Selective Lase Melting, Laser Metal Deposition and Bounded Metal Deposition, a comprehensive comparison

Rick asks you which of the three possible metal AM processes would be best for the part: Selective Laser Melting (SLM), Laser Metals Deposition (LMD), or a recently developed process called Bound Metal Deposition (BDM) by a company called Desktop Metal.

The new design of bracket can be manufactured by any additive manufacturing process, but the material limitation has limited it to just three of the below mention process. Now best of them has to be recommended based on how it will manufactured product means pre-processing, processing and post processing. Other than this the process will also be evaluated on working principal/pattern and what advantages and limitations they have in processing the new design of bracket.

1. Selective laser melting SLM
2. Laser Metal Deposition
3. Bound Metal Deposition

Working

Selective laser melting will manufactured the bracket in two simple steps, first a layer of powder is spread on the machine table and then a laser will print a 2D shape of product by melting (that solidifies instantly) the power of desire shape. Laser metal deposition complete this in single step where a power is melted at the nozzle outlet by a laser and then spread by nozzle in a specific shape on the table. Similarly, bounded metal deposition also melts a binding material mixed with powder to deposit a layer of material on machine table.

Working pattern

Selective laser melting and laser metal deposition does not need any specific post processing process other than cleaning and surface finish if required but bounded metal deposition required binder curing process and melting process in furnace. Surface finish of the laser metal deposition is low as compared to selective layer deposition due to highly converged laser beam which only melts the metal where required in very controlled manner where laser metal deposition spread a paste of metal whose flow or spread cannot be controlled once it leave nozzle.

Bracket Manufacturing

Selective Laser milting, laser metal deposition and bounded metal deposition processes are very similar is terms of depositing the material to manufactured the bracket that is 2D layers of metal is deposited to develop a 3D product but steps in achieving this are very different. Is selective laser melting table used based moves downward with each layer finished where a new layer of powder is deposited which is then metaled by laser to create new 2D layer of metal where laser only moves on 2D plan. Laser metal deposition method use little complex approach where nozzle remain fixed in vertical position and table moves with six degree of freedom to deposit material layers. Bounded metal deposition work by depositing layers of material on static table and heat moves with 3 linear degree of freedom 3DOF.

Advantages and Limitations

Selective laser melting use laser which does not involve much of movement as compared to other two process means machine working is simple understand. Ability of this process to use multiple laser to manufacture one part or use each laser to manufacture multiple parts at once is most prominent feature which other two process lack. This makes an effective production rate of this machine for high volume batch production. Laser metal deposition seems to be the fastest process available with minimum steps required and fast speed of table and laser as compared to selective laser melting and bounded metal deposition but working of this process seems difficult to understand as compared to other two processes due to 6DOF required by table to manufactured product. Bounded metal deposition seems simple as compared to other two processes but number of steps involves in post processing make this process least favorite for this process due to high production rate.

Selection

So based on above discussion selective laser melting can be recommended as best process available for new bracket design as it has simple working process, less steps involve, processing multiple parts at once, high production rate and low or no post processing required.

3D printing and traditional supply chain

Additive Manufacturing AM also know as 3D Printing innovation may have an innovative effect on the current supply chain set-up.  The innovation has the ability to reduce the need for heavy-volume manufacturing facilities as well as low-level assembling staff, while dramatically lowering supply chain costs. We can 3D print on sale in terms of effects on stock and logistical support. 

3D printing ensures that we no longer need to keep the produced goods packed on the shelf or stored in depots.  We often produce the required product anytime we need it. Conclusively, this brings down the supply chain to its smallest bits, bringing improved efficiency to the network. 

These efficiency gains span the whole supply chain, from manufacturing costs to production, storage and to the part itself. Thus reducing waste, optimizing flexibility, and enhancing production run hours.

3D Printing and Traditional Supply Chain Relation

The conventional supply chain paradigm is centered on existing market limitations, rapid manufacturing efficiencies, minimum price requirements, bulk assembly staff, etc. However, 3D printing circumvents such restrictions. 

3D printing recognizes its usefulness in small-volume manufacturing, consumer-specific products, products capable of far greater functionality than is achievable via conventional methods. It thus excludes both bulk volume manufacturing facilities and low-level manufacturing staff, effectively reducing the supply chain to half. 

From the above perspective, shipping goods around the world is no longer financially effective because production can be achieved virtually anywhere at the equivalent value or even cheaper [4]. 

Modern resources are virtual information, wired and linked computer produces quicker and much more effective products than ever before. Which requires a modern supply chain framework?

Including regional procurement help, 3D printing technology has the ability to cut existing global supply chain systems and reconstitute them as a modern, decentralized network. In addition, the innovation establishes an intricate partnership between development, sales and marketing. 

Now, Consider the discrepancies between contemporary more conventional supply chain relative to what it might look like in the coming future with innovative 3D printers and the supply chain

3D printing impact on the supply chain 

Decentralize production in 3D printing

The technique's 'portable' evolution will allow corporations to take production sooner to local markets or to clients. As nothing more than a consequence, the production would be in favor of more central manufacturing centers as we'll see a turn away from industrial manufacture in low-cost regions. 

