Importance of Checking/QC in Engineering 1

My current firm is ISO 9001 certified so obviously yes all drawings, calculations, reports, and other deliverables must be checked and documented that it was checked.

CuriousElectron,

"Quality control" is one of those terms you need to define before you try to discuss it in any way. To me, quality assurance is the overall process of assuring quality. Quality control is the process of inspecting work to ensure it meets quality standards.

In that context, checking/reviewing engineering design drawings and calculations is quality control.

I am unemployed at the moment, so I am not dealing with current corporate practise. In general, I figure that checking of drawings and calculations is worthwhile if the checker catches mistakes that would cost more than the checker. Review by an experienced, trusted checker is a good performance review of engineers, designers and drafters.

If it were me, under most conditions, I would make checking optional, at the discretion of the appropriate manager. If the drawings involve significant tooling and/or inventory costs, or safety, I would insist on checking. I would define clearly what is meant by "checking". We need to define who is qualified to do it. We need to define quality standards, and management must buy into this and back up the checker in the event of any conflict.

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JHG

Ultimately we check our calculations by, for example, crashing a very expensive prototype filled with very expensive instruments into a concrete wall at a very expensive facility. We find it cost effective to check our calculations before test item contacts wall. However nobody actually checks the calculations line by line, mistakes tend to be found in interim tests. For example, if I calculate a spring rate and get it wrong, then that spring rate would go into a model and would give strange results, which would be noticed by me, most likely, or whoever is using the model or results. That's not a great example, because even if a mistake is made and the results are never noticed, then was it really a mistake?

Cheers

Greg Locock


New here? Try reading these, they might help FAQ731-376

We check our design drawings thoroughly. Calculations are checked when requested, but it's very time consuming and I find it's better to run independent calculations on suspicious items.
We have reviews at an intermediate submittal and the final (or near final) submittal.
There's a definition in engineering law called "Standard of Care." We're not expected to be perfect, just follow the Standard of Care that a competent individual performing our work would. If we're sued, that's all the law requires. Performing reviews on our work is evidence that we're performing (or exceeding) to an average standard of care.

Independent checks of calculations by an experienced hand are the ideal. For me the most important check is of the table of contents: are all items included.

Yup. Ethical engineering by definition involves a/another SME checking every step in the design process - concept, detailed design, and drafting. That SME may choose to simply do a high level review without getting into calcs, but if anything seems suspicious then they're welcome to challenge you to prove your work good. Both lean and agile are facts and data-driven, you either have the data to prove yourself correct or you dont do it. As for drafting, that's typically left for a draftsman with an experienced checker validating the quality of their work before engineering approves the final print. Print quality is probably the biggest make/break in business. Lay out 3-4 similar supplier prints, compare the layout/views, and you can quickly see if they shoot from the hip or if they are very methodical and process/data driven as a company.

CWB1 said:

Ethical engineering by definition involves a/another SME checking every step in the design process - concept, detailed design, and drafting.

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I recall you making a similar statement in a previous thread - I'm curious where this definition is coming from because it is not something that I have run across before?

Our modern ethical duties are usually traced back in ethics texts to 4-5 ancient Greek tenets requiring professionals to proactively protect basic human rights. In engineering we dont concern ourselves with most of them, but our three duties are all based on nonmaleficence - the old "do no harm." Humans are irresolvably error-prone and as we approach 6σ finding our own errors becomes increasingly difficult, so the natural conclusion is that to give due-diligence to protecting the public, client, and profession we must have our work checked by an unbiased SME. That's been the basic standard of care taught from my first semester of college through every annual ethics and legal refresher of my career. Personally I am a big fan of CY-my-A, but I understand the single-engineer firm's reticence to schedule reviews outside of their four walls for small projects. Many do exactly that however and as one attorney told us a few years ago - that review could be the difference between a lawsuit and prison. To each their own and the usual disclaimers apply about my not being a lawyer, consulting your own, sleeping in the Holiday Inn, etc.