Simply put, SPC can help your shop's quality control efforts by gathering data to monitor the production process, allowing you to operate at highest capacity and create a baseline that you can continuously work to improve upon.
This helps to ensure that the process operates as efficiently as possible, producing more products to spec and thus, reducing scrap. Statistical process control (aka SPC) employs statistical methods to monitor and control a process, enabling more efficient quality control. Why Does Your Shop Need Statistical Process Control?