As a result of this, Companies would be able to manufacture parts closer to the people, rather than depending on imported products. This is particularly pertinent in periods of economic uncertainty, for instance during a trade war where the cost of importing products will escalate exponentially worldwide.

Drive product customization in 3D printing

In the new world, 3D printing technology is considered a tool-less method that provides the suppliers unparalleled flexibility to customize products and deliver it to mark of consumer individual needs and improve customer service. 

It would also lead to far more flexible supply chains that can respond rapidly to market shifts. Ultimately there would be an amalgamation of design, manufacturing and delivery into one supply chain mechanism with better participation of the consumer in the whole cycle of design and development.

3d Printing reduces complexity and improve time-to-market

3D printing utilizes the application Computer-Aided Design (CAD), which involves human involvement on both the rear and front ends. It is for sure that someone has to build the simple drawings that are normally kept in the form of CAD files for users to print an object even in your homes using a 3D printer. 

The suppliers and developers are actually selling their CAD files to interested people. 3D printing technology also integrates the number of parts and the manufacturing processes involved. 

It would have a huge impact on overall world supply chains, declining complexity faced during the production, reducing overall processing and production expenses which in-turn leads to improving the overall lea time and therefore boosting time-to-market.

Improve resource efficiency  in 3D printing

As things progress at present, products are made in wholly different locations than where they are to be used by the consumers, which sometimes comes up as both the producer and consumer are in separate continents. 

Such products need to be shipped to the end consumers, whether by aircraft, truck, rail or road, all of which utilize gases that generate polluting emissions. Through pervasive 3D printing technology, most products can be built on computers and produced right at the consumer’s door, thereby minimizing both shipping costs and environment pollution. 

Therefore, 3D printing is a cleaner form of manufacturing and is both power-efficient and expense-efficient. This generates nearly negligible disposal, reduces the chance of oversupply and surplus demand. Arguably, costs for 3D printing at this moment are high, but they do not remain that way long.

Rationalize inventory and logistics in 3D printing

During the current days when the development of the products is on-demand call, it reduces the need to move products around regions and countries.

It would have a huge effect on business services and logistics, along with the reduced number of SKUs needed for development, which would have the ability to transcend tariffs.

Through 3D printing, the output can become more flexible and will be more suited to adapt to consumer demands. That ensures shipping and storage would be less work-in-progress and completed goods and less mechanization of current inventory. 

Though the price per package could be higher with decreased capacity and less obsolete inventory, the average expense of the supply chain network can be smaller than that of the conventional supply chain. 

3D Printing facilitates a digital production system built-to-order, which in certain situations enables product selection to be held back throughout the supply chain phase. 

International networks of 3D printing facilities would provide opportunities to companies for rapidly adapting the changes in consumer demand and to easily and efficiently launch innovative goods. 

A new wave of product creativity could allow more flexible production methods. The innovation has the ability to reframe conventional forms of production in the longer term. The idea of producing goods in big, intricate facilities may become out of date as businesses adopt the more versatile additive development model.

Consequences for the logistics industry  

• The effects of this modern processing innovation for the logistics sector are immense:

• North America and Europe might theoretically be 'near-sourced' to a percentage of the products that were historically manufactured in China or other Asian markets. This will reduce the levels of shipping and air freight.

• Product configuration means a decrease in inventory prices when products are ordered. This will decrease the supply chain management needs.

• The manufacturer-wholesaler-retailer partnership may be profoundly influenced by build-to-order manufacturing strategies. The retail environment will be significantly different in the future too

• New logistics market will arise with regard to the collection and transportation of raw resources required for 3D Printing. As 3D Printers become more available to the general public, such materials will expand the home distribution demand

• The Transportation Supply Parts industry will be among the first to be impacted as billions of funds are actually expended on holding stock 

The Age of 3D Printing

The manufacturing sector has been associated with factory production, small machine-tools, assembly lines, and productivity gains after the 17-18th Century Industrial Revolution. Thus talking about production without tools and equipment, production lines, or supply chains is surprising. That's what the potential of 3D printing technology acquiring position appears,. Presently we can manufacture components, equipment, and devices right from our home or office. We just have to design, alter or import a virtual 3D model of an item to be prototyped using PC. 3D printers are often used to generate cost-effectively customized, overhauled components at the site where they are going to be utilized which was not possible earlier.

3D Printing

3D printing, often recognized as additive manufacturing – AM (as both terms are exchangeable now) is an engineering process used to create strong three-dimensional structures built in layers from a virtual illustration without a mold or cutting machine. 3D printing incorporates computer-aided design (CAD) to turn the design into a 3D model. The design is then fragmented into 2-D plans, which direct the 3D printer where the content layers will be deposited. The additive method adds successive thin layers of material to create a final 3-D model. Plastics, glass, rubber, polymers, paper, sand and glue blends and even human tissue can be used as input materials.  The development of a 3D artifact includes 3 simple ingredients-a computer model, feeding material and a 3D printer

Pros and Cons of 3D Printing

Advantages and disadvantages of 3D Printing

Pros	Cons
Reduced fixed-up costs and low tooling expenses	Slower manufacturing pace
Lesser manufacturing cost	Higher initial costs
Less manufacturing time and expense (increasing product-design rate)	Uncertain intellectual property obligations
Environmental-friendly: minimal CO2 impact	Variation in operation and quality
Cheaper cost for limited quantities and complicated crafted components	Restricted commodity range, sometime
Faster shipping period	Restricted product size
Complicated components fairly easy to porotype	Logistics uncertainty (3D printing incorporated to the supply chain)
Versatility including customer customization	Minimal large series efficiency.

