i-Bolt

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Rhino Assembly Corporation and Load Control Technologies have formed a partnership to offer Bolt Ultrasonic Fastener systems technology to manufacturing facilities in North America. As an overview, most joint failures are not due to joint design or the fastener selection. More often, they are the result of insufficient or inconsistent clamp load at assembly.

Problems such as bolt fatigue and vibration loosening, which account for over 75% of all bolted joint failures, can usually be prevented by achieving and maintaining a correct level of clamp load in the joint. A variation in installed fastener clamp load of 30% is typical with tightening control methods based on the measurement of applied torque, torque-angle, etc. These techniques do not allow postassembly direct load inspections.

With Load Control Technologies (LCT) i-Bolt® Technology end users are able to tighten fasteners directly to load with ± 3% typical accuracy using any kind of tool including high speed impulse and impact wrenches. All assembly torque, yield and friction issues are completely eliminated and significant cost savings can be achieved on labor, warranty, maintenance and design just to name a few areas. At anytime after assembly and during the life of the joint, the operator will also be able to inspect the residual load in each joint in less than two seconds and without disturbing the joint. Companies like GM, Daimler and Boeing have extensively validated i-Bolt® and currently benefit from what the technology offers.

The i-Bolt® Technology takes the end users fasteners and places a permanent transducer (only 50 microns thick) at the top or the bottom of each bolt. Form, fit or function of the fastener is not affected or changed. Unlike conventional ultrasonics, the technology doesn’t require parallel surfaces and is not dependant on common transducer attachment procedures.

Each bolt type and joint is first ultrasonically qualified by LCT. The end user fills out an application form (AIF) for each joint/bolt type (please go to www.LoadCT.com). LCT replicates the end user’s joint, generates the ultrasonic parameters and stores the ultrasonic signatures (including the zero load reading) of each individual bolt against their respective unique id’s in the transducer embedded 2-D barcode. Once a joint/bolt type is qualified it is so for the life of it –bolts can be ordered indefinitely (as previously stated, it is a one time event). So, once the end user receives the i-Bolts they are ready to be used. T

he transducer is permanent and enables load inspections throughout the life of the joint at any time with near perfect repeatability and an accuracy of ±5% independent of the operator. This is great for quality assurance and preventive maintenance as the end users can now measure load in the actual joint (without affecting it or changing it) to determine the installed loads achieved with their current tightening process. In addition it provides traceability for each bolt.

There is also the option for continuous load monitoring and the capability for real time field testing. Design engineers now have the potential of using smaller, lighter or fewer fasteners by tightening directly to load with i-Bolt®. The ± 3% assembly accuracy allows the use of the full strength of the fastener without going into yield. For more information or to schedule a demonstration please contact Rhino Assembly Corporation.

Precise Direct Measurement of Load in Fasteners During Assembly and Inspection

  • Load controlled tightening with shorter assembly time and reduced manufaturing cost
  • Applicable to all fasteners and all tools achieving 3% (3s) installed load accuracy independent of who the operator is
  • Precise non-destructive post-assembly load inspection in less than 2 seconds
  • Unique Traceability of each fastener with automatic data logging and database for each individual bolt.

 i-Bolt Fastener Benefits

  • Precise: More accurate than any known laboratory or calibration technique
  • Fail-Safe: Reliable load control of every fastener
  • Directly Measures the critical specified perameters
  • In Every Bolt: It is the only place load can be measured reliably
  • In Production: Load measurements while tightening with all types of production tools
  • Plus: 100% ultrasonic testing of every fastener, precise post-assembly inspection of every fastener, inherent traceablity of every fastener

i-Bolt Technical Information

i-Bolt® Technology equips each fastener with a proprietary low-cost, permanent ultrasonic transducer at the top, bottom, or both ends of the bolt. Load measurements are made via the pulse echo technique to 3σ accuracy better than ±3%. Each instrumented bolt is also equipped with the i-Bolt® patented transducer-embedded 2D-barcode. Every fastener is fully traceable and includes a database and automatic data logging. There is no special fastener preparation, no acoustic coupling problems, and no highly-trained technician requirements as is the case for removable ultrasonic solutions.

Challenging economic, environmental and safety demands keep driving up the costs of design, production, maintenance, and repair for the Automotive, Aerospace, Industrial and Construction communities. Overwhelmingly, the biggest portion of these costs is directly related to assembly of joints, maintaining joint integrity and dealing with bolted joint failures. It is a never-ending cycle as joint integrity and joint failure concerns lead to over-design of fasteners utilized in the different applications, which further increase weight and cost.

