Mechanical Module 3 PDF

Module 3 Modern Manufacturing Tools and Techniques CNC: Introduction, components of CNC, advantages and applications of CNC, CNC Machining centres and Turning Centers, Concepts of Smart Manufacturing and Industrial IoT. Additive Manufacturing: Introduction to reverse Engineering, Traditional...

Module 3 Modern Manufacturing Tools and Techniques CNC: Introduction, components of CNC, advantages and applications of CNC, CNC Machining centres and Turning Centers, Concepts of Smart Manufacturing and Industrial IoT. Additive Manufacturing: Introduction to reverse Engineering, Traditional manufacturing vs. Additive Manufacturing, Computer aided design (CAD) and Computer aided manufacturing (CAM) and Additive Manufacturing (AM), Different AM processes, Rapid Prototyping, Rapid Tooling, 3D printing: Introduction, Classification of 3D printing process, Applications to various fields.  CNC Basics and Advance Dr. Rahul Kumar, SOE, DSU  Introduction Machining is basically removal of material, most often metal, from the work-piece, using one or more cutting tools to achieve the desired dimensions. There are different machining processes, such as, turning, milling, boring etc. For example, as seen in a turning operation of lathes, the “job” or the work-piece rotates in a chuck, while the tool moves in two dimensions translationally. On the other hand, in milling, it is the cutter which rotates on a spindle, while the work-piece, which is fastened to a table, moves in X-Y dimensions. While, a precise and high speed rotational motion is needed for good finish of the machined surface, for dimensional accuracy, precise position and velocity control of the table drive are essential. Dr. Rahul Kumar, SOE, DSU Contd… Dr. Rahul Kumar, SOE, DSU  Contd… For all metal-cutting processes, the cutting speed, feed, and depth of cut are important parameters. Dr. Rahul Kumar, SOE, DSU  Why Computer Numerical Control? Modern precision manufacturing demands extreme dimensional accuracy and surface finish. Such performance is very difficult to achieve manually, if not impossible, even with expert operators. In cases where it is possible, it takes much higher time due to the need for frequent dimensional measurement to prevent overcutting. Dr. Rahul Kumar, SOE, DSU  Numerical Control Automatically controlling a machine tool based on a set of pre programmed machining and movement instructions is known as numerical control, or NC. In a typical NC system the motion and machining instructions and the related numerical data, together called a part program, used to be written on a punched tape. The part program is arranged in the form of blocks of information, each related to a particular operation in a sequence of operations needed for producing a mechanical component. The punched tape used to be read one block at a time. Each block contained, in a particular syntax, information needed for processing a particular machining instruction such as, the segment length, its cutting speed, feed, etc. Dr. Rahul Kumar, SOE, DSU  Contd… These pieces of information are related to the final dimensions of the work-piece (length, width, and radii of circles) and the contour forms (linear, circular, or other) as per the drawing. Based on these dimensions, motion commands were given separately for each axis of motion. Other instructions and related machining parameters, such as cutting speed, feed rate, as well as auxiliary functions related to coolant flow, spindle speed, part clamping, are also provided in part programs depending on manufacturing specifications such as tolerance and surface finish. Punched tapes are mostly obsolete now, being replaced by magnetic disks and optical disks. Dr. Rahul Kumar, SOE, DSU  Computer Numerical Control Computer Numerically Controlled (CNC) machine tools, the modern versions of NC machines have an embedded system involving several microprocessors and related electronics as the Machine Control Unit (MCU). Initially, these were developed in the seventies in the US and Japan. However, they became much more popular in Japan than in the US. In CNC systems multiple microprocessors and programmable logic controllers work in parallel for simultaneous servo position and velocity control of several axes of a machine for contour cutting as well as monitoring of the cutting process and the machine tool. Dr. Rahul Kumar, SOE, DSU  Parts of CNC Machine: Input Device These are the device that is used to input part programs in a CNC machine. There are three commonly used input devices, & these are punch tape readers, magnetic tape readers, and computers Machine Control Unit (MCU) This is the heart of the CNC machine. It performs all the controls functions of the CNC machine, the various tasks performed by the MCU are It reads the coded instructions givens in it. It decodes the coded Machineinstruction. Tools A CNC machine tool always has a slidings table & a spindle to control position and speed. The machine tables are controlled in the X and Y-axis direction, & the spindle is controlled in the Z-axis direction. Feedback System Driving System The system consists of transducers that act as The driving system of the CNC machine sensors. It is also called a measurement system. It consists of an amplifier circuit, drive motors, consists of position and motion transducers that and ball lead screws. The MCU feeds the continuously monitor the position and speed of the signals (i.e., position and speed) of eachDr.axis cutting Rahul Kumar, tool located at any given moment. SOE, DSU into the amplifier circuit.  Classification of NC Systems CNC machine tool systems can be classified in various ways such as : 1. Point-to-point or contouring : depending on whether the machine cuts metal while the work-piece moves relative to the tool. 2. Incremental or absolute : depending on the type of coordinate system adopted to parameterise the motion commands. 