deposited powder to form a structure 12 to ensure the powder is aligned with the nozzle it is necessary to calibrate the deposition apparatus in one embodiment the alignment procedure is achieved with the assistance of the apparatus depicted in fig2 the apparatus comprises a container 20 with a cover 22 formed of a material which may be ablated by the laser beam 2 for a co 2 laser the preferred material of the cover is perspex the cover is preferably integral with the container though there are advantages in providing a removable and replaceable cover as collected powder from the alignment process may be easily removed from the container and reused the container may be formed of a material that is resistant to perforation by the beam and powder which may settle on the cover 22 and may contribute to an incorrect measurement of the amount of powder collected in the container will not be taken into consideration the container is placed in location within the direct laser deposition apparatus with the focus of the beam 2 on the cover 22 with the powder supply off the laser is switched on and a beam directed at the container 20 till a perforation 26 is made in the cover 22 the perforation has approximately.