Industrial application

As the platform gains popularity and versatility, AM's effect continues to grow, rendering it as a viable means of development in a number of industries [8]. Many businesses have implemented AM over the last few years and are able to pull out the actual advantages of the system. The pharmaceutical, automobile and aviation industry are among the markets with the highest scope for growth. AM allows items to be printed in distant areas, so the distribution of products is no more a constraint. Another main advantage of AM is Space Technologies [9,10]. NASA tested AM at zero gravity, hoping to create on-demand production for astronauts. This will require component parts to be produced in Space for maintenance and repair of the space station. It would also reduce the need for a spaceship to travel to the space station to supply components, thereby significantly reducing the turnaround time on replacements. The decreasing timeframe would entail lowering inventory and improving cost efficiency

3D printing “The future Technology”

Though 3D printing has been surfacing around the globe for years, recently in near years it has entered the mainstream for its uses. New 3D printing applications are continuously being created but the popularity of the applications has recently increased. Although 3D printing technology might appear as sci-fi, it's scientifically reality and only making presence known now.  Below are some of the implementations in the modern world:

3D Printing in Aerospace

The increasing cost of the infrastructure of aeronautics is best explained by the inefficient depreciation of tooling expenses over a small amount of production. In commercial 3D printing, regardless of whether you print a single item or a larger sequence, there is no effect on the amortization because you don't need to build a mold. Thus, for aerospace industries, the additive manufacturing method is well suited to fast series growth. You may be thrilled to hear that certain non-critical 3D printed pieces were already in use on airplanes. GE now has more than 300 3D printers and GE Aviation intends 100,000 additive parts to be produced by 2020. Seventeen 3D printed pieces have been mounted by the US Air Force on the C5 Super Galaxy and could save tens of thousands of dollars. Airbus / EADS, Rolls-Royce and BAE Systems are other elevated-profile consumers of the application. Boeing is also dreaming of designing entire planes using 3D printers on a wide scale.

3D Printing in Medical

There have been many 3D printing applications in the pharmaceutical field during the last few years.   These vary from bioprinting – where the synthesis of cells and enzymes produces tissue-like structures copying their natural equivalents – to therapeutic instruments such as prosthetics. The 3D printed prosthetics was an example of the durability of 3D printing. Production of prosthetics that incorporate a patient is difficult and expensive. Modulated prosthetics may be designed and manufactured at considerably reduced costs with 3D printing. The technique is now being used in the production of stock goods, such as hip and knee replacements, and specialized patient-specific devices, such as hearing aids, orthotic foot insoles, design prosthetics. Lead reports include Open Bionics, a UK-based maker of 3D prosthetic arms that received a £4.6 million investment in February 2019 to carry the company to the foreign market.

3D Printing in Automotive

Several automobile manufacturers are already using 3D printing to assist with prototyping. After the 1980s, Ford has employed 3D manufacturing technology. Modern processes will take multiple months and $500,000, according to Ford's official site, but for 3D printing, the same cycle requires four days and $3,000. Future prospects are virtually unlimited. Big Rep, a 3D printer service, introduced the first 3D printed motorcycle in January 2019. The ride, which isn't on the competition, has taken three days to print and costs only £2000.

3D Printing in Construction

While the innovation is in its development period, but major improvements have been made in the building sector with the usage of 3D printers as construction companies continue to realize the technology's usefulness. 3D concrete printing is quickly growing and is projected to hit $56.4 M by 2021. Increasingly firms are starting up to build new, creative ventures in the industry. Russian 3D printing company, for example, Apis-Cor has built a whole house in just 24 hours.

3D Printing and Challenges faced

As among the most revolutionary technologies to affect the manufacturing sector and the global supply network, 3D printing technology has got its name in the top evolved technologies. Many claim that the technology simply improves some facets of the manufacturing cycle, while others suggest that technology would revolutionize and substitute current operating systems. Either innovative or evolutionary, 3D printing technology is acknowledged as a significant development which will affect supply chains greatly. The aim of this paper is to address fundamental issues relating 3D printing technologies and the ways for modifying the production system and supply chain. For every emerging technological tool, AM production networks have problems that need to be tackled. Three main areas face challenges:

3D Printing in Engineering and technology

•Unique design criteria and load details for each particular AM system.

•Significant expenditure in technical education and system expertise is required

•Minor variations in material properties will hinder (sometimes) one-to-one substitution

•Comprehensive heat treatment and machining processes are currently at lower stages of mechanization

3D Printing and Management of data

•Long term regional or institutional differentiation between design and manufacturing entities requires safe shift of design which includes a development file, content specifications etc.
•Prototype might only be produced on a licensed printer and must therefore be allowed to print the component
•Design and development data must be trackable to original demands.