3. Open-loop or closed-loop : depending on the control system adopted for axis motion control. Dr. Rahul Kumar, SOE, DSU  Point-to-point systems Point-to-point (PTP) systems are the ones where, either the work piece or the cutting tool is moved with respect to the other as stationary until it arrives at the desired position and then the cutting tool performs the required task with the motion axes stationary. Such systems are used, typically, to perform hole operations such as drilling, boring, reaming, tapping and punching. In a PTP system, the path of the cutting tool and its feed rate while traveling from one point to the next are not significant, since, the tool is not cutting while there is motion. Therefore, such systems require only control of only the final position of the tool. The path from the starting point to the final position need not be controlled. Dr. Rahul Kumar, SOE, DSU  Contouring systems In contouring systems, the tool is cutting while the axes of motion are moving, such as in a milling machine. All axes of motion might move simultaneously, each at a different velocity. When a nonlinear path is required, the axial velocity changes, even within the segment. For example, cutting a circular contour requires sinusoidal rates of change in both axes. The motion controller is therefore required to synchronize the axes of motion to generate a predetermined path, generally a line or a circular arc. Dr. Rahul Kumar, SOE, DSU  Coordinate Systems The coordinate system is defined by the definition of the translational and rotational motion coordinates. Each translational axis of motion defines a direction in which the cutting tool moves relative to the work piece. The main three axes of motion are referred to as the X, Y and Z axes. The Z axis is perpendicular to both X and Y in order to create a right-hand coordinate system, A positive motion in the Z direction moves the cutting tool away from the work-piece. The location of the origin is generally adjustable. Figure 3 shows the coordinate system for turning as in a lathe while Fig. 4 shows the system for drilling and milling. Dr. Rahul Kumar, SOE, DSU  Contd… For a lathe, the in feed/radial axis is the x-axis, the carriage/length axis is the z-axis. There is no need for a y-axis because the tool moves in a plane through the rotational centre of the work. Coordinates on the work piece shown below are relative to the work. Dr. Rahul Kumar, SOE, DSU  Contd… In drilling and milling machines the X and Y axes are horizontal. For example, a positive motion command in the drill moves the X axis from left to right, the Y axis from front to back, and the Z axis toward the top. In the lathe only two axes are required to command the motions of the tool. Since the spindle is horizontal, the Z axis is horizontal as well. The cross axis is denoted by X. A positive position command moves the Z axis from left to right and the X axis from back to front in order to create the right-hand coordinate system. Dr. Rahul Kumar, SOE, DSU  Incremental Systems In an incremental system the movements in each Part program block are expressed as the displacements along each coordinate axes with reference to the final position achieved at the end of executing the previous program block. Consider, for example, the trajectory of rectilinear motions shown in following figure for a PTP system. In an incremental system, the motion parameters, along the X-axis, for the segments, A-B, B-C, C-D, D-E, E-F and F-A, would be given as, 50, 20, 60, -30, -70 and –30, respectively. Dr. Rahul Kumar, SOE, DSU  Absolute System An absolute NC system is one in which all position coordinates are referred to one fixed origin called the zero point. The zero point may be defined at any suitable point within the limits of the machine tool table and can be redefined from time to time. Any particular definition of the zero point remains valid till another definition is made. In the previous figure, considering the X-coordinate for point A as zero, the X-coordinate for points B and C would be 50 and 70, respectively, in an absolute coordinate system. Most modem CNC systems permit application of both incremental and absolute programming methods. Even within a specific part program the method can be changed Dr. Rahul Kumar, SOE, DSU  Part Programming A part program is a set of instructions often referred to as blocks, each of which refers to a segment of the machining operation performed by the machine tool. Each block may contain several code words in sequence. These provide: Coordinate values (X, Y, Z, etc.) to specify the desired motion of a tool relative to a work piece. The coordinate values are specified within motion code word and related interpolation parameters to indicate the type of motion required (e.g. point-to-point, or continuous straight or continuous circular) between the start and end coordinates. The CNC system computes the instantaneous motion command signals from these code words and applies them to drive units of the machine. Dr. Rahul Kumar, SOE, DSU  Contd… Machining parameters such as, feed rate, spindle speed, tool number, tool offset compensation parameters etc. Codes for initiating machine tool functions like starting and stopping of the spindle, on/off control of coolant flow and optional stop. In addition to these coded functions, spindle speeds, feeds and the required tool numbers to perform machining in a desired sequence are also given. Program execution control codes, such as block skip or end of block codes, block number etc. Statements for configuring the subsystems on the machine tool such as programming the axes, configuring the data acquisition system etc. Dr. Rahul Kumar, SOE, DSU  Contd… A typical block of a Part program is shown below. Note that the block contains a variety of code words such G codes, M codes etc. Each of these code words configure a particular aspect of the machine, to be used during the machining of the particular segment that the block programmes. Dr. Rahul Kumar, SOE, DSU  Contd… A typical sequence of operations in a part program would be, Introductory functions such as units, coordinate definitions, coordinate conventions, such as, absolute or relative etc. Feeds, speeds, etc. Coolants, doors, etc. Cutting tool movements and tool changes Shutdown Dr. Rahul Kumar, SOE, DSU  A basic list