How to Eliminate Mechanical,
Vibrational Loosening, Clampload &
Corrosion Failures In Your Products
Before We Start
• This webinar will be available afterwards at
designworldonline.com & email
• Q&A at the end of the prese...
Moderator

Presenter

Paul Heney

Doug Lescarbeau

Design World

Henkel
How Non-Traditional Products Can
Improve Reliability:
Chemical Threadlockers Eliminate
the Root Cause of Threaded
Fastener...
Doug Lescarbeau
• North American Director of Technology
Management for Loctite branded
Anaerobic Products, Henkel Corporat...
Criteria for Bolted Joint Success
• Fastener delivers
design clamp load
• Fastener maintains
clamp load
• Fastener can be
...
Root Cause Analysis
• Root Cause analysis often does not go far enough, often
stopping when a bolt has failed.
• Failure c...
Bolted Joint Mechanics
• A bolted joint is basically a wedge wrapped around a
cylindrical part.
• As the bolt is tightened...
Bolted Joint Mechanics
• Clamp load is generated by putting energy into the
system
• Most commonly by applying a set torqu...
Bolted Joint Mechanics
• Tolerances exist to allow
the parts to be
assembled
• Gaps allow side-to-side
movement when the
f...
Vibration Loosening
• Rate of movement will vary.
• Disassembly can be very rapid if a harmonic frequency is
reached.
• Re...
Vibration Loosening
• Consider the joint as a wedge
• Any back and forth movement tends to move
components in the path of ...
Traditional Systems
• Many mechanical methods are available to lock
threaded assemblies
Mechanical locking systems:
• They...
Traditional Threadlocking Devices

Spring washer

Nut with nylon insert

Castellated nut

Star washer

Tab washer

Lock nu...
Performance Testing
Junkers Transverse Shock Tester

16
Non-Traditional Solution
• Chemical threadlockers address the root cause of the
loosening failure by eliminating the empty...
Performance Testing
Locking Device
Chemical Threadlocker

$0.04

Ribbed flange bolt

$0.50

Saw toothed flange nut
Chemica...
Corrosion
• Traditional Locking Devices do not seal the thread
• Non-Traditional chemical threadlockers lock out moisture
...
How is Corrosion a failure?
• Seizure failure mode resulted in a shaft failure.
• Root cause analysis would likely determi...
How is Corrosion a failure?
• The gland assembly couldn't be adjusted because the
nuts on the gland follower had seized in...
Non-Traditional Solution
• Chemical threadlockers address the root cause of
corrosion by eliminating the empty space in th...
Clamp Load
• The third mode of failure of a bolt is lack of adequate
clamp load on assembly
• Many variables involved in w...
Traditional Approach
Methods to precisely determine the correct bolt stretch

• Micrometer on a bolt, to directly measure ...
Clamp Load Variables
Only a small amount of the energy from a torque wrench goes into
stretching the bolt and producing cl...
Bolted Joint Mechanics
• Friction can be controlled using lubricants.
• The presence or absence of a lubricant will greatl...
Lubricity - Bolt Variability Study
• Experiment to verify if surface finish and under-head bolt
design would produce a var...
Lubricity - Bolt Variability Study
• 5/8”-NC Grade 5 Zinc plated bolts and nuts from five
different bolt manufacturers.
• ...
Lubricity - Bolt Variability Study
• Bolt system placed in Skidmore-Wilhelm clamp load
tester.
• Pressure measured and dir...
Lubricity - Bolt Variability Study
• When the bolted system is torqued it squeezes a
hydraulic reservoir

30
Lubricity - Bolt Variability Study
• First study tested bolts in ‘as-received’ condition to
illustrate the variance in cla...
Lubricity - Bolt Variability Study
• In second study, same bolts from five manufacturers
• Using a chemical threadlocker
•...
Bolt Variability Study
• Liquid threadlocker reduced variability, by providing a
constant lubricity.
• Some variance remai...
Friction Factor or K Value
• What is it?
• As joints have a large number of variables, all variables
were wrapped up into ...
Lubricity Factor or K Value
• Tested a range of chemical and mechanical locking
systems in the Skidmore-Wilhelm tester.
• ...
Friction Factor or K Value
• Goal of any material is to be repeatable and close to the
standard value.
• Good result is a ...
Friction Factor or K Value
• A higher K value (indicating lower lubricity) is a concern
• It means the correct clamp load ...
Friction Factor or K Value
• Mechanical locking device of two interlocking washers
with built in ramps was tested
• They r...
Non-Traditional Solution
• Chemical threadlockers act as a lubricant during fastener
tightening.
• Not used for just threa...
What is Failure in a Bolted Joint?
• Failure to maintain proper clamp load over time
– Vibration Loosening
• Failure to de...
Summary
• Root Cause analysis can be taken to greater depth when
a fastener system fails.
• Exact mode of failure of faste...
Chemical Threadlocking Advances
• Concern about disassembly have been addressed with
color defined strength controlled for...
Chemical Threadlocking Advances
• Concern about process robustness has been addressed
with primerless, oil tolerant cure c...
Chemical Threadlocking Advances
Concern about migration and/or spillage has been
addressed with innovative semi-solid stic...
Chemical Threadlocking Advances
Concern about application control has been addressed with
simple process equipment

