BRX210 ‘Mechanical Blueprint Reading’ Unit #1 Drawings and Prints

After studying this unit, you will be able to: Explain the difference between drawings and prints Explain the difference between drawings and prints Explain the advantages of CAD drawings Explain the advantages of CAD drawings Describe print making processes Describe print making processes Handle prints correctly Handle prints correctly

Drawings Two types: Two types: 1. Machine drawings 1. Machine drawings Used to produce one unique part Used to produce one unique part 2. Assembly drawings 2. Assembly drawings Used to show how different parts are connected Used to show how different parts are connected

Hand Drafting Creation of drawings using pencils, triangles, straightedges, and other drafting tools Creation of drawings using pencils, triangles, straightedges, and other drafting tools It is a very time consuming process It is a very time consuming process Few drawings are created this way today Few drawings are created this way today

Computer-Aided Drafting (CAD) Created using computer software Created using computer software Several components of a CAD system: Several components of a CAD system: CPU (Central Processing Unit) CPU (Central Processing Unit) Main body of the computer Main body of the computer Where the information is stored and processed Where the information is stored and processed Monitor Monitor Screen used to view the drawing Screen used to view the drawing Keyboard Keyboard Used to input text and numbers Used to input text and numbers

Digitizer (Mouse) Digitizer (Mouse) Input device used to control an on-screen cursor Input device used to control an on-screen cursor Plotter Plotter Used to create the actual physical drawing on paper Used to create the actual physical drawing on paper Modem Modem Used to transfer information between computers anywhere in the world Used to transfer information between computers anywhere in the world

CAD Advantages Increased productivity Increased productivity More accurate drawings More accurate drawings Easier drawing storage Easier drawing storage Easier drawing management Easier drawing management

Prints A print is a copy of a drawing A print is a copy of a drawing Prints can be made quicker and more affordable than plotted drawings Prints can be made quicker and more affordable than plotted drawings Often, the term ‘blueprint’ is used instead of ‘print’ Often, the term ‘blueprint’ is used instead of ‘print’ Blueprint – older method with dark blue background and white lines and symbols Blueprint – older method with dark blue background and white lines and symbols Two methods of creating prints: Two methods of creating prints: Photocopying Photocopying Diazo process Diazo process

Engineering Copies Use an electrostatic process to reproduce drawings Use an electrostatic process to reproduce drawings Similar to common copier machines Similar to common copier machines Designed to handle larger size drawings Designed to handle larger size drawings

Diazo Process Still used today though slowly being replaced by the faster engineering copiers Still used today though slowly being replaced by the faster engineering copiers Diazo process is a photochemical process using light and chemicals (ammonia) to produce drawings Diazo process is a photochemical process using light and chemicals (ammonia) to produce drawings Often referred to as ‘bluelines’ due to blue lines on white background Often referred to as ‘bluelines’ due to blue lines on white background Always exact duplicates of the original and much sharper than engineering copies Always exact duplicates of the original and much sharper than engineering copies

Care of Drawings and Prints Original drawings should be stored in a safe place Original drawings should be stored in a safe place Protect from: Protect from: Water Water Weather Weather Oil Oil Always roll and fold properly Always roll and fold properly