3D Printing Impacts in business

•Local production provides substantial availability / lead time advantages for spare parts delivery compared with central printing
•Enabling networks across decades of usage
•Preservation of intellectual property for concept and printing information
•Paves the way to alternative market models and operating modes

•Designs can be approved for printing by registered end users

Additive Manufacturing Model Advantages  

Capital saving in 3D Printing:

• Capital reductions.

• Removes necessity of massive inventories

• Eradicate the need for large processing plants

• Decrease shipping costs

• Minimize overhaul fines

• Improve the efficiency of an economic lot

• More cost-effective and reliable packaging options

• Deliver unique prototypes at reduced expense

• Reduce manpower

Good time response of 3D Printing:

• Removes the time difference between designing and production

• Reduced production times

• Allowing production on requests.

• Enhancing operation efficiency

• Less use of intermediates in supply chain process

Improvement in Quality in 3D Printing:

• Minimize manufacturing waste

• Enhance performance

• Integrate consumer input

• Deliver efficient goods in several markets

• Remove drag-and-drop surplus components

• Ambiguity management of demand

3D Printing Impact on Environment:

• Fewer harmful environmental effects

• Eliminating greenhouse gas emissions

In the new world, 3D printing commences, specifically as a way of creating prototypes. The latest technical developments and 3D printing technologies indicate that the innovation has the ability to radically change other aspects of real life. AM's effect on supply chains has several forms, such as streamlined manufacturing techniques, decreased resource loss for leaner processing, improved efficiency, decreased expense, quicker demand responses, and flexible processing capacity. 3D printing also sets up fresh markets and has the opportunity of reducing prices and rising earnings. As a consequence, supply chain will respond rapidly to business developments. It opens up fresh markets and provides other incentives for businesses seeking to increase productivity of manufacturing. AM streamlines conventional techniques significantly, which has the ability of becoming the standard over the coming decades. The platform allows design independence using regular CAD applications, which is not restricted to new production technologies. This also allows price efficient customization of goods. 

Though, 3D print development, needs to conquer one huge hurdle. To offer us more knowledge on all of its strengths and inventions, there are already perceptions about 3D printing from the time of its inception more than five years ago. The circumstance looks very different today as it presents the argument that 3D printing improves raw material use is deceptive. The 3D printing would have a huge effect on waste logistics.  As far as material savings and waste quantity is concerned   A well-designed production method utilizing 3D printing would be beneficial. A further false impression of 3D printing is that its key scope is for components constructed of plastics.  The technology's biggest advantage is the usage of a large variety of substances, not just plastics. For example, Metal 3D Printing possesses the capacity and considerable ability to generate complex, seamless components with physical properties that can often surpass those of traditionally produced pieces. Ultimately, the system has the power to transform the method we produce essential parts entirely.

3D Printing (3DP) and Selective Laser Melting (SLM), a comprehensive comparison

1. Working Process

3D printing is an additive manufacturing process that creates physical objects from digital design. In 3DP layer of powder is deposited automatically in the tray. Then print head applies resin to power layer and it dries almost immediately. When the layer dried another layer will be added to finish the model. The working principle of SLM differs from 3DP and it works on the principle of melting. Powder heated and melted and forms pool of liquid where its phase changes from liquid to solid by reforming and hardening. The final part wont porous, thereby it can be used for wide range of applications.

3D Printing (3DP) and Selective Laser Sintering (SLS), a comprehensive comparison

1. Working Process

3D printing creates physical objects from digital design. The material used is power which is located in a build chamber. A printing head deposits liquid binder on to powder, thus it bonded together and forms layer. The build platform is lowered down an amount equal to the layer created. This process repeated to complete the 3D part. SLS principle completely differs from 3DP and works based on sintering principle. The powder material is heated and bonded together by fusion and forms layer. Heat source for sintering process is generated by laser. A Cad model imported to SLS system and completed layer by layer.

SLS vs SLM: 6 Points Comparison between Selective Laser Melting and Selective Laser Sintering

1. Working Process of SLS vs SLM

Starting SLS vs SLM on the working principle. SLM (selective laser melting ) works on the principle of melting. The working is same as SLS (selective laser sintering) where as the power is melted instead of sintering. 

Melting actually creates a pool where the materials can consolidate before reforming and hardening to create new solid structure. 

The final part won’t be porous, thereby making it suitable for a greater range of applications. In SLM, powdered material is melted, whereas in SLS the powder is heated below its melting point (sintering). 

When laser heats the powder material to below melting point, it forms solid by fusion. The working principle is almost same in both printing method.

2. Process Variations of SLM vs SLS

Discussing the process variation for SLM vs SLS. Some Selective Laser Melting SLM industries are works with some other material like magnesium for light weight construction. 

Varieties of materials are tried in SLM process; however very little work has done on gold and its alloys. God and alloys are used to manufacture dental crowns. 

