m be certain. Series 646 Hydraulic Collet Grips Product Information Model 646.10 Model 646.
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Contents Technical Support 5 How to Get Technical Support Before You Contact MTS 5 5 If You Contact MTS by Phone 7 Problem Submittal Form in MTS Manuals 8 Preface 9 Before You Begin Conventions 9 10 Documentation Conventions 10 Introduction 13 Series 646 Hydraulic Collet Grips Component Identification About Series 646 Hydraulic Collet Grips About Gripping Specimens Collet Sets Couplings 16 16 16 Spiral Washers Specifications 14 16 17 18 Series 646 Hydraulic Collet Grips Dimensions 18
Installation 33 646 Hydraulic Grip Lift Points About Axial Grip Installation 33 34 Axial Grip Installation Procedure 36 About Axial-Torsional Grip Installation 40 Axial Torsional Grip Installation Procedure Grip Alignment 41 45 How to Preload the Spiral Washers 45 Grip Water Cooling Assembly Configurations for Servohydraulic Frames 48 Operation 51 Determine the Gripping Pressure Grip Alignment Markings 52 54 Installing a Collet for a Round Specimen Installing a Collet for a Flat Specimen 55
Technical Support How to Get Technical Support Start with your manuals The manuals supplied by MTS provide most of the information you need to use and maintain your equipment. If your equipment includes software, look for online help and README files that contain additional product information. If you cannot find answers to your technical questions from these sources, you can use the Internet, e-mail, telephone, or fax to contact MTS for assistance. Technical support methods www.mts.
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Preface Before You Begin Safety first! Other MTS manuals Before you use your MTS product or system, read and understand the Safety manual and any other safety information provided with your system. Improper installation, operation, or maintenance can result in hazardous conditions that can cause severe personal injury or death, or damage to your equipment and specimen. Again, read and understand the safety information provided with your system before you continue.
Conventions Conventions Documentation Conventions The following paragraphs describe some of the conventions that are used in your MTS manuals. Hazard conventions Hazard notices may be embedded in this manual. These notices contain safety information that is specific to the activity to be performed. Hazard notices immediately precede the step or procedure that may lead to an associated hazard. Read all hazard notices carefully and follow all directions and recommendations.
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Conventions 12 Preface Series 646 Hydraulic Collet Grips
Introduction MTS Series 646 Hydraulic Collet Grips grasp and hold a specimen in place during testing, and provide a constant, hydraulically actuated gripping force regardless of the applied test loads. They are designed to perform in a wide variety of testing applications including high and low cycle fatigue, tension, and compression testing.
Series 646 Hydraulic Collet Grips Component Identification Force Transducer (attached to the load unit crosshead) Shim Adapter Plate Spiral Washers Threaded Mounting Stud Collets Threaded Mounting Stud Spiral Washers Upper Coupling Upper Grip Hydraulic Pressure and Return Ports Lower Grip Lower Coupling Actuator Rod Shim Load Unit Base Plate Axial Grip Mounting 14 Introduction Axial/Torsional Grip Mounting Series 646 Hydraulic Collet Grips
Hydraulic Grip Components ITEM DESCRIPTION Load unit crosshead and base plate Provides the structure to mount the grips and other components in the force train. It is also the reaction mass for the force train. The crosshead and base plate are connected with columns. Force transducer Measures the axial forces applied to the specimen. An axial-torsional version also measures the rotational forces applied to the specimen. The force transducer can be located in the base or the crosshead of the load unit.
About Series 646 Hydraulic Collet Grips The Series 646 Hydraulic Collet Grips are mounted in a load unit to secure the specimen under test. Hydraulic pressure to the grips is supplied by an external hydraulic grip supply. Grip Housing Collet Hydraulic Release Port Hydraulic Pressure Port Grip Piston Preload Chamber Grip Cross Section About Gripping Specimens The grips provide a constant, hydraulically actuated gripping force regardless of the applied test loads.
distributed between the surfaces of the spiral washers and the stud in a ratio of the relative stiffness of the parts. The spiral washers have a large surface area and therefore greater stiffness. They react to most of the load and keep the stress in the stud below its fatigue runout level. Couplings Special upper and lower couplings clamp the grips to the actuator and force transducer for axial-torsional grips.
