Mfg tooling 01 intro

Tech 3113

Manufacturing Tooling

Nageswara Rao Posinasetti

1. Introduction

December 2, 2015Nageswara Rao Posinasetti 2

Reduce the overall cost of manufacturing a product by

producing acceptable parts at lowest cost.

Increase the production rate by designing tools that will

produce parts as quickly as possible.

Maintain quality by designing tools which will consistently

produce parts with the required precision.

Reduce the cost of special tooling by making every

design as cost effective and efficient as possible.

Design tools that will be safe and easy to operate.


Objectives of tool design

Cutting tools, tool holders and cutting fluids

Machine tools

Jigs and fixtures

Gages and measuring instruments

Dies for sheet metal cutting and forming

Dies for forging, cold finishing and extrusion

Fixtures for welding, riveting and other

mechanical fastening


Responsibilities of tool designer

Statement and analysis of the problem

Analysis of the requirements

Development of initial ideas

Development of design alternatives

Finalization of design ideas


The Tool Design Process

Problem without tooling

What the tool is supposed to do?

Drill four holes

Bottleneck in assembly

Low productivity with out tooling


Statement of the problem

Must perform certain functions

Must meet certain minimum precision requirements

Must keep the cost to a minimum

Must be available when the production schedule requires it

Must be operated safely

Must meet other requirements such as adaptability to the machine tool, etc.


Analysis of the requirements

Estimating cost of tooling


Cost of material

Cost of manufacturing

Cost of assembling

Cost of standard parts

Cost of tryout


What is tool cost?

Estimate the volume and mass - CAD

Steel – 7.843 g/cm3


Cost of material

It includes

Cost of machining

Cost of heat treatment


Cost of manufacturing

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Making a Cost Estimate

This ability comes by experience

Cost estimating procedures depends on

the source

Purchase finished component

Have a vendor produce the component

In house manufacture


The Cost of Machined Components

Control factors that determine the cost of

machined components are:

From what material is the component

produced?

Cost of material

Cost of scrap

Ease with which the material can be removed

(machined)



What type of machine is used to manufacture

the component?

Lathe, horizontal mill, vertical mill, and so on.

Cost of machine tool, tools and fixtures used

What are the major dimensions of the

component?

Size of the machine required

That determines the machine overhead cost



How many machined surfaces are there,

and how much material is to be removed?

Gives a good estimate of time required for

machining

How many components are made?

Fixturing requirements

Setting times and costs



What tolerance and surface finishes are

required?

Tighter tolerances are more expensive

What is the labor rate for machinists?


Thumb rules for estimation

This is relatively easier part.

Check with vendor.


Cost of standard parts

Drilling and fitting time and costs

Depends on

Number of parts

Complexity

Precision required

Skill of the operator and judgment

Prefers a rule of thumb rather than

sophisticated analysis


Cost of Assembling and Tryout

Using the listed alternatives, prepare a comparative analysis for the following tooling problem: A total of 950 flange plates require four holes accurately drilled 90 degrees apart to mate with a connector valve. Which of the listed alternatives is the most economically desirable?

A. Have a machinist who earns $20.00 per hour lay out and drill each part at a rate of 2 minutes per part.

B. Use a template jig, capable of producing 50 parts per hour and costing $50.00, in the production department, where an operator earns $10.00 per hour.

C. Use a duplex jig, which costs $500.00 and can produce a part every 26 seconds, in the production department, where an operator earns $10.00 per hour.


Tooling Economics

Option a: Cost per piece = 20/30 = $0.67

Option b: Production rate = 60/1.2 = 50 per hour

Cost per piece = 50/950 + 10/50 = 0.05 + 0.20 = $0.25

Option c: Production rate = 3600/26 = 138 per hour

Cost per piece = 500/950 + 10/138 = 0.53 + 0.07 = $0.60

Cost per piece = 500/5000 + 10/138 = 0.10 + 0.07 = $0.17 (If 5000 pieces are to be produced)


Tooling Economics

C = Initial cost of the fixture

I = interest rate on investment, say 6%

M = maintenance cost of fixture, say 10%

T = tax requirement on fixture investment, say 4%

D = depreciation of fixture, say 50%

Make depreciation 100% if the cost is to be recovered in one year.

