Department of Mechanical Engineering, The Ohio State University Sl. #1GATEWAY Machines & Machining Issues

Department of Mechanical Engineering, The Ohio State University Sl. #2GATEWAY Material Removal Process Mechanical Machining Milling Grinding Turning Drilling All hard materials

Department of Mechanical Engineering, The Ohio State University Sl. #3GATEWAY Machining DOF (Degrees of Freedom) DOF- # of independently controllable axes of motion-- excluding spindle rotation or tool translation responsible for cutting. 1 DOF- Drill Press 2 DOF- Lathe 3 DOF- 3 independent axis motions between tool & table Can use a ball end mill w/ 3 axis machine- for smoothest contour Following a true 3-D contour requires a minimum of 3 DOF 2 1/2 DOF- 3 independent axes, but can only move 2 at a time > 3 DOF- Generally allows rotation of spindle wrist or table Helps keep tool normal to workpiece/ fewer separate fixtures 5 DOF- Minimum to follow any normal at any point

Department of Mechanical Engineering, The Ohio State University Sl. #4GATEWAY Turning Operations  Turning (Performed on lathe)  Part is moving and tool is stationary.  Used to make parts of round cross section  Screws, shafts, pistons....  Number of various lathe operations  Turning, facing, boring, drilling, parting, threading

Department of Mechanical Engineering, The Ohio State University Sl. #5GATEWAY Lathe Components Machine Components (Main items) Bed: Supports all other machine parts Carriage: Slides along the machine ways  Head stock: Power train of system (spindle included)  Tail Stock: Fixes piece at end opposite to the head stock  Swing: Maximum diameter of the machinable piece  Lead screw: controls the feed per revolution with a great deal of precision

Department of Mechanical Engineering, The Ohio State University Sl. #6GATEWAY Ref: Fig. 8.52, Kalpakjian. Manufacturing Processes for Engineering Materials 2 nd Ed, Addison-Wesley Lathe Spindle Speed Selector Headstock Spindle Ways Tool Post Cross Slide Carriage (saddle) Center Tailstock quill Tailstock Feed Rod Lead Screw BedApron Compound Rest & Slide (swivels) Feed change gear box

Department of Mechanical Engineering, The Ohio State University Sl. #7GATEWAY Lathe Tools Lathe tools  Left handed  Right handed  Threading  Boring  Groove  Parting (Cut-Off )

Department of Mechanical Engineering, The Ohio State University Sl. #8GATEWAY Lathe Operations Ref: Fig. 8.51, Kalpakjian. Manufacturing Processes for Engineering Materials 2 nd Ed, Addison-Wesley 1991.

Department of Mechanical Engineering, The Ohio State University Sl. #9GATEWAY Cutting Speeds Typical Lathe Cutting Speeds Nominally ft./min. Roughing cuts -Depth of cut greater then.02 in -Feed speed of in/rev. Finishing Cuts -Lower than roughing cuts.

Department of Mechanical Engineering, The Ohio State University Sl. #10GATEWAY Milling Types of Milling Machines  Horizontal Milling Machine  Vertical Milling Machine

Department of Mechanical Engineering, The Ohio State University Sl. #11GATEWAY Mill Cutting Direction Cutting direction- Depending on the orientation of the workpiece feed w.r.t. the rotation of the cutting tool. Climb (Down) Milling- Maximum thickness of chip at start of cut. Conventional (Up) Milling- Maximum thickness of chip at end of cut Ref: Figure J-48, Kibbe,et al. Machine Tool Practices 5 th Ed, Prentice Hall,1995. Ref: Figure J-48, Kibbe,et al. Machine Tool Practices 5 th Ed, Prentice Hall,1995.

Department of Mechanical Engineering, The Ohio State University Sl. #12GATEWAY Vertical Knee Milling Machine Base and Column- support structure Knee- Connected to slide on column- can move up and down Saddle- Engages slide on top of knee- can be moved in and out. Table- Engages slide atop of saddle- moved lengthwise. Holds workpiece. Ram- Engages swiveling slide atop column. Toolhead- Attached to end of ram, contains motor and quill. Quill- Non rotating, but contains rotating spindle. Can be moved up and down. Ref: Kibbe,et al. Machine Tool Practices 5 th Ed, Prentice Hall,1995, p Ref: Figure 8.69, Kalpakjian. Manufacturing Processes for Engineering Materials 2 nd Ed, Addison-Wesley 1991.

Department of Mechanical Engineering, The Ohio State University Sl. #13GATEWAY Vertical Milling Machine Flexible Versatile Newer machines – more DOF

Department of Mechanical Engineering, The Ohio State University Sl. #14GATEWAY Bed Mill  Similar to vertical knee milling machines  Less versatile than knee mill  No knee - Bed does not move up and down  Vertical motion possible in head only  Controllable range of motion of head larger than in knee mill (total range of motion less)  Bed mill stiffer than knee mill

Department of Mechanical Engineering, The Ohio State University Sl. #15GATEWAY Vertical Milling Applications Collet Ref: Process Selection, KG Swift and JD Booker, p.98.

Department of Mechanical Engineering, The Ohio State University Sl. #16GATEWAY Scallop Height w/ Ball Nosed End Mill

Department of Mechanical Engineering, The Ohio State University Sl. #17GATEWAY Scallop Height- Ball Nose on an Incline

Department of Mechanical Engineering, The Ohio State University Sl. #18GATEWAY Horizontal Milling Machine COMPONENTS Base & Column Knee Saddle Table Spindle Overarm & Arbor Support Ref: Figure 8.68, Kalpakjian. Manufacturing Processes for Engineering Materials 2 nd Ed, Addison-Wesley 1991.