45
Chemical Threadlocking Advances
Concern about special performance characteristics has
been addressed with specialized form...
Questions

47
Robert Dunkel
• Professional Engineer
• Based in Mississauga, Ontario, Canada
• Manager of Technical Call Center for USA
&...
LOCTITE® Resources
One on One Support

1-800-LOCTITE
www.loctitethreadlockers.com
doug.lescarbeau@henkel.com
rob.dunkel@he...
Thank You
• This webinar will be available at
designworldonline.com & email
• Tweet with hashtag #DWwebinar

• Connect wit...
How to Eliminate Mechanical, Vibrational Loosening, Clampload & Corrosion Failures In Your Products
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How to Eliminate Mechanical, Vibrational Loosening, Clampload & Corrosion Failures In Your Products

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Equipment reliability can be greatly improved by ensuring that all threaded fasteners used in the assembly are secure and will not fail. When critical pieces of equipment fail, root cause failure analysis is often employed to determine the cause. In many cases, the cause is a loosened fastener.
This webinar:
-Compares the reliability, performance and loosening resistance of various mechanical and chemical threadlocking systems
-Showcases process friendly assembly automation threadlocking equipment
-Demonstrates how to disassemble equipment secured with various types of liquid threadlocker including removable medium strength and permanent high strength grades
-Highlights the latest advancements in liquid threadlockers including primerless, oil tolerant, high temperature performance threadlockers, and those designed for mil-spec, food grade, plastic parts, and health & safety formulas

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How to Eliminate Mechanical, Vibrational Loosening, Clampload & Corrosion Failures In Your Products

