Working document. P a

OET-010 Manufacturing Processes TAG Rubric MET

Objective

3. Distinguish between

different fabrication

processes such as

welding, fasteners,

and adhesives.

COURSE OUTLINE

SURVEY OF MANUFACTURING PROCESSES INSTRUCTOR: STEVE SYKES

Mon/Wed 2:30PM – 5:15PM OFFICE: 778-7946 (Room 434)

TEXT: MODERN MANUFACTURING PROCESSES

SME - DAVID L. GOETSCH Email:ssykes@edisonohio.edu

WEEK DATE LAB/ACTIVITY LECTURE/DEMONSTRATION ASSIGNMENTS

WEEKLY SCHEDULE OF TOPICS, ACTIVITIES, AND ASSIGNMENTS

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1/12

1/19-21

1/26

2/02

2/09

2/16

2/23

3/02

3/09

3/16

3/23

3/30

4/06

4/13

4/20

4/27

5/04

Lecture

Lecture

Lecture

Exam 1,

Lecture

Lecture

Lab

Exam 2

Spring Break

Lecture

Lecture/Lab

Lecture

Exam 3, Lab

Lecture

Lecture/Lab

Lecture/Lab

Exam 4

Brief overview of course

Introduction of Manufacturing Processes

Manufacturing Safety

Engineering Materials, Metals, Physical Metallurgy

Heat Treatment

Welding/Related Processes

Welding Related Processes

Welding Symbols

Welding Lab

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Pattern Making, Casting Processes

Sand Castings

Sand Castings (lab)

Field Trip

Metrology, Metal Cutting Theory

Turning Processes/

Milling Processes

Final’s Week

Manufacturing Research Presentation

Chap. 1,17

HO

Chap. 2

Chap. 7

Chap. 14

Chap. 14

Hand-out

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Chap. 5

Handout

Handout

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Chap. 9

Chap. 9

Chap. 10

Fillet Weld

Base Metal – metal to be welded

Bond Line – the junction of the weld metal and the base metal

Depth of Fusion – the distance that fusion extends into the base metal

Face of Weld – the exposed surface of a weld on the side from which the weld was made

Leg of Fillet Weld – the distance from the root of the joint to the toe of the fillet weld

Root of Weld – the shortest distance from the root of the fillet weld to its face

Throat of Fillet Weld – the point or points at which the bottom of the weld intersects the base metal surface or surfaces

Toe of a Weld – the junction between the face of a weld and the base metal

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4

7 6 3

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3

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Groove Weld

Bevel Angle – the angle formed between the prepared edge of a member and a plane perpendicular to the surface

of a member

Groove Angle – the total included angle of the groove between parts to be joined by a groove weld

Groove Face – the surface of a member included in the groove

Root Face – that portion of the groove face adjacent to the root of the joint

Root Opening – the separation between the members to be joined at the root of the joint

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3 5

5

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Forces in Welding

Shielded Metal Arc Welding (SMAW)

an arc welding process which produces coalescence of metals by heating them with an arc between a coveredelectrode and the work. Shielding is obtained from decomposition of the electrode covering. Pressure is notused and filler metal is obtained from the electrode. (Stick )

5

Standard Location of Element of a Welding Symbol

6

Weld Fillet Gage

Checking Fillet Throat Size Checking Fillet Leg Size

Fasteners in Aviation

• Fastener Overview:

– Types of Fastener: • Permanent Fastening

– Welding

– Adhesive Bonding

– Riveting

• Temporary Fastening – Threaded

– Non-Threaded

Permanent Fastening

Welding

Adhesive Bonding

Riveting

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Adhesive Bonding

10

• Adhesive bonded

composite test strips

Riveting

11

• Rivet joints on a

Cessna 152

Adhesives and Glues

Definition

• An adhesive is a compound that adheres or bonds two items together.

• The use of the terms adhesive and glue is confused.

– Historically natural compounds used as an adhesive were called glues

• Historically, glue only referred to protein colloids prepared from animal tissues.

– Synthetic compounds were called adhesives.

• Today the meaning of the term “adhesive” has been extended to any type of glue-like substances that is used to attach one material to another.

History of Adhesives

• The first adhesives were gums and other plant resins. – Vegetable gums:

• Guar gum

• Gum Arabic

• Archaeologists have found 6000-year-old ceramic vessels that had broken and been repaired using plant resin.

• Most early adhesives were animal glues made by rendering animal products. – Native Americans use of buffalo hooves

– Hide glue

– Bone glue

– Fish glue

– Rabbit skin glue

History--cont.

• Native Americans in what is now the eastern United States used a mixture of spruce gum and fat as adhesives and as caulk to waterproof seams in their birch bark canoes.

• During the times of Babylonia, tar-like glue was used for gluing statues.

• Egypt was one of the most prominent users of adhesives.

– The Egyptians used animal glues to adhere tombs, furniture, ivory, and papyrus.

• Mongols used adhesives to make their short bows.

• In Europe in the Middle Ages, egg whites were used to decorate parchments with gold leaves.

• In the 1700s, the first glue factory was founded in Holland, which manufactured hide glue.

• In the 1750s, the British introduced fish glue.

• As the modernization continued, new patents were issued by using rubber, bones, starch, fish, and casein.

Adhesive/Glue Terms

• Pot time – The amount of time that can elapse between when the adhesive is exposed/mixed until the

reaction develops to the point that the adhesive will not produce a good joint. – Movement of the joint during this time should not reduce the strength of the joint. – Varies with the type of adhesive and the environment.

