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TitleAws Whb-5 Hdbk
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Page 1

Copyright American Welding Society
Provided by IHS under license with AWS Licensee=Aramco HQ/9980755100

Not for Resale, 06/14/2006 04:08:58 MDTNo reproduction or networking permitted without license from IHS

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Page 2

AWS WHB-5 ôL( 07811265 00096111 -~ 6 ~-~
~

Welding Handbook
Seventh Edition, Volume 5

Engineering, Costs,
Quality, and Safety

Copyright American Welding Society
Provided by IHS under license with AWS Licensee=Aramco HQ/9980755100

Not for Resale, 06/14/2006 04:08:58 MDTNo reproduction or networking permitted without license from IHS

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Page 224

AWS WHB--5 CH*S * * W 07842b5 0007872 3 ~- W ___-__

Auromarion and Control / 189

(2) Determination of welding conditions
and production cycle times (includes set-up time,
indexing times, welding time, unloading, etc.)

(3) Establishment of working relationships
with equipment manufacturers

(4) Identification of operator skills and
safety requirements

(5) Evaluation of the effects of distortion,
fit-up tolerances, heat buildup, weid spatter, etc.

(6) Provision of welded specimens for test-
ing and evaluation

Feasibility tests can be conducted by the
user, the equipment manufacturer, or a subcon-
tractor. The tests should be conducted in two or
more phases. Initial testing should be performed
by the user to determine the optimum balance
between welding conditions, weid quality, and
component fit-up tolerances. The results should
be provided to the equipment manufacturer for
subsequent testing of the automatic equipment.
After installation in the user’s plant, testing of the
equipment to verify production capability may

.

.

i

- bewarranted.

FACILITIES

Utilities
Electrical power, air, and water require-

ments for automatic welding equipment are usu-
ally within the ranges of typical machinery used
in a fabrication shop. One exception may be
resistance welding equipment that can require
high electrid power demands.

Where cooling water is required, a recircu-
lating cooling system is recommended to con-
serve water. A compressed air supply may
require filters, driers, or oilers.

Voltage stabity in the power lines should
be measured with a recording voltmeter or oscil-
lograph. If voltage fluctuations exceed the range
recommended by the equipment manufacturer,
heavier service lines or a consfant voltage trans-
former can be installed.

Location
The f o l i o h g factors should be considered

in evaluating the location of an automatic weld-
ing system:

(I) Safety - clearances, arc radiation expo-
sure, fume control, spatter

(2) Work area conditions - lighting, tem-
perature, humidity, cleanliness, vibrations

The effects of lighting, noise, and smoke on
the operator should be considered. Many auto-
matic welding operations require some observa-
tion by the operator or other attendant workers.
Therefore, working conditions in the area should
be conducive to stable, reliable performance.

Safety requirements, such as a clear area
around the machine, can normally be determined
from the manufacturer’s specifications. Collision
hazards include possible contacts with material
handling equipment, fuctures, hand took, etc.,
and should receive special consideration.

Specifications
User requirements are generally written for

custom designed machines, and the specifca-
tions are made a part of the purchase (or lease)
order. Manufacturer specifications are used to
define standard equipment. Specifications serve
the following purposes:

(i) Define the performance expectations of
the purchaser and the supplier.

(2) Establish minimum quantitative require-
ments for defining the equipment.

(3) Provide uniform criteria to allow com-
parison of several vendor proposals against the
purchaser’s needs.

(4) Provide support groups (maintenance,
programming, etc.) with an information base in
preparing for delivery of the equipment.