of ‘G’ operation codes G00 - Rapid move (not cutting) G78 - multiple threading cycle G31 - Stop on input G01 - Linear move G33-35 - thread cutting functions G80 - fixed cycle cancel G35 - wait for input to go low G81-89 - fixed cycles specified by G02 - Clockwise circular motion machine tool manufacturers G36 - wait for input to go high G81 - drilling cycle G03 - Counter clockwise circular G40 - cutter compensation cancel G82 - straight drilling cycle with dwell motion G41 - cutter compensation to the G83 - drilling cycle G04 - Dwell left G83 - peck drilling cycle G05 - Pause (for operator intervention)G42 - cutter compensation to the G84 - taping cycle right G85 - reaming cycle G08 - Acceleration G85 - boring cycle G43 - tool length compensation, G09 - Deceleration G86 - boring with spindle off and dwell positive cycle G17 - x-y plane for circular G44 - tool length compensation, G89 - boring cycle with dwell G71 - set metric units or stock removal interpolation negative G72 - indicate finishing cycle G90 - absolute dimension program G50 G91 - incremental dimensions G18 - z-x plane for circular G72 -- 3D Pre-set position circular interpolation clockwise G19 - y-z plane for circular interpolation G70 - set inch based units or G73 - turning cycle contour G92 - Spindle speed limit interpolation G93 - Coordinate system setting finishing cycle interpolation counter G73 - 3D circular G20 - turning cycle or inch data G94 - Feed rate in ipm clockwise G95 - Feed rate in ipr specification G74 - facing cycle contour G96 - Surface cutting speed G21 - thread cutting cycle or metric G74.1 - disable 360 degree arcs G97 - Rotational speed in rpm data specification G75 - pattern repeating G98 - withdraw the tool to the starting G75.1 - enable 360 degree arcs G24 - face turning cycle point or feed per minute G76 - deep hole drilling, cut cycle in z-axis G25 - wait for input to go low G77 - cut-in cycle in x-axis G99 - withdraw the tool to a safe plane or G26 - wait for input to go high feed per revolution G28 - return to reference point Dr. Rahul Kumar, SOE, DSU G101 - Spline interpolation G29 - return from reference point  M-Codes control machine functions M00 - program stop M30 - end of tape (rewind) M09 - turn off accessory M35 - set output #2 off M01 - optional stop using stop button M10 - turn on accessory M36 - set output #2 on M02 - end of program M11 - turn off accessory or tool M38 - put stepper motors on low M03 - spindle on CW change power standby M17 - subroutine end M47 - restart a program M04 - spindle on CCW M20 - tailstock back continuously, or a fixed number M05 - spindle off M20 - Chain to next program of times M06 - tool change M21 - tailstock forward M71 - puff blowing on M22 - Write current position to M72 - puff blowing off M07 - flood with coolant data file M96 - compensate for rounded M08 - mist with coolant M25 - open chuck external curves M08 - turn on accessory (e.g. AC powerM25 - set output #1 off M97 - compensate for sharp outlet) M26 - close chuck external curves M09 - coolant off M26 - set output #1 on M98 - subprogram call M99 - return from subprogram, jump instruction M101 - move x-axis home M102 - move y-axis home M103 - move z-axis home Dr. Rahul Kumar, SOE, DSU  Advantages of CNC Machining Machining is accurate and have very high precision Time taken to perform a job is very less Number of operators required to operate a machine are reduced No possibility of human error Reliable Even very complex designs can also be made Low maintenance required CNC Machining Produces Little to No Waste. Zero Defects and Greater Accuracy. Faster and Efficient Production. Quicker Assembly. Enhanced Personnel Safety. Reduction in Energy Consumption. Dr. Rahul Kumar, SOE, DSU  Smart Manufacturing Smart manufacturing (SM) is a technology-driven approach that utilizes Internet-connected machinery to monitor the production process. The goal of SM is to identify opportunities for automating operations and use data analytics to improve manufacturing performance. SM is a specific application of the Industrial Internet of Things (IIoT). Deployments involve embedding sensors in manufacturing machines to collect data on their operational status and performance. In the past, that information typically was kept in local databases on individual devices and used only to assess the cause of equipment failures after they occurred. Now, by analyzing the data streaming off an entire factory's worth of machines, or even across multiple facilities, manufacturing engineers and data analysts can look for signs that particular parts may fail, enabling preventive maintenance to avoid unplanned downtime on devices. Dr. Rahul Kumar, SOE, DSU In addition to the Internet of Things, there are a number of technologies that will help enable smart manufacturing, including: Artificial intelligence (AI)/machine learning – enables automatic decision-making based on the reams of data that manufacturing companies collect. AI/machine learning can analyze all this data and make intelligent decisions based on the inputted information. Drones and driverless vehicles – can increase productivity by reducing the number of workers needed to do rote tasks, such as moving vehicles across a facility. Block-chain – Blockchain's benefits, including immutability, traceability and disintermediation, can provide a fast and efficient way to record and store data. Edge computing – edge computing helps manufacturers turn massive amounts of machine- generated data into actionable data to gain insights to improve decision-making. To accomplish this, it uses resources connected to a network, such as alarms or temperature sensors, enabling data analytics to happen at the data source. Predictive analytics – companies can analyze the use huge amounts of data they collect from all their data sources to anticipate problems and improve forecasting. Digital twins – companies can use digital twins to model their processes, networks and machines in a virtual environment, then use them to predict problems before they happen as well as boost efficiency and productivity. Dr. Rahul Kumar, SOE, DSU  How SM