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Bridging the Gap between a Chemical Professional and Mechanical Design Engineer

Posted on 4/11/2017 9:09:22 AM By Dan Daley
  

My first ASC Blog post recounted an example at an OEM truck manufacturer where I worked as the Senior Materials Engineering Manager for 30 years.  I underscored why it is critical for a Materials Engineer to facilitate the communication to the Manufacturing Division of the requirements of structural joints in vehicle assembly.

In Materials Engineering, we also had sway with knowledgeable suppliers calling on our company.  We learned to leverage the product knowledge of technical sales representatives for the benefit of the in-plant teams we supported.  A new adhesive supplier calling on Navistar’s Materials Engineering Group was typically nonplussed to discover that we (material engineers) were both gatekeepers and influencers of the adhesive sale.  An adhesive sales rep’s success was wholly dependent on good reciprocal communication with mechanical design engineers.  Chemicals professionals and mechanical design engineers each speak a different language – which is where we (material engineers) came in – as language translators bridging the gap.

My son, Brian, worked at a car dealership while earning an engineering degree. Brian’s day at the car dealership would either take off or take a nose dive when an engineer walked through the door to buy a car.  Engineers tend to be a tough sell but my son’s advice for winning over an engineer (notwithstanding the irony) is:

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By comparison, a technical sale involves educating the user and is much more consultative.  Still, there are parallels to car sales. As a materials engineer, I have always viewed a product claim as incomplete without data to back it up.  After all, as W. Edwards Deming said “In God we trust, all others must bring data.”

Design engineers can learn a great deal about selecting and designing with the proper adhesive for their application from online webinars, articles, and guides.  These are focused on how to answer the questions the adhesive community needs to know in order to get to the “right” adhesive. And to teach a deeper understanding of adhesives. They often do not address what the design engineer wants to know or what he needs to further his project.

Following is the simplest example I used quite frequently – and simple is a good starting point:  A mounting tape supplier published some nice design guidelines on using mounting tapes that recommend static loads of 4 square inches of tape per pound of load, with an application pressure of 10 psi for a flexible adherend, or 30 psi for a rigid one – for our purposes this is the basis for design/concept feasibility.  

Consider a vehicle assembly project that involves the grill-surround of a heavy-duty severe-service truck, which – as it happens – is a commonly suggested mounting tape application.  Hypothetically speaking, the grill-surround could be made with various materials but let’s say it is chrome-plated aluminum that weighs about 3 pounds and measures 30 inches on each side. Per the supplier’s guidelines, this application requires 12 square inches of tape.  With a 120-inch perimeter, the engineer’s initial assumption is to require a continuous perimeter application.  Using ½” wide tape the total area equals 60 square inches of tape.  The application pressure is in the range of 360 lbs. (12 sq. in. x 30psi) to 1800 lbs. (60 sq. in. x 30psi) – although the 1800 lbs. fixture pressure may compromise the appearance of a light aluminum stamping and present design challenges to the tooling group.

Photo source:  Equipment World

While there are more factors to be considered in the design such as dynamic loading, mating compound surfaces, environmental factors and process requirements – the engineer has a solid starting point to progress the design. They know the amount of material to use, how to determine where to apply it and they can reference published data sheets on available thicknesses.

Any further barriers to this type of application can be worked through and solved with the help of the design and manufacturing engineering teams.  The least desirable outcome is a failed application due to a flawed design or poor process implementation.

The key to a clear (mutual) understanding between a design engineer and chemicals professional is summarized below.

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