Assignment#17:17.4

Assignment 17.4

Total cost = Fixed cost + (Variable cost X Quantity)

TC = FC + VC (Q)

Identify the cost whether it is fixed cost or variable cost

Fixed cost	Variable cost
Plant manager and stuff $180,000	Raw material and components costs$2,150,000
Faxes and insurance $50,000	Director labor $950,000
Plant and equipment depreciation $120,000	Direct expenses $60,000
Warehouse expenses $60,000	Utilities for plant $70,000
Engineering salaries (plant) $90,000	Office utilities $10,000
Engineering expenses (plant) $30,000
Administrative staff salaries $120,000
Sales staff, salaries and commissions$100,000
Total Fixed cost $750,000	Total Variable cost $3,240,000

Quantity=60 units

Profit margin=15%

Manufacturing cost:

TC = FC + VC (Q)

= $750,000 + $3,240,000 (60)

= $195,150,000

Selling price:

15 X $195,150,000 = $29,272,500

100

$195,150,000 + $29,272,500 = $224,422,500

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Assignment#8: FMEA

Also called: potential failure modes and effects analysis; failure modes, effects and criticality analysis (FMECA).

Failure modes and effects analysis (FMEA) is a step-by-step approach for identifying all possible failures in a design, a manufacturing or assembly process, or a product or service.

“Failure modes” means the ways, or modes, in which something might fail. Failures are any errors or defects, especially ones that affect the customer, and can be potential or actual.

“Effects analysis” refers to studying the consequences of those failures.

Failures are prioritized according to how serious their consequences are, how frequently they occur and how easily they can be detected. The purpose of the FMEA is to take actions to eliminate or reduce failures, starting with the highest-priority ones.

Failure modes and effects analysis also documents current knowledge and actions about the risks of failures, for use in continuous improvement. FMEA is used during design to prevent failures. Later it’s used for control, before and during ongoing operation of the process. Ideally, FMEA begins during the earliest conceptual stages of design and continues throughout the life of the product or service.

Begun in the 1940s by the U.S. military, FMEA was further developed by the aerospace and automotive industries. Several industries maintain formal FMEA standards.

What follows is an overview and reference. Before undertaking an FMEA process, learn more about standards and specific methods in your organization and industry through other references and training.

When to Use FMEA

• When a process, product or service is being designed or redesigned, after quality function deployment.
• When an existing process, product or service is being applied in a new way.
• Before developing control plans for a new or modified process.
• When improvement goals are planned for an existing process, product or service.
• When analyzing failures of an existing process, product or service.
•  Periodically throughout the life of the process, product or service

FMEA Procedure

(Again, this is a general procedure. Specific details may vary with standards of your organization or industry.)

