Tag: mentor

One + One-half = Four

“Rick?” Becca burst into her colleagues office with her laptop half open. “In the 3D-Printer specification you state that the extruding-head must move precisely to four equally spaced positions.”

Rick let go of his mouse, leaned back and put his finger tips together. “Yah, that’s because there are four filament spools for four polymers. What’s the problem?”

Becca closed and clutched her warm laptop under one arm. “You said the production cost is limited to $50.00 each for the actuator sub-assembly and the electronics. That’s impossible, the stepper motor and driver electronics alone will take more than half that, even if we produce a million of them.”

Rick leaned forward, palms up. “The specification doesn’t require a stepper. Your requirement is to design the machine to move four print-head assemblies, including feed spools to one of four positions, three inches apart, to an accuracy of…”

“I know the resolution, 0.1 millimeters, and that’s going to require either a stepper with gear-head, or servo motor system.”

Rick raised an eye-brow and breathed deep.

“What else is there?” Becca leaned over Rick’s desk. “If there were only two spools, this would be easy, I could just use a solenoid or a pneumatic piston to make the tool change. Whether extended or retracted, the cylinder would stop precisely.”

“You’re trying to do this all by yourself aren’t you?” Becca lowered her shoulders and took a breath thinking, “I knew he’d say something like that. He’s always…”

“Did you consider using two cylinders?” Rick said. “What if you mounted two cylinders end-to-end?”

Becca placed a finger on her chin, lips pressed together, and turned her eyes toward the wall.

Rick leaned back in his chair.

“It wont’ work,” Becca concluded. That will give you three positions, not four.”

“Look, you need to play with some options here. Get together with another perspective, someone who thinks…”

“I know, I know. Someone who thinks a little different.”

Rick folded his arms.” Your too stiff, too binary in your thinking.”

Becca opened her mouth to speak, but nothing emerged. “Binary? What does he mean by that?” She moved her laptop to the other arm, turned, and walked out. “Stiff? Binary?” Becca stopped in the doorway. “Hey. Binary!”

Rick turned his head toward the door. “Becca?”

“Binary,” she repeated as she turned back. “Binary is zero (0) and one (1)…”

“Yes?”

“Not necessarily two zeros, nor two ones.”

“Keep going…” Rick encouraged.

“In a binary system,” she paused, “there are four possible combinations of zero and one.” Becca put her laptop on rick’s desk then went to the whiteboard thinking, “Why do I have the feeling he’s going to be right again?” She wrote, 00, 01, 10, and 11 with a squeaky marker. “Two values, four combinations.”

“Keep going,” Rick said, “But use a different marker, please. How do you get four positions from…”

“From two cylinders?” Becca interrupted. “I got it! Two different sizes! Specifically two cylinders of different strokes.”

Rick stood up and smiled, “But what specific strokes?”

Becca wrote on the board, S(total) = S1 + S2.

“So,” Rick mentored slowly, “what combinations of S1 and S2 will give you…”

“Will give four equal spaces, three inches apart?” Becca drew and populated a table of values for all possible combinations. “Yes! Three and six?”

A relieved smile grew on Ricks face.

She turned and exclaimed, “One three inch, and one six inch cylinder!”

“You see,” Rick said. “I knew you would figure it…”

Becca interrupted, “You knew that all along, didn’t you?”

“No,” Rick rubbed his nose. “It was really you.”

Mentor Discussion and Exercises

Conversation, study, and new perspectives often reveal additional solutions.

  1. Draw and populate the binary table to show four equally spaced lengths given two cylinders of different strokes.
  2. Why didn’t Rick specify the use of cylinders in his specification?
  3. What other methods could be used to achieve cost effective equal spaced actuator positioning?
  4. If mounting two cylinders end to end makes the overall assembly too big, what other cylinder mounting configurations could be used?
  5. Why do 3D Printers often have multiple filament spools?

#engineerclips

The Minor in Engineering – Wireless

“Grandpa?” 5 year-old Ben eagerly grabbed me one holiday, while the other kids played soccer.

“Yes Ben?” I replied, looking down at the blond bundle of thought.

Ben hesitated then found the right words. “How does electricity move without wires?”

His mother gave a familiar nod as such curious tenacity was routine.

“Well Ben,” I said not knowing what I’d say next. “When electricity flows in a wire, it…”

“No,” Ben asserted. “Not in a wire; without wires!”

Ben locked eyes with mine, one hand gripping a double-a battery, the other a Lego(R) creation with levers and cranks.

Experience told me it was time for an illustration.

“Let’s get paper and pencil.”

Off he went and returned quickly.

