What is swaging

Swaging is a mechanical deformation technique of reducing or shaping the cross-section of rods or tubes by means of repeated impacts or blows, especially in order to reduce cross-section.

Swaging is similar to the forging process in which the dimensions of items are altered using dies into which the item is forced.

Swaging is usually a cold working process but sometimes also done by hot working.

Swaging is a noisy operation but it can be reduced by proper mounting of the machine or by the use of the enclosure.

Types of swaging :

Swaging can be classified as the following category :

• Internal swaging 
• External swaging
• Combination swaging
• Dual swaging 
• Rotary swaging

Internal swaging can provide grip to hose material, and be used to improve flow area through tubing or hoses. While external swaging is the opposite of internal swaging. 

Combination swaging is similar to external swaging, except for the fact it involves welding ends together. It also is known to be more cost-effective than external swaging. 

Dual swaging uses both internal and external swaging and involves compressing both aspects by the same amount. Rotary swaging is an operation where the two dies which are free to move radially are held in a spindle that rotates continuously. 

Operation :

In swaging operation, the work material is completely restricted by the die which is given the requisite external shape. These dies intermittently hammer the stock to produce deformation. This hammering action producing the necessary shape also ensure good surface quality, better grain structure and high tensile strength. 

This is simply carried out by any unskilled operator.

Advantages of swaging :

• The parts produced by swaging have tolerance in the range ± 0.05 mm to ± 0.5 mm
• Improved mechanical properties.
• The use of lubricants helps in obtaining a better work surface finish and longer die life.
• Tungsten and molybdenum are generally swaged at elevated temperatures as they have low ductility at room temperature.
• Hot swaging is also used to form long or steep tapers, and for large reductions.

Where swaging is used :

• This process mostly used in car design. 
• Repairing the musical instrument.
• Also used in circuit boards, hose fittings, pipe fittings, lock bolts, sawing blade teeth.
• Typical parts manufactured by this process like screwdrivers, furniture legs, tapered bar and tubes.
• Swaging used in manufacturing industries for pointing the end of a workpiece. 

What is die casting

Die casting is a permanent mould manufacturing process. It was first developed in the early 1900s. Die casting is a widely spread technique for which the metal is forced into the mould cavity under high pressure and produced geometrical complex metal parts through the use of reusable moulds is called dies. In this process involves furnace, metal, die casting machine and die. The mould cavity is like intricate in designs that enable in producing complex shapes with good surface finish, high accuracy and attractiveness.

Working principle of die casting :

Die casting process complete in five stages that we can discuss below :

1. Clamping
2. Injection
3. Cooling
4. Ejection
5. Trimming

Above mentioned five stages this process the die consists of two parts. one part is called stationary half or cover die which is fixed to the die casting machine. The second part is called moving half or ejector die that is moved out for the extraction of the casting. The casting cycle starts when two parts of the die are apart. The lubricant is sprayed on the die cavity manually or automatically because casting will not stick to the die. The two die halves are closed and clamped. The required amount of metal is injected into the die. After the casting is solidified under the pressure the die is opened and casting is ejected. It will also have cooling channels to extract the heat of the molten metal to maintain proper die temperature.

The die casting machine is two types :

1. Hot chamber die casting
2. Cold chamber die casting 

In between two types, the main difference is that in the hot chamber machine, the holding furnace for the liquid metal is integral with the die casting machine. wherein cold chamber machine, the metal is melted in a separate furnace after that metal is poured into the die casting machine with a ladle for each casting cycle is called shot.

Hot chamber dies casting machine :

Hot chamber process is also called gooseneck casting. Hot chamber machines are used for alloys with low melting temperatures, such as zinc, tin, and lead. The gooseneck is made of grey alloy or ductile iron or of cast steel. The operating sequence of this process is typical injection pressures for a hot chamber die casting machine are between 1000 and 5000 psi. After the molten metal has been injected into the die cavity and then the plunger remains down, holding the pressure while the casting solidifies. After solidification, the hydraulic system retracts the plunger and the part can be ejected by the clamping unit.  the plunger moves back returning the used liquid metal to the gooseneck. The casting which is in the ejector die is now ejected then the plunger uncovers the filling hole, letting the liquid metal from the furnace to enter the gooseneck.

