Comparison Test

The following is a report of comparison tests made between two different Accutac machines performed by the Boeing Co.

Bob,

As part of an effort to determine consistent and equivalent data between the Boeing Accutac apparatus and the new Accutac recently manufactured, a prepreg tack experiment was constructed. Over the course of the last year Boeing MR&D has collaborated with Accutac in generating data and suggestions that has resulted in optimizing the new apparatus and test technique. It is the Boeing teams position that the new Accutac tack test apparatus produces an end result of tack data that is consistent and equivalent to the Boeing Accutac apparatus located in Boeing MR&D's charaterization lab.

Experiment

BMS 8-256 3k70PW carbon fabric prepreg was evaluated for tack in order to determine if any test procedure or equipment error existed between the two tack test apparatus'. A Boeing sampling plan across the width and down the length of the prepreg was used to minimize known variables of prepreg fabric tack. Historic Boeing tack data has indicated that greater degrees of tack exist on the selvadge edges of the fabric when compared to the middle of the prepreg. In addition, Boeing data also indicates a more uniform tack down the length of the prepreg. Thus the sampling plan was adjusted for these known variables. A population size of 12 samples was used in order to determine an approximate confidence level between 85 and 90%. As part of the test procedure and in order to minimize the effect of temperature and humidity, Accutac Industries brought their new tack test apparatus to the Boeing MR&D lab facility to do side by side testing with Boeing's Accutac. Temperature and humidity at the time of the evaluation was 73 +or- 1 degree F and 44 +or- 2% RH.

DATA

CONCLUSION

A remarkable 0% difference exists between the average tack values for the Boeing and the new Accutac test apparatus for the above experiment. Based on the above positive facts and data, it is the position of Boeing MR&D that equivalency and consistent data exists between the two Accutac test apparatus'.

Terry Pelton MR&D, Material Qualification 253-931-5756, 5L-05