Weld-design-review

to avoid overrunning costs

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Weld-design-review is possibly seen as a needless hindrance.

That is unfortunate.

An experienced engineer may have a rich knowledge from long years of study.

And Practice from previous design achievements.

And nevertheless be unmindful to important welding issues.
That is where Weld-design-review comes in handy.

As one who received along the years heaps of mail requesting welding information, I can testify that frequently the questions submitted reveal depths of ignorance unsuspected by the inquirer.

Good design takes care of functionality and of stress calculations.

Welding experts will not mingle, generally, with those items.

Notwithstanding previous experience, important subtle design details may elude the attention of someone whose job is much larger in scope.

It should be appreciated that welding technology is quite complex a field of knowledge that requires years of study and practice to be adequately mastered.

A professional Weld-design-review can quickly point to problematic issues that, if addressed in time, avoid hindrances and extra costs affecting production.

It should be remarked that the benefits of cooperative preparation work is necessary not only for Weld-design-review of requirements, but also for assuring smooth and economic production.

Weld-design-review items briefly reminded

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Designers know the materials to use and the stresses they can comfortably sustain.

New material classes become available from time to time.
Designers should be aware of them. One such new class is in the process of being developed.

A presentation on High Entropy Alloys (NEW) and a page on Online Resources (NEW) was published (8) in Issue 141 of Practical Welding Letter for May 2015.
Click on PWL#141 to see them.

Designers may however not be fully aware of special requirements likely to ease welding and inspection processes, if taken care of by selecting suitable Specifications.

Or how to avoid costly post weld treatments.

A small premium to be paid for special material quality may be returned many time over if it assures increased production or inspection gains.

Furthermore, if suggestions to consider new materials or joining techniques are advanced by someone knowledgeable, the designer, when given the opportunity, may quickly appreciate the advantages.

Consumables will become part of the structure: their selection cannot be left to the purchasing agent.
They must be specified with productivity in mind, and quite possibly rated by a few welding tests.

While performing a Weld-design-review, it would be wise to review the purchase orders, to make sure that important and essential requirements, like Specifications and Documentation, are taken care of adequately, both for compliance with customer orders and for additional requirements that may prove important.

At this stage items with limited supply or long wait should be identified and taken special care of, to avoid costly bottle necks.

Some of the details may seem negligible but affect fatigue life of structural assemblies. Simple changes in joint preparation may go a long way in reducing machining time and costs.

Weld-design-review will perform checks for manufacturability, inspectability and maintainability.

Suitable provisions for fool-proof assembly, for fit in place slots and for critical dimensions assurance can remarkably improve productivity by reducing additional fit up work.

Selection of ways and means to fabricate any construction is not part of the designer's job. That should be taken care of by those who know.

The choices however will possibly influence quality and inspection requirements which need to be respected.

Minor design changes though may improve production, if suggested in time.

Are fixtures and assembly jigs required? Will positioners help in presenting the assemblies to welding in the most favorable position?
Will that improve productivity and justify the expense of buying or leasing equipment?

Is a skilled and qualified workforce available? Is some additional training necessary? Is robotic welding available or advisable?
Are there any changes in design to be introduced depending on the answers to these questions?

Somewhere along the process some study of the expenses incurred by applying different technologies should be performed, in order to find out how to maximize productivity at minimum costs.

The designer is not responsible for the correct production choices, but should be conscious that drawing requirements, whether justified or not, may ease or hinder production.

Designers may not be alert to special tolerance requirements to be enforced on items undergoing assembly for welding in robotic cells.

Except if required by Code, the use of test pieces to qualify Welding Procedure Specifications may not be recognized by some designers as essential to the success of the project.

Welds should be specified in drawings using the standard AWS A2.4—Standard Symbols for Welding, Brazing, and Nondestructive Examination or equivalent.

For complex structures also a Weld Map must be provided for indicating the required succession of individual welds.

The influence of the correct weld sequence in minimizing distortion cannot be overemphasized. The designer may not be aware of such consequences.

Notes are essential part of drawings specifying special means or procedures to be employed for certain production steps.

While planning the production program one should establish which sub assemblies must be built in what order to assure an organic growth of the structure.

Some thought should be dedicated to special requirements affecting hoisting, moving, assembling, and transporting.

Was the designer aware of such issues? Is the needed equipment available? How much will it cost?

It is possible that available commercial design software be of help in suggesting necessary steps and in asking questions overlooked by the designer.

Designers should be aware of the fact that by avoiding Weld-design-review they incur serious risk to overlook surprises in their design, however otherwise qualified.

It has been suggested in a respected engineering forum, that the recommendation to seek help from a welding professional for Weld-design-review, is a self serving proposition when coming from such experts who are interested in providing expertise.

This view is not fair, because no less authority than the AWS Welding Handbook, warns that "designers should refrain from relying entirely upon their own knowledge and experience, which may be generalized. They are encouraged to consult with welding experts whenever appropriate."

See also from the author of this Weld Site the article:
Design for welding: Letter to an engineer
from the Link: The Fabricator .

An Article introducing a new website page on Mechanical Properties and a Mid Month Bulletin with online references to the same subject, were published (8) in Issue 142 of Practical Welding Letter for June 2015.
Click on PWL#142 to see it.

An Article oon Advice to the New Welding Engineer was published (2) in Issue 143 of Practical Welding Letter for July 2015.
Click on PWL#143 to see it.

In a recent advertisement under the title
So you are the new Welding Engineer?
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http://www.aws.org/conferences/2014NWEConf.html
the AWS proposed a Conference to be held at FABTECH, Nov 11-12, 2014 at the
Georgia World Congress Center, Atlanta Georgia

The following is the introductory comment:

"Every one of us who is designing, planning, developing, or supervising
welding operation is working with people
whose knowledge of welding is limited.

Some have seen serious and costly errors made in manufacturing when
“common knowledge” was not known by key people."

It goes on with the following statement:
"Our objective is to provide a broad-brush
overview of the real-world concerns
that must be considered in most fabrication situations."

The Conference lists 13 subjects to be discussed at the conference.
These can be seen at the link given above. It is hoped that the Proceedings
of the Conference will later be made available to all interested.

It is suggested that readers who have Design Responsibility,
and cannot honestly claim to be familiar with all of the items
discussed in the Conference pointed at above, would do well
to plan to submit their projects to Weld-design-review.

Watch the Hobart Institute Video on
Blueprint Reading for Welders and Fitters
https://www.youtube.com/watch?v=dtlw35JCsZw

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Artwork for Hobby

Artwork for Hobby
[From https://www.welding-advisers.com/artwork-for-hobby.html]

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