In the hot chamber die casting process the direct immersion in the molten metal allows for quick and convenient mould injection, it also results in increased corrosion susceptibility. Because of these characteristics, the hot-chamber die casting process is best suited for applications that utilize metals with low melting points and high fluidity. Good metals for the hot-chamber die casting process include lead, magnesium, zinc and copper. 

Cold chamber dies casting machine :

The hot chamber process is used for most of the low melting temperature alloys while materials such as aluminium and brass. High melting temperature makes it difficult to cast them with the use of a hot chamber process because gooseneck of the hot chamber machine is continuously in contact with the molten metal.

In the cold chamber process, the molten metal is poured with a ladle into the shot chamber. this process reduces the contact time between the liquid metal and the shot chamber.

The operation is similar to that of the hot chamber process start with the spraying die lubricants throughout the die cavity and closing the die when molten metal is ladled into the shot chamber of the machine either manually or by hand or by means of the auto ladle. Then plunger forces the metal into the die cavity and maintains the plunger the pressure till it solidifies then die opens. The casting is ejected. At the same time plunger returns to its original position and completing the operation.

For hot chamber die casting characteristics is too corrosive for the immersion design while the cold-chamber process can be an excellent alternative. 

Die design :

Hot-working tool steels are normally used for the preparation of the dies, die inserts and cores. The die must allow the molten metal to flow easily into all of the cavities. Equally important is the removal of the solidified casting from the die, that is why the draft angle must be applied to the walls of the part cavity. The design of the die must also accommodate any complex features on the part such as undercuts will require additional die pieces. 

• For zinc alloy, the normal die material is AISI P20 for low volume and H13 for high volume.
• For aluminium and magnesium H13 and H11 are used.
• For copper alloy H20, H21 and H22 are used as die material.

High-grade tool steel is the most common and is typically used for 100-150,000 cycles. Steels with low carbon content are more resistant to cracking and can be used for 1,000,000 cycles.

Benefits of the die casting process :

• High quality :

Parts which are produced by this process have a long service life and its quality is high.

• High reliability :

By this process, uniform parts are produced and all are highly reliable.

• Quick production :

In that process just die casting tooling is required after produced one part this process is quick as compared to another manufacturing process of making uniform parts.

• Minimal assembly :

Assembled of parts that are used in die casting machine are easy.

• Versatile design :

Die casting application :

• It is suitable for casting medium-sized parts with complex details.
• It is widely used in manufacturing commercial, industrial products, automobile industries and aerospace.
• The typical products like carburettors, crank-cases, magnetos, handlebar housing, other parts of scooters, motorcycles and mopeds, zip fasteners and gears.

Properties and characteristics of the die casting process :

• Parts manufactured by this process are close tolerance, very high surface finish and thin intricate walls.
• Production rate is very high.
• Equipment cost for die casting is generally high but its assembly is easy.
• This process is highly automated so the labour cost is low.
• Parts that manufactured by this process are with superior mechanical properties because of rapid cooling.
• Ejector pins will usually leave small round marks on the metal casting so this will be observed on the surface of manufactured parts.

Because of these properties and characteristics, this process has many advantages and it is widely used in manufacturing industries

What is polishing process

Polishing is a surface finishing process performed by a polishing wheel for the purpose of removing appreciable metal to take out scratches, tool marks, pits and other defects from rough surface. The process of polishing with abrasives starts with coarse once and graduates to fine once. 

Polishing is the method of rubbing or using a chemical action to create a soft and shiny surface.

