Lecture 2: Art to Part, Machining Operations, and Intro to Process Variable Objectives Understand the workflow in taking design concepts from art to part Be able to examine a <a href="/keyword/manufacturing-processes/" >manufacturing processes</a> to distinguish Process Variables (PVs) from Design Parameters (DPs) Be familiar with <a href="/keyword/manufacturing-processes/" >manufacturing processes</a> seen in the labs including PVs influenced DPs Methods Introduce the workflow in taking concepts from art to part. Introduce <a href="/keyword/manufacturing-processes/" >manufacturing processes</a> (operations) that will be seen in the labs. Examine the process variables and influenced design parameters for some processes that will be used in the labs Reference Material Machining material removal by chip formation In machining operations relative motion of a tool's <a href="/keyword/cutting-edge/" >cutting edge</a> in contact with a workpiece causes a chip of workpiece material to shear off and flow along the rake face of the cutting tool1. Machining operations may be grouped into several categories based on size and number of <a href="/keyword/cutting-edge/" >cutting edge</a> s in contact with the workpiece at one time and the methods for generating the relative motion of the <a href="/keyword/cutting-edge/" >cutting edge</a> s with the workpiece material. Two common types of machining are milling and turning. Milling and Turning The primary differences between milling and turning are the method of fixturing the cutting tools and work pieces and the method for generation of the relative motion between the cutting tool and the workpiece. A typical milling operation will have the workpiece fixed to a table and a cutting tool with one or several <a href="/keyword/cutting-edge/" >cutting edge</a> s fixed to a spindle which is able to rotate about the center axis of the cutting tool. The cutting tool and workpiece are then brought into contact with relative motion by repositioning the table or the spindle or some combination of the two. A typical turning operation will fix the workpiece in a spindle that is able to rotate about the primary axis of the workpiece and the cutting tool is fixed to a linear positioning system. The cutting tool and workpiece are then brought into contact 1 It is typically desirable for the cutting tool material to be harder than the workpiece material. with relative motion typically by motion of the linear positioning system to which the cutting tool is fixed. Manufacturing Engineers Reference Book Koshal, D. (1993). Manufacturing Engineer's Reference Book . Elsevier. Online version available at: http://www.knovel.com/knovel2/Toc.jsp?BookID=431&amp;VerticalID=0 Sections 5.1 and 5.2 Lecture Notes Art to Part, Machining Operations, and Intro to Process Variable Objectives Understand the workflow in taking concepts from art to part Methods Introduce the workflow in taking design concepts from art to part. Be familiar with manufacturing Introduce <a href="/keyword/manufacturing-processes/" >manufacturing processes</a> seen in the labs processes that will be seen in the labs Examine the process Be able to examine a variables and influenced <a href="/keyword/manufacturing-processes/" >manufacturing processes</a> to design parameters for distinguish Process Variables (PVs) from Design Parameters some processes that will be used in the labs (DPs) Solid model (Art) Information flow in CNC Art Part Setup(s) Fixturing Fixture Workpiece Workpiece probe (locates part zero) Machine tool (mill, lathe, VMC, HMC) Machined part Part zero Processes Identify features Tool path (CAM) Load tools Variable selection Tools Feed Speed Depth of cut Tool offsets Clean up Return tools De-burr part Part inspection Lecture Notes Machining operations in ME1800 Turning Milling (Lathe / Turning Center) Horizontal / Vertical X Z (Milling Machine / Machining Center) Horizontal / Vertical Z Y X Saw Cutting Drilling (Band Saw) Horizontal / Vertical Tapping (Milling Machine / Drill Press / Hand Drill) (Milling Machine / hand tapping) Manufacturing Process Material removal by chip formation Relative motion Milling cutting tool edge workpiece Turning Workpiece fixed to &quot;table&quot; Cutting tool rotates in a spindle Workpiece rotates in a spindle Cutting tool fix to a &quot;table&quot; Milling Operations Facing Pocketing Contouring (Profiling) Drilling Rigid Tapping Roughing Finishing Lecture Notes Operations: Roughing Contouring OD ID (Boring) Face OD ID (Boring) Face OD ID Cutoff Turning Common Terms: Feed Speed distance/time distance/revolution Grooving Depth of Cut distance Surface Speed Spindle Speed Threading Rigid Tapping Turning straight down view rotation chuck not shown workpiece T1 uncut chip thickness <a href="/keyword/cutting-edge/" >cutting edge</a> tool tool rake face feed T1= feed cos(scea) side <a href="/keyword/cutting-edge/" >cutting edge</a> angle (scea) Process Variables (PVs) Parameters (independent variables) that are set that determine how the process will run Examples Speed Spindle &quot;RPM&quot; Surface &quot;SPM&quot; Axial feed &quot;Z feedrate&quot;, Radial feed &quot;XY feedrate&quot; Feedrate These parameters influence the economics of the process and the quality of the part through influencing the mechanics of the deformation process Depth of cut &quot;incremental depth&quot; Width of cut &quot;Step over&quot; Lecture Notes More PVs in machining Tools Machine Mini Mill, SL10... Tool holder, and the holder's holder... Cutting insert: WC-cobalt composite coatings - TiN often with ceramic Fixtures hold the workpiece Spindles turn the workpiece (lathe) and turn the tool (milling machine) CAM software Coordinate systems (Datum Surfaces) Tool path selection what is optimized? Type of operation CAM Software Esprit 2007 Look at process pages and help file Further slides for reference Lecture Notes Milling Operations Facing Pocketing Contouring (Profiling) Drilling Rigid Tapping Roughing Finishing Facing Cuts the top surface of the workpiece Pocketing Removes material form inside &quot;Pockets&quot;) Lecture Notes Contouring Cuts around the &quot;edge&quot; of the part Drilling Used for making holes in the workpiece Rigid Tapping Used for cutting threads into previously drilled holes Threads can also be milled or formed Lecture Notes Milling Climb and Conventional Manufacturing Engineer's Reference Book Edited by: Koshal, D. 1993 Elsevier Collet Holder Face Mill Lecture Notes Flat Endmill End Mill Ball Endmill Drilling Operations -- Drills Turning Facing Feed in X dir. Depth of Cut in Z dir. Lecture Notes Turning OD Turning Feed in Z dir. Depth of Cut in X dir. Turning Grooving / Cutoff Turning Grooving / Cutoff Lecture Notes Turning Boring ID Turning Turning Threading Turning Rigid Tapping Lecture Notes Historical development of machine tools Evidence of turning as early as 700BC Turning metals 15th century Eli Whitney in New Haven CT events milling machine replaces highly skilled operators of files used for making rifles 1818 High-speed steel early 20th century Early controls (mass production interchangeable parts) Wilkinson's boring machine - steam engine ~1776 cam surfaces and preset stops full time skilled machinist required fro intricate parts NC -&gt; CNC Precision air foils WWII and cold war 1947 John Parsons jig bore with punch cards 1949 MIT &quot;programmable&quot; milling machine 1952 three axis commercial NC milling machine