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Stretch forming

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berkaitan dg mata kuliah Proses Produksi with Dr.Eng.Ir. RUDI SUHRADI RACHMAT, M.Eng

Stretch forming is a metal forming process in which a piece of sheet metal is stretched and bent simultaneously over a die in order to form large contoured parts. Stretch forming is performed on a stretch press, in which a piece of sheet metal is securely gripped along its edges by gripping jaws. The gripping jaws are each attached to a carriage that is pulled by pneumatic or hydraulic force to stretch the sheet. The tooling used in this process is a stretch form block, called a form die, which is a solid contoured piece against which the sheet metal will be pressed. The most common stretch presses are oriented vertically, in which the form die rests on a press table that can be raised into the sheet by a hydraulic ram. As the form die is driven into the sheet, which is gripped tightly at its edges, the tensile forces increase and the sheet plastically deforms into a new shape. Horizontal stretch presses mount the form die sideways on a stationary press table, while the gripping jaws pull the sheet horizontally around the form die.

Stretch Forming
Stretch Forming

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Deep drawing

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Deep Drawing

berkaitan dg mata kuliah Proses Produksi with Dr.Eng.Ir. RUDI SUHRADI RACHMAT, M.Eng

Deep drawing is a metal forming process in which sheet metal is stretched into the desired part shape. A tool pushes downward on the sheet metal, forcing it into a die cavity in the shape of the desired part. The tensile forces applied to the sheet cause it to plastically deform into a cup-shaped part. Deep drawn parts are characterized by a depth equal to more than half of the diameter of the part. These parts can have a variety of cross sections with straight, tapered, or even curved walls, but cylindrical or rectangular parts are most common. Deep drawing is most effective with ductile metals, such as aluminum, brass, copper, and mild steel. Examples of parts formed with deep drawing include automotive bodies and fuel tanks, cans, cups, kitchen sinks, and pots and pans.

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Roll forming

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berkaitan dg mata kuliah Proses Produksi with Dr.Eng.Ir. RUDI SUHRADI RACHMAT, M.Eng

Roll forming, sometimes spelled rollforming, is a metal forming process in which sheet metal is progressively shaped through a series of bending operations. The process is performed on a roll forming line in which the sheet metal stock is fed through a series of roll stations. Each station has a roller, referred to as a roller die, positioned on both sides of the sheet. The shape and size of the roller die may be unique to that station, or several identical roller dies may be used in different positions. The roller dies may be above and below the sheet, along the sides, at an angle, etc. As the sheet is forced through the roller dies in each roll station, it plastically deforms and bends. Each roll station performs one stage in the complete bending of the sheet to form the desired part. The roller dies are lubricated to reduce friction between the die and the sheet, thus reducing the tool wear. Also, lubricant can allow for a higher production rate, which will also depend on the material thickness, number of roll stations, and radius of each bend. The roll forming line can also include other sheet metal fabrication operations before or after the roll forming, such as punching or shearing.
Roll Forming Line
Roll Forming Line

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Bending

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berkaitan dg mata kuliah Proses Produksi with Dr.Eng.Ir. RUDI SUHRADI RACHMAT, M.Eng

Bending is a metal forming process in which a force is applied to a piece of sheet metal, causing it to bend at an angle and form the desired shape. A bending operation causes deformation along one axis, but a sequence of several different operations can be performed to create a complex part. Bent parts can be quite small, such as a bracket, or up to 20 feet in length, such as a large enclosure or chassis. A bend can be characterized by several different parameters, shown in the image below.

Bending Diagram
Bending Diagram

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Machining

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berkaitan dg mata kuliah Proses Produksi with Dr.Eng.Ir. RUDI SUHRADI RACHMAT, M.Eng

Machining is a term used to describe a variety of material removal processes in which a cutting tool removes unwanted material from a workpiece to produce the desired shape. The workpiece is typically cut from a larger piece of stock, which is available in a variety of standard shapes, such as flat sheets, solid bars, hollow tubes, and shaped beams. Machining can also be performed on an existing part, such as a casting or forging.

Flat sheet
Flat sheet
Rectangular bar
Rectangular bar
Round tube
Round tube
I-beam
I-beam

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Shell mold casting

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Shell Mold Casting

berkaitan dg mata kuliah Proses Produksi with Dr.Eng.Ir. RUDI SUHRADI RACHMAT, M.Eng

Shell mold casting is a metal casting process similar to sand casting, in that molten metal is poured into an expendable mold. However, in shell mold casting, the mold is a thin-walled shell created from applying a sand-resin mixture around a pattern. The pattern, a metal piece in the shape of the desired part, is reused to form multiple shell molds. A reusable pattern allows for higher production rates, while the disposable molds enable complex geometries to be cast. Shell mold casting requires the use of a metal pattern, oven, sand-resin mixture, dump box, and molten metal.

