Complex sentence: General Electric and the Metallurgical Laboratory developed a new welding technique to seal the cans airtight, and the new equipment for this was installed in the production line at Alcoa in October 1943.
Split into simpler sentences: General Electric and the Metallurgical Laboratory developed a new welding technique to seal the cans airtight. The new equipment was installed in the production line at Alcoa in October 1943.