  1. 1. How to Eliminate Mechanical, Vibrational Loosening, Clampload & Corrosion Failures In Your Products
  2. 2. Before We Start • This webinar will be available afterwards at designworldonline.com & email • Q&A at the end of the presentation • Hashtag for this webinar: #DWwebinar 3
  3. 3. Moderator Presenter Paul Heney Doug Lescarbeau Design World Henkel
  4. 4. How Non-Traditional Products Can Improve Reliability: Chemical Threadlockers Eliminate the Root Cause of Threaded Fastener Failure Doug Lescarbeau Henkel Corporation 5
  5. 5. Doug Lescarbeau • North American Director of Technology Management for Loctite branded Anaerobic Products, Henkel Corporation • Involved in Reliability Improvement programs for 30+ years • Expert for product development and advancement in Anaerobic Technologies including threadlocking, thread sealing, retaining and gasketing products. • Expert solution provider for market leading companies, including custom product development and R&D applied technology breakthroughs. 6
  6. 6. Criteria for Bolted Joint Success • Fastener delivers design clamp load • Fastener maintains clamp load • Fastener can be disassembled when required 7
  7. 7. Root Cause Analysis • Root Cause analysis often does not go far enough, often stopping when a bolt has failed. • Failure can be either broken or yielded, or when clamp load is lost. • Why do bolts break? Typically because clamp load is lost, bolts become loose, and then they get sheared. • Need to go further and understand the mechanics of the bolted joint • This will lead to true root cause analysis, the failure being a vibrational locking system was not employed, or not enough clamp load was delivered. 8
  8. 8. Bolted Joint Mechanics • A bolted joint is basically a wedge wrapped around a cylindrical part. • As the bolt is tightened, the threads effectively wedge the two parts together. • The more the bolt is rotated the more clamp load is achieved on the assembly. 9
  9. 9. Bolted Joint Mechanics • Clamp load is generated by putting energy into the system • Most commonly by applying a set torque to the fastener, to stretch the bolt. • The bolt stretch compresses the assembly to create the clamp load. 10
  10. 10. Bolted Joint Mechanics • Tolerances exist to allow the parts to be assembled • Gaps allow side-to-side movement when the fastener is exposed to vibration or thermal expansion/contraction • Air space is where corrosion will form. Leads to Seizure. 11
  11. 11. Vibration Loosening • Rate of movement will vary. • Disassembly can be very rapid if a harmonic frequency is reached. • Results are reduced clamp load. This ultimately causes the fastened assembly to fail. • Most fasteners are subject to some level of vibration. 12
  12. 12. Vibration Loosening • Consider the joint as a wedge • Any back and forth movement tends to move components in the path of least resistance • Downhill motion in a nut and bolt joint will result in disassembly. 13
  13. 13. Traditional Systems • Many mechanical methods are available to lock threaded assemblies Mechanical locking systems: • They do not eliminate the gap from tolerance in the threads, the root cause of the failure • They rely on friction to stop motion • Require extensive inventory to fit all shapes and sizes. 14
  14. 14. Traditional Threadlocking Devices Spring washer Nut with nylon insert Castellated nut Star washer Tab washer Lock nut Tooth flanged bolt Ramp Washers 15
  15. 15. Performance Testing Junkers Transverse Shock Tester 16
  16. 16. Non-Traditional Solution • Chemical threadlockers address the root cause of the loosening failure by eliminating the empty space in the threaded assembly. • Simply put it unitizes the assembly by putting a solid chunk of plastic in the threads • Physically prevents relative motion between the nut and the bolt. 17
  17. 17. Performance Testing Locking Device Chemical Threadlocker $0.04 Ribbed flange bolt $0.50 Saw toothed flange nut Chemical Threadlocker Cost $0.11 Elastic stop nut $0.08 Tooth lock washer $0.04 Spring washer $0.04 18
  18. 18. Corrosion • Traditional Locking Devices do not seal the thread • Non-Traditional chemical threadlockers lock out moisture 19
  19. 19. How is Corrosion a failure? • Seizure failure mode resulted in a shaft failure. • Root cause analysis would likely determine that there was inadequate packing gland pressure and flow. Why? 20
  20. 20. How is Corrosion a failure? • The gland assembly couldn't be adjusted because the nuts on the gland follower had seized in place • Heat built up in the packing, expanded, choking the gland of cooling water flow, thereby creating more heat and expansion, thereby causing the packing to squeeze against the shaft and wear it out. 21
  21. 21. Non-Traditional Solution • Chemical threadlockers address the root cause of corrosion by eliminating the empty space in the threaded assembly. • It seals the assembly by filling the space with a chemical resistant thermoset plastic. 22
  22. 22. Clamp Load • The third mode of failure of a bolt is lack of adequate clamp load on assembly • Many variables involved in what clamp load delivers • Lubricity is key to assembly, but not everything 23
  23. 23. Traditional Approach Methods to precisely determine the correct bolt stretch • Micrometer on a bolt, to directly measure bolt stretch. – Good for critical applications like wind tower bases, but is a slow and delicate process. • Torque to yield bolts used in the automotive cylinder head assembly. – Creates an even clamp load by permanently stretching, clamp load a function of the steel metallurgy. – Downside is bolts are single use only. • The most common method remains a torque wrench 24
  24. 24. Clamp Load Variables Only a small amount of the energy from a torque wrench goes into stretching the bolt and producing clamp load. Significant amounts of energy are converted into heat through friction • • • • • • • • Tolerance Surface finish (roughness) Nut face profile Bolt size Surface coatings Cleanliness Thread lubrication Torque tool accuracy/calibration These have a negative impact on reliability by affecting clamp load 25
  25. 25. Bolted Joint Mechanics • Friction can be controlled using lubricants. • The presence or absence of a lubricant will greatly change the friction co-efficient by lubricating the joint. • Bolts received from a manufacturer may have permanent coating or plating, residual cutting fluids, anti-corrosion oils, etc. • The challenge is these are not documented, and often overlooked as to their influence on the bolted joint. 26