Purpose of polishing : 

The primary purpose of polishing is to change the texture of the surface instead of the form. Polishing can produce highly reflective mirror surfaces. It removes the material at a very low rate.

Benefits of polishing : 

• Strength of polished products is normally higher than their rougher counterpart owing to the removal of stress concentration present in the rough surface. 
• Polishing with very fine abrasive differs physically from coarser abrasion, in that material is removed on a molecular level so that the rate is correlated point rather than to the melting point of the material being polished. 
• In polishing usually accuracy of size and shape of the finished surface is not important, but sometimes tolerance of 0.025 mm or less can be obtained in machining polishing.

What is grinding? | Reason | Advantages

What is grinding?

Grinding is the abrasive machining that uses grinding wheel or grinder as the cutting tool and an abrasive material rubs against the metal parts and removes tiny pieces of material.

Grinding is used to the finishing process of the workpiece which must show high surface quality, accuracy and shape, and dimension. With the use of this process also removes little metal 0.25 to 0.50 mm and the accuracy in dimension in the order of 0.000025 mm. 

Grinding is done on surfaces of almost all conceivable shapes and all kinds of materials.

Grinding may be classified in two groups :

1.Rough or non-precision grinding

2.Precision grinding

• Cylindrical grinding 
• Internal grinding 
• Centre-less grinding 
• Surface grinding

Reasons for grinding :

• The material is too hard to be machined economically.
• Grinding can also produce very close flatness tolerance.
• Good machining of tough materials.
• Finishing flat as well as cylindrical surfaces.

Advantages of grinding :

• Obtain good dimensional accuracy.
• Good surface finish.
• Good form and location accuracy.
• Applicable to both hardened and unhardened material.

What is milling | Operations | Applications | Advantages

Milling is a type of machining during which the rotary motion is always performed by a tool, and feed motion is performed by a tool or by a workpiece. The machines that are used for milling are called milling machines. 

Milling is the most common form of machining, a process of material removal, which by cutting off the unwanted material can create a variety of features on a part. The workpiece is a piece of pre-shaped material that is secured to the fixture that is attached within the milling machine to a platform itself. The cutting toil with sharp teeth is also secured in the milling machine and rotates at high speeds. By feeding the workpiece into the rotating cutter, the material is cut away from this workpiece in the form of small chips to create the desired shape. 

The milling machine can also hold more than one cutters at a time this is why a milling machine finds wide application in production work. 

Milling machine used to produce non-axially symmetrical parts with many features, such as holes, slots, pockets, and even three-dimensional contours of the surface.

Milling machinery can be operated manually using a device called a computer numerical control or CNC milling machine. There are often one or two additional axes in addition to the traditional X, Y, and Z axes found in a manual machine and a CNC friction machine. These additional axes can provide greater flexibility and accuracy. 

CNC machines eliminate the need for a machine operator which can prevent possible accidents as well as save on labour costs. The main advantage of the milling machine is that it can be used with a high degree of accuracy to literally perform any operation.

According to the relative moment between tool and workpiece milling is classified below:

1. Down Milling :

The down milling is also called climb milling.

It is the process of removing metal by a cutter that is rotated in the same direction of travel of the workpiece. 

2. Up Milling :

The up milling is called conventional milling.

It is the process of removing metal by a cutter which is rotated against the direction of travel of the workpiece.

There is another major milling process classify below :

1. Face Milling :

In this milling process cutting action occurs primarily at the end corners of the milling cutter. Face milling is used to cut flat surfaces into the workpiece or to cut flat-bottomed cavities.

2. Peripheral Milling :

In this milling process cutting action occurs primarily along the cutter's circumference, so that the cutter's shape finishes with the cross-section of the milled surface. In this case, cutter blades can be viewed as scooping out the workpiece material. Peripheral friction is suitable for cutting deep slots, threads, and gear teeth. 