Specifications Specifications Contents Series 646 Hydraulic Collet Grips Dimensions 18 Series 646 Hydraulic Collet Grips Force and Torque Capacities 20 Series 646 Hydraulic Collet Grips Specifications—Round Specimens Series 646 Hydraulic Collet Grips Specifications—Flat Specimens 22 23 Series 646 Hydraulic Collet Grips Specifications—Threaded Specimens 24 Series 646 Hydraulic Collet Grips Dimensions The following sections provide the dimensions of the Series 646 Hydraulic Collet Grips.
Specifications Model 646 Grip with Furnace Extensions Dimensions Mounting holes in the base of each grip are threaded in either SI International (millimeter) or U.S. Customary (inch) thread dimensions, as shown for dimension “A” in the pervious table. PARAMETER DIMENSION* A (mounting threads) M27 x 2mm or 1 in–14 B 172 mm (6.77 in) C 224 mm (8.80 in) D 115 mm (4.52 in) E (wrench flats) 29 mm (1.125 in) F (travel) 3.2 mm (0.125 in) G (specimen adapter wrench flats) 32 mm (1.
Specifications Series 646 Hydraulic Collet Grips Force and Torque Capacities The amount of torque the grips can produce is reduced with biaxial operation. The amount of torque is affected by the amount of axial force and the size of the specimen. The following graphs illustrate the axial-torsional performance envelope of the Model 646.10 and Model 646.25 Hydraulic Collet Grips. Series 646 Collet Grip Specifications MODEL AXIAL CAPACITY* TORSIONAL CAPACITY* WEIGHT 646.
Specifications 20000 Specimen Diameter .25 " dia .375" dia .5" dia .75" dia 20 mm dia Torque (in-lbs) 15000 10000 5000 22000 20000 18000 16000 14000 12000 10000 8000 6000 4000 2000 0 Force (lbs) Model 646.25 Maximum Torque versus Axial Load Note Series 646 Hydraulic Collet Grips The Series 646.25 Axial-Torsional Grips are capable of holding full torque and full load with specimen sizes greater than 24.6 mm (0.97 in).
Specifications Series 646 Hydraulic Collet Grips Specifications—Round Specimens SI METRIC MODEL U.S. CUSTOMARY D* X L PART NUMBER D* X L PART NUMBER 646.10 8 x 30 mm 038-058-904 0.25 x 1.2 in. 038-058-905 646.10 12 x 30 mm 038-058-903 0.375 x 1.2 in. 038-058-906 646.10 15 x 30 mm 038-058-902 0.5 x 1.2 in. 038-058-907 646.10 30 x 30 mm 038-058-901 1.0 x 1.2 in. 038-058-908 646.25 20 x 58 mm 038-059-203 0.5 x 2.3 in. 038-059-205 646.25 30 x 58 mm 038-059-204 0.75 x 2.3 in.
Specifications Series 646 Hydraulic Collet Grips Specifications—Flat Specimens SI METRIC MODEL U.S. CUSTOMARY T X W X L* PART NUMBER T X W X L* PART NUMBER 646.10 1.5 x 6.0 x 25 mm 038-059-104 0.0625 x 0.25 x 1.0 in 038-059-101 646.10 3.0 x 12 x 25 mm 038-059-105 0.125 x 0.5 x 1.0 in 038-059-102 646.10 6.0 x 24 x 25 mm 038-059-106 0.25 x 1.0 x 1.0 in 038-059-103 646.25 - - 0.25 x 1.0 x 2.2 in 038-059-301 646.25 - - 0.375 x 1.5 x 2.2 in 038-059-302 646.25 - - 0.5 x 2.0 x 2.
Specifications Series 646 Hydraulic Collet Grips Specifications—Threaded Specimens SI METRIC MODEL U.S. CUSTOMARY THREAD L* PART NUMBER THREAD L* PART NUMBER 646.10 M6 x 1 mm 11 mm 038-059-004 1/4-20 UNC-2A 0.44 in 038-059-001 646.10 M10 x 1.5 mm 16 mm 038-059-005 3/8-16 UNC-2A 0.62 in 038-059-002 646.10 M16 x 2 mm 25 mm 038-059-006 1/2-13 UNC-2A 0.81 in 038-059-003 * The tolerance for the length (L) is ±0.762 mm (±0.03 in).
Safety Information General Safety Practices: Grips and Fixtures Typically, grips and fixtures are part of equipment used in MTS testing systems. This section provides general information about safety issues that pertain to systems that use grips and fixtures.
of the hazards that apply to your system at all times. Use these safety guidelines to help learn and identify hazards so that you can establish appropriate training and operating procedures and acquire appropriate safety equipment (such as gloves, goggles, and hearing protection).
