Frequently Asked Questions                                                                              Visit Our Home Page

 

Q: Will the Reliability MTBF Prediction Report that I purchase from your website satisfy my requirement for an MTBF?

 

A: Yes!  We have been producing Reliability Prediction Reports for over 30 years.  Our clients are companies that must qualify their equipment to Commercial, DOD, DOE, DOT, FAA, NASA, NRC or FDA requirements.  Click the “Performance” button on our web page to see our clients and projects.

 

Our reports incorporate the Parts Count methods for failure rate assignment as defined in MIL-HDBK-217 and Bellcore TR-332.  These data sources provide the most widely accepted failure rate data and are the industry standards for reliability MTBF predictions.  These standards are well known by experts in the reliability engineering field. 

 

Our reports are conservative.  The Parts Count method defined in MIL-HDBK-217 and Bellcore TR-332 assumes an electrical stress ratio of applied stress divided by rated stress = 0.5.  Additionally, the mathematical model we use does not reflect redundant circuitry.  It reflects the reliability series model only.  If your equipment contains redundancy and you are looking for the best possible MTBF value, we can incorporate the redundant model into the report for an additional charge.  However, for most MTBF requirements, the conservative series model will suffice.

 

Q: What is the quickest and least expensive way I can get a Reliability MTBF Prediction Report?

 

A: Begin by visiting our “Instant MTBF” web page.  Click on the link that reads “View and print blank Data Input Sheets”.  Give the data input sheets to an engineer and ask him to write down the quantities of each part type in your equipment.  (Note: If you want your report to reflect the system breakdown by assembly, have the engineer fill out one set of Data Input Sheets for each assembly in your system).

 

Once the data input sheets are filled in, visit our “Instant MTBF” web page. Click the “Continue To Step 1” button to begin entering the parts quantities into the computer.  There are 4 steps to complete this process: 

  1. Enter the user contact information
  2. Enter the parts quantities
  3. Confirm that the data has been entered correctly by clicking the Approved button
  4. Enter your credit card payment information

 

Once the above steps are completed, the Reliability MTBF Prediction Report should arrive in your e-mail within 10 to 15 minutes.

 

Q: What if I can’t find one of my parts listed on your Data Input Sheets?

 

A: Three suggestions:  1.  Enter the part as a “special part” in the space provided at the bottom of the Data Input Sheet.  2.  Enter part quantities adjacent to a part on the data input sheet that is most similar to your part.  3.  Send us your parts list or bill of materials (BOM) and we will enter the quantities for you.  For this service we charge $1500.00, because an engineer is required to be involved, and we offer a schedule of 24 hours.

 

Q: What Environment should I use for the Reliability MTBF Prediction Report?

 

A: You will need to select one environment from the following table.  The Environment Description, Part Ambient Temperature and Semiconductor Junction Temperature may help you choose the environment that is appropriate for your equipment.

 

Abb.

Environment Description

Part Ambient

Temp. ~ ºC.

Semiconductor

Junction Temp. ~ ºC.

GB

Ground, Benign

30

50

GF

Ground, Fixed

40

60

GM

Ground, Mobile

45

65

NS

Naval, Sheltered

40

60

NU

Naval, Unsheltered

45

65

AIC

Airborne, Inhabited Cargo

55

75

AIF

Airborne, Inhabited Fighter

55

75

AUC

Airborne, Uninhabited Cargo

70

90

AUF

Airborne, Uninhabited Fighter

70

90

ARW

Airborne, Rotary Winged

55

75

SF

Space, Flight

30

50

MF

Missile, Flight

45

65

ML

Missile, Launch

55

75

CL

Cannon, Launch

40

60