differs from traditional manufacturing approaches Traditional manufacturing methods, developed during the age of mass production, focus on economy of scale and machine utilization. The thinking was that if a machine was idle, it was losing money, so companies kept them running continuously. To achieve customer satisfaction, traditional manufacturing companies keep large inventories on hand so they can fulfill potential orders. This is known as batch-and-queue processing – a mass production approach to operations where the parts are processed and moved to the next process, whether they're needed or not, Smartand wait in a line (queue). manufacturing, on the other hand, is a collaborative, fully-integrated manufacturing system that responds in real-time to meet changing the conditions and demands in the factory, in the supply network, and in the needs of the customers. The goal of smart manufacturing is to optimize the manufacturing process using a technology-driven approach that utilizes Internet-connected machinery to monitor the production process. Smart manufacturing enables organizations to identify opportunities for automating operations and use data analytics to improve manufacturing performance. Dr. Rahul Kumar, SOE, DSU Reverse Engineering Purposes solved Dissection and analysis Experience and knowledge for an individual’s personal database Competitive benchmarking Dr. Rahul Kumar, SOE, DSU Introduction to additive manufacturing Introduction to AM Dr. Rahul Kumar, SOE, DSU  Additive Manufacturing INTRODUCTION: WHAT IS IT: Additive Manufacturing by ASTM (American Society for Testing and Materials ): “Process of joining materials to make objects from 3D model data, usually layer upon layer, as opposed to subtractive manufacturing methodologies, such as traditional machining” NAMING: Rapid Prototyping: This term was used in the beginning of the professional use of the technology because the main application was the manufacturing of prototypes, mock ups and sample parts.  Introduction to AM Additive Manufacturing (AM) refers to a process by which digital 3D design data is used to build up a component in layers by depositing material. “What You See Is What You Build (WYSIWYB) Process” Dr. Rahul Kumar, SOE, DSU Additive vs. Subtractive Manufacturing Features that represent problems using CNC machining Dr. Rahul Kumar, SOE, DSU  Distinction Between AM and CNC Machining AM shares some of its DNA with CNC machining technology. CNC is also a computer-based technology that is used to manufacture products. CNC differs mainly in that it is primarily a subtractive rather than additive process, requiring a block of material that must be at least as big as the part that is to be made. Dr. Rahul Kumar, SOE, DSU  The Generic AM Process Generic process of CAD Dr. toRahul part, showing Kumar, SOE, DSU all eight stages  The Generic AM Process Step 1: CAD All AM parts must start from a software model that fully describes the external geometry. This can involve the use of almost any professional CAD solid modeling software, but the output must be a 3D solid or surface representation. Reverse engineering equipment (e.g., laser and optical scanning) can also be used to create this representation. Step 2: Conversion to STL This file describes the external closed surfaces of the original CAD model and forms the basis for calculation of the slices. Dr. Rahul Kumar, SOE, DSU  The Generic AM Process Step 3: Transfer to AM Machine and STL File. The STL file describing the part must be transferred to the AM machine. Here, there may be some general manipulation of the file so that it is the correct size, position, and orientation for building. Step 4: Machine Setup The AM machine must be properly set up prior to the build process. Such settings would relate to the build parameters like the material constraints, energy source, layer thickness, timings, etc. Step 5: Build Building the part is mainly an automated process and the machine can largely carry on without supervision. Only superficial monitoring of the machine needs to take place at this time to ensure no errors have taken place like running out of material, power or software glitches, etc. Dr. Rahul Kumar, SOE, DSU  The Generic AM Process Step 6: Removal Once the AM machine has completed the build, the parts must be removed. This may require interaction with the machine, which may have safety interlocks to ensure for example that the operating temperatures are sufficiently low or that there are no actively moving parts. Step 7: Post-processing Once removed from the machine, parts may require an amount of additional cleaning up before they are ready for use. Parts may be weak at this stage or they may have supporting features that must be removed. Step 8: Application Parts may now be ready to be used. However, they may also require additional treatment before they are acceptable for use. For example, they may require priming and painting to give an acceptable surface texture and finish. Dr. Rahul Kumar, SOE, DSU Classification of AM processes Dr. Rahul Kumar, SOE, DSU  Additive Manufacturing Stereolithography (SL) It is widely recognized as the first 3D printing process. SL is a laser-based process that works with photopolymer resins, that react with the laser and cure to form a solid in a very precise way to produce very accurate parts. It is a complex process in which the photopolymer resin is held in a vat with a movable platform inside. A laser beam is directed in the X-Y axes across the surface of the resin according to the 3D data supplied to the machine (the.stl file), whereby the resin hardens precisely where the laser hits the surface. Once the layer is completed, the platform within the vat drops down by a fraction (in the Z axis) and the subsequent layer is traced out by the laser. This continues until the entire object is completed and the platform can be raised out of the vat for removal. Because of the nature of the SL process, it requires support structures for some parts, specifically those with overhangs or undercuts. These structures need to be manually removed. In terms of other post processing steps, many objects 3D printed using SL need to be cleaned and cured. Curing involves subjecting the part to intense light in an oven-like machine to fully harden the resin. Stereolithography is generally accepted as being one of the most accurate 3D printing processes with excellent surface finish. However limiting factors include the post-processing steps required and the stability of the materials over time, which can become more brittle.  