Most joint failures are not due to the joint design or the fastener. More often, they are the result of insufficient or inconsistent clamp load at assembly. Problems such as bolt fatigue and vibration loosening, which account for over 75% of all bolted joint failures, can usually be prevented by achieving and maintaining a correct level of clamp load in the joint. A variation in installed fastener clamp load of ±30% and ±15% is typical with tightening control methods based on the measurement of applied Torque and Torque-Angle respectively. No post-assembly direct load inspections are possible with these techniques. Furthermore, in multiple bolt joints, much of this initial bolt clamp load can be lost as adjacent bolts in the joint are tightened. Load indicating or crushable washers (i.e., washers which deform when a specified load has been reached) are generally inaccurate, and only indicate that a bolt was, at one time, at the required load. It may have since lost most of its initial clamp load as adjacent bolts were tightened. Consequently, load-indicating washers are mostly used only for inspection purposes to indicate that a bolt was tightened.

Achieving high consistent clamp loads in bolted joints during assembly is essential for bolted joint integrity and eliminating costly and often disastrous failures. Non-destructive post-assembly direct load inspections are also vital and significantly reduce maintenance and repair costs. Load Control Technologies i-Bolt® Ultrasonic Fastener Systems provide precise direct measurement of load in fasteners during assembly and inspection. Clamp load measurements are made to accuracies better than ±3% (3σ) for assembly and ±5% (3σ) for inspection, independent of who the operator is, and also allowing for more economical and efficient joint designs.

The i-Bolt® Ultrasonic Fastener System is the complete solution for bolted joint integrity making it possible to tighten and inspect directly to Load instead of Torque or Torque-Angle. i-Bolt® is applicable to all fasteners and all tools resulting in shorter assembly times and reduced manufacturing costs. It is the only solution that provides unique traceability of each fastener with automatic data logging and a database for each individual bolt. No other solution can guarantee i-Bolt®’s ±3% (3σ) tightening load accuracy. Furthermore, these accuracies are also achievable with impact tightening tools opening the door to many applications where their use is forbidden due to torque control inaccuracies. Achieving and maintaining the design load in a bolted joint is now a reality - a reality which results in the prevention and elimination of most joint failures, and also yields significant cost savings.

Inspection

  • Provides fastener identification through 2-D bar code
  • Retrieves zero-load acoustic signature and previous assembly/inspection data
  • Provides typical inspection load accuracy ~ ±5% (3s)
  • Creates automatic data logging

i-Bolt Tracking and Database

Every i-Bolt has an automated tracking database. This database features:

  • Unique identification and traceability of every fastener
  • All fastener related procurement, design, and manufacturing
  • Complete storage of assembly and inspection historical data
  • Zero-load acoustic signature for every fastener measured and stored at fastener manufacturer QC
  • Data for over 20 million bolts in portable measurement instrument. Unlimited when connected to FAstener Database with internet, connection via Bluetooth*, wired (USB) or wireless LAN (802.11bg), or GPRS/Cellphone

Equipment

Dimensions: 5.25"(W) 8.6"(H) 6.8"(L)
Weight: 5.0 pounds

The LoadMaster® 3300 can be used as a portable bolt load unit for inspecting fastener load or for measuring and controlling load during assembly with a hand wrench, an electric or pneumatic power tool or an impulse or impact wrench. The unit measures bolt load at a rate of 500 per second and has the capability of storing complete tightening curve data for display, analysis and logging in the Load Control Technologies Internet-accessible "e-Bolt®" fastener database. The portable load measurement unit hot-sync.'s with a PC for transparent bi-directional data transfer via Bluetooth® or an USB interface. PC software provides full data display and analysis capability.

The LoadMaster® 3300 includes:  

  • Portable load measurement unit
  • Hot sync. cradle with charger and calibration fastener
  • Software for the user-supplied Internet-enabled PC for the hot sync. data transfer, data display, and analysis
  • Torque and angle transducer interface
  • Optically isolated power tool control lines
  • Bolt identification scanner
  • Temperature probe
  • Load measurement cable
  • Load measurement probe (standard, magnetic)
  • LoadMaster® 3300 Manual
  • Bluetooth® software & hardware
  • Lithium Ion battery (18HA), two shifts ( 16 hours)

Integration into Existing Assembly Tools

All types of existing hand-powered and powered production assembly tools, including low-cost impulse and impact tools, can be easily adapted for precise load control with ultrasonic fasteners. The transducer is configured so that it can be pulsed and read using a single, inexpensive, spring-loaded contact embodied into the drive of an existing tool. The return path of the signal is provided through the tool's socket.

The LoadMaster® 3300 is connected to the tool or incorporated in the housing of the tool itself. The LoadMaster® generates the transducer excitation pulse, makes the precision ultrasonic pulse-echo time-of-flight measurements and translate these measurements into precise load readings, which are read by the assembly tool controller as the fastener is being tightened. Only minor software modifications to an existing standard tool controller are required to monitor and stop on the required load, instead of torque. Eventually, with ultrasonic fasteners, torque and angle transducers could be eliminated allowing a significant reduction in tool cost.

The use of impulse and impact tools with ultrasonic fastener technology has the potential to revolutionize fastener assembly in a number of industries. Modified impact and impulse tools offer an order of magnitude reduction in tool cost, an order of magnitude improvement in tightening accuracy (±30% to ±3% [3s]), and an approximate 50% reduction in assembly time.