Document NGzgDn4zxvwgaXLy15rz224OQ

TP-112 satisfactory pieces were molded, meeting all dimensional require ments. The Durez 1544 preforms were then tried, and at the pre heater setting used for the BMMA-5715, the Durez preforms gassed severely and could not be molded. The preform temperature was decreased to approximately 255F, and at the 25 second cure, all pieces had shrunk excessively when gauged. It was not until the cure time had been raised to 45 seconds that acceptable pieces were made; thus the BMMA-5715 realized a reduction in cure time of 20 seconds over the Durez 1544. In addition, the BMMA-5715 had no orange-peel and had a glossier surface than did the Durez. In conclusion, then, from the results of this evalua tion, and the previous one at Tech-Art (see TP-105), the im proved medium-impact molding material BMMA-5715 has been found to be competitive with all materials against which it has been evaluated. It was unfortunate that Wiggins had no mold in operation which could evaluate the transfer molding character istics of this material. However, from the compression work done, it has been evident that the BMMA-5715 material has an excellent appearance, fast cure, good preheat latitude, and very good retention of dimensions. It was interesting to note that in this evaluation there was no problem with skin blis tering or piece and flash release as had been briefly encoun tered at Tech-Art. The material has been released for trial at Allen-Bradley and Cutler-Hammer and a production trial will be scheduled soon to uncover what problems, if any, will be involved when the material is produced on a larger scale. PERIOD COVERED: April 7, 1964 NOTEBOOK REFERENCE: 7394 ATTACHMENTS: None LDF:gvc 3- - UCASB00939009