Additive Manufacturing Digital Light Processing (DLP) DLP is a similar process to Stereolithography in that it is a 3D printing process that works with photopolymers. The major difference is the light source. DLP uses a more conventional light source, such as an arc lamp, with a liquid crystal display panel or a deformable mirror device (DMD), which is applied to the entire surface of the vat of photopolymer resin in a single pass, generally making it faster than SL. Also like SL, DLP produces highly accurate parts with excellent resolution, but its similarities also include the same requirements for support structures and post-curing. However, one advantage of DLP over SL is that only a shallow vat of resin is required to facilitate the process, which generally results in less waste and lower running costs.  Additive Manufacturing Laser sintering and laser melting (SL, SLM) These are interchangeable terms that refer to a laser based 3D Printing process that works with powdered materials. The laser is traced across a powder bed of tightly Compacted powdered material, according to the 3D data fed to the machine, in the X-Y axes. As the laser interacts with the surface of the powdered material it sinters, or fuses, the particles to each other forming a solid. As each layer is completed the powder bed drops incrementally and a roller smoothes the powder over the surface of the bed prior to the next pass of the laser for the subsequent layer to be formed and fused with the previous layer. The build chamber is completely sealed as it is necessary to maintain a precise temperature during the process specific to the melting point of the powdered material of choice. Once finished, the entire powder bed is removed from the machine and the excess powder can be removed to leave the ‘printed’ parts. One of the key advantages of this process is that the powder bed serves as an in-process support structure for overhangs and undercuts, and therefore complex shapes that could not be manufactured in any other way are possible with this process.  Additive Manufacturing Laser sintering and laser melting (SL, SLM) However, on the downside, because of the high temperatures required for laser sintering, cooling times can be considerable. Furthermore, porosity has been an historical issue with this process, and while there have been significant improvements towards fully dense parts, some applications still necessitate infiltration with another material to improve mechanical characteristics. Laser sintering can process plastic and metal materials, although metal sintering does require a much higher powered laser and higher in-process temperatures. Parts produced with this process are much stronger than with SL or DLP, although generally the surface finish and accuracy is not as good.  Additive Manufacturing Fused Deposition Modelling FDM & Freeform Fabrication FFF 3D printing utilizing the extrusion of thermoplastic material is easily the most common — and recognizable — 3DP process. The most popular name for the process is Fused Deposition Modelling, due to its longevity, however this is a trade name, registered by Stratasys, the company that originally developed it. Stratasys’ FDM technology has been around since the early 1990’s and today is an industrial grade 3D printing process. However, the proliferation of entry-level 3D printers that have emerged since 2009 largely utilize a similar process, generally referred to as Freeform Fabrication, but in a more basic form due to patents still held by Stratasys. The process works by melting plastic filament that is deposited, via a heated extruder, a layer at a time, onto a build platform according to the 3D data supplied to the printer. Each layer hardens as it is deposited and bonds to the previous layer.  Additive Manufacturing Short Additive introduction to the technology Manufacturing Fused Deposition Modelling (FDM) & Freeform Fabrication (FFF) Stratasys has developed a range of proprietary industrial grade materials for its FDM process that are suitable for some production applications. At the entry-level end of the market, materials are more limited, but the range is growing. The most common materials for entry-level FFF 3D printers are ABS and PLA. The FDM/FFF processes require support structures for any applications with overhanging geometries. For FDM, this entails a second, water-soluble material, which allows support structures to be relatively easily washed away, once the print is complete. Alternatively, breakaway support materials are also possible, which can be removed by manually snapping them off the part. Support structures, or lack thereof, have generally been a limitation of the entry level FFF 3D printers. However, as the systems have evolved and improved to incorporate dual extrusion heads, it has become less of an issue. In terms of models produced, the FDM process from Stratasys is an accurate and reliable process that is relatively office/studio- friendly, although extensive post-processing can be required. At the entry-level, as would be expected, the FFF process produces much less accurate models, but things are constantly improving. The process can be slow for some part geometries and layer-to- layer adhesion can be a problem, resulting in parts that are not watertight. Again, post-processing using Acetone can resolve these issues.  Additive Manufacturing Short Additive introduction to the technology Manufacturing Laminated object manufacturing (LOM) It is a rapid prototyping system developed by Helisys Inc. In it, layers of adhesive-coated paper, plastic, or metal laminates are successively glued together and cut to shape with a knife or laser cutter. Objects printed with this technique may be additionally modified by machining or drilling after printing. Typical layer resolution for this process is defined by the material feedstock and usually ranges in thickness from one to a few sheets of copy paper.  