S = setup cost per year = setup cost per batch * setup cost


Tooling Economics

t = time saved because of the fixture, hours

a = Labor hourly cost

A=Cost of saving due to fixture = a * t

Y=Yearly cost of fixture = S + C*(I+M+T+D)

n = Annual production rate

N = Pieces to be made per

year to justify fixture =

It is necessary n > NDecember 2, 2015Nageswara Rao Posinasetti 23

Tooling Economics

A

Y

Economical cost of fixture,

Number of years for fixture to pay itself


Tooling Economics

DTMI

S-taN

C

T)M(IC-S-taN

C

Years

The Initial cost of a fixture is $ 500. Given that the interest rate on investment as 6%, maintenance cost of fixture is 10%, tax requirement on fixture investment is 4% and the depreciation of fixture is to be taken as 50% per year. Setup cost of the fixture is about $10 per single setup. If the time saved because of the use of fixture is about 0.03 hours with a labor hourly cost of $10, calculate the number of parts to be produced per year to offset the cost of the fixture. If the cost of the fixture is to be recovered in the first year, what should be the production volume required? If the economical batch size of manufacture for the parts is 1000, how many batches should be produced per year to offset the cost of the fixture?



Q5

C = Initial cost of the fixture $ 500.00

I = interest rate on investment 6%

M = maintenance cost of fixture 10%

T = tax requirement on fixture investment 4%

D = depreciation of fixture 50%

S = setup cost $ 10.00

Y=Yearly cost of fixture = S + C*(I+M+T+D) $ 675.00

t = time saved because of the fixture, hours 0.03

a = Labour hourly cost $ 10.00

A=Cost of saving due to fixture = a * t $ 0.30

Number of pieces to be made per year 2,250

Make depreciation 100% if the cost is to be recovered in one year. 100%

Yearly cost of the fixture if the cost is to be recovered in one year. $ 800.00

Number of pieces to be produced if the cost is to be recovered in

one year. 2,667

Economical batch size of manufacture 1000

Number of batches 3

Setup cost per year = setup cost per batch * Number of batches $ 30.00

Y=Yearly cost of fixture = S + C*(I+M+T+D) $ 3,175.00

Number of pieces to be made per year 10,583

Design alternatives

Create Analyze in terms of these criteria

Alternatives Function Quality Cost Date Auxiliary

A

B

.

.


Temporary tooling

Permanent tooling


Economics of Design

Break-even charts are perhaps most

widely used to determine profits based on

anticipated sales.

They have other uses, however, such as

for selecting equipment or for measuring

the advisability of increased automation.


Break-Even Charts

To determine which of two machines is

most economical, the fixed cost and

variable cost of each machine are plotted

The total cost is composed of the sum of

the fixed and variable costs.


Break-Even Charts

Fixed cost, which relates to the initial investment on the equipment and tools required for the process.

Variable cost on the other hand varies with the actual number of objects made.

The total cost is the sum of both fixed and variable cost.


Break Even Analysis

TC = total cost

FC = fixed cost

VC = variable cost per piece

N = production quantity


N VC + FC = TC


N C V + C F = N C V + C F 2211

C V - C V

C F - C F = N

21

12

N = Break even quantity

Permanent mould casting, ($)

Die casting($)

Tooling 3600 7000Setup cost 6.8 17.0Labor cost 0.50 0.33Material cost 0.50 0.25


An aluminum canopy can be obtained by either permanent

mould casting or die casting process. The costs in dollars in

either case are

Find out the break-even quantity of production

from 1000 to 15 000 pieces.