The gold power is cohesive and non- flowing in nature. Selective Laser Sintering SLS selective laser sintering has some limitations when compared to SLM. 

However SLS also has variety of methods like DMSL (Direct Metal Laser Sintering), which use powerful laser to micro-weld the raw material. Yb-fibre or CO2 will be used up to 100W and DMLS used up to 200W.

3. Processing materials of SLS vs SLM

For a greater selective laser sintering vs selective laser melting let us comparing the materials they can process. The normal materials used in selective laser melting  SLM are stainless steel, aluminum or titanium alloys. 

SLM materials are selected depending on the properties like strength, ductility and biocompatibility based on the application. 

Titanium based materials are used in biomedical application due to their good mechanical properties, high bio compatibility and corrosion resistance. SLM works with metals, where as SLS generally works with plastics, glass, ceramics. 

Selective Laser Sintering SLS don’t restrict metals; the same can be used in DMLS. Aluminum filled and glass filled nylon material is used in SLS. 

Nylon is the ideal material, because of its light weight, high durability and heat resistant etc.

4. Design aspects SLM vs SLS

In SLM vs SLS, unlike SLS, SLM is very difficult to control, because of large energy input of laser beam. SLM parts can further processed as many welding part. 

SLM also requires support structures however i can be act as heat transfer medium which can reduce thermal stress and prevents wrapping. 

Selective Laser Sintering SLS is easy to control and better than FDM. Thinner layers also can be achievable by using DMLS. 

The un-sintered powder will act as a support and there is no need to provide additional supports. The layer thickness depends on type of material used and post processing can be done by traditional process.

5. Quality aspects of selective laser sintering vs selective laser melting

Considering the 1uality aspects of the processes for selective laser sintering vs selective laser melting. Selective Laser Melting SLM is a proven technology to produce near net-shape parts up to 99.9% relative density. 

It has good mechanical properties. Tolerance and surface finishes are limited. However it can be improved through post processing. 

The tolerances are ±0.05-0.2mm, however this will vary machine to machine. SLS parts may require stress relieving and annealing to reduce internal residual stress. SLS chamber is maintained with N2 atmosphere which will prevent explosion of powder. 

Additional curing may also required when using ceramic parts. The machine needs thorough cleaning to avoid powder contamination. The achievable tolerance is ±0.05-0.25 mm; may vary material to material.

6. Economical aspects for SLS vs SLM

Discussing the economical aspects for SLS vs SLM. Selective Laser Melting SLM machines are very economical, minimal materials used; time saving and offers reduced cost/cycle time. 

100% usage of lasers cannot be achieved in selective laser melting SLM. It is very compact machines and minimum layer thickness also achievable. 

The process of final approval takes longer time for development and qualification of this technology. Selective laser sintering SLS has high energy requirement. 

It is an automated process but needs skilled man power. The initial investment is huge; however the direct labor costs are low. 

The leftover powder can be re-used and the material utilization also higher. The powder material cost vary in the market depends on its properties.

Fused Deposition Modelling (FDM) and Selective Laser Sintering (SLS), a comprehensive comparison

1. Working Process

Fused Deposition Modelling FDM is an additive manufacturing technology, works on the principle of sintering. The plastic polymer is feeded to a heated nozzle, which will lay down it in layers to produce a product. The number of layers on a product is the deciding factor of manufacturing time. The principle of SLS completely differs from FDM. It works on the principle of sintering. In FDM filament is heated in the nozzle, whereas in SLS, the powder is heated by controlled laser pulse. The laser heats the powder and it forms solids by fusion. SLS don’t require support material since the power itself can act as support.

Fused Deposition Modeling - 3D Printing

Fused deposition modeling is an additive layer manufacturing process also known as layer by layer manufacturing process because in this process a 3 dimensional object is made by adding very thin 2 dimensional layers. Process starts with generating the computer aided design (CAD model) of the component which needed to be manufactured. Then second step is to convert the computer aided design file in to STL (standard triangulation language) file, this file format is internationally accepted by all additive layer manufacturing machines. Third step is to slice the 3 dimensional STL file into 2 D cross sections, this is done by the additive layer manufacturing machine. In fourth step the physical development of the desire component is done. After complete manufacturing of the component the post processing is required which is fifth step where finishing process like cleaning and curing is done and final the component is read to be used. 

3D PRINTING OF ENGINE CYLINDER BLOCK

Additive layer technology more commonly known as the 3D printing or layer by layer manufacturing technology is the most discussed and used (at small level) manufacturing method now a days. 

As engineers are trying to manufacture more and more products through additive layer manufacturing so in this post we will try to select a an additive layer manufacturing process for engine cylinder block by working on following steps

1. Study the current Manufacturing Process

2. Select one additive layer manufacturing process 

3. Study the new manufacturing process

4. Compare the present and new manufacturing processes

5. Conclude the result about the additive layer manufacturing of engine cylinder block

1.0 Introduction to 3D Printing of Engine Block

3D printing work opposite to the conventional subtractive method was parts are manufacture by removing the material from a work piece. In additive layer manufacturing the parts are made by combining the successive layer of material one over the other under a control environment [1]. 

