Strengthening Investment to Grow Manufacturing in America Act This bill provides incentives, investment, and resources for U.S. small manufacturers. Specifically, the bill increases the maximum loan guarantee rate for Small Business Association (SBA) loans to manufacturers, and it increases the limit for loans to be used for plant acquisition, construction, conversion, and expansion. The bill also eliminates guarantee fees paid by small manufacturers for loans under $350,000 and reduces the fees on loans over that amount. For acquisition and construction loans, the bill reduces the financing requirement for small manufacturers and increases the allowable debt refinancing for facility expansions. Small manufacturers are further authorized to lease a greater percentage of their facility to obtain financing. In addition, the bill authorizes discount debentures to manufacturers and provides leverage capacity in the Small Business Investment Company program for investments in small manufacturers (1) in low or moderate income areas, rural areas, or areas of high unemployment; or (2) that are veteran-, minority-, or women-owned, have demonstrated employment growth, or are vital to national security. The bill further directs the SBA to use its existing resources to provide training and education to small manufacturers on how to navigate application processes for receiving assistance from SBA programs. Lastly, the bill directs the SBA to ensure its business loan programs provide adequate support for innovative technologies in manufacturing.