machine for this application. When not in use, the swing arms permit the oven to be swung completely out of the way of the load train. |
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| d) Environmental Chambers |
| Low temperature environmental chambers with temperature and/or humidity control are also available. These chambers are of mainly stainless steel construction and are designed with the same accessibility as the test ovens. Depending on the size of the chamber, they are either mounted on the TTST Series machine by use of swivel arms or are separately attached by use of other means such as a roll out platform. |
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| e) Customized Electronics Packages |
| The ATM line of DC and AC conditioners may also be supplied in rack mounted versions for excitation and amplification of multiple source Wheatstone bridge type device input signals. Other manufacturer's load cells and extensometers may also be adapted for use with ATM equipment. Please contact ATM for further details. |
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