Initially this method was mostly used for rapid prototyping but with time the manufacturer realized its importance and own they are used for the production of functional products [2]. Currently the additive layer manufacturing is basically used for the production of the equipment used in aerospace and high performance cars because of very high cost of the equipment used in this process [3]. 

Here a brief study about the suggestion of an additive layer manufacturing for the manufacturing of cylinder block of a V-6 engine has been conducted here. Before suggestion of the ALM process, the current manufacturing process and material requirements will be discuss along with the brief discussion of the product.

1.1 Cylinder Block

An engine block is the core of the engine which houses nearly all of the components required for the engine to function properly. The block is typically arranged in a “V,” inline, or horizontally-opposed (also referred to as flat) configuration and the number of cylinders range from either 3 to as much as 16. Because engine blocks are a critical component of an engine, it must satisfy a number of functional requirements. These requirements include lasting the life of the vehicle, housing internal moving parts and fluids, ease of service and maintenance, and withstand pressures created by the combustion process [4].

Figure 1 Cylinder Block of IC Engine

1.2 Material for Cylinder Block

Following are some of the properties that a material should have in order to process it for manufacturing of cylinder block [5]

• Cheap

• Good Cast ability 

• Good impressions

• Good Machine ability

• Rigid and strong

• Good abrasion resistance,

• Good corrosion resistance,

• High thermal expansion,

• High thermal conductivity,

• Low density.

Some of the material that are already in use in different manufacturing organization for production of cylinder block are cast iron, aluminum alloy and magnesium alloy. Aluminum alloys are now mostly used for high performance in light vehicle due to its low density and high strength [4] [8].

1.3 Manufacturing Process for Cylinder Block

There are number of manufacturing processes been used by different companies like Honda is using pressure die casting [6] and BMW is using sand casting [7] for their cylinder block production. Many other processes like machining from solid and lost form process are also being processed in different companies. Selection of the process really depends on the material and functional requirements of the engine cylinder block.

2.0 Current Manufacturing Process of Cylinder Block

The manufacturing process that will be discussed here is the sand casting and data mention below is being taken from the discovery channel documentary that show the complete manufacturing process of V-6 cylinder block [8]. 

Manufacturing process starts with the preparation of the sand and glue mixture that will be used for the production of cores. A single mold for a cylinder block is made up of 18 different cores and all are made for the master pattern made of steel. There is one main core with which all other 17 cores are attached. Iron liners are placed in the bores of the cylinder bore core, this help avoid abrasion. Some of the cores have to be glue to improve the strength and prevent the braking while assembling. Process of making and assembling and the cores are completely automated which decrease the time but increase the cost of operation.

After mold is complete the aluminum alloy ingots are melted in the gas fired furnace where temperature ranges up to 800 degree centigrade. Mold bores are heated with the electric current because the melted aluminum alloy bounds better with the hot metal. Molten aluminum alloys are feed from the bottom of the mold to avoid the oxide formation and can be a problem when molten material is feed from the top of the mold. 

After the solidification the mold is place in the oven can thermal sand reclaim oven where it spend six hours to dissolve al the glue and recover all the sand. Sand remains inside the cylinder block is removed by tilting the block sidewise. Extra material in the shape of riser will be removed by the help of CNC machines. CNC machines will be used to do the finishing process of the cylinder block.

Process up till now is a general process for the production of the every engine cylinder block. Further detailing and finishing will be done according to the use of the cylinder block. After completing the process a visual test is conducted to check for any defect present in the product.

3.0 Current Manufacturing Process Steps

Following are the steps arranged in the sequence for the manufacturing of engine cylinder block as explained in the above [8]

1. CAD Drawing

2. Mater Pattern Preparation

3. Preparing Sand and Glue Mixture

4. Core Production

5. Cores Assembly

6. Melting Aluminum

7. Pouring

8. Sand Recovery Oven

9. Primary Machining

10. Final Machining

3.1 CAD Drawings

First step is to create the detail CAD drawing of the engine cylinder block and then divide it into different section according to the manufacturing process to manufacture the master pattern of each section. This step required highly skilled labor and good CAD software which not cost much. Time of this process is usually in days and cost of the process is low to moderate

3.2 Master Pattern

Master pattern is required for each sand core used to make a complete sand mold for the casting a one complete engine cylinder block. There are 18 total master patterns, one for each core. Creating a master pattern required a third party because manufacturing master pattern required highly skilled labor and expansive machinery. Manufacturing time is usually in days for a single master pattern, so manufacturing 18 master patterns required at least 4-5 month. Cost of this process is very high but it is one time process [9].

3.3 Preparing Sand and Glue Mixture

A separate mixing machine is used for the preparing the sand and glue mixture. Quality of the mixture is really important as this thing define the surface finish and some defects in the final product [10]. Sand and glue are mixed in predetermined quantity due to which this step required low labor skills and have low operation cost but is a continuous process because new mold is required every time. 

3.4 Cores Production

To make a core, sand and glue mixture is blows into the cavity having master pattern. Here the sand and glue get hard with the help of gas which activities the hardener due to which sand takes the shape of the master pattern. This process is fully automatic which increase the rate of production but this come at increase cost in term of robots installation and operation [8]. This process of core making is continuous process because core need to broke in order to remove the cylinder block [10].

