Abstract: A method is provided for preparing an estimate for sheet metal working. Data of bending lines and data of an associated processing time for the bending lines is stored. Data of holes and data of an associated processing time for the holes is stored. A three-dimensional view and a development drawing which realizes the three-dimensional view are prepared based on an orthographic drawing. A bending line and a hole on a product are detected based on at least one of data of the three-dimensional view and data of the development drawing. A processing time of the specified bending line is calculated based on the associated data of the bending lines. A processing time of the specified hole on the product is calculated based on the associated data of the holes. The processing time of the bending line and the processing time of the hole are stored in a processing time memory. A total processing time necessary to process the product is calculated by adding up the processing times stored in the processing time memory.

Abstract: An order receiver, when requested to make an estimate of a product, makes an estimate and calculates a delivery time while designing the product, and notifies them to a purchaser. A purchaser (3) requests an order receiver (5) an estimate of a product. The order receiver (5) prepares a 3-D profile sketch (V) from the three-side drawings of the product. The 3-D profile sketch (V) is divided into a plurality of components for a proper working. Development drawings for respective components are produced. Material costs, blanking costs are calculated from the development drawings. Bending processes are determined from respective development drawings. Bending hours and bending costs are calculated from the bending processes. Then, the components are assembled into a product. A welding cost, painting cost and an assembling cost are calculated from the product. A delivery time and an estimate are notified to the purchaser based on the costs and times to thereby shorten a lead time in producing the product.