1.  Assemble a cross-functional team of people with diverse knowledge about the process, product or service and customer needs. Functions often included are: design, manufacturing, quality, testing, reliability, maintenance, purchasing (and suppliers), sales, marketing (and customers) and customer service.
2.   Identify the scope of the FMEA. Is it for concept, system, design, process or service? What are the boundaries? How detailed should we be? Use flowcharts to identify the scope and to make sure every team member understands it in detail. (From here on, we’ll use the word “scope” to mean the system, design, process or service that is the subject of your FMEA.)
3. Fill in the identifying information at the top of your FMEA form. Figure 1 shows a typical format. The remaining steps ask for information that will go into the columns of the form.
4.  Identify the functions of your scope. Ask, “What is the purpose of this system, design, process or service? What do our customers expect it to do?” Name it with a verb followed by a noun. Usually you will break the scope into separate subsystems, items, parts, assemblies or process steps and identify the function of each.
5. For each function, identify all the ways failure could happen. These are potential failure modes. If necessary, go back and rewrite the function with more detail to be sure the failure modes show a loss of that function.
6. For each failure mode, identify all the consequences on the system, related systems, process, related processes, product, service, customer or regulations. These are potential effects of failure. Ask, “What does the customer experience because of this failure? What happens when this failure occurs?”
7. For each failure mode, determine all the potential root causes. Use tools classified as cause analysis tool, as well as the best knowledge and experience of the team. List all possible causes for each failure mode on the FMEA form.
8. For each cause, determine the occurrence rating, or O. This rating estimates the probability of failure occurring for that reason during the lifetime of your scope. Occurrence is usually rated on a scale from 1 to 10, where 1 is extremely unlikely and 10 is inevitable. On the FMEA table, list the occurrence rating for each cause.
9.  For each cause, identify current process controls. These are tests, procedures or mechanisms that you now have in place to keep failures from reaching the customer. These controls might prevent the cause from happening, reduce the likelihood that it will happen or detect failure after the cause has already happened but before the customer is affected.
10.  For each control, determine the detection rating, or D. This rating estimates how well the controls can detect either the cause or its failure mode after they have happened but before the customer is affected. Detection is usually rated on a scale from 1 to 10, where 1 means the control is absolutely certain to detect the problem and 10 means the control is certain not to detect the problem (or no control exists). On the FMEA table, list the detection rating for each cause.
11. (Optional for most industries) Is this failure mode associated with a critical characteristic? (Critical characteristics are measurements or indicators that reflect safety or compliance with government regulations and need special controls.) If so, a column labeled “Classification” receives a Y or N to show whether special controls are needed. Usually, critical characteristics have a severity of 9 or 10 and occurrence and detection ratings above 3.
12. Calculate the risk priority number, or RPN, which equals S × O × D. Also calculate Criticality by multiplying severity by occurrence, S × O. These numbers provide guidance for ranking potential failures in the order they should be addressed.
13.  Identify recommended actions. These actions may be design or process changes to lower severity or occurrence. They may be additional controls to improve detection. Also note who is responsible for the actions and target completion dates.
14. As actions are completed, note results and the date on the FMEA form. Also, note new S, O or D ratings and new RPNs.

Credit

FMEA Example

A bank performed a process FMEA on their ATM system. Figure 1 shows part of it—the function “dispense cash” and a few of the failure modes for that function. The optional “Classification” column was not used. Only the headings are shown for the rightmost (action) columns.

Notice that RPN and criticality prioritize causes differently. According to the RPN, “machine jams” and “heavy computer network traffic” are the first and second highest risks.

One high value for severity or occurrence times a detection rating of 10 generates a high RPN. Criticality does not include the detection rating, so it rates highest the only cause with medium to high values for both severity and occurrence: “out of cash.” The team should use their experience and judgment to determine appropriate priorities for action.

Benefits

Major benefits derived from a properly implemented FMECA effort are as follows:

1. It provides a documented method for selecting a design with a high probability of successful operation and safety.
2. A documented uniform method of assessing potential failure mechanisms, failure modes and their impact on system operation, resulting in a list of failure modes ranked according to the seriousness of their system impact and likelihood of occurrence.
3. Early identification of single failure points (SFPS) and system interface problems, which may be critical to mission success and/or safety. They also provide a method of verifying that switching between redundant elements is not jeopardized by postulated single failures.
4. An effective method for evaluating the effect of proposed changes to the design and/or operational procedures on mission success and safety.
5. A basis for in-flight troubleshooting procedures and for locating performance monitoring and fault-detection devices.
6. Criteria for early planning of tests.

From the above list, early identifications of SFPS, input to the troubleshooting procedure and locating of performance monitoring / fault detection devices are probably the most important benefits of the FMECA. In addition, the FMECA procedures are straightforward and allow orderly evaluation of the design.

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Assignment#7: Hot Isostatic Process (HIP)

Brief hot isostatic process (HIP)

Hot isostatic pressing (HIP) is a manufacturing process used to reduce the porosity of metals and increase the density of many ceramic materials. This improves the material's mechanical properties and workability.