Additive Manufacturing Short Additive introduction to the technology Manufacturing Binder Jetting There are two 3D printing process that utilize a jetting technique. Binder jetting: where the material being jetted is a binder, and is selectively sprayed into a powder bed of the part material to fuse it a layer at a time to create/print the required part. As is the case with other powder bed systems, once a layer is completed, the powder bed drops incrementally and a roller or blade smoothes the powder over the surface of the bed, prior to the next pass of the jet heads, with the binder for the subsequent layer to be formed and fused with the previous layer. Advantages of this process, like with SLS, include the fact that the need for supports is negated because the powder bed itself provides this functionality. Furthermore, a range of different materials can be used, including ceramics and food. A further distinctive advantage of the process is the ability to easily add a full colour palette which can be added to the binder. The parts resulting directly from the machine, however, are not as strong as with the sintering process and require post-processing to ensure durability.  Additive Manufacturing Short Additive introduction to the technology Manufacturing AM Materials However, there are now way too many proprietary materials from the many different 3D printer vendors to cover them all here. Instead, we will look at the most popular types of material in a more generic way. And also a couple of materials that stand out. Powder Liquid Based Solid Based Based  Additive Manufacturing Short Additive introduction to the technology Manufacturing AM Materials Nylon, or Polyamide, is commonly used in powder form with the sintering process or in filament form with the FDM process. It is a strong, flexible and durable plastic material that has proved reliable for 3D printing. It is naturally white in colour but it can be coloured — pre- or post printing. This material can also be combined (in powder format) with powdered aluminium to produce another common 3D printing material for sintering Alumide. ABS is another common plastic used for 3D printing, and is widely used on the entry-level FDM 3D printers in filament form. It is a particularly strong plastic and comes in a wide range of colours. ABS can be bought in filament form from a number of non- proprietary sources, which is another reason why it is so popular. PLA is a bio-degradable plastic material that has gained traction with 3D printing for this very reason. It can be utilized in resin format for DLP/SL processes as well as in filament form for the FDM process. It is offered in a variety of colours, including transparent, which has proven to be a useful option for some applications of 3D printing. However it is not as durable oars flexible as ABS.  Additive Manufacturing Short Additive introduction to the technology Manufacturing AM Materials Lay-Wood is a specially developed 3D printing material for entry- level extrusion 3D printers. It comes in filament form and is a wood/polymer composite (also referred to as WPC). A growing number of metals and metal composites are used for industrial grade 3D printing. Two of the most common are aluminium and cobalt derivatives. One of the strongest and therefore most commonly used metals for 3D printing is Stainless Steel in powder form for the sintering/ melting/EBM processes. It is naturally silver, but can be plated with other materials to give a gold or bronze effect. In the last couple of years Gold and Silver have been added to the range of metal materials that can be 3D printed directly, with obvious applications across the jewellery sector. These are both very strong materials and are processed in powder form. Titanium is one of the strongest possible metal materials and has been used for 3D printing industrial applications for some time. Supplied in powder form, it can be used for the sintering/melting/ EBM processes.  Additive Manufacturing Short Additive introduction to the technology Manufacturing AM Materials Ceramics Ceramics are a relatively new group of materials that can be used for 3D printing with various levels of success. The particular thing to note with these materials is that, post printing, the ceramic parts need to undergo the same processes as any ceramic part made using traditional methods of production - namely firing and glazing. Paper Standard A4 copier paper is a 3D printing material employed by the proprietary SDL process supplied by Mcor Technologies. The company operates a notably different business model to other 3D printing vendors, whereby the capital outlay for the machine is in the mid-range, but the emphasis is very much on an easily obtainable, cost-effective material supply, that can be bought locally. 3D printed models made with paper are safe, environmentally friendly, easily recyclable and require no post-processing. Bio Materials There is a huge amount of research being conducted into the potential of 3D printing bio materials for a host of medical (and other) applications. Living tissue is being investigated at a number of leading institutions with a view to developing applications that include printing human organs for transplant, as well as external tissues for replacement body parts. Other research in this area is focused on developing food stuffs - meat being the prime example.  