3. Chamfer Milling : 

A chamfered end mill makes a peripheral cut along a workpiece edge or a feature in this milling process to create an angled surface known as a chamfer. This chamfer can typically be machined on either the outside or inside of a part with an angle of 45 degrees and can either follow a straight or curved path. 

4. End Milling :

To machine a specified feature such as a profile slot, pocket, or even a complex surface contour, an end mill makes either peripheral or slot cuts determined by the step-over distance across the workpiece. The depth of the feature can be machined in a single pass, or it can be reached through machining at a lower axial cutting depth and multiple passes. 

Milling operation capabilities : 

• Shapes - Solid cubic and complex, Flat, Thin-walled cylindrical, cubic and complex, and solid cylindrical. 
• Part size - Length : 0.04 to 72 in Width : 0.04 to 72 in 
• Materials - Metals such as Alloy Steel, Carbon Steel, Cast Iron, Stainless Steel, Aluminum, Copper, Magnesium, Zinc
• Material - Ceramics such as Composites, Lead, Nickel, Tin, Titanium, Elastomer, Thermoplastics, Thermosets
• Surface finish - Typical: 32 to 125 µin Feasible: 8 to 500 µin
• Tolerance - Typical: + or - 0.001 in Feasible: + or - 0.0005 in

Milling Machine Operation :

1. Plain Milling

2. Face Milling

3. Side Milling

4. Straddle Milling

5. Angular Milling

6. Gang Milling

7. Form Milling

8. Profile Milling

9. End Milling

10. Saw Milling

11. Milling keyways, grooves, and slots.

12. Gear cutting

13. Helical Milling

14. Cam Milling

15. Thread Milling

For detailed information for all of the above operation: Milling machine operation

Types of Milling Machines :

There are many different types of milling machine available. Milling machines are categorized by their orientation to their workpiece and their degree of motion.

Knee-Type :

Knee-type milling machines use a knee-supported vertical workspace, which is a vertical casting adjustable. The knee supports a saddle and a customizable workspace can be adjusted.

Plain Vertical and Horizontal :

Milling machines can be oriented either vertically or horizontally with a standard work surface. Typically, the tool assembly is attached to a turret and swivel, typically parallel to the workspace. To enforce tight tolerances, the turret and swivel allow the tool to move freely around the workpiece. 

Universal Horizontal Milling Machine :

A universal horizontal milling machine differs from the horizontal plain type because it has a table swivel housing that allows the table to move 45 degrees from the horizontal standard position. This movement of the workpiece facilitates angular or helical milling operations.

Ram-Type and Universal Ram-Type Milling Machines :

In relation to the workpiece, a ram-type machine is used to allow the tooling to position itself on a larger range of space. On a movable housing, the ram-type machine has a spindle that can move in a set horizontal plane. The universal ram-type milling machine includes a swivel housing that increases the range of movement of cutting. 

Swivel Cutter Head Ram-Type Milling Machine :

A milling machine can rotate from a fully vertical position to a completely horizontal position with a swivel cutter. The work table also moves, providing a very liberal movement and orientation degree for the user. Many swivel cutters include settings that are both automatic or manually driven, increasing the options for operation. 

Advantages of the milling process :

• All material was compatible. 
• Very good tolerances.  
• Short lead times. 

Disadvantages of the milling process :

• Limited shape complexity. 
• Part may require several operations and machines. 
• High equipment costs. 
• Significant tool wear. 
• A large amount of scrap. 

Applications of the milling process :

• Machines components
• Engine components

Read related posts:

1. Milling machine introduction
2. Difference between turning and milling
3. Working principle of milling machine
4. Milling machine safety precautions
5. Milling machine parts
6. Lubrication used in milling machine
7. Types of milling cutter

What is reaming? | Purpose | Applications | Advantages

What is reaming?

Reaming is a finishing process that is performed with the multi-edged tools that provide high precision holes and also used for enlarging or finishing a hole previously drilled without changing the chemical and physical properties. 