The HIP process subjects a component to both elevated temperature and isostatic gas pressure in a high pressure containment vessel. The pressurizing gas most widely used is argon. An inert gas is used, so that the material does not chemically react. The chamber is heated, causing the pressure inside the vessel to increase. Many systems use associated gas pumping to achieve the necessary pressure level. Pressure is applied to the material from all directions (hence the term "isostatic").

HIPing is one of the answers to solving your precision and complex casting and manufacturing needs.

HIP is a production process of unique benefit in the precision casting, powder metal, metal bonding and ceramics industries. HIP improves the performance and yield of precision castings. HIP consolidates powders of metals, ceramics or carbides into fully dense, complex parts wit net or near net shapes. HIP is also used for diffusion bonding similar and dissimilar materials and for applying wear or corrosion resistant coatings to parts exposed to stringent operating conditions.

Hot Isostatic Pressing is a process in which components are subjected to the simultaneous application of heat and high pressure in an inter gas medium. The pressure is uniform in all directions or isostatic. Using hot isostatic pressure, the material is changed, in simpler terms, to a ‘plastic state’ which collapses the voids. The clean surfaces of the voids bond together making the components or parts stronger. In most cases, voids that were collapsed do not change or alter the shape of the parts orcomponents.

Hot Isostatic Pressing results in startling improvements in materials’ mechanical properties, as well as significantly reduced scrap losses and decreased rework and weld repair. Of high significance is the marked reduction in the statistical spread or scatter usually associated with the cast material properties. The net result is improved reliability and efficiency of material utilization in case components.

Discuss the mechanics of the process

Credit: Sandvik

Production process for hot isostatic pressing

Powder metallurgically based hot isostatic pressing (PM HIP) technology for its near-net shape products.

The production process step by step

The production process from the melt to the finished product takes place in three stages. Powder is produced by inert gas atomization. The powder is canned in sheet metal capsules, giving the product the desired shape. The capsules are consolidated into full density under high pressure and temperature by hot isostatic pressing (HIP).

Melting and atomization

The melt produced in an induction furnace is tapped into an induction-heated ladle where further alloying elements can be added in a protective atmosphere. The ladle also permits stirring and temperature control of the melt throughout the process.

When the melt is tapped from the bottom of the ladle it is discharged directly into the atomization chamber. The molten steel is broken up by jets of inert gas and the atomized melt solidifies into small spherical particles of high purity and low oxygen content and with a diameter less than 500 micron. The powder is stored under inert gas hermetically-sealed vessels.

Canning

The powder is canned in capsules of mild steel, which are produced by sheet metal forming and welding. The capsule is designed to give the fully dense end product the desired shape. Compound products can be produced by designing capsules with separate compartments for different powders or enclosing parts of solid material together with the powder.

Hot isostatic pressing (HIP)

The capsules are placed in a hot isostatic press where they are subjected to high pressure and temperatures. The hot isostatic pressing parameters of pressure, temperature and time are predertermined to give the material full density.

Post treatment

Depending on the type of material and the application, the PM HIP products will be heat treated, machined and subjected to various types of quality control, such as ultrasonic inspection, dye penetrant testing, testing of mechanical properties.

The mild steel sheet used in the can remains on the product after the hot isostatic pressing and heat treatment and is removed by machining or by acid pickling.

Notes

For processing castings, metal powders can also be turned to compact solids by this method, the inert gas is applied between 7,350 psi (50.7 MPa) and 45,000 psi (310 MPa), with 15,000 psi (100 MPa) being most common. Process soak temperatures range from 900 °F (482 °C) for aluminium castings to 2,400 °F (1,320 °C) for nickel-based superalloys. When castings are treated with HIP, the simultaneous application of heat and pressure eliminates internal voids and microporosity through a combination of plastic deformation, creep, and diffusion bonding; this process improves fatigue resistance of the component. Primary applications are the reduction of microshrinkage, the consolidation of powder metals, ceramic composites and metal cladding. Hot isostatic pressing is also used as part of a sintering (powder metallurgy) process and for fabrication of metal matrix composites.