Locate and read hazard placards/labels Find, read, and follow the hazard placard instructions located on the equipment. These placards are placed strategically on the equipment to call attention to areas such as known crush points, electrical voltage, and high pressure hazards. Know facility safe procedures Most facilities have internal procedures and rules regarding safe practices within the facility. Be aware of these safe practices and incorporate them into your daily operation of the system.
Remove flammable fluids Remove flammable fluids from their containers or from components before you install the container or component. If desired, you can replace the flammable fluid with a non-flammable fluid to maintain the proper proportion of weight and balance. Check bolt ratings and torques To ensure a reliable product, fasteners (such as bolts and tie rods) used in MTSmanufactured systems are torqued to specific requirements.
Wear appropriate personal protection Wear eye protection when you work with high-pressure hydraulic fluid, breakable specimens, or when anything characteristic to the specimen could break apart. Wear ear protection when you work near electric motors, pumps, or other devices that generate high noise levels. Some systems can create sound pressure levels that exceed 70 dbA during operation.
hydraulic pressure to dissipate before you remove and replace the hose or any pressurized component. Stay clear of moving equipment/avoid crush points Stay clear of mechanical linkages, connecting cables, and hoses that move because you can get pinched, crushed, tangled, or dragged along with the equipment. High forces generated by the system can pinch, cut, or crush anything in the path of the equipment and cause serious injury. Stay clear of any potential crush points.
text that describes the hazard, the potential result if the hazard is ignored, and general instructions about how to avoid the hazard. The following label is typically located on the grip. DESCRIPTION LABEL 646 Hydraulic Collet Grip Force Capacity: 100 kN / 22 kip Max Operating Pressure: 45 MPa / 6,500 psi Model No. Serial No. Part No. Rev. Level MTS Systems Corporation 14000 Technology Drive Eden Prairie MN U.S.A. 55344-2247 Grip PN 5213251-01 Part # 513251-01 Grip ID label.
Safety Information Series 646 Hydraulic Collet Grips
Installation This section describes how to install and align the Series 646 Hydraulic Collet Grips.
About Axial Grip Installation Installing the grips in a load unit force train involves attaching one grip onto the end of the actuator rod and one grip to the force transducer. The grips are mounted to the load unit with connector studs. The following figure shows the components used for most installations.
Required equipment Equipment and materials required to install the grips include: • Molykote G·n paste lubricant. • Each grip model/load unit combination has a unique attachment kit. The appropriate attachment kit includes an installation drawing that shows what components should be installed. • Adequately sized wood blocks or plywood sheet (or equivalent). • A lifting device and appropriately sized double swivel eyebolts, as needed.
Shims If a specific orientation of the grips is required, shims are typically used to achieve that desired orientation. Use the following table to determine the proper shims. Axial Grip Installation Procedure The following procedure assumes the actuator is mounted in the base of the load unit and the force transducer is mounted to the crosshead. If you have a load unit with the actuator mounted to the crosshead, make the appropriate changes to the following procedure.
Note Although it is possible for the grips to be installed by one person, MTS recommends using two people to lift, handle, and position the grips. 1. Set up the load unit. A. Turn on the system hydraulic pressure. B. Adjust the actuator and crosshead position as necessary to allow adequate room to install the grips. C. Turn the hydraulic pressure off. Ensure that system hydraulic pressure has been reduced to zero before proceeding. D. Clean and lubricate the mounting studs.
D. Position the lower grip to align it with the actuator rod. You might need to stabilize the grip over the actuator. • Place appropriately sized wood blocks across the load unit base plate, on opposite sides of the actuator piston rod. • For heavy grips, insert the double swivel eyebolts into the threaded holes provided on the grip chamber. Attach a lifting device to the double swivel eyebolts and carefully raise the grip. Important NO STANDARD EYEBOLTS should be used to lift the grip. E.
F. Turn on hydraulic pressure and slowly raise the lower grip until the stud on the upper grip just makes contact with the force transducer. Reposition the grip, as necessary, for proper thread alignment. G. Slowly screw the grip into the force transducer until it is snug. 4. Align the grips. Once the grips are lightly tightened, check the alignment between the upper and lower grips. The rotational alignment is critical when you use collets for flat specimens.
