User Manual

ManualsBrandsMaxBotix ManualsSonar Range FindersMaxBotix XL MaxSonar AE1 Ultrasonic Ranger

Reliability Demonstration Report

MaxBotix

Inc.

Document Release: 05/12/2010, pg. 1 of 10

MaxBotix, MaxSonar, XL & WR are trademarks of MaxBotix Inc.

Email:

info@maxbotix.com

Web:

www.maxbotix.com

Reliability Demonstration Test (RDT) Report

for

High Temperature Operational Life (MTBF)

and

Temperature Cycling (MTBF)

for the MaxSonar™, Product Lines

Technical Information Prepared By

Carl Myhre – Systems Engineer

Document Formatted By

Nicole Smith – Account Executive

Document Approved By

Bob Gross – CEO/Chief Engineer

Summary of content (10 pages)

PAGE 1
Reliability Demonstration Report Reliability Demonstration Test (RDT) Report for High Temperature Operational Life (MTBF) and Temperature Cycling (MTBF) for the MaxSonar™, Product Lines Technical Information Prepared By Carl Myhre – Systems Engineer Document Formatted By Nicole Smith – Account Executive Document Approved By Bob Gross – CEO/Chief Engineer MaxBotix ® Inc. MaxBotix, MaxSonar, XL & WR are trademarks of MaxBotix Inc. v1.1b • 07/2009 • Copyright 2005-2010 Document Release: 05/12/2010, pg.
PAGE 2
Reliability Demonstration Report Reliability Demonstration Test Executive Summary This test was conducted to verify and document the reliability of the Maxbotix MaxSonar™ product lines. Test parameters were selected that, if met, would establish and verify a mean time between failure (MTBF) of at least 200,000 hours.
PAGE 3
Reliability Demonstration Report Table of Contents 1 Reliability Demonstration Test Executive Summary page 2 2 High Temperature Operational Life Test (MTBF) page 4 2.1 MTBF Test Scope 2.2 MTBF Test Specifications 2.3 MTBF Test Results 3 Temperature Cycling Life Test (MTBF) page 5 3.1 Temperature Cycles Test Scope 3.2 Temperature Cycles Test Specifications 3.3 Temperature Cycles Test Results 4 Appendix page 6 4.1 Typical Temperature Cycle Timeline 4.2 PVC Temperature Considerations 4.
PAGE 4
Reliability Demonstration Report 2 High Temperature Operational Life Test (MTBF) 2.1 Test scope The purpose of this test was to use High Temperature Operational Life Testing to demonstrate the long-term operation of our Maxbotix Inc., MaxSonar™ sensor line. The test started on January 18, 2010 and ended on March 15, 2010. 2.2 Test Samples The test was carried out on 50 units.
PAGE 5
Reliability Demonstration Report 3 Temperature Cycling Life Test 3.1 Test scope The purpose of this test was to use Thermal Cycling Testing to demonstrate the long-term operation of our Maxbotix Inc., MaxSonar™ sensor line. (This temperature cycling test was designed to work in tandem with the mean-life test to establish the ability of the MaxSonar™ sensor to operate in temperature conditions ranging between -40°C and +65°C.) The test was conducted at Maxbotix Inc.
PAGE 6
Reliability Demonstration Report 4 Appendix 4.1 Typical Temperature Cycle Timeline *The above chart includes the analog offset voltage of one test unit to confirm that units in the test chamber reached the desired temperatures at the same time as the chamber. Offset voltage is normalized using the equation below. T = m ×V + b T = Temperature V = Offset Voltage Measured m = 146.4 Kelvin/Volt b = -138.05288 Kelvin MaxBotix ® Inc. MaxBotix, MaxSonar, XL & WR are trademarks of MaxBotix Inc. v1.
PAGE 7
Reliability Demonstration Report 4.2 PVC Temperature Considerations For the WR-MaxSonar products the PVC housing is subject to the physical limitations of the plastic exterior. In order to prevent cold flow the sensors should only see limited operation at temperatures of 85°C for limited periods of time (30 minutes or less).
PAGE 8
Reliability Demonstration Report 4.3 Activation Energies of Integrated Circuit Components Failure Mode Activation energy in eV Oxide Breakdown 0.3 - 0.5 eV Corrosion 0.3 - 0.5 eV Electo-migration 0.45 - 1.0 eV Ionic Migration 0.6 - 1.4 eV Assembly Defects 0.5 - 0.7 eV For the purposes of our calculations an activation value of 0.53 eV was used. This aggrees with the rule of thumb of doubling the equivalent product usage hours for every 10°C above the normal operational temperature.
PAGE 9
Reliability Demonstration Report 4.5 High Temperature Operational Life (MTBF) Because we observed no failures during our test we computed MTBF using a Chisquared distribution. For the purposes of this test a level of confidence of 90% was considered acceptable. The MTBF formula using a Chi-squared distribution is: MTBF = 2 ⋅ ( N ⋅ T ) ⋅ Af X 2 [α , (2( n + 1) )] where: MTBF = Mean time between failures 2 is the N is the Number of elements = 50 sensors T = Total test time = 1340.
PAGE 10
Reliability Demonstration Report 4.6 Temperature Cycling (MTBF) The equation below is used to model the relation between increased temperature and the acceleration of the aging of a product as compared to its normal operational temperature. 1 .9  ∆T  Af =  t   ∆Ts   Hs    H  t 0.333  Ea  1 1   e× −     k  TMaxS TMaxT   Af = acceleration factor Ea = activation energy in electon-volts (eV) = 0.53 eV k = Boltzmann’s constant = 8.