Advantages and disadvantages

Advantages of HIP products

The ability to manufacture tailor-made powder metallurgically-based (PM) HIP products with irregular shapes and complex geometry offers several advantages over castings, forgings and fabricated materials, both in terms of design flexibility and material properties.

Four main advantages with HIP products

1. Increased design flexibility

Hot isostatic pressing allows for considerable design flexibility in shaping components, making it especially suitable for products such as flanges, valve bodies, manifolds, hubs and pump parts. Often involving irregular shapes and small runs of a type and size, each HIP product/component can be individually designed so that it is guaranteed to meet its operating conditions.

2. Reduction of costly operations

The ability to manufacture products with irregular shapes and complex geometry means less need for costly operations like machining and welding.

3. Improved process safety

The elimination of critical welds makes HIP products contribute to increased process safety.

4. Enhanced material properties

The fine microstructure and isostatic pressure with which the HIP products are processed result in isotropic mechanical properties, in other words, properties that are equal in all directions. The isotropic properties, with no segregations, can contribute to, for example, lighter constructions. And resistance to corrosion and hydrogen-induced stress cracking (HISC).

Credit: Sandvik

Possible HIP Limitations

•  Volumetric Shrinkage
• Surface-Connected Porosity
•  Pressurizing gas will enter pores and hold them open (need to HIP prior to machining).
•  Incipient Melting
•  If a compositional gradient (segregation) exists within a part, the local melting temperature may be lower than the HIP temperature.
• Eutectic Melting
• Solid state reactions between parts and support tooling must be considered.
• Creep Deformation
• Care must be taken with thin wall section parts.
• Material Cleanliness.
• HIP can only eliminate internal porosity; other defects such as inclusions will remain.

How HIP can improve

Application areas

Many HIP products are used for a wide range of applications within, for example, offshore and power generation. Here are some examples of hot isostatic pressed (HIP) products:

• Hubs
• Manifolds
• Pump housings
• Steam chests
• Stressometers
• Swivels
• Turbine rotor shafts
• Valve bodies
• Wye pieces

Enhanced product properties

The ability to manufacture HIP products with irregular shapes and complex geometry offers several advantages over castings, forgings and fabricated materials, both in terms of design flexibility and material properties.

The fine microstructure and isostatic pressure with which the HIP products are processed result in isotropic mechanical properties, in other words, properties that are equal in all directions. The isotropic properties can contribute to, for example, lighter constructions.

How HIP can impact the design

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Assignment#6: Design Drawing for Project

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Assignment#5: Fingernail Clipper

QUESTION: The standard fingernail clipper is an excellent illustration of the integral style of product architecture. The clipper system consist of four individual components lever (A),pin (B),upper clipper arm (C),and lower clipper arm (D). Sketch a fingernail clipper, label its four components, and describe the functionality provided by each component.

Design a new fingernail clipper with totally modular product architecture. Make a  sketch and label the function provided by each part. Compare the nuber of parts in this design with the original standard nail clipper.

ZWILLING J.A. HENCKELS TWIN® BEAUTY NAIL CLIPPER

A mechanism description

By Jack Zhou

1.0 Introduction

The Zwilling J.A. Henckels TWIN Beauty nail clipper is a brushed stainless steel fingernail trimming device. Using a jaw-like mechanism, it is able to cleanly cut fingernails to a desired length and contour. The nail clipper is about 2.25 inches long and 0.5 inches wide. It is unique from other nail clippers in that it can be folded into a compact storage position (figure 2). In this position, the blades are unable to move, and the nail clipper is only an eighth of an inch thick. The closed blades make the clipper safer to handle, and the low height makes it easy to store. There are three main components to the nail clipper: the housing, the lower blade, and the handle.