  26. 26. Lubricity - Bolt Variability Study • Experiment to verify if surface finish and under-head bolt design would produce a variance in torque • Industrial distributors indicated that zinc plated steel was the most commonly supplied bolt material. • As the zinc coating prevents rust, no oil film was observed. 27
  27. 27. Lubricity - Bolt Variability Study • 5/8”-NC Grade 5 Zinc plated bolts and nuts from five different bolt manufacturers. • Bolts were assembled with a calibrated torque wrench to 112 foot-pounds (152 Nm), the standard SAE Grade 5 recommendations for steel bolts. 28
  28. 28. Lubricity - Bolt Variability Study • Bolt system placed in Skidmore-Wilhelm clamp load tester. • Pressure measured and directly correlated by knowledge of the diameter of the piston to measure the clamp load. 29
  29. 29. Lubricity - Bolt Variability Study • When the bolted system is torqued it squeezes a hydraulic reservoir 30
  30. 30. Lubricity - Bolt Variability Study • First study tested bolts in ‘as-received’ condition to illustrate the variance in clamp load. • Table 1 shows it produced a clamp load range of 4100 lbs (21%). 21% range 31
  31. 31. Lubricity - Bolt Variability Study • In second study, same bolts from five manufacturers • Using a chemical threadlocker • Range dropped from 4100 to 1300 pounds of clamp load difference with chemical threadlocker. 12% range 32
  32. 32. Bolt Variability Study • Liquid threadlocker reduced variability, by providing a constant lubricity. • Some variance remains, which is normal 12% range 33
  33. 33. Friction Factor or K Value • What is it? • As joints have a large number of variables, all variables were wrapped up into one number. • It is experimentally determined, not a calculation • It is useful for approximations, but over time its actual meaning has become unclear to users. • It is now common for end users to ask for the “K” value, as if it is an independently measurable value, not a collection of variables. 34
  34. 34. Lubricity Factor or K Value • Tested a range of chemical and mechanical locking systems in the Skidmore-Wilhelm tester. • 5/8” bolts were utilized. • Most standard values for K are calculated on 3/8” fasteners. Size changes value. 35
  35. 35. Friction Factor or K Value • Goal of any material is to be repeatable and close to the standard value. • Good result is a K close to what an oiled bolt delivers. • Lower K value (indicating higher lubricity) is acceptable, as long as the assembly torque is dropped to ensure bolts are not over tightened.. 36
  36. 36. Friction Factor or K Value • A higher K value (indicating lower lubricity) is a concern • It means the correct clamp load will not be generated. The actual clamp load achieved is shown below 37
  37. 37. Friction Factor or K Value • Mechanical locking device of two interlocking washers with built in ramps was tested • They require a lot of energy to overcome fiction and deliver a substantial increase in K value (higher friction) • If the same torque specification used as an oiled bolt a significant drop in clamp load will result 38
  38. 38. Non-Traditional Solution • Chemical threadlockers act as a lubricant during fastener tightening. • Not used for just threadlocking. Actually used to reduce variability of bolt tolerance • K value achieved reasonably close to oiled values • Allows applied torque to be converted into high clamp load instead of dissipating as friction or heat. • Once cured, chemical threadlockers provide a reliable seal, preventing leaks, galling and corrosion that can seize threads and prevent disassembly. 39
  39. 39. What is Failure in a Bolted Joint? • Failure to maintain proper clamp load over time – Vibration Loosening • Failure to deliver adequate clamp load on assembly – Lubricity key to assembly • Failure to come apart when required – Corroded assembly 40
  40. 40. Summary • Root Cause analysis can be taken to greater depth when a fastener system fails. • Exact mode of failure of fastener system needs to be identified. • Non-traditional solutions can be more effective at resolving root cause of issue, versus treating symptom. 41
  41. 41. Chemical Threadlocking Advances • Concern about disassembly have been addressed with color defined strength controlled formulations Low Medium High 42
  42. 42. Chemical Threadlocking Advances • Concern about process robustness has been addressed with primerless, oil tolerant cure chemistry Performance on Oiled Substrates Breakaway M10 black oxide Strength Retention [%] 60 50 40 30 20 10 0 Hydrophobic (Evolution SXR 5W-30) Emulsion (Aquasafe 21) Solvent based (SafeCoat DW 30 X) Oil Type Loctite 262 Control Loctite 271 Control Loctite 263 43
  43. 43. Chemical Threadlocking Advances Concern about migration and/or spillage has been addressed with innovative semi-solid stick and tape formats 44
  44. 44. Chemical Threadlocking Advances Concern about application control has been addressed with simple process equipment 45
  45. 45. Chemical Threadlocking Advances Concern about special performance characteristics has been addressed with specialized formulations Purity Certified Rated to 650F Extreme Temperature Low Halogen MSDS Health Rating of 1 Multi substrate Plastic Fastener Health & Safety FDA Reg Compliant Food Grade Certified Performance Military Specified 46
  46. 46. Questions 47
  47. 47. Robert Dunkel • Professional Engineer • Based in Mississauga, Ontario, Canada • Manager of Technical Call Center for USA & Canada • Manage Technical Service for Canada • Specialist in Loctite branded threadlockers • Involved in Reliability Improvement programs for 10 years 48
  48. 48. LOCTITE® Resources One on One Support 1-800-LOCTITE www.loctitethreadlockers.com doug.lescarbeau@henkel.com rob.dunkel@henkel.com 49
  49. 49. Thank You • This webinar will be available at designworldonline.com & email • Tweet with hashtag #DWwebinar • Connect with Design World – Twitter: @DesignWorld – Facebook: facebook.com/engineeringexchange – LinkedIn: Design World Group – YouTube: youtube.com/designworldvideo • Discuss this on EngineeringExchange.com

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