Environment
Strict environmental requirements are not

normally specified for automatic welding equip-
ment. However, extended exposure to a hostile
environment can reduce equipment Me. When
installing automatic welding equipment, it is best
to provide as much protection as possible. Unlike
conventional welding machines, automatic equip-
ment often contains vulnerable electronic and
mechanical devices. A clean environment will
help assure good performance and long machine
Me. Potentialenvironmental problems with auto-
matic welding equipment are listed in Table 5.1,

Copyright American Welding Society
Provided by IHS under license with AWS Licensee=Aramco HQ/9980755100

Not for Resale, 06/14/2006 04:08:58 MDTNo reproduction or networking permitted without license from IHS

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Page 225

190 / AUTOMATION AND CONTROL

Table 5.1
Potential environmental problems with

automatic welding equipment

Environmental
factor Potential problem areas

Temperature Electronic and mechani-
Humidity cal accuracies

Common moisture Electronic components
and rust

Salt air Electronic components
and severe corrosion

Vibration Electronics and servo
Dust and dirt stability

Abrasive Gears, bearings, etc,

Nonabrasive Air-cooled components

Magnetic Collection on solid state
devices

Lighting, noise, fumes, Operator efficiency
and smoke

The environment for automatic welding
operations should meet the minimum require-
ments specified by the equipment manufacturer.
A harsh environment can rapidly degrade the
performance of the machine, create costly main-
tenance problems, and shorten the overall useful
life of the system. Considering the cost of auto-
matic welding equipment, investment in provid-
ing a suitable environment is often justified.

PROCUREMENT SCHEDULING

Scheduling the acquisition and instaliation
of an automatic welding machine can be straight-
forward for machines of standard design. These
machines include those that are inventoried and
have been tested with actual production parts by
the manufacturer. On the other hand, custom
designed systems that automate new welding
processes or involve unique and difficult applica-
tions may require a lengthy debugging period
that can cause scheduling difficulties. A sug-
gested checklist for procurement scheduling is
given in Table 5.2.

Table 5.2
Procurement scheduling checklist

1.

2.

3.

4.

5.

6.

I.
8.

9.

10.

11.

12.

13.

Identify potential welding applications

Estimate potential costs savings

Research literature for similar application case

Identify potential equipment suppliers

Perform welding tests to determine feasibility,
and identify limitations

Obtain approvals from engineering, manufac-
turing, quality control, and other depart-
ments, as required

Prepare equipment and fixturing specifications

Obtain budgetary proposals from potential

Appropriate procurement funds

Select an equipment supplier

Monitor design, construction, and test of the
equipment by the supplier

Install and checkout the equipment

Perform pilot production welding tests

histories

equipment suppliers

14. Turn the equipment over to production

TRAINING AND EDUCATION

Skills Required
The basic job skilis for automatic welding

are a good knowledge of the welding process and
training in the programming of automaticequip
ment.

Knowledge of the Welding Process. Fut&
automatic or flexible automatic welding systems
may not require a trained welder. However, a
skilled welding operator may be required by the
governing welding code or specification. Weld-
ing skiils are an asset for applications where the
operator performs a decision making role. Bead
placement in multiple-pass arc welded joints and
in-process adjustments of welding variables are
examples of duties that may require basic weld-
ing skills.

Copyright American Welding Society
Provided by IHS under license with AWS Licensee=Aramco HQ/9980755100

Not for Resale, 06/14/2006 04:08:58 MDTNo reproduction or networking permitted without license from IHS

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Page 447

414 / SAFE PRACTICES

base adhesives. Showers, wash bowls, mild soaps,
clean towels, refatting creams, and protective
equipment should be provided.

Curing agents should be removed from the
hands with soap and water. Resins should be
removed with soap and water, alcohol, or a suit-
able solvent. Any solvent should be used spar-
ingly and be foliowed by washing with soap and
water. In case of allergic reaction or burning,
prompt medical aid should be obtained.

Work Area. Areas in which adhesives are
handled should be separated from other opera-
tions. These areas should contain the foliowing
facilities in addition to the proper fire equipment:

(1) A sink with running water.
(2) An eye shower or nnse fountain
(3) First aid kit
(4) Ventilating facilities
Ovens, presses, and other curing equipment

should be individually vented to remove fume.

with their bare hands. Those gloves should be
discarded or cleaned using procedures that re-
move the particular adhesive. Cleaning may
require solvents, soap and water, or both. Hands,
arms, face, and neck should be coated with a
commercial bamer ointment or cream. This type
of material may provide short-term protection
and facilitate removal of adhesive components
by washing.