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Sand casting,

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berkaitan dg mata kuliah Proses Produksi with Dr.Eng.Ir. RUDI SUHRADI RACHMAT, M.Eng

Sand casting, the most widely used casting process, utilizes expendable sand molds to form complex metal parts that can be made of nearly any alloy. Because the sand mold must be destroyed in order to remove the part, called the casting, sand casting typically has a low production rate. The sand casting process involves the use of a furnace, metal, pattern, and sand mold. The metal is melted in the furnace and then ladled and poured into the cavity of the sand mold, which is formed by the pattern. The sand mold separates along a parting line and the solidified casting can be removed. The steps in this process are described in greater detail in the next section.

Sand casting mold overview
Sand casting overview

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Permanent Mold Casting

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Permanent Mold Casting

berkaitan dg mata kuliah Proses Produksi with Dr.Eng.Ir. RUDI SUHRADI RACHMAT, M.Eng

Permanent mold casting is a metal casting process that shares similarities to both sand casting and die casting. As in sand casting, molten metal is poured into a mold which is clamped shut until the material cools and solidifies into the desired part shape. However, sand casting uses an expendable mold which is destroyed after each cycle. Permanent mold casting, like die casting, uses a metal mold (die) that is typically made from steel or cast iron and can be reused for several thousand cycles. Because the molten metal is poured into the die and not forcibly injected, permanent mold casting is often referred to as gravity die casting.

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Investment casting

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Investment Casting

berkaitan dg mata kuliah Proses Produksi with Dr.Eng.Ir. RUDI SUHRADI RACHMAT, M.Eng

Investment casting is one of the oldest manufacturing processes, dating back thousands of years, in which molten metal is poured into an expendable ceramic mold. The mold is formed by using a wax pattern – a disposable piece in the shape of the desired part. The pattern is surrounded, or “invested”, into ceramic slurry that hardens into the mold. Investment casting is often referred to as “lost-wax casting” because the wax pattern is melted out of the mold after it has been formed. Lox-wax processes are one-to-one (one pattern creates one part), which increases production time and costs relative to other casting processes. However, since the mold is destroyed during the process, parts with complex geometries and intricate details can be created.

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Die casting

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Die casting hot chamber machine overviewberkaitan dg mata kuliah Proses Produksi with Dr.Eng.Ir. RUDI SUHRADI RACHMAT, M.Eng

Die casting is a manufacturing process that can produce geometrically complex metal parts through the use of reusable molds, called dies. The die casting process involves the use of a furnace, metal, die casting machine, and die. The metal, typically a non-ferrous alloy such as aluminum or zinc, is melted in the furnace and then injected into the dies in the die casting machine. There are two main types of die casting machines – hot chamber machines (used for alloys with low melting temperatures, such as zinc) and cold chamber machines (used for alloys with high melting temperatures, such as aluminum). The differences between these machines will be detailed in the sections on equipment and tooling. However, in both machines, after the molten metal is injected into the dies, it rapidly cools and solidifies into the final part, called the casting. The steps in this process are described in greater detail in the next section.

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Centrifugal Casting

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Centrifugal Casting

berkaitan dg mata kuliah Proses Produksi with Dr.Eng.Ir. RUDI SUHRADI RACHMAT, M.Eng

Centrifugal casting, sometimes called rotocasting, is a metal casting process that uses centrifugal force to form cylindrical parts. This differs from most metal casting processes, which use gravity or pressure to fill the mold. In centrifugal casting, a permanent mold made from steel, cast iron, or graphite is typically used. However, the use of expendable sand molds is also possible. The casting process is usually performed on a horizontal centrifugal casting machine (vertical machines are also available) and includes the following steps: Lagi

Thermoforming

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Thermoforming - Vacuum Forming

berkaitan dg mata kuliah Proses Produksi with Dr.Eng.Ir. RUDI SUHRADI RACHMAT, M.Eng

Thermoforming describes the process of heating a thermoplastic sheet to its softening point, stretching it over or into a single-sided mold, and holding it in place while it cools and solidifies into the desired shape. The thermoplastic sheet is clamped into a holding device and heated by an oven using either convection or radiant heat until it is softened. The sheet is then held horizontally over a mold and pressed into or stretched over the mold using vacuum pressure, air pressure, or mechanical force. The softened sheet conforms to the shape of the mold and is held in place until it cools. The excess material is then trimmed away and the formed part is released. Excess material can be reground, mixed with unused plastic, and reformed into thermoplastic sheets.

