1 An Introduction to Machining Technology Chapter

Permission granted to reproduce for educational use only.© Goodheart-Willcox Co., Inc. Objectives Discuss how modern machine technology affects the workforce Give a brief explanation of the evolution of machine tools Provide an overview of machining processes Explain how CNC machining equipment operates Describe the role of the machinist

Permission granted to reproduce for educational use only.© Goodheart-Willcox Co., Inc. Introduction to Machine Tools Ability to manufacture parts with precision and speed Machinist are highly skilled in use of machine tools

Permission granted to reproduce for educational use only.© Goodheart-Willcox Co., Inc. Evolution of Machine Tools Defined as class of machines which can reproduce themselves Many variations and sizes

Permission granted to reproduce for educational use only.© Goodheart-Willcox Co., Inc. Early Machine Tools First handmade and human-powered, 1200 BC First true machine tool is boring mill, 1774 Continued advancements throughout history Opening up of industry to women helped America greatly during WWII

Permission granted to reproduce for educational use only.© Goodheart-Willcox Co., Inc. Power Sources Evolved throughout history –Hand –Foot –Animal –Water –Steam –Central electrical –Individual electrical

Permission granted to reproduce for educational use only.© Goodheart-Willcox Co., Inc. Basic Machine Tool Operation Almost all have evolved from the lathe Most important operation is turning Goodheart-Willcox Publisher

Permission granted to reproduce for educational use only.© Goodheart-Willcox Co., Inc. Sawing Machines Multitoothed saw blades cut away material Variety of forms Two basic operations –Cutoff sawing –Band machining

Permission granted to reproduce for educational use only.© Goodheart-Willcox Co., Inc. Drill Press (Willis Machinery and Tools Corp.) Goodheart-Willcox Publisher

Permission granted to reproduce for educational use only.© Goodheart-Willcox Co., Inc. Grinding Machine Removes metal by rotating abrasive wheel or belt against the work Two basic categories –Offhand grinding –Precision grinding

Permission granted to reproduce for educational use only.© Goodheart-Willcox Co., Inc. Milling Machine Goodheart-Willcox Publisher

Permission granted to reproduce for educational use only.© Goodheart-Willcox Co., Inc. Broaching Machine Designed to push or pull multitoothed cutter across the work Each tooth removes only a small amount of material

Permission granted to reproduce for educational use only.© Goodheart-Willcox Co., Inc. Nontraditional Machining Processes Machining operations not evolved from the lathe –Electrical discharge machining (EDM) –Electrochemical machining (ECM) –Chemical milling –Chemical blanking

Permission granted to reproduce for educational use only.© Goodheart-Willcox Co., Inc. Nontraditional Machining Processes (Cont.) –Hydrodynamic machining (HDM) –Ultrasonic machining –Electron beam machining (EBM) –Laser machining

Permission granted to reproduce for educational use only.© Goodheart-Willcox Co., Inc. Automating the Machining Process The development of numerical control Cutting tool movement on three axes Available to industry in 1955

Permission granted to reproduce for educational use only.© Goodheart-Willcox Co., Inc. Computer Numerical Control (CNC) Easier to use than manual machines Onboard computers run programs Offers several benefits –Accuracy –Repeatability –Flexibility

Permission granted to reproduce for educational use only.© Goodheart-Willcox Co., Inc. Use of Robotic Systems Permits machine tools to operate unattended Other useful industrial applications –Operate in hazardous environments –Perform tedious operations –Handle heavy materials –Position parts with repetitive precision

Permission granted to reproduce for educational use only.© Goodheart-Willcox Co., Inc. Use of Robotic Systems (Cont.) (Rainer Plendl/Shutterstock.com)

Permission granted to reproduce for educational use only.© Goodheart-Willcox Co., Inc. Evolving Role of the Machinist CNC machine tools has led to decline in highly skilled machinists Still in demand due to knowledge of machining technology Must be able to perform a wide variety of activities

Permission granted to reproduce for educational use only.© Goodheart-Willcox Co., Inc. Acquiring Machining Skills and Knowledge Multiyear salaried apprentice program Other training in related subjects NIMS developed a set of skills standards –Used to certify workers