The reaming process took after the drilling process it removes a relatively small amount of material. 

No specific machine is used for reaming can be performed on drilling machine, lathe machine, milling machine, and machining centres or by hands.

Purpose of reaming : 

Reaming is applied to accurately finish drilled holes with a good surface finish and size. It offers the advantages that a greater number of holes can be produced with consistently good quality. 

• Reaming required which has exact diameter required. 
• It requires has an adequate edge profile. 
• It is required where the well-sharpened surface needed. 
• Reaming calls for a hole that has been exactly pre-machined. 
• The use of lubricants will prolong the life tool so reaming is applied for fitting holes and taper holes. 

Design and types of reamer : 

There are two types of reamers one is hand reamers and another one is machine reamers. Both are mainly differing with respect to the shank and to the cutting portion. 

                                             

Hand reamers are used primarily for assembly work to improve the fitting of parts. A long taper lead is the main features of this reamers. This ensures that the hole is well guided and prevents canting. Through the milled square and a tap wrench with clockwise rotation and slight pressure, the reamers are inserted into the hole. 

Machine reamers are used for reaming on drilling machines and lathe machines. The work spindle guides them. Lead, therefore, does not need to be as long as hand reamers. Cutting is by the lead with reaming, while the straight portion is used to smooth the hole.

Applications of the reaming process :

Any components requiring precise, cylindrical or tapered holes with good surface finish, either blind or through, such as drilling, after primary hole-making.

Advantages of the reaming process :

• The rates of production range from 10-500/h.
• Low cost of tooling and equipment.
• Finishing costs low and also required cleaning and deburring as well.
• Decreasing feed rate improves surface finish.
• Reaming is carried out for optimum conditions at one-third of the speed and two-thirds of the feed rate of drilling.
• Most precise holes are centre drilled, drilled, bored and reamed to finished size.
• It is possible to obtain surface roughness values of 0.4–6.3 μm Ra.

Reaming and boring is a similar type of process but there is some difference between reaming and boring but for the purpose of both this process are same, a similar type of working so both of them are useful in manufacturing industries.

What is Burnishing? Burnishing Tools | Roller Burnishing | Advantages | Applications

Introduction of Burnishing process: 

Burnishing a finish machining process is the plastic deformation of a surface due to sliding contact with another object.

Burnishing can be defined as a process in which a smooth but hard tool using sufficient pressure is rubbed on the surface of the metal.

Burnishing is a polishing and work hardening of a metallic surface will smooth and harden the surface, creating a finish which will last longer than one that hasn't been burnished.

Burnishing tools:

Burnishing process works on a variety of different metals such as stainless steel, aluminium, cast iron, and brass, making available for today's manufacturers a wide variety of burnishing tools. Burnishing can eliminate secondary process which cuts down cycle time an ultimately saves money. Now, let's look at some common burning tool types.

• Diamond burnishing tools : 

This is one of the most versatile burnishing tools. It can be used on a variety of metals and can produce a dense, smooth surface. Setting up for diamond burning is fast and cost-effective, and secondary processes such as grinding are not needed. Overall, this processing tool is efficient and will show high-quality results. 

• Multi-roll burnishing tools :

It can offer accurate sizing and can show significant improvements in the surface finish of steel and high ductility materials. They can produce in just one pass 2 to 8 Ra microinch finishes. It can be run on almost any machine tool, CNC or manual lathe. These burning tools can be fully interchanged with burning tools in the Madison style.

• Carbide roll burnishing tools : 

It can be used so that there is no need for secondary operations this helps to reduce costs significantly. This tools remove any surface impurities and produce a 4 to 8 Ra micro inch finish in just one pass. Feature an economic tool life with the option to recondition the rolls. 

