In 1914 they added plant # 5, with 16 kilns, just to the north of plant # 4, the Newell plant. By 1919-1920 they were ready to expand again. The industry was changing greatly at this time. New technologies for better and more efficient production required the introduction of science and scientists into the business. Laughlin's hired Albert Victor Bleininger, a scientist in ceramics. Bleininger would remain with the company until his death in 1946. His first task was to build plant # 6. This plant was built across the valley to the south of plants # 4 and was the largest pottery ever constructed in the world. It was to be a leader in the worldwide manufacturing of ceramics. The plant was state-of-the-art. A major innovation was the construction of tunnel kilns. The tunnel kilns unlike the bottle kilns were of continuous operation. The plant also had other technological advantages, streamlining the process of making the ware. The plant was 290 feet wide, 800 feet long with a basement 80 feet by 800feet where the clay, flint and feldspar were mixed.
1n 1927 they built plant # 7 and replaced the bottle kilns in plants # 4 and # 5 with tunnel kilns. The three older plants in East Liverpool were soon obsolete and were abandoned in 1929. To replace them, in 1928, Laughlin's built plant # 8 just south of plant # 6. This new plant was 1,200 feet long and 300 feet wide and employed 900 people, equal to the combined numbers at plants # 6 and # 7. At peak employment The Homer Laughlin China Company employed 3,500 people.
In 1927 they hired one of the world’s foremost ceramists, Frederick Hurten Rhead. Rhead would stay with the company until his death in 1942. Rhead's first job was to update the catalogue, most of which had been in production for decades. The newest ware was called Yellowstone and was a cream, light-yellow. Introduced in 1926 it was advertised as, "possessing a warmth of tone that appeals to many persons of good taste more strongly than the dead white body that has ruled the market for so many years". He slowly changed the product over a space of several years. In 1935 he created Fiesta ware which would become the companies most popular and most collected line of Homer Laughlin China. Fiesta was discontinued in 1959, replaced with Fiesta Ironstone which was discontinued in 1973. Fiesta ware with new colors was reintroduced in 1986 to celebrate to celebrate its 50th anniversary. Rhea also created Harlequin which was the Woolworth Companies biggest seller. It was reintroduced into the line in 1979 to celebrate Homer Laughlin's Centennial.
Peak production for the company was in 1948 when they produced 10,129,449 dishes.