    

2.1 The housing

The housing forms most of the body of the nail clipper. It determines the length, width, and height of the clipper. The housing consists of a few components: the upper blade, the hook catches, the housing hinge pin, the spring, and the spring holding pin. They are shown below in figure 3:

The upper blade is hooked down and comes to a very sharp edge. The lower

blade comes up towards the upper blade when the tip of the nail is in between them.

The blades slice through the nail and the tip is sheared off. The front of the blade is

curved into the clipper (this is in the top view of figure 3), so that it can cut the nail to

follow the natural contour of the fingertip.

The hook catches are two metal protrusions that the hook on the back of the

handle can grab. They hold the handle down when the nail clipper is in storage mode.

The housing hinge pin is a cylindrical pin that acts as a hinge for the lower blade

to rotate around. The ends of the pin are flush against the sides of the housing.

The spring is a thin piece of stainless steel, attached to the housing only by the

spring holding pin. The steel is bent at a slight upwards angle, but is flexible and can be

pushed down. The tip of the spring is in constant contact with the spring notch of the

lower blade. The purpose of the spring is to provide an upward force against the lower

blade so that when the user releases pressure on the handle after pushing it down to

close the blades, the blades will return to their original open position. The spring is held

in place by the spring holding pin, which is just a pin that rivets the spring to the

housing.

The lower blade/handle cavity is a completely hollow area in the housing. This is

to make space for the lower blade, as well as to store the handle when the clipper is

closed.

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Video#1: Cup Invention

http://www.youtube.com/watch?v=q6u_Ag6UTqs

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Assignment#3: Mechanical Pencil and the Morphology Chart

Origins of the Mechanical Pencil

The mechanical pencil is a seemingly simple utensil whose invention and development actually took decades. Being an ever-sharp pencil it was at one time thought to be the perfect tool for basic writing and to some people, still is. The convenience of allowing the user to draw consistent lines and never need sharpening is largely taken for granted as this pencil was not always as refined as it is today.

1822: Invention

The actual mechanical pencil was invented and patented in England by Sampson Mordan and Gabriel Riddle in 1822. What they had was more or less a refillable lead holder rather than a sophisticated mechanical pencil. Those who frequently used them would commonly carry around uniform pieces of lead in their pockets. Back then there was a shortage of the soft graphite that was used in regular pencils and the importation of lower quality graphite was needed to meet demands. This adaptation was one of the main sources of inspiration for Mordan and Riddle to invent such a device.

1860: Along Comes Faber

In 1860, a German named A.W. Faber invented a more advanced model to help drafters in architecture. Faber, an already renowned maker and manufacturer of writing utensils designed a holder that was more hollow and allowed for a longer lead to be fitted. A year later, Faber invented and patented the twist locking-clutch mechanism.

1862-1899: Upgrades and Improvements

Many small upgrades were implemented in the later part of the 19^th century. The most notable of which were the spring-loaded pencils developed in 1877 and the twist-feed mechanism which was introduced 1895. However, it wasn’t until 1915 that the mechanical pencil was truly sprung on the world.

1915: No Longer a Lead Holder

Up until this point the mechanical pencil had been called a number of things, mostly some variation of lead holder or push pencil. Then in 1915, two men in two different countries came out with designs that would change the mechanical pencil forever. Tokuji Hayakawa, a metal worker in Japan, implemented the use of a metal shaft, a screw-based mechanism, and sharp lead. Introduced as the Ever-Ready Sharp Pencil, the new design actually did not sell well overnight as many were unfamiliar to the metal body of the pencil and we’re hesitant to buy into it. However, after a major company in Tokyo and Osaka put in large orders, the new pencil began to fly off the shelves. Years later, Hayakawa would get his company name form that pencil, Sharp. At the same time in the United States, a man named Charles Keeran from Illinois designed a ratchet-based mechanism in which the lead is held by two or three jaws at the tip of the pencil. The user could then press a button with their thumb at the opposite end and push the lead forward as the momentarily separate. Both of these men are credited with the invention of the true “Mechanical Pencil” and usually have their separate stories combined into one given their significance and bizarrely similar timing.