“Okay.” I drew a simple image of a battery, which he recognized from prior engineering collaboration. Then I drew a line representing a wire, a switch, and a light bulb all in one circuit loop.

TMIE_Wireless_Image

“Remember this?” I pointed at the break in the circuit. “When you close this switch, the electricity flows throught the wire, through the light, and makes it glow.”

“I know grandpa, but what about…”

“Okay,” I interupted while moving my finger around the loop.

Ben followed carefully.

“When electricity, or charge, flows through a wire,” I continued, “it creates an invisible magnetic field around the wire.”

Ben studied my face again, his jaw dropped a little. “A magnetic field?”

“Or a force. If I open and close this switch again and again, it will create magnetic waves moving out away from the wire.”

I drew a similar nearby circuit with a smaller light, no switch, no battery, just a wire loop with small light.

“Now Ben, when you open and close this switch on the first circuit, it creates magnetic waves that go over to the other circuit, like the waves on the beach.”

I drew a series of arcs radiating across the paper.

“When the waves hit the new wire, it forces electricity to flow in the wire, and if the new circuit is sensitive enough, that electricity can be used to signal, or turn other things on and off.”

Ben looked at me, then at the paper, then at me again. I could almost hear the gears turning in his brain, or in this case, electrons orbiting his central processor.

“Let’s do it grandpa,” as he darted for his dad’s toolbox, “with real wire and batteries.”

“But don’t you want to play soccer?”

“No!” he said without explanation. “Let’s build a remote control.” He held up his Lego(R) machine, eyes as wide as the moon.

 

Announcement – Engineering Stories in Paperback

Engineering Stories is now in paperback! Seven stories illustrated, formatted, and published in a handsome professionally bound book for some ernest reading. Listen to these endorsements by engineering academic professionals on the back cover.

“A fabulous collection of realistic engineering adventure stories! Ken Hardman connects the design and development process we teach in engineering school to the exciting challenges faced every day in real engineering practice.” Steven D. Eppinger, Professor of Engineering Systems at MIT, co-author Product Design and Development

“Ken Hardman’s stories about engineering are a joy to read. In them he captures the excitement of engineers developing solutions to realistic technical problems. By describing the engineering process through fictional characters in fictional settings, Hardman invites the reader to participate in the adventure of invention and discovery.” Henry Petroski, A.S. Vesic Professor of Civil Engineering, Duke University, and author of, among other books, To Engineer Is Human, To Forgive Design, and An Engineer’s Alphabet.

Engineering Stories are for:

  • The high school student who wonders if engineering is for them,
  • The K12 career counselor or teacher who needs more depth in explaining engineering to students,
  • The parent or grandparent or friend who would like to encourage a youth toward a satisfying, useful, and profitable career,
  • The college engineering freshman who is deciding what major to declare,
  • The older college engineering student who cries for ways to apply their engineering academics, anxious to experience real engineering, real companies, and real teams, and
  • The young engineering professional who wants to live the engineering experiences of there peers, gaining encouragement and insight to move forward in their career.

“Ken Hardman has done a masterful job—even spellbinding—in depicting what real Science, Technology, Engineering, and Math (STEM) projects, and the people and circumstances involved in them, are actually like in the real world! Having myself been involved for more than fifty years in the types of projects that Ken writes about—and the use of case studies in engineering education for more than forty years—I can say without equivocation that Ken’s case writing ability is superb! Page after page challenges you to use your creative juices, and you feel as if you are right in the lab, conference room—or wherever—huddled around some hardware as part of a team effort working through the technical, as well as the people issues, to get the problem solved! Each engineering story has been carefully chosen to share important skills, topics and essential abilities of great engineers and scientists at work! These stories will help you experience—just about as close to first hand as possible—the joys of creation and problem solving which result from learning and applying skills in a world where all of us have the opportunity to make things better.” Robert H. Todd, PhD, P.E., Fellow of The American Society of Engineering Education, Professor Emeritus Department of Mechanical Engineering Brigham Young University

“Engineering Stories has boiled down the relationship between an engineering education and real-world engineering situations to its core! I know of no better introduction for engineering students preparing to work in industry. Anybody seriously considering a career in engineering will benefit from and enjoy reading Engineering Stories!” Braden Hancock, Mechanical Engineering Student at Brigham Young University, ASME 2012 Kenneth Andrew Roe Scholarship recipient

(If you are not inclined to acquire the paperback, continue to enjoy the same individual stories that are available for free at the authors website. Whether online or paperback, discover the career of engineering through Engineering Stories.)

http://www.amazon.com/Engineering-Stories-Realistic-Fiction-STEM/dp/1483949869