Advantages of the burnishing process:

• Improves revolution size and finish such as cylinders and conical surfaces.
• It is possible to burn internal and external surfaces.
• Improves the hardness of the surface.
• Increases wear resistance and decrease fatigue and fight corrosion.
• It also eliminates the processes of grinding and honing that can be expensive.
• Mirror finish in one pass and accurate sizing, close tolerance and eliminate lapping and honing process too. 
• Long tool life and no operator skill required. 
• Machining time is short. 

Most widely used burnishing process is Roller Burnishing.

Roller burnishing:

Roller burnishing is a super-finishing process and cold rolling process without removal of metal. A set of rollers is used to roll on with adequate pressure on the component surface resulting in a fine surface through the planetary rotation of hardened rollers over a bored or turned metal surface. 

In the roller burnishing operation compresses the projections into the indentation thus forming a smooth mirror finished surface. It is possible to burnish any material not exceeding 40 Rockwell Hardness C.

The result of this process is a mirror-like finish with a tough, work-hardened, wear and corrosion-resistant surface. 

Advantages of roller burnishing process:

• Surface finish is good as a mirror Rz < 1 µm / Ra < 0.16 µm can be obtained. 
• It is possible to achieve very close and consistent dimensional tolerance.
• Accurate sizing and short cycle time. 
• Single-pass operation and very less cycle time are required to complete the job to required surface finish and tolerance.
• The surface hardens at the same time ensures that the processed surface to become stronger, and more slippery. 
• Reduces reworks and rejections.
• No sawdust and residues occur so no noise and damage to the environment. 
• It is too much economical, low spare part consumption and saves time, money and energy. 

Application of Roller Burnishing Tools:

Bright tools are used in sectors such as

• Automobile
• Aircraft
• Defence
• Spacecraft
• Railways
• Textile
• Machine Tool
• Motors and Pump Industry
• Hydraulic and Pneumatic Farm Equipment
• Home Appliances 

Explore more information:

1. Advantages of the burnishing process
2. Advantages and disadvantages of roller burnishing process

Staking manufacturing process

Staking is a process where two or more parts can be joined by creating an interference fit between the two pieces. It is a method of fastening by squeezing protrusion formed in one part inside a hole in the second part and then deforming the protrusion. The act of this deformation causes radial expansion of the inner part and locks it in the hole. 

Staking is a method of securing parts together with punch and hammer by pushing the surface metal.

Staking can be performed with a wide variety of technologies which are following below. 

• Thermal tooling
• Thermal punch or Hot punch
• Hot Air Cold Upset
• Ultrasonic staking 
• Cold forming
• Impulse staking
• Infrared staking 

What is extrusion? | Classification | Working principle | Extrusion ratio |

Extrusion is a compressive deformation process. In this process confining the metal is formed in a closed cavity and then allowing it to flow from only one opening so that metal takes the shape of the opening. The operation is identical to the squeezing of toothpaste out of toothpaste tube.

In an extrusion process, a material is pushed through the die of the desired cross-section so it creates the object of fixed-cross section profile that what we need because of this its ability to create very complex cross-sectional area and it also works for brittle material.

Extrusions can be either very thick in cross-section or very thin and can be either solid or hollow with the proper tooling, extrusions may be tapered or stepped. 

The remaining extruded stock after finishing the forging process is then cut to convenient stock size and used as specific products, assembly components or as raw stock material for further processing.

Extrusion process working principle:

The equipment consists of a cylinder or container in which the billet is loaded with the heated metal. On one end of the container, the die plate with the necessary opening is fixed. From the other end, a plunger or ram compresses the metal billet against the container walls and the die plate, thus forcing it to flow through the die opening, and acquiring the shape of the opening. The extrude metal is then carried by the metal-handling system as it comes out of the die. 

By the extrusion process, it is possible to make components which have a constant cross-section over any length as can be had by the rolling process. Also, extrusion is a single-pass process unlike rolling. Generally, brittle materials can also be very easily extruded. It is possible to produce sharp corners and re-entrant angles. 