• Set time – Starts with the assembly of the joint. – Any stress applied to the joint during this time will reduce the strength of the joint. – For some adhesives it is the amount of time pressure should be held on the joint.

• Cure time – The amount of time before the adhesive reaches maximum strength. – Varies with the type of adhesive an the environment

Advantages and

Disadvantages of

Adhesive Bonding

Advantages

No stress concentrations due to

piercing of the adherend

Improved fatigue resistance

Lighter weight structures

Ability to join and seal simultaneously

Ability to join shock-sensitive

substrates

Can be less expensive than

mechanical fasteners

Process can be easily automated

Disadvantages

Strength is dependent upon the

condition of the adherend surface

Limited non destructive quality control

methods

Can be more expensive

Bond quality is dependent upon many

variables

No single universal adhesive for all

applications

Limited disassembly and repair

Categories of Adhesives

• Structural – Natural – Synthetic adhesives

– Thermoplastic adhesives

– Thermosetting

• Pressure sensitive

Structural adhesives harden by one

of four (4) methods:

1. Evaporation of a solvent or water

(white glue),

2. Reaction with radiation (dental

adhesives),

3. Chemical reaction (two part

epoxy)

4. Cooling (hot melt)

• Pressure sensitive adhesives (PSA’s) form a bond simply by the

application of light pressure to marry the adhesive with the adherend.

• Pressure sensitive adhesives are designed with a balance between flow

and resistance to flow.

• PSA’s are designed for either permanent or removable applications

Natural Adhesives

Type Notes

Fish Improved temperature resistance, resistance to water compared to above

Animal Made from collagen, (Skin/bone) with sugar and glycerol added for flexibility.

Supplied as powder/bead which is dissolved in water

Casein Made from milk precipitated with acid. Supplied a powder for mixing with water.

Improved properties compared to all above glues

Vegetable Based on starch, dextrine.

Supplied as a powder for mixing with water.

Low strength.

Low resistance to water/high temps

Generally set by solvent evaporation.

They are generally of low strength and are susceptible to moisture and mold.

Their use is restricted to the joining of low strength materials.

http://www.roymech.co.uk/Useful_Tables/Adhesives/Nat_Adhesives.html

Synthetic Adhesives Elastomers

Based on natural and synthetic rubbers set by solvent evaporation or heat curing.

They have relatively low shear strength and suffer from creep and are therefore used for unstressed joints.

They are useful for flexible bonds with plastics and rubbers.

Natural Rubber Rubber solution with bonding be evaporation of solvent.

Not suitable for loaded structures or adverse environments.

Good for water but low resistance to oils and solvents

Polychloroprene (Neoprene)

Polyurethene Two component adhesives which can be formulated for applications.

Resistant to acids, oils some solvents and alkalis.

Susceptible to moisture.

Load bearing duties viable.

Flexible bonds suitable for shock and vibratory loading.

High strength joints

Silicone Rubber Set at room temperatures.

Has a high temperature service temperature of up to 300o C.

Low shear strength. Very good sealing /space filling adhesive - widely used

for glazing

http://www.roymech.co.uk/Useful_Tables/Adhesives/Adhesives.html#Types

Thermoplastic Adhesives

• Fusible

• Soluble

• Poor heat and creep resistant.

• They are normally used for low/medium loads.

• They have good resistance to oils but poor resistance to water.

Polyvinyl Acetate

(PVA)

Supplied as an emulsion in water, for porous materials, especially wood

Shear strength is good

Resistant to oil

Poor resistance to water

Low heat tolerance ( White glue)

Cyanoacrylates Harden quickly in seconds based on catalytic action of surface moisture.

Good for rubber.

Care needed when used with metals in moist warm conditions. "Superglue"

Thermo Setting Adhesives

Type Info

Resorcinol

resins

Good water resistance.

Used for exterior plywood.

Polyesters

(unsaturated)

Usually made to harden by chemical action rather than by the

evaporation of solvents and thus cure with little shrinkage.

Polyamides High performance adhesives requiring higher curing temperatures

and bonding pressures (up to 0.7 MPa ).

High cost adhesive.

Epoxy resins Epoxy (mostly 2-part) adhesives have good strength and chemical

resistance, do not produce volatiles during curing, and have low

shrinkage.

Form extremely strong and durable bonds with most materials in

well-designed joints.

Single part adhesives require heat for setting or long setting times.

Set as a result of the build up of molecular chains to produce a rigid cross linked structure.

Using Adhesives

• Apply adhesive – Uniform layer

– Some suggest using a notched applicator.

– Insure joint has sufficient adhesive to form a squeeze line when the joint is clamped.

• No squeeze line = insufficient adhesive (starved joint)

• Excessive adhesive squeezing out = wasted adhesive

• Select the best

adhesive for the

materials being used

and the

environment.

– Follow manufacturers

instructions.

• Prepare joint

– Clean

– Close fitting

– Dampen

Using Adhesives--cont.

• Force surfaces together – Use correct amount of pressure

• Insufficient pressure will result in a poor joint

• Excessive pressure may reduce joint strength

– Clamps

– Nails or other fasteners

Adhesive Failure

• Adhesives can fail at several different points.

• Common failures are: – Cohesive – Adhesive (Interfacial) – Mixed fracture – Alternating crack path