3.5 Core Assembly Line

There is one master core which the other 17 core are attached to make a single mold for the cylinder block casting. Process of the cores assembly is done with the help of robots [8] and it’s a continuous process because a new mold is requiring for every new casting. 

3.6 Melting Aluminum Alloy

Aluminum alloy ingots are placed inside the gas fired furnace where temperature is about 800 degree centigrade. This process required careful handling due molted metal but this is continuous and a low cost process. 

3.7 Pouring

In manufacturing of engine cylinder block the process of pouring the molten metal for filling the mold cavity is done from the bottom to avoid the formation of oxide [8]. This process has usually had low labor and equipment and processing cost because of its automation. 

3.8 Sand Recovery Oven

After the solidification the mold is place in the sand recovery oven for six hours which dissolve all the glue present in the sand due to which all the sand is recovered. Sand present inside the cylinder block cavity can be removed my tilting the cylinder block side wise with the help of robotics [8]. This preprocess usually have low labor and processing cost associated with it because it can be done on many cylinder block molds in single time.

3.9 Primary Machining

After engine cylinder block is obtain form the sand recovery oven the process of machining is done to remove all the extra material present in the form of runner and riser and to provide some finishing to the engine cylinder block [8]. This process is usually done on the CNC machine have high equipment cost, and required skilled labor for processing but the high processing speed make it best for mass production processes [9].

3.10 Final Machining

Final machine is done by highly precise CNC machines due to high level of dimensional tolerance required for piston bores and all other parts. This process is usually done on the CNC machine have high equipment cost, and required skilled labor for processing but the high processing speed make it best for mass production processes [9].

 

4.0 Additive Layer Manufacturing Or 3D printing Processes

Additive layer manufacturing technique manufacture a 3D product by adding layers of the materials one above the other that why this process is also known as layer by layer manufacturing. On the basis of the phase of the raw material used the additive layer manufacturing can be divided into three types 1. Liquid base processes 2. Powder base processes and 3. Solid base processes. Each of these processes is further divided into subtypes shown below

• Liquid Based Processes

1. Stereolithography Apparatus(SLA)

• Solid Based Processes

2. Fused Deposition Modeling (FDM)

3. Laminated Object Modeling(LOM)

4. Multi Jet Modeling

• Powder Based Processes

1. Selective laser Sintering(SLS)

2. Selective Laser Melting(SLM)

3. Zcorps 3D printer

All of the above mention additive layer processes have same number of steps involves in manufacturing of any product. Selection of a process for a product depends on the product requirements like material, ultimate tensile strength, density and performance of the product. Along with this some post process is required in some of the processes which should be considered while selecting the additive layer manufacturing process for a product. 

While selecting an additive layer manufacturing process for the engine cylinder block material is the most important factor because currently aluminum alloys are the standard material used for the process and some of available processes have limited range of process able materials. ‘

Second point the maximum ultimate tensile strength that can be achieved by the manufacturing the cylinder block through any of the process is also important because cylinder work under high temperature and stresses and ultimate tensile strength of some of the processes is limited. 

Density is also an important factor which contributes in proper functioning of product. Some of the process produces low density products and some produce full density products. Some of the additive layer process required post curing of the product, this factor should also be considered because of the cost involve in this process.  

Following is table that shows some of the features of the additive layer manufacturing processes [11].

It clear that from the above comparison that selective laser sintering and selective laser melting can be used for the manufacturing of engine cylinder block as they can provide highest ultimate tensile strength and can process the required aluminum alloy. Selective laser melting has one advantage over selective laser melting that it does not required post curing of product and it can produce fully dense parts. 

So selective laser melting SLM is the process selected from all the available additive layer manufacturing process for the manufacturing of engine cylinder blocks due to its ability to manufacture fully dense engine cylinder blocks from aluminum alloys with maximum ultimate tensile strength.

 

5.0 Selective Laser Melting

Selective lase melting is an additive layer manufacturing process that make use of the laser power to completely melt the material present in the form of powder which on solidification makes a single very thin 3D layer of 2D cross section of a product. In this may layer after layer is added to make a complete 3D product. 

To manufacture an engine cylinder block through selective laser melting the steps are going to be the same that involve in the selective laser melting process. Following are the steps with details about the manufacturing of engine cylinder block through selective laser melting

5.1 Preparing CAD Model

First step in manufacturing of cylinder block through SLM is preparing a complete detailed CAD model of the cylinder block. This process required skilled labor but it is one time process with low equipment cost. This process may take days to a week. 

5.2 STL file Generation

Second step is converting the CAD model of cylinder block file into STL file which SLM machine can read. This is also a onetime process which is done by the same CAD preparing labor on the same CAD generating equipment and takes only few minutes.

5.3 Slicing the STL file

Third step is to slice the STL file into 2D cross section which is used by the machine to manufacture the layers while processing. These layers are combined to form a 3D product. This is also onetime process performed by same labor and equipment and takes only few minutes.