What is the extrusion ratio? 

It is the ratio of the area of a cross-section of the billet to the area of a cross-section of the extruded material.

R = Ao / Af 

The parameter used in extrusion is shape factor, the ratio of perimeter to the cross-section of the part. An extruded rod has the lowest shape factor.

The typical extrusion ratio values are between 20 to 50. Low extrusion ratios are used for intermediate operations when the billets are extruded to a given diameter before the final extrusion. 

The extrusion process is used for manufacturing long and straight metal parts with the shape of solid round, rectangular, T shapes, L shapes, and tubes. 

Extrusion speed depends on the work material. Some light alloys may be extruded at a speed of 0.05 m/s, whereas for copper alloys it may be as high as 4.50 m/s. Too high an extrusion speed causing lateral cracks because of excessive heat generation in the extruded metal.

Classification of the extrusion process:

Extrusion process mainly divide into two types one is hot extrusion and the other is cold extrusion. 

Hot extrusion : 

• Forward hot extrusion 
• Backward hot extrusion

Cold extrusion : 

• Forward cold extrusion 

In the forward cold extrusion hydrostatic extrusion. 

• Backward cold extrusion

In backward cold extrusion also two subtype one is cold extrusion forging and other is impact extrusion. 


Explore more information: 

1. Advantages and Disadvantages of Extrusion

What is investment casting? | Operation procedure| Advantage | Disadvantage | Application

What is investment casting?

Investment casting is an industrial process based on lost-wax casting the oldest metal forming technique in which wax pattern is surrounded by an investment compound and then baked so that the investment is hardened to form a mould and the pattern material may be melted and run-off. 

Operation procedure for investment casting:

Step-1: Produce a master pattern.
Step-2: Create a mould. 
Step-3: Production of patterns such as heat disposable wax, plastic and polystyrene.
Step-4: Assembly of these patterns onto a gating system.
Step-5: Apply investment material or covering the pattern assembly with refractory slurry. 
Step-6: Melting the pattern assembly and remove the pattern material. 
Step-7: Burnout preheating. 
Step-8: Firing the mould to remove the last traces of the pattern material 
Step-9: Pouring.
Step-10: Knockout, cutoff and finishing.

Some important facts about investment casting:

• Investment casting is also called precision casting.
• It is a manufacturing process that allows the casting of extremely complex parts, with a good surface finish. 
• Very thin sections range about 0.015in (0.4mm) can be produced by this process. 
• Investment casting also allows for high dimensional accuracy. Tolerance is as low as 0.003in (0.076mm) have been claimed. 
• Manufactured parts are generally small and any metal can be investment cast. 
• Parts of the investment process may be automated. 
• Investment casting is a complicated process and also expensive. 

Advantages of investment casting:

• A complex shape which is difficult to produce by any other method is easily produced by this process.
• Formation of hollow interiors in cylinders without cores.
• Almost any metal can be cast and any intricate parts can be castable. 
• Very close tolerance and better surface finish can be produced.
• Dimensions should not vary because there is no parting line.
• Controlled mechanical properties can be obtained.

Disadvantages of investment casting:

• Investment castings require very long production cycle times as compared to other casting processes so time-consuming process. 
• Difficult to cast objects requiring cores.
• More expensive process because of large manual labour involved in the preparation of pattern and the mould.
• This process is virtually infeasible for high volume manufacturing due to its high cost and long cycle times.
• Holes cannot be smaller than 1/16 inch (1.6mm) and should be no deeper than about 1.5 times the diameter. 

For detailed information:

Read more >> Advantages and disadvantages of investment casting

Application of investment casting:

This process was used in the olden days for preparation of jewellery and surgical instruments.

Nowadays this process is used for making products like vanes and blades for the gas turbine, shuttle eyes for weaving, waveguides for radars, bolts and triggers for firearms, stainless steel valve bodies and impellers for turbochargers.