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Machines & Machining Issues. Material Removal Process. Mechanical Machining. Turning. Milling. Drilling. Grinding. All hard materials. Machining DOF (Degrees of Freedom). DOF - # of independently controllable axes of motion-- excluding spindle

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Material removal process l.jpg
Material Removal Process

Mechanical Machining

Turning

Milling

Drilling

Grinding

All hard materials


Machining dof degrees of freedom l.jpg
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


Turning operations l.jpg
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


Lathe components l.jpg
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


Lathe l.jpg

Spindle

Speed

Selector

Headstock

Spindle

Ways

Cross Slide

Tool Post

Carriage (saddle)

Center

Tailstock quill

Feed change

gear box

Tailstock

Compound

Rest &

Slide (swivels)

Apron

Bed

Lead

Screw

Feed

Rod

Lathe

Ref: Fig. 8.52, Kalpakjian. Manufacturing Processes for Engineering Materials 2nd Ed, Addison-Wesley 1991.


Lathe tools l.jpg
Lathe Tools

Lathe tools

  • Left handed

  • Right handed

  • Threading

  • Boring

  • Groove

  • Parting (Cut-Off )


Lathe operations l.jpg
Lathe Operations

Ref: Fig. 8.51, Kalpakjian. Manufacturing Processes for Engineering Materials 2nd Ed, Addison-Wesley 1991.


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Cutting Speeds

Typical Lathe Cutting Speeds

  • Nominally 30 - 800 ft./min.

  • Roughing cuts

    • Depth of cut greater then .02 in

    • Feed speed of .008 - .08 in/rev.

  • Finishing Cuts

    • Lower than roughing cuts.


Milling l.jpg
Milling

Types of Milling Machines

  • Horizontal Milling Machine

  • Vertical Milling Machine


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Mill Cutting Direction

Cutting direction- Depending on the orientation of the workpiece feed w.r.t. the rotation of the cutting tool.

  • Conventional (Up) Milling-Maximum thickness of chip at end of cut

Ref: Figure J-48, Kibbe ,et al. Machine Tool

Practices 5th Ed, Prentice Hall,1995.

  • Climb (Down) Milling- Maximum thickness of chip at start of cut.

Ref: Figure J-48, Kibbe ,et al. Machine Tool

Practices 5th Ed, Prentice Hall,1995.


Vertical knee milling machine l.jpg
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: Figure 8.69, Kalpakjian. Manufacturing Processes for

Engineering Materials 2nd Ed, Addison-Wesley 1991.

Ref: Kibbe ,et al. Machine Tool Practices 5th Ed, Prentice Hall,1995, p 550-551


Vertical milling machine l.jpg
Vertical Milling Machine

  • Flexible

  • Versatile

  • Newer machines – more DOF


Bed mill l.jpg
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


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Vertical Milling Applications

Collet

Ref: Process Selection, KG Swift and JD Booker, p.98.




Horizontal milling machine l.jpg
Horizontal Milling Machine

COMPONENTS

Base & Column

Knee

Saddle

Table

Spindle

Overarm & Arbor Support

Ref: Figure 8.68, Kalpakjian. Manufacturing Processes for Engineering Materials 2nd Ed, Addison-Wesley 1991.


Types horizontal milling operations l.jpg
Types Horizontal Milling Operations

  • Slab-Axis of cutter //

  • to workpiece surface

  • Face- Axis of rotation |

  • to workpiece surface

Figure 8.63b, Kalpakjian. Manufacturing Processes for

Engineering Materials 2nd Ed, Addison-Wesley 1991.

Figure 8.63a, Kalpakjian. Manufacturing Processes for

Engineering Materials 2nd Ed, Addison-Wesley 1991.

  • Side- Axis of cutter //

  • to workpiece surface

Figure 8.67c, Kalpakjian. Manufacturing Processes for

Engineering Materials 2nd Ed, Addison-Wesley 1991.


Slide20 l.jpg

Drilling

Any component requiring cylindrical holes.

Engine Blocks, Machine Components

Ref: Process Selection, KG Swift and JD Booker, p.104.


Grinding and abrasive processes l.jpg
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


Grinding machines l.jpg
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


Surface grinders l.jpg
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 5th Ed, Prentice Hall,1995.


Cylindrical grinders l.jpg
Cylindrical Grinders

Centerless Type

Center/Roll Type

Ref: Figures N-8, N-17, N-18, Kibbe ,et al. Machine Tool Practices 5th Ed, Prentice Hall,1995.


Surface roughness l.jpg

(

)

|a| + |b| + |c| + |d| + …

n

Ra=

Surface Roughness

Surface roughness is generally described with 1 of 2 methods

Ra- Arithmetic Mean Value- the average of the absolute values

of the deviations from the center line of the surface

Rq (formerly RMS)- Root Mean Squared-


Roughness units l.jpg
Roughness Units

Both generally given in micrometers (microns) or microinches

  • 1 Micrometer = 1mm = 1 micron = 10-6 meters

  • 1 Microinch = 1min= 10-6 inches

  • 1min = 0.025 mm

  • 1mm = 40 min

  • Human hair ~ 40 mm


Typical arithmetic average roughness l.jpg
Typical Arithmetic Average Roughness

Ref: Fig. 8.35, Kalpakjian. Manufacturing Processes for Engineering Materials 2nd Ed, Addison-Wesley 1991.


Summary l.jpg
Summary

  • Four types of mechanical removal processes

    • Turning

    • Milling

    • Drilling

    • Grinding

  • Finish of workpiece


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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-9109794). 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 Materials2nd Ed, Addison-Wesley 1991

  • Kibbe ,et al. Machine Tool Practices5th Ed, Prentice Hall,1995

  • Swift, KG and JD Booker, Process Selection, Arnold/John Wiley& Sons Inc., New York, 1997


Disclaimer l.jpg
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.