March 17, 2011


It’s really interesting those things you remember.  If I crawled into Mr. Peabody’s “Way back Machine” and traveled back to one spring day in 1965, I might be sitting in my senior level machine design class.  This class was taught by one Mr. Robert J. Maxwell.  Bob Maxwell, an Irishman, stood about five feet-two inches tall, on his tallest day, but he was an absolute giant in the class room.  He was a remarkably gifted teacher who knew his subject “cold” and knew how to teach it. Hands down, one of the very best teachers at the university.  A student really wanted to do well for Robert Maxwell.

OK, we are sitting there and “big” Bob says the following:

Do you know the half-life of and engineer?  Well, at the present rate of technology, it’s about six years.  Six years and at least one-half of every thing you have learned will be down the drain-and unless you keep up and stay educated, you may be there with it.”

He went on to explain that, if we continued as engineers, a good portion of what we know would be obsolete in one-half a decade.  Startling information when you are a graduating senior and feel you know it all.  Now please keep in mind that this was before cell phones, Game Boy, Wii, i-Pod, i-Pad, bar codes, RFID, etc.  You get the picture.  He knew that for many professions, education would be a life-long necessity, engineering certainly one.

As I moved into professional life as a “blue-collar” engineer, I acknowledged the need to continue my education but had great difficulty in finding the time.  (There were also three kids in the mix.)  This was before the desktop PC and Al Gore had not invented the Internet as yet.  On-line courses were two decades away.  We are much more fortunate today and the possibilities for course-work are really extraordinary.   There is a depth and breadth of information available on a wide range of subjects.    There are several excellent organizations offering course work required to fulfill needed RPE requirements towards continued certification.  These coursed provide a tremendous service if you need the credits or just “bone up” relative to a particular subject.  I write for and publish through PDHonline.org and can certainly recommend them to you as being a resource for continued education.  Find a resource that is accredited and has ties with professional organizations.  I feel that’s a must.

In our country today, there are thirty-six states that require continuing education and most specify between twelve and fifteen CEU hours per year.  Fourteen states do not require annual participation but I do suspect they have their own education process.  I have a partial list of states vs. their requirements, given below:

Tennessee   24 hours biannually

Illinois          30 hours biannually

Texas             15 annually

Florida           8 biannually

Alaska         24 biannually

New York   36 triannually

Pennsylvania   24 biannually

Indiana       30 biannually

Ohio              15 annually

New Mexico  30 biannually

Minnesota      24 biannually

Bob Maxwell was correct, if you can breath, you need to stay engaged.  To do that, go read a book—take a course—join a technical society.  Information is out there and just waiting on you to take notice.  The great thing about on-line courses, you can take them at your speed and no commute to class.


We are always trying to find new methods to do “old” things.  This fact is true for most professions and certainly for the engineering and manufacturing disciplines.  The term “best practice” was coined by manufacturing engineers to describe the art of doing it better.  Better usually means faster, with fewer people and certainly with less expense.    Meeting and/or coming under your speficied budget will give an engineer, and certainly an engineering manager, “hero status”. No two ways about it.  When I worked for the General Electric Company, we had a “million dollar club”.  The engineer who saved the company a million dollars got to keep his job.  ( Just kidding here but I’m not too far from being correct! )

There is one technology available today that can “kick the can down the road” and provide those coveted dollar savings we all get famout for–RAPID PROTOTYPING.

Rapid prototyping is definitely a technology that has, and is, changing the way companies and commercial entities do business.   We can certainly say this “emerging technology” has gained tremendous momentum over the past decade.  The applications and uses represent a “best practice” for manufacturers and producers in general.  

Being able to obtain prototype parts quickly allows a company to test for component form, fit and function and can help launch a product much faster than your competition.   This can allows for adjustments in design, materials, size, shape, assembly, color and manufacturability of individual components and subassemblies.   Rapid prototyping is one methodology that allows this to happen.   It also is an extremely valuable tool for sales and marketing evaluation at the earliest stages of any program.   Generally, an engineering scope study is initially performed in which all elements of the development program are evaluated.  Having the ability to obtain parts “up front” provides a valuable advantage and definitely complements the decision making process.   Several rapid prototyping processes are available for today’s product design teams while other prototyping processes utilize traditional manufacturing methods, such as 1.)  CNC Machining, 2.)  Laser Cutting, 3.)  Water Jet Cutting, 4.) EDN Machining, etc.   Rapid prototyping technologies emerged in the ‘80s and have improved considerably over a relatively short period of time.   There are several viable options available today that take advantage of rapid prototyping technologies.   All of the methods shown below are considered to be examples of rapid prototyping and manufacturing technologies.  

  • (SLA) Stereolithography
  • (SLS) Selective Laser Sintering
  • (FDM) Fused Deposition Modeling
  • (3DP) Three Dimensional Printing
  • (Pjet) Poly-Jet
  • Laminated Object Manufacturing

 All six (6) of the technologies given above require the following preparatory steps:

  • Create a 3-D model of the component using a computer aided design (CAD) program.  There are various CAD modeling programs available today but the “additative manufacturing” process MUST begin by developing a three-dimensional representation of the part to be produced.  It is important to note that an experienced CAD engineer/designer is an indispensible component for success.  As you can see, RP&M processes were required to wait on three-dimensional modeling before the technology came to fruition.  
  • Generally, the CAD file must go through a CAD to RP&M translator.  This step assures that the CAD data is input to the modeling machine in the “tessellated” STL format.  This format has become the standard for RP&M processes.  With this operation, the boundary surfaces of the object are represented as numerous tiny triangles.  (VERY INDENSIBLE TO THE PROCESS!)
  • The next step involves generating supports in a separate CAD file.  CAD designers/engineers may accomplish this task directly, or with special software.  One such software is “Bridgeworks”.  Supports are needed and used for the following three reasons:
  1. To ensure that the recoater blade will not strike the platform upon which the part is being built.
  2. To ensure that any small distortions of the platform will not lead to problems during part building.
  3. To provide a simple means of removing the part from the platform upon it completion.
  • Next step— the appropriate software will “chop” the CAD model into thin layers—typically 5 to 10 layers per millimeter (MM).  Software has improved greatly over the past years and these improvements allow for much better surface finishes and much better detail in part description.  The part and supports must be sliced or mathematically sectioned by the computer into a series of parallel and horizontal planes like the floors of a very tall building.  Also during this process, the layer thickness, as discussed above, the intended building style, the cure depth, the desired hatch spacing, the line width compensation values and the shrinkage compensation factor(s) are selected and assigned.
  • Merging is the next step where the supports, the part and any additional supports and parts have their computer representations merged.  This is a crucial and allows for the production of multiple parts connected by a “web” which can be broken after the parts are molded.
  • Next, certain operational parameters are selected, such as the number or recoater blade sweeps per layer, the sweep period, and the desired “Z”-wait amount of time is selected. “Z”-wait is the amount of time in seconds the system is instructed to pause after recoating.  The purpose of this intentional pause is to allow any resin surface nonuniformities to undergo fluid dynamic relaxation.  The output of this step is the selection of the relevant parameters.
  • The last step is to “build the model”

As you can see, this is a specialized technology and one dependent upon state of the art computer aided drawings, laser technology and a fairly new engineering called mecatronics–the combination of mechanical enginnering and electronics.  In short–WE NEED INDIVIDUALS WHO CAN BE TRAINED ! to maintain our competative edge.

Many thanks,

Bob J.

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