Additive Manufacturing Short Additive introduction to the technology Manufacturing AM Materials Food Experiments with extruders for 3D printing food substances has increased dramatically over the last couple of years. Chocolate is the most common (and desirable). There are also printers that work with sugar and some experiments with pasta and meat. Looking to the future, research is being undertaken, to utilize 3D printing technology to produce finely balanced whole meals. Other And finally, one company that does have a unique (proprietary) material offering is Stratasys, with its digital materials for the Objet Connex 3D printing platform. This offering means that standard Objet 3D printing materials can be combined during the printing process — in various and specified concentrations to form new materials with the required properties. Up to 140 different Digital Materials can be realized from combining the existing primary materials in different ways.  Additive Manufacturing Short Additive introduction to the technology Manufacturing Advantages: Design complexity and freedom: The advent of 3D printing has seen a proliferation of products (designed in digital environments), which involve levels of complexity that simply could not be produced physically in any other way. While this advantage has been taken up by designers and artists to impressive visual effect, it has also made a significant impact on industrial applications, whereby applications are being developed to materialize complex components that are proving to be both lighter and stronger than their predecessors. Speed: You can create complex parts within hours , with limited human resources. Only machine operator is needed for loading the data and the powder material, start the process and finally for the finishing. During the manufacturing process no operator is needed. Customisation 3D printing processes allow for mass customisation — the ability to personalize products according to individual needs and requirements. Even within the same build chamber, the nature of 3D printing means that numerous products can be manufactured at the same time according to the end-users requirements at no additional process cost. Extreme Lightweight design AM enable weight reduction via topological optimization  Additive Manufacturing Short Additive introduction to the technology Manufacturing Advantages: Tool-less For industrial manufacturing, one of the most cost-, time- and labor-intensive stages of the product development process is the production of the tools. For low to medium volume applications, industrial 3D printing — or additive manufacturing — can eliminate the need for tool production and, therefore, the costs, lead times and labor associated with it. This is an extremely attractive proposition, that an increasing number or manufacturers are taking advantage of. Furthermore, because of the complexity advantages stated above, products and components can be designed specifically to avoid assembly requirements with intricate geometry and complex features further eliminating the labor and costs associated with assembly processes. Sustainable / Environmentally Friendly 3D printing is also emerging as an energy-efficient technology that can provide environmental efficiencies in terms of both the manufacturing process itself, utilising up to 90% of standard materials, and, therefore, creating less waste, but also throughout an additively manufactured product’s operating life, by way of lighter and stronger design that imposes a reduced carbon footprint compared with traditionally manufactured products. No storage cost Since 3D printers can “print” products as and when needed, and does not cost more than mass manufacturing, no expense on storage of goods is required. Increased employment opportunities Widespread use of 3D printing technology will increase the demand for designers and technicians to operate 3D printers and create blueprints for products.  Additive Manufacturing Additive Short Manufacturing introduction to the technology Disadvantages: Questionable Accuracy 3D printing is primarily a prototyping technology, meaning that parts created via the technology are mainly test parts. As with any viable test part, the dimensions have to be precise in order for engineers to get an accurate read on whether or not a part is feasible. While 3D printers have made advances in accuracy in recent years, many of the plastic materials still come with an accuracy disclaimer. For instance, many materials print to either +/- 0.1 mm in accuracy, meaning there is room for error. Support material removal When production volumes are small, the removal of support material is usually not a big issue. When the volumes are much higher, it becomes an important consideration. Support material that is physically attached is of most concern. Limitations of raw material At present, 3D printers can work with approximately 100 different raw materials. This is insignificant when compared with the enormous range of raw materials used in traditional manufacturing. More research is required to devise methods to enable 3D printed products to be more durable and robust. Considerable effort required for application design and for setting process parameters Complex set of around 180 material, process and other parameters and specific design required to fully profit from the technology Material cost: Today, the cost of most materials for additive systems ( Powder ) is slightly greater than that of those used for traditional manufacturing.  Additive Manufacturing Short Additive introduction to the technology Manufacturing Disadvantages: Material properties: A limited choice of materials is available. Actually, materials and there properties (e.g., tensile property, tensile strength, yield strength, and fatigue) have not been fully characterized. Also, in terms of surface quality, even the best RM processes need perhaps secondary machining and polishing to reach acceptable tolerance and surface finish. Intellectual property issues The ease with which replicas can be created using 3D technology raises issues over intellectual property rights. The availability of blueprints online free of cost may change with for-profit organizations wanting to generate profits from this new technology. Limitations of size 3D printing technology is currently limited by size constraints. Very large objects are still not feasible when built using 3D printers. Cost of printers The cost of buying a 3D printer still does not make its purchase by the average householder feasible. Also, different 3D printers are required in order to print different types of objects. Also, printers that can manufacture in colour are costlier than those that print monochrome objects. Unchecked production of dangerous items Liberator, the world’s first 3D printed functional gun, showed how easy it was to produce one’s own weapons, provided one had access to the design and a 3D printer. Governments will need to devise ways and means to check this dangerous tendency.  