Today mechanical pencils are widely used throughout all businesses and educational institutions. “Lead Holders” are still used but primarily in architectural design and are clearly distinguished from your everyday mechanical pencil.

Alice Jenkins, is a writer who has always had a passion for penmanship and writing history. She writes for pensXpress, a leading supplier of personalized pens for dedicated writers and pen enthusiasts.

What is a Mechanical Pencil?

A mechanical pencil is a type of pencil in which the graphite lead is not attached to the outer casing as is in standard pencils. The lead consists of a thin stick of graphite, wax and clay. This means that the lead can be extended as it wears away removing the need for sharpening. Some mechanical pencils used recycled industrial carbon in place of graphite.

What are the different sizes in mechanical pencils?

Nearly all mechanical pencils can be refilled by the lead that are available that are made for the pencil. Mostly the lead ranges from 0.5 mm to 2 mm in diameter. Instead of a sharpener a 'pointer' is used to sharpen the lead. These pencils have different lead thicknesses and sizes that are easily available and HB and B hardness leads are the most often used as separate leads tend not to have as many grades available as a standard pencil. This pencil would be a good choice for drawing and sketching. Many mechanical pencils come complete with an eraser. This is also replaceable and easily available.

What is the history of mechanical pencil?

The mechanical pencil was invented in 1822 by Sampson Mordan and Gabriel Riddle, in England. It was more of a refillable lead holder than a mechanical pencil, as users carried uniform pieces of lead in their pockets to use when necessary. Then slowly the pencil companies modified and gave us the best light weight with extraordinary clear lead to use.

What are the advantages of a mechanical pencil?

•             The lead is so thin that it's always sharp.

•             Allowing precise and uniform strokes without the hassle of constant sharpening.

•             They are also environmentally friendly, saving wood and eliminating the wood shavings of traditional pencil.

•             With a Mechanical Pencil you can change the lead type or color when it suits you. There is also no need to sharpen the lead.

What are the disadvantages of a mechanical pencil?

•             A mechanical pencil is more mechanically complicated than a standard pencil, which means it may break easier.

•             Mechanical pencils will be more expensive initially than standard pencils.

•             Mostly mechanical pencils will only hold one particular lead width; you may have to spend money buying various pencils to accommodate all the different types of lead you intend to use.

Mechanical Pencil Feature

Those are features of the mechanical pencil:

      Rubber Grip - Usually mechanical pencil is wrapped with soft black rubber for comfortable gripping between the thumb, index, and middle finger while writing or drawing.

·        

      Cone Cap - Located at the bottom, provides a pointed opening where lead rods can be ejected for writing. It also protect the lead from breaking.

·         

      The pocket clamp holder - Located at the top, can clamp around T-shirt pockets allowing for hands-free carrying and easy access.

·         

      Eraser - inserted at the top, can erase lead particles from paper, wood or other mediums it has been applied.  The eraser can also be removed allowing it to be replaced.

·       

            Eraser Holder – Hold the eraser and provides an opening where lead rods can be loaded into the hollow barrel of the Mechanical Pencil.

·         

      Aluminum and hi-impact plastic - internal mechanical hollow part assembly that is designed to ejects lead rods out of the bottom of the Mechanical Pencil.

·         

      Lead Size - Lead sizes vary from 0.2 right up to several millimeters in width. Make sure the pencil used has the right sized lead.

·         

      Retractable Tip - The great mechanical pencils can retract their lead sleeve to protect your pockets and the sleeve itself in when you are on the move. It also prevent the lead from breaking.

·        

      Lead Grade Indicator – the indicator that show what grade and size of lead compatible to that mechanical pencil – 0.5, 0.7, HB, 2B,  etc

·        

      Lead Advance - Most mechanical pencils have a simple top press button to advance the lead, others advance because of a twist or even a shake. 

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