Assembly drawings are used to guide factory workers during the manufacturing process of detailed parts. Assemblers, welders, inspectors and fitters are consulted during plan preparation. Each part is drafted according to predetermined standards and guidelines and approved by the designers before being manufactured. Detailed mounting plans and work instructions to be carried out at the site are provided to the worker in charge of assembling the manufactured parts. All design and delivery procedures are predetermined, adjusted and written in-house and then provided to customers according to their requirements.