Additive Manufacturing Short Additive introduction to the technology Manufacturing The AM value chain consists of five steps – AM system providers are active in most areas of the value chain Application Material System Software Production design Mainly: Creation of >Usually stand- >Differentiation > Support for end >Different production metal powder alone powder bed between process customers scenarios: > Powder with high fusion systems control and > Can be complex - Large OEM purity and a very > System providers enhancement and demanding - Contract narrow distribution with low levels of software > Done by system manufacturer/service of the granular size vertical integration, > Process control providers, software provider (usually 30µm) standard from system prov. developers and/or - Specialized part > Hard to get from components > Add-on software service providers manufacturer large providers due usually made by such as automatic > Not every service > Production is normally to small orders contract support generation, provider is able to not done >Usually sold by manufacturers design optimization design applications by AM System providers AM system > Providers By specialized providers integrate companies components system & software Players: Players: Players: Players: Players: > Höganäs > EOS > Materialise > 3T PRD > 3T PRD > TLS Technik > SLM Solutions > netfabb > Concept Laser > Janke Engin. > San > Concept Laser > With > EOS > Layer Wise > etc. > etc. > etc. > etc. > etc.  Additive Manufacturing Short 3D introduction Printing to the technology History of 3D Printing: 2000- 1980-2000 The earliest 3D printing technologies first became visible in the late 1980’s, at which time they were called Rapid Prototyping (RP) technologies. This is because the processes were originally conceived as a fast and more cost-effective method for creating prototypes for product development within industry. 1983 Charles Hull invents Stereolithography (SLA) Charles ‘Chuck’ Hull was the first to develop a technology for creating solid objects from a CAD/CAM file, inventing the process he termed ‘stereolithography’ in 1983. SLA works by curing and solidifying successive layers of liquid photopolymer resin using an ultraviolet laser. The field that came to be known variously as 'additive  3D Printing “3D PRINTING’S POTENTIAL TO REVOLUTIONIZE MANUFACTURING IS QUICKLY BECOMING A REALITY.”  3D Printing Technology The starting point for any 3D printing process is a 3D digital model, which can be created using a variety of 3D software programmes. The model is then ‘sliced’ into layers, thereby converting the design into a file readable by the 3D printer. The material processed by the 3D printer is then layered according to the design and the process. Dr. Rahul Kumar, SOE, DSU l available types of 3D Printers Dr. Rahul Kumar, SOE, DSU  3D Printing, Additive Manufacturing and Rapid Prototyping Between the terms 3D printing and additive manufacturing, there is no difference. 3D printing and additive manufacturing are synonyms for the same process. Both terms reference the process of building parts by joining material layer by layer from a CAD file. The term rapid prototyping is different from 3D printing/additive manufacturing. Rapid prototyping is the technique of fabricating a prototype model from a CAD file. In other words, 3D printing/additive manufacturing is the process, and rapid prototyping is the end result. Rapid prototyping is one ofDr. Rahul many applications Kumar, SOE, DSU under the 3D  Current and future applications of 3D Printing Biomedical Engineering In recent years scientists and engineers have already been able to use 3D printing technology to create body parts and parts of organs. Aerospace and Automobile Manufacturing High technology companies such as aerospace and automobile manufacturers have been using 3D printing as a prototyping tool for some time now Construction and Architecture Architects and city planners have been using 3D printers to create a model of the layout or shape of a building for many years. Now they are looking for ways of employing the 3D printing concept to create entire buildings. Dr. Rahul Kumar, SOE, DSU  Computer Aided Manufacturing Computer-aided manufacturing (CAM) also known as computer-aided machining is the use of software to control machine tools in the manufacturing of work pieces. It is the use of software and computer-controlled machinery to automate a manufacturing process. CAM is a subsequent computer-aided process after computer-aided design (CAD) and sometimes computer- aided engineering (CAE), as the model generated in CAD and verified in CAE can be input into CAM software, which then controls the machine tool. Without CAM, there is no CAD. CAD focuses on the design of a product or part. How it looks, how it functions. CAM focuses on how to makeDr.it. Rahul Kumar, SOE, DSU  CAD to CAM Process The start of every engineering process begins in the world of CAD. Engineers will make either a 2D or 3D drawing, whether that’s a crankshaft for an automobile, the inner skeleton of a kitchen faucet, or the hidden electronics in a circuit board. In CAD, any design is called a model and contains a set of physical properties that will be used by a CAM system. When a design is complete in CAD, it can then be loaded into CAM. This is traditionally done by exporting a CAD file and then importing it into CAM software. Once your CAD model is imported into CAM, the software starts preparing the model for machining. Machining is the controlled process of transforming raw material into a defined shape through actions like cutting, drilling, or boring. Dr. Rahul Kumar, SOE, DSU