Department of Mechanical Engineering, The Ohio State University Sl. #19GATEWAY Types Horizontal Milling Operations Slab - Axis of cutter // to workpiece surface Face - Axis of rotation | to workpiece surface Side - Axis of cutter // to workpiece surface Figure 8.63b, Kalpakjian. Manufacturing Processes for Engineering Materials 2 nd Ed, Addison-Wesley Figure 8.67c, Kalpakjian. Manufacturing Processes for Engineering Materials 2 nd Ed, Addison-Wesley Figure 8.63a, Kalpakjian. Manufacturing Processes for Engineering Materials 2 nd Ed, Addison-Wesley 1991.

Department of Mechanical Engineering, The Ohio State University Sl. #20GATEWAY Drilling Any component requiring cylindrical holes. Engine Blocks, Machine Components Ref: Process Selection, KG Swift and JD Booker, p.104.

Department of Mechanical Engineering, The Ohio State University Sl. #21GATEWAY Grinding and Abrasive Processes Abrasive Processes- Generally slower (more expensive) than other traditional machining processes. Used on very hard materials, and can achieve HIGH (virtually unmatched) levels of precision and finish. Grinding Deburring Honing Polishing Lapping Superfinishing

Department of Mechanical Engineering, The Ohio State University Sl. #22GATEWAY Grinding Machines Pedestal Grinder Surface Grinder Type I- Horizontal spindle w/ reciprocating table Type II- Horizontal spindle w/ rotary table Type III- Vertical spindle, table either reciprocates or rotates (blanchard) Cylindrical Grinder Center-type Roll-type- workpiece in bearings rather than on centers Centerless Grinder- workpiece supported on rest blade, grinding wheel on one side, regulating wheel on the other Internal Cylindrical Grinder Tool Cutting Grinders Specialty Grinders Form Grinders and Generating Types

Department of Mechanical Engineering, The Ohio State University Sl. #23GATEWAY Surface Grinders Type I Type II Type III Reciprocating Table Rotating Table Ref: Figures N-1, N-3,N-4, & N-5, Kibbe,et al. Machine Tool Practices 5 th Ed, Prentice Hall,1995.

Department of Mechanical Engineering, The Ohio State University Sl. #24GATEWAY Cylindrical Grinders Center/Roll Type Centerless Type Ref: Figures N-8, N-17, N-18, Kibbe,et al. Machine Tool Practices 5 th Ed, Prentice Hall,1995.

Department of Mechanical Engineering, The Ohio State University Sl. #25GATEWAY Surface Roughness Surface roughness is generally described with 1 of 2 methods R a - Arithmetic Mean Value- the average of the absolute values of the deviations from the center line of the surface R q (formerly RMS)- Root Mean Squared- Ra=Ra= |a| + |b| + |c| + |d| + … n ( )

Department of Mechanical Engineering, The Ohio State University Sl. #26GATEWAY Roughness Units  1 Micrometer = 1  m = 1 micron = meters  1 Microinch = 1  in= inches  1  in =  m  1  m = 40  in  Human hair ~ 40  m Both generally given in micrometers (microns) or microinches

Department of Mechanical Engineering, The Ohio State University Sl. #27GATEWAY Typical Arithmetic Average Roughness Ref: Fig. 8.35, Kalpakjian. Manufacturing Processes for Engineering Materials 2 nd Ed, Addison-Wesley 1991.

Department of Mechanical Engineering, The Ohio State University Sl. #28GATEWAY Summary  Four types of mechanical removal processes  Turning  Milling  Drilling  Grinding  Finish of workpiece

Department of Mechanical Engineering, The Ohio State University Sl. #29GATEWAY Credits  This module is intended as a supplement to design classes in mechanical engineering. It was developed at The Ohio State University under the NSF sponsored Gateway Coalition (grant EEC ). Contributing members include:  Gary Kinzel …………………………………….. Project supervisor  Chris Hubert and Alan Bonifas..……………... Primary authors  Phuong Pham and Matt Detrick ……….…….. Module revisions  L. Pham ……………………………………..….. Audio voice References: Kalpakjian, Manufacturing Processes for Engineering Materials 2 nd Ed, Addison-Wesley 1991 Kibbe,et al. Machine Tool Practices 5 th Ed, Prentice Hall,1995 Swift, KG and JD Booker, Process Selection, Arnold/John Wiley& Sons Inc., New York, 1997

Department of Mechanical Engineering, The Ohio State University Sl. #30GATEWAY Disclaimer This information is provided “as is” for general educational purposes; it can change over time and should be interpreted with regards to this particular circumstance. While much effort is made to provide complete information, Ohio State University and Gateway do not guarantee the accuracy and reliability of any information contained or displayed in the presentation. We disclaim any warranty, expressed or implied, including the warranties of fitness for a particular purpose. We do not assume any legal liability or responsibility for the accuracy, completeness, reliability, timeliness or usefulness of any information, or processes disclosed. Nor will Ohio State University or Gateway be held liable for any improper or incorrect use of the information described and/or contain herein and assumes no responsibility for anyone’s use of the information. Reference to any specific commercial product, process, or service by trade name, trademark, manufacture, or otherwise does not necessarily constitute or imply its endorsement.