Fuli face shields should be worn for eye
protection whenever the possibility of splashing
exists, otherwise glasses or goggles should be
worn. In case of imtation, the eyes should be
immediately flushed with water and then prompt-
ly treated by a physician.

Protective clothing should be worn at all
times by those who work with the adhesives.
Shop coats, aprons, or coverallsmay be suitable,
and they should be cleaned before reuse.

Metric Conversion Factors Vent hoods should be provided at mixing and application stations. _ _
I in. = 25.4 mm
1 ft = 0.305 m
1 ft3 = 0.028 m3
1 ft/min 5.08 mm/s

Protective Devices. Plastic or rubber gloves
should be worn at aii times when working with
potentially toxic adhesives. Contaminated gloves
must not contact objects that others may touch

Copyright American Welding Society
Provided by IHS under license with AWS Licensee=Aramco HQ/9980755100

Not for Resale, 06/14/2006 04:08:58 MDTNo reproduction or networking permitted without license from IHS

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Page 448

Safe Practices/ 415

SUPPLEMENTARY READING LIST

ANSIIASC Z49.1-1983, Safety in Welding and
Cutting. M i d American Welding Society.

ANSI/NFPA 51-1983, Oxygen-Fuel Gas Sys-
tems for Welding, Cutting and Allied Pro-
cesses, Quincy, MA. National Fire Protec-
tion Association.

ANSIINFPA 51B-1977, Cutting and Welding
Processes, Quincy, M A National Fire Pro-
tection Association.

Arc Welding and Cutting Noise, M i h . : Ameri-
can Welding Society, 1979.

Balchin, N.C., Health and Safety in Welding and
Allied Processes, 3rd Ed., England: The
Welding Institute, 1983.

Barthold, L.O., et al., Electrostatic effects of
overheadtransmbion lines, Part I- Hazara3
and Eflects, IEEE Transactions, Power
Apparatus and Systems, Vol. PAS-91,1972
422-444.

Cornpressed Gas Association, Inc., Handbook
of Compressed Gases, 2nd Ed., New York
Van Nostrand Reinhold Co., 1981.

Dalziel, Charles F., Effects of electric current on
man, ASEE Journal, 1973, June: 18-23.

Effects of Welding on Health I , II, III, and IV,
Miami: American Welding Society, 1979,
1981, 1983.

Fumes and Gases in the Welding EZlvironment,
Miami: American Welding Society, 1979.

Handling Acetylene Cylinders in Fire Situations,
SB-4, New York: ampressed Gas Associa-
tion, 1972.

Metals Handbook, Vol. 4, Heat Treating, 9th
Ed., Metais Park, O H American Society
for Metals, 1981: 389-416.

Recommended Safe Practices for Electron Beam
Weldingand Cutting, A WSl2.1-78, Miami,
American Welding Society, 1978.

Recommended Safe Practices for the Prepara-
tion for Welding and Cutting of Containers
mat Have Held Hazardous Substances,
A WS F4.1-80, Miami: American Welding
Society, 1980.

Recommended Safe Practices for Thermal
Spraying, A WSC2.1-73, Miami, American
Welding Society, 1973.

Safe Handling of Compressed Gases in Contain-
ers, P-I, New York: Compressed Gas ASS+
ciation, 1974.

The Facts About Fume, England: The Welding
Institute, 1976.

m e Welding Enviomment, Miami: American
Welding Society, 1973.

Ultraviolet Reflectance of Paint, Miami: Ameri-
can Welding Society, 1976.

Welding Fume Control with Mechanical Venti-
lafion, 2nd Ed., San Francisco: Fireman’s
Fund Insurance Companies, 198 1.

Copyright American Welding Society
Provided by IHS under license with AWS Licensee=Aramco HQ/9980755100

Not for Resale, 06/14/2006 04:08:58 MDTNo reproduction or networking permitted without license from IHS

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