5.4 Preparations

Fourth step is to make all the necessary adjustment on the SLM equipment to start the manufacturing process. This process is needed to be done every time and have high labor cost and takes few minutes to hours.

5.5 Processing

Fifth step is the manufacturing process of cylinder block where machine manufacture layer after layer to complete a 3D physical product. This process required skilled labor and have very long processing time usually in day for a single product. For a product like cylinder block it may take weeks to complete. The equipment cost related to this process is very high.

5.6 Post Processing

After the manufacture process is completed the process of cleaning and finishing starts where extra powder and waste material is removed from the final product it a finished product. In SLM no post curing is required which make it little faster than the SLS. Post processing is continuous process which needs to be done every final product to make it a finished product. This process has moderate labor and equipment cost associated with it and have small processing time. 

6.0 Comparison between current and selected manufacturing process

As mention above the current manufacturing process of the cylinder block was sand casting that is being used by the company BMW and the recommended additive layer manufacturing process on the basis of the some factors discussed above is selective laser melting. Now both the process should be compared to check that the selected additive layer manufacturing process is economically better than the current manufacturing process. Following are some of the factors on which the comparison will be made

1. Number of Processing Steps

2. Time of Processing

3. Labor Requirements

4. Manufacturing Cost

5. Product Cost

6.1 Number of Process Steps

In sand casting of engine cylinder block there are about 10 man steps [8] where as in the selective laser melting process there are only six steps involves [11]. Therefore the manufacturing of cylinder block by the SLM will be much shorter than the current sand casting process.

6.2 Time of Processing

In sand casting of engine cylinder block the time of making the master molds is in months and then the time for sand core manufacturing and assembly to make a mold is in days for manual process and in hours for fully automatic process. Pouring, solidification and post processing may require days so complete manufacturing of cylinder block will be in days [12]. In SLM the there is no need of molds and cores so there lot of time saving in this process. In SLM melting and solidification occurs in seconds and also there is no need of post process [13] so SLM safe a lot of time as compared to sand casting

6.3 Labor Requirement

In sand casting there is requirement of highly skilled labor at every stage of cylinder block manufacturing [9] but in SLM a single labor can control the complete process [13] due to which SLM is quite economical and effective in this respective 

6.4 Manufacturing Cost

Due to less number of steps involve in SLM, the cost of manufacturing in SLM is less than the sand casting due to its high greater number of steps involves but the cost of the machine is a big problem in the way of this process installation. Cost of the SLM machine is about few million dollars

6.5 Product Cost

Cost of engine cylinder block produce by the SLM will be less than the one produce by the sand casting due to less number of steps involve, low processing time and less number of labor required for the production.

7.0 Conclusion

The objective of selecting an additive layer manufacturing process for the production of engine cylinder block has been successfully completed and selective laser melting is the process selected. Careful comparison of current and selected process shows that the production through the SLM process will have less processing steps with small processing time required for production. The required labor to carry out the process is also less as compared to sand casting. Due to all of the factor mention above the manufacturing cost and product will be lower than the one produce made by the sand casting. 

 

References

[1] Create it real (2012) 3D Printer Technology – Animation of layering [online] available at http://www.createitreal.com/index.php/technology/process 

[2] Excel. Jon (2010), the rise of additive layer manufacturing [Online] available at http://www.theengineer.co.uk/issues/24-may-2010/the-rise-of-additive-manufacturing/ 

[3] Farinia Group (n.d) what is Additive Layer Manufacturing (ALM) [online] available at http://www.farinia.com/additive-manufacturing/3d-technique/additive-layer-manufacturing 

[4] Hieu Nguyen (2005) Manufacturing Processes and Engineering Materials Used in Automotive Engine Blocks, School of Engineering Grand Valley State University, EGR250 – Materials Science and Engineering Section B

[5] What-When-How (n.d) Engine Construction [online] available at http://what-when-how.com/automobile/cylinder-block-automobile/ 

[6]Honda Manufacturing (n.d) High Pressure Die casting, Engine Manufacturing, [online] Available at http://www.hondamanufacturing.co.uk/our_plants/engine-manufacturing/high-pressure-die-casting/ 

[7] Cars (2015) BMW Engine Block Casting [online] Available at https://www.youtube.com/watch?v=N2hYTdrzujI 

[8] How its made (2013) How its Made Engine Blocks [online] Available at https://www.youtube.com/watch?v=wr4_B9EXWSo 

[9] K. G. Swift and J. D. Booker (2013) Machining Process, Manufacturing Process Selection Handbook, Elsevier Ltd, 

[10] Mikell P. Groover (2010) Chapter 11 Metal Casting properties, Fundamental of modern manufacturing materials, processes and system. 4th edition

[11] K. G. Swift and J. D. Booker (2013) Rapid Prototyping processes, Manufacturing Process Selection Handbook, Elsevier Ltd,

[12] K. G. Swift and J. D. Booker (2013) Metal Casting, Manufacturing Process Selection Handbook, Elsevier Ltd

[13] Ihar Yadroitsau (n.d) Direct Manufacturing of 3D Objects by Selective Laser Melting of Metal Powders