GUIDED TOUR Unit Objectives clearly identify the knowledge and skills to be obtained when the units in the section are completed. Key Words listed at the beginning of each unit are important terms to be learned. These words appear in bold/ital type when introduced in the text and are defi ned in the Glossary. Illustrations are designed to clearly and simply communicate the specifi c topic. Sample prints provide examples of the types of welding prints encountered in industry. 1 Copyright Goodheart-Willcox Co., Inc. May not be reproduced or posted to a publicly accessible website.. Unit 1 After completing Unit 1, you will be able to: ❍ Describe the various processes for making original drawings. ❍ Define and describe the parts of a print. ❍ Explain the various methods used to reproduce a drawing. ❍ Describe the advantages of developing drawings with a CAD system. ❍ Explain traditional printmaking processes. ❍ Explain the importance of welding information found on a print. ❍ List precautions in the care of prints. Key Words bluelines blueprint blueprint process computer-aided design (CAD) system computer-aided manufacturing (CAM) diazo process drawings electrostatic process engineering copiers imaging systems Prints—The Language of Industry Drawings are used by the welding industry to communicate ideas in graphic or picture form. Drawings are often the only means of showing the construction of a complex product and structures, Figure 1-1. Drawings are called the “language of industry.” It is a precise language that utilizes symbols. Symbols (lines and figures) have specific meanings to accurately describe the shape, size, material, finish, and fabrication of an object. The symbols are standardized and used as a universal language around the world. This standardization makes it possible to interpret and understand drawings made in other countries.. Original drawings are seldom on a job or a They would soon become worn or soiled, making them difficult to read. Also, workers at differ-- ent locations producing the various parts or subassemblies of a product or structure each need a set of drawings. This means several sets of identical drawings are needed at same Drawing a set of plans each person who needs impractical because of costs. Creating new originals to replace drawings are damaged or ruined also costly. Reproductions, or prints, of original ings or CAD model are used To ensure quality and of parts, version control of prints critical. Prints often have a version or revision number that indicates the most recent print revision. ink jet printers laser printers microfilm process plotters print reproductions symbols tracing white print xerography Copy yrig yr 78 Welding Print Reading Copyright Goodheart-Willcox Co., Inc. May not be reproduced or posted to a publicly accessible website. process drawing would include the dimensions, notes, and tolerances needed to complete machine opera- tions on a part. For welding, the process drawing would include the symbols, dimensions, and notes needed to prepare and weld the part. Parts List A parts list (also called a material list, schedule of parts, or bill of materials) includes all of the parts required in the manufacture of a product. It usually appears above the title block (which is in the lower right-hand corner). Also included is a description of each part, the quantity of each part needed per assem- bly, part number, and the number of the drawing used to manufacture each part. If the product is fabricated from parts provided by a number of different manufacturers, the name of the manufacturer of each component is also included. See Figure 6-12 for a typical parts list. Specialized Drawings When a product is made in quantity, specialized drawings show separate detail drawings usually pre- pared for each specific manufacturing process. Figures 6-8, 6-9, and 6-10 show individual detail drawings of the same object for cutting stock, weld- ing, and machining. Erection Drawing An erection drawing is a type of assembly draw- ing. For the welder, an erection drawing provides the information needed to fabricate (usually in the field) and erect structures such as buildings, bridges, trans- mission line towers, etc., Figure 6-11. Process Drawing A process drawing includes all of the detail information needed to complete a specific process or group of processes on a part. For example, a machining Figure 6-4. A detail drawing includes all information needed to manufacture or fabricate one part. HUTTER ENGINEERING 1 heart-Willcox ea Co., Inc. May not be reproduced or posted to a publicly accessible website interpret and understand drawings made in other countries Origi nal drawings ar e se ld om ffound oun d on a job ssite i te or iin n a ffactory. ac tory. They wou ld soon become worn or soiled, makin g them difficult to read. Also, workers at differ e nt locations producin g the various parts or subassemblies of a product or structure e ac h nee d a set o f drawings. T hi s means tthat h at severa l sets o f identical drawings are needed at tthe h e same ttime. i me. Draw ing a set o f pl ans ffor or eac h person w h o nee ds tthem h em iis s i mpract ical b ecause o f tthe h e costs. Creat ing new originals to replace drawings tthatta h are d ama ged or rui ne d iis s al so cost ly. Reproducti ons , or pri nts, o f tthe h e or igi nal ddraw-- raw in g s or CAD mo del are use d iin n tthese h ese ssituations. ituations. To ensure qua lity iin n tthe h e productionproduction an d ffabrication abrication o f p arts, vers ion contro l o f tthe h e pri nts iis s critical. Pri nts of ten wwill ill have a version or revision number that indicates the most recent p rint revision. 58 Welding Print Reading Copyright Goodheart-Willcox Co., Inc. May not be reproduced or posted to a publicly accessible website. Sectional views (or sections) permit the true internal shape of a complex object to be shown with- out the confusion caused by a myriad of hidden lines. A sect ional view shows how the object would appear if an imaginary cut (known as the cutting plane) were made through the object perpendicular to the direc- tion of sight. Shown in Figure 5-14, the section or portion of the object between the eye and the cutting plane is removed or broken away to reveal the interior features of the object. This makes the shape of the object more understandable. Figure 5-15A shows the exterior surface of a pin. Notice that the interior features shown in Figure 5-15B are easier to visualize if a full section view is provided. Cutting-Plane Line The cutting-plane line indicates the point from which the imaginary cut of the section is taken from the part, Figure 5-16. The arrows at the end of the cutting-plane line show the direction of sight for viewing the section. Three forms of cutting-plane lines are accepted for general use, Figure 5-17. Sections are usually identified with bold capital letters (A-A, B-B, etc.) if they are moved to another position on the drawing. Figure 5-14. A sectional view shows how an object would appear if an imaginary cut were made through the object perpendicular to the direction of sight. This allows interior features to be seen without the confusion of many hidden object lines. Figure 5-12. Only two views are needed on simple objects like this piston pin, which can be fully illustrated on a drawing with little difficulty. Figure 5-13. A complex object with many interior features may result in a drawing with a maze of confusing hidden lines. Figure 5-15. A—The exterior surfaces of a pin are shown. B—The interior features of a pin are shown. B A