Thermoforming is commonly used for food packaging, but has many applications from plastic toys to aircraft windscreens to cafeteria trays. Thin-gauge (less than 0.060 inches) sheets are mostly used for rigid or disposable packaging, while thick-gauge (greater than 0.120 inches) sheets are typically used for cosmetic permanent surfaces on automobiles, shower enclosures, and electronic equipment. A variety of thermoplastic materials can be used in this process, including the following:

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Metal Injection Molding

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MIM Feedstock preparation

berkaitan dg mata kuliah Proses Produksi with Dr.Eng.Ir. RUDI SUHRADI RACHMAT, M.Eng

Metal Injection Molding (MIM) is a variation on traditional plastic injection molding that enables the fabrication of solid metal parts utilizing injection molding technology. In this process, the raw material, referred to as the feedstock, is a powder mixture of metal and polymer. For this reason, MIM is sometimes referred to as Powder Injection Molding (PIM). Using a standard injection molding machine, the powder is melted and injected into a mold, where it cools and solidifies into the shape of the desired part. Subsequent heating processes remove the unwanted polymer and produce a high-density metal part.

Metal injection molding is best suited for the high-volume production of small metal parts. As with injection molding, these parts may be geometrically complex and have thin walls and fine details. The use of metal powders enables a wide variety of ferrous and non ferrous alloys to be used and for the material properties (strength, hardness, wear resistance, corrosion resistance, etc.) to be close to those of wrought metals. Also, because the metal is not melted in the MIM process (unlike metal casting processes), high temperature alloys can be used without any negative affect on tool life. Metals commonly used for MIM parts include the following:

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Injection molding

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Injection molding machine overviewberkaitan dg mata kuliah Proses Produksi with Dr.Eng.Ir. RUDI SUHRADI RACHMAT, M.Eng

Injection molding is the most commonly used manufacturing process for the fabrication of plastic parts. A wide variety of products are manufactured using injection molding, which vary greatly in their size, complexity, and application. The injection molding process requires the use of an injection molding machine, raw plastic material, and a mold. The plastic is melted in the injection molding machine and then injected into the mold, where it cools and solidifies into the final part. The steps in this process are described in greater detail in the next section. Lagi

Blow molding

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Extrusion Blow Molding

berkaitan dg mata kuliah Proses Produksi with Dr.Eng.Ir. RUDI SUHRADI RACHMAT, M.Eng

Blow molding is a manufacturing process that is used to create hollow plastic parts by inflating a heated plastic tube until it fills a mold and forms the desired shape. The raw material in this process is a thermoplastic in the form of small pellets or granules, which is first melted and formed into a hollow tube, called the parison. There are various ways of forming the parison, as explained below. The parison is then clamped between two mold halves and inflated by pressurized air until it conforms to the inner shape of the mold cavity. Typical pressures are 25 to 150 psi, far less than for injection molding. Lastly, after the part has cooled, the mold halves are separated and the part is ejected. Lagi

Proses Manufaktur

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berkaitan dg mata kuliah Proses Produksi with Dr.Eng.Ir. RUDI SUHRADI RACHMAT, M.Eng

Proses Manufaktur

  • Metal forming

Hot rolling, Cold rolling, drawing, stamping, forging

  •  Joining

Welding, brazing, soldering, kelingan

  •  Casting

GDC, LPDC, HPDC, SSC (Semi Solid Metal Casting)

  •  Machining

Bubut, frais, bor, dll

  •  Powder metallurgy

Proses Casting

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Proses Casting

mata kuliah Proses Produksi with Dr.Eng.Ir. RUDI SUHRADI RACHMAT, M.Eng

Definisi Proses Casting

Arti istilah casting / foundry dalam bahasa indonesia adalah pengecoran.

Sebuah proses dimana logam cair dialirkan kedalam cetakan dengan menggunakan gaya gravitasi atau bantuan tekanan, sehingga logam tersebut membeku didalam cetakan sesuai dengan bentuk cetakan.

Pengecoran / Casting adalah suatu proses manufaktur yang menggunakan logam cair dan cetakan untuk menghasilkan parts dengan bentuk yang mendekati bentuk geometri akhir produk jadi. Logam cair akan dituangkan atau ditekan ke dalam cetakan yang memiliki rongga sesuai dengan bentuk yang diinginkan. Setelah logam cair memenuhi rongga dan kembali ke bentuk padat, selanjutnya cetakan disingkirkan dan hasil cor dapat digunakan untuk proses sekunder. Pasir hijau untuk pengecoran digunakan sekitar 75 percent dari 23 million tons coran yang diproduksi dalam USA setiap tahunnya.

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