introduction to mfg tooling

Tech 3113 Manufacturing Tooling

Nageswara Rao Posinasetti

1. Introduction

April 22, 2023Nageswara 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.April 22, 2023Nageswara Rao Posinasetti 3

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 fasteningApril 22, 2023Nageswara Rao Posinasetti 4

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

April 22, 2023 Nageswara Rao Posinasetti12

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?


Courtesy: David Ullman – Mechanical Design Process, McGraw Hill, 2010


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 $30.00 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 $15.00 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 $15.00 per hour.


Tooling Economics

Option a: Cost per piece = 30/30 = $1.00

Option b: Production rate = 60/1.2 = 50 per hour Cost per piece = 50/950 + 15/50 = 0.05 + 0.30 = $0.35

Option c: Production rate = 3600/26 = 138 per hour Cost per piece = 500/950 + 15/138 = 0.53 + 0.11 = $0.64 Cost per piece = 500/2500 + 15/138 = 0.20 + 0.11 =

$0.31 (If 2500 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 costApril 22, 2023Nageswara Rao Posinasetti 23

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 > N


Tooling Economics

AY

Economical cost of fixture,

Number of years for fixture to pay itself


Tooling Economics

DTMIS-taN

C

T)M(IC-S-taNC

Years


Q5 Q6 Q7 Q8C = Initial cost of the fixture ₹

25,000.00 ₹ 35,000.00

₹ 45,000.00

₹ 35,000.00

I = interest rate on investment 6% 6% 6% 6%M = maintenance cost of fixture 10% 10% 8% 8%T = tax requirement on fixture investment 4% 4% 4% 4%D = depreciation of fixture 50% 50% 60% 50%S = setup cost ₹

500.00 ₹ 600.00

₹ 1,200.00

₹ 800.00

₹ 18,000.00

₹ 25,100.00

₹ 36,300.00

₹ 24,600.00

t = time saved because of the fixture, hours 0.03

0.04

0.03

0.03

a = Labour hourly cost ₹ 100.00

₹ 100.00

₹ 200.00

₹ 200.00

₹ 3.00

₹ 4.00

₹ 6.00

₹ 6.00

Number of pieces to be made per year 6,000

6,275

6,050

4,100

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

₹ 30,500.00

₹ 42,600.00

₹ 54,300.00

₹ 42,100.00

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

10,167

10,650

9,050

7,017

Economical batch size of manufacture 1000 1500 2000 1500Number of batches 6 5 4 3

Setup cost per year = setup cost per batch * setup cost ₹ 3,000.00

₹ 3,000.00

₹ 4,800.00

₹ 2,400.00

₹ 20,500.00

₹ 27,500.00

₹ 39,900.00

₹ 26,200.00

Number of pieces to be made per year 6,833

6,875

6,650

4,367

Design alternativesCreate Analyze in terms of these criteria

Alternatives Function Quality Cost Date Auxiliary

AB..


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 VC 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 7017.00Labor 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 7580.005000 8606.80 9917.0010,000 13,606.80 12,800.0015,000 18606.80 15717.00

Break even quantity =

= 8119.52

58.000.180.36067017

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?


introduction to mfg tooling

Documents

tool cost

cost of machine tool

cost of materialcost

cost of manufacturingdecember

cost of machiningcost

cost of materialit

lowest cost

cost effective