Manufacturing variations in the automated fiber placement (AFP) process are one of the causes of gaps and overlaps. These manufacturing variations can be due to robot inaccuracy, tow lateral movement on the roller, tow width variation or tow compaction. An experimental setup was built to measure and investigate these various sources of manufacturing variations and their relative contributions to gap and overlap defects. This setup consisted of a commercial AFP head instrumented with additional sensors. Among all the measured sources of variations, lateral movement of the tow on the compaction roller was the biggest contributor to gaps and overlaps. The distributions of these sources of variations were fit with probability density functions. Random samples from these fits were used to simulate adjacent tows and predict the occurrence of gap and overlap defects. The distribution of predicted gaps correlated closely with the distribution of experimentally measured gaps. Thus, this approach of using statistical information about the sources of manufacturing variations to predict the frequency and magnitude of defects in a layup was validated.@en

Manufacturing variations in the AFP process are one of the causes of gaps and overlaps. These manufacturing variations can be due to robot inaccuracy, tape lateral movement on the roller, tape width variation or tape compaction. These manufacturing variations result in incorrect position or incorrect geometry of the laid tape. An experimental setup was built to measure and investigate the causes of these manufacturing variations and their relative contributions to gap and overlap defects. This setup consisted of an instrumented AFP head. A laser tracker measured the achieved trajectory of the AFP head. A camera measured the lateral movement of the tape on the roller. Laser line scanners measured tape width before and after layup. Experimental results show that the 99^th percentile absolute deviations for each of the four measured sources vary from 0.119 mm to 0.534 mm as compared to the specified tape width of 6.35 mm. Among all the measured sources of variations, lateral movement of the tape on the compaction roller was the biggest contributor to gaps and overlaps.

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