Charged particle beam control during additive layer manufacture

Abstract

A computer-implemented method of generating scan instructions for forming a product using additive layer manufacture as a series of layers is provided. The method comprises determining a beam acceleration voltage to be used when forming the product; for each hatch area of layers of the product, determining a respective beam current to be used when forming the hatch area and providing a respective beam current value to the hatch area description in the scan pattern instruction file; and for each line of each hatch area, determining a respective beam spot size to be used when scanning the beam along the line and providing a respective beam spot size value to the line description in the scan pattern instruction file, and determining a respective series of beam step sizes and beam step dwell times to be used when scanning the beam along the line, and providing a respective series of beam position values and beam step dwell times to the line description in the scan pattern instruction file thereby defining how the beam is to be scanned along the line. Also provided are a file of scan instructions, an additive layer manufacture apparatus, and a method of forming a product using the additive layer manufacturing apparatus.