About Axial-Torsional Grip Installation Installing the grips in a load unit force train involves attaching one grip onto the end of the actuator rod and one grip to the force transducer or crosshead. The grips are mounted to the load unit with axial/torsional couplings. The following figure shows the components used for most installations.
Required equipment Equipment and materials required to install the grips include: • Molykote G·n paste lubricant • Each grip model/load unit combination has a unique attachment kit. The appropriate attachment kit includes an installation drawing that shows what components should be installed. • Adequately sized wood blocks or plywood sheet (or equivalent). • A lifting device and appropriately sized double swivel eyebolts as needed.
Note The label on the coupling indentifies which component should be connected to each side of the coupling. Each end of the coupling has different threads. C. Turn on hydraulic pressure and raise the actuator rod until it is in full contact with the end of the grip. Reposition the grip, as necessary, to center it over the actuator rod. D. Select the lower grip coupling set. Place the lower grip coupling half with the threaded holes against the actuator and grip threads.
8 1 5 4 3 6 2 7 Torque the socket head screws first to 10%, then to 50%, and finally to 100% of the torque specified on the attachment kit drawing. C. Note D. Note Remove the socket head cap screws from the upper coupling and place the screws and coupling halves within easy reach and oriented properly for installation on the grips. The label on the coupling indentifies which component should be connected to each side of the coupling.
G. Select the upper coupling set. Place the coupling half with the threaded holes against the adapter and grip threads. Rotate it back and forth, as necessary, until the threads mesh with the actuator and grip threads. H. Place the other coupling half against the actuator and grip threads. While holding the two halves together, thread the socket head cap screws into the coupling until they are finger tight. I.
Grip Alignment This section describes how to align the rotation of the grips. The following information applies only to the axial grips because you can adjust the actuator rotation with the axial-torsional grips. The grips can be rotated several ways: with spiral washers, shim washers, and it might be possible to rotate the actuator rod to achieve the desired orientation. Spiral washers can offer up to 30° of rotation. They are also used to preload the connector studs to prevent backlash.
WARNING The next step may apply a force greater than the force train capacity. Exceeding the tensile load capacity of any element in the force train can cause equipment damage or personal injury. It is necessary to temporarily exceed the tensile load capacity; this is accomplished by increasing the output pressure of the HPU. 6. Apply a static tensile force 10 to 20% higher than the maximum force to be applied during testing.
7. Using spanner wrenches, rotate the two halves of the spiral washers in opposite directions to tighten them as shown in the following figure. The opening between the washers must not exceed an arc of 30° from the closed position. If more than a 30° arc is created: A. Remove the tensile load from the specimen. B. Remove the specimen (see the appropriate procedure). C. Tighten the grips on the mounting studs, or place a shim on the stud. D. Repeat Steps 5 through 7 of this procedure.
Grip Water Cooling Assembly Configurations for Servohydraulic Frames Cut hoses to required length at installation. MTS provides a hose (quantity 1) with the water cooling assembly for connection to the water service. See the following table for the hose length provided by MTS. The water cooling manifold will mount to any flat 9” x 8” (229 mm x 203 mm) magnetic surface. PART NUMBER HOSE LENGTH FOR WATER SERVICE SUPPLIED BY MTS (QUANTITY 1) 057-697-501 none 057-697-502 12 ft (3.
Water Tubing Routing (Top View) Water Tubing Routing (Back View) Series 646 Hydraulic Collet Grips Installation 49
Installation Series 646 Hydraulic Collet Grips
Operation This section describes how to use the Series 646 Hydraulic Collet Grips Contents Determine the Gripping Pressure Grip Alignment Markings 52 54 Installing a Collet for a Round Specimen Installing a Collet for a Flat Specimen 55 56 Installing a Collet for a Threaded Specimen Installing a Round or Flat Specimen Installing a Threaded Specimen Adjust Water Cooling Flow Removing Specimen Basic operation Grip controls 57 59 60 62 63 Operation of the hydraulic wedge grips consists of the f
Determine the Gripping Pressure The amount of hydraulic pressure to be applied to the grips must be sufficient to prevent backlash between the specimen ends and the specimen adapters, and also between the mating threads of the specimen adapters and the grip extensions, during all parts of the loading cycle.
Required Pressure for the Applied Force Series 646 Hydraulic Collet Grips Operation 53
Grip Alignment Markings The following figure shows how to identify the alignment marks on the surface of the grip.