Permanent mould casting($)

Die casting($)

Tooling 3600 7000

Setup cost 6.8 17.0

Fixed cost 3606.80 7017.00


Permanent mould casting($)

Die casting($)

Tooling 3600 7000

Setup cost 6.8 17.0

Fixed cost 3606.80 7017.00

Labor cost 0.50 0.33

Material cost 0.50 0.25

Variable cost 1.00 0.58


Prod quantity

Permanent mould casting, ($)

Die casting($)

1000 4606.80 7580.00

5000 8606.80 9917.00

10,000 13,606.80 12,800.00

15,000 18606.80 15717.00

Break even quantity =

= 8119.52

58.000.1

80.36067017

Draw and dimension with due consideration for

someone using the drawing to make the item in

the tool room.

Do not crowd views or dimensions.

Analyze each cut to be sure it can be done with

standard tools.

Use only as many views as necessary to show

all required detail.


Tool Drawings

Surface roughness must be specified.

Tolerances and fits peculiar to tools need special consideration. It is not economical as a rule to tolerance both details

of a pair of mating parts as is required on production part detailing.

In cases where a hole and a plug are on different details to be made and mated, the fit tolerance should be put on the male piece and the hole should carry a nominal size.


Tool Drawings

The stock list of any tool drawings should

indicate all sizes required to obtain the

right amount for each detail.

As far as possible, stock sizes known to be

on hand should be used, but in all cases,

available sizes should be specified. A proper,

finished detail is dependent upon starting with

the right material.


Tool Drawings

Use notes to convey ideas that cannot be

communicated by conventional drawing.

Heat treatments and finishes are usually

identified as specification references

rather than being spelled out on each

drawing.


Tool Drawings

Secondary operations such as surface grinding, machining of edges, polishing, heat treating, or similar specifications should be kept to a minimum.

Only employ these operations when they are important to the overall function of the tool; otherwise these operations will only add cost, not quality to the tool.


Tool Drawings

Apply tolerances realistically. Overly tight

tolerances can add a great deal of

additional cost with little or no added value

to the tool.

The function of the detail should determine

the specific tolerance, not a standard title

block tolerance value.


Tool Drawings

Layout the part in an identifying color (red

is suggested).

Layout any cutting tools. Possible

interference or other confining items

should be indicated in another identifying

color (blue suggested). Use of the cutting

tool should not damage the machine or the

fixture.


Tooling Layout

Indicate all locating requirements for the part. There are three locating planes: use three points in one, two points in the second, and only one point in the third plane.

This is called the 3-2-1 locate system. Do not locate on the parting line of castings or forgings. All locators must be accessible for simple cleaning of chips and dirt.


Tooling Layout

Indicate all clamping requirements for the part.

Be careful to avoid marking or deforming finished or delicate surfaces.

Consider the clamping movements of the operator so injury to the hands or unsafe situations are eliminated.

Be sure it is possible to load and unload the part.


Tooling Layout

Layout the details with due considerations

to stock sizes, so as to minimize

machining requirements.

Use full scale in the layout if possible.

Indicate the use of standard fixture parts

(shelf items) whenever possible.


Tooling Layout

Identify each different item or detail of any

design by the use of balloons with leaders

and arrows pointing to the detail in the

view that best shows the outline of the

item. These should not go to a line that is

common to other details.


Tooling Layout

Safety should be designed into the tooling.

Cutting should never be performed against a

clamp, because of vibration and tool chatter.

Instead, parts should be nested against pins in

order to take the cutter load.

Rigidity and fool proofing should always be built

into the tooling.


Safety as Related to Tool Design

Make drill jigs large enough to hold without the danger of spinning.

Small drill jigs should always be clamped in a vise or against a bar or backstop.

Install plexiglass guards around all milling and fIycutting operations where chips endanger workers or work areas.


Safety as Related to Tool Design

Questions?


Presentations & Public Speaking

Mfg tooling 01 intro