Installing a Collet for a Round Specimen To install a collet assembly for a round specimen into the grip housing: Spanner Wrench Holes Top View Alignment Mark Coat the threads on the collet with Molykote G-n paste Cutaway Side View Bumper Collet Retainer Socket Head Cap Screw Round Collet 1. Ensure that the grips are in the release condition and that hydraulic pressure is turned off. 2.
Installing a Collet for a Flat Specimen To install a collet assembly for a flat specimen into the grip housing: Alignment Mark Top View Spanner Wrench Holes Coat the threads on the collet with Molykote G-n paste Cutaway Side View Rubber Platen Flat Collet 1. Ensure that the grips are in the release condition and that hydraulic pressure is turned off. 2. Clean the specimen contacting surfaces of the collet with acetone or any other volatile solvent that does not leave a residue. 3.
Installing a Collet for a Threaded Specimen Important The 646 Hydraulic Collet grip has a very small amount of grip stroke. Specimen size and placement is critical to ensure proper specimen preload. Failure to follow the proper procedure will result in force and displacement disruptions, premature specimen failure, and possibly grip failure. 1. Put both grips in the fully released position. Place the control valve in the “release” position with hydraulic power to the load frame.
Spanner Wrench Holes Top View Alignment Mark Retainer Collet (coat the sides with Molykote G-n paste) Cutaway Side View Threaded Insert Preload Platen (coat the sides with Molykote G-n paste) Retainer Screw Threaded Collet This procedure describes how to install threaded collets. 1. Ensure that the grips are in the release condition and that hydraulic pressure is turned off. 2.
Installing a Round or Flat Specimen To install a round or flat specimen into the appropriate collet assembly: Prerequisite Procedure This procedure assumes that the proper collet has been selected and is installed. 1. Adjust the hydraulic grip supply pressure to the minimum level. 2. Select system force control in the most sensitive range available. CAUTION If you use displacement control during specimen installation, you can cause specimen damaging forces.
Installing a Threaded Specimen To load a threaded specimen into the grips: Prerequisite Procedure This procedure assumes that the preload platen is installed and the proper collet has been selected for the specimen being tested. 1. Adjust the hydraulic grip supply pressure to the minimum level. 2. Select system force control in the most sensitive range available. CAUTION If you use displacement control during specimen installation, you can cause specimen damaging forces.
6. Place the remaining collet retainer over the remaining threaded insert. Ensure that the collet retainer is oriented so the side with the spanner holes will be facing the upper grip. 7. Thread the threaded insert with the collet retainer onto the lower end of the specimen until the same number of threads are left exposed as in Step 5 above. 8. Apply system hydraulic pressure to the load unit. 9. Extend the actuator until the collet retainer contacts the lower grip. 10.
Note A knocking noise coming from the grip when a cyclic load is being applied to the specimen indicates: Hydraulic pressure—to the grip might not be set high enough. Increase the grip pressure at the hydraulic grip supply until the knocking stops. Do not exceed a grip pressure of 45 MPa (6500 psi ). Specimen in the lower grip—is not making contact with the preload platen. Unlock the lower grip and screw the threaded insert further up onto the specimen, and then lock the grip.
Removing Specimen To remove a round or flat specimen from the grips: 1. If not applied, apply system hydraulic pressure to the load unit. 2. Release the upper and lower grips. 3. Remove the specimen. If the specimen is not fractured, it may be necessary to adjust the position of the actuator. If the specimen is installed in threaded collets, proceed as follows: A. Using a spanner wrench, unthread the collet retainer from the upper grip. B. Adjust the position of the actuator away from the upper grip.
Operation Series 646 Hydraulic Collet Grips
Maintenance Hydraulic Hoses and Fittings Check the hydraulic hoses and fittings monthly. Ensure that hoses are routed properly and not wearing. Also ensure fittings are not leaking. Collets After approximately 25 hours of operation, or upon completion of a test, the collets should be removed and an anti-seizing compound applied to the outer threads of the collet. To service the collet: 1. Remove the collet from the grip housing (perform the applicable procedure as described in “Removing Specimen”). 2.
Maintenance Series 646 Hydraulic Collet Grips
m MTS Systems Corporation 14000 Technology Drive Eden Prairie, Minnesota 55344-2290 USA Toll Free Phone: 800-328-2255 (within the U.S. or Canada) Phone: 952-937-4000 (outside the U.S. or Canada) Fax: 952-937-4515 E-mail: info@mts.com Internet: www.mts.
