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Our conversation with mechanical engineer Jim Heilman delves into exciting advances being made with plastic materials, the types of molding equipment used to manufacture high-volume plastic parts, and whether or not the movie industry can be trusted to provide good career advice.
- Dustin Hoffman appeared in his first staring role as twenty-year old Benjamin Braddock in the 1967 movie, The Graduate. Benjamin was advised to go into plastics.
- The American Film Institute has listed the single word quotation, “Plastics,” as the 42nd most memorable movie quote in American cinema.
- Our guest for this episode is mechanical engineer Jim Heilman, who joined us previously for episodes about recruiting and empathy.
- Plastics is the third (or fourth) largest manufacturing industry in the United States.
- While natural plastics do exist, the majority of today’s plastics are derived crude oil, petroleum products, or natural gas.
- Bakelite was one of the first plastics made from synthetic components.
- Thermosetting polymers are usually liquid prior to being cured through the application of heat. Once hardened, a thermoset resin cannot be reshaped.
- Thermoplastics do not undergo a chemical change when heated, and can thus be repeatedly remolded. Thermoplastic polymers are commonly produced in pellets, before being shaped into their final product form by melting and pressing, or injection molding.
- Although work on recycling thermoset plastics continues, it is much easier to recycle thermoplastic polymers.
- Plastics used in commercial products can often be identified by the Resin Identification Code.
- The most widely used method of manufacturing plastic parts is injection molding, which forces hot liquid plastic into a metal mold. Once the polymer material cools, the solidified part is removed.
- A “sprue” is excess material that solidifies in a passageway between mold cavities.
- Most injection molds are constructed from tool steel, although aluminum molds can also be utilized (usually for lower production volumes).
- Thermoforming involves heating a sheet of plastic, then pulling a vacuum that causes the sheet to assume the profile of an underlying mold.
- Injection molding machines are categorized by their mold orientation (horizontal or vertical), clamping mechanism (hydraulic, mechanical, or electric) and their clamping tonnage.
- Good design practices can reduce parting lines on injection molded parts.
- Blow molding inserts hollow polymer material into the the interior of a mold, then uses air (or another fluid) to force the material to expand (like a balloon), causing it to assume the shape of the mold interior.
- Jim mentions LiquiForm technology, which uses consumable liquid instead of compressed air to hydraulically form and fill a molded container.
- Extrusion molding forces plastic through a die, thus forcing the heated material to assume a desired profile.
- Jeff relates extrusion molding to making shapes with a Play-Doh Fun Factory.
- Rotational molding distributes heated plastic around the interior of a hollow mold, causing the soft material to stick to the mold walls.
- Compression molding applies heat and pressure to plastic material as it sits within a mold.
- Our guest frequently uses the International Plastics Handbook (Osswald et al., 2006) and Injection Mould Design (Pye, 1989) as reference texts.
- Jim mentions several colleges known for their strength in plastics engineering:
- Scientific (or decoupled) molding attempts to optimize the molding process.
- Plastics firms make use of process engineers, project engineers, and manufacturing engineers.
- A new self-cleaning mold technology may further increase the productivity of injection molding.
- Jeff jokes about transparent aluminum, although researchers may yet make it a reality.
- Jim notes that Stratasys is the industry leader in 3D printing.
- Our guest sees a bright future for young engineers interested in plastics manufacturing.
- Listeners may reach Jim via email: discover -=+at+=- frontiernet -dot- net. He may also be reached via his company website.
Thanks to Steven Depolo for use of the image titled “Bottled Water Macros December 02, 20106.” Podcast theme music by Paul Stevenson.
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In a completely off-the-cuff discussion, Adam, Brian, Carmen and Jeff wander through subjects including finite state machines, power circuit wiring, and the economic implications of technological advances.
- Jeff is busy preparing to teach a Software Carpentry course, as well as revising the Mechatronics course he taught the past two years.
- Although there are certain conceptual advantages to having students automate their devices using an FPGA (field-programmable gate array) rather than an Arduino board, one downside is the need to teach a hardware description language (HDL), such as Verilog or VHDL.
- On a past episode of The Amp Hour, Dave Vandenbout of XESS Corporation talked about MyHDL, a software package for programming FPGA devices using the Python language.
- One should apparently avoid schematic capture as a means for programming FPGA devices.
- A finite state machine (FSM) can be a handy mathematical abstraction when programming physical devices that have distinct operating modes.
- A quote about finite state machines that Jeff refers to, but never states:
“The formal, mathematical definition of an FSM is such brain numbing, eye popping mumbo jumbo I feel certain that 9 out of 10 electronic engineering and IT students switch off in the first 5 minutes of the FSM lecture series, never to ever benefit from the power of FSMs in their work. This is not difficult stuff, it’s just made to look difficult by the academics!” — David Stonier-Gibson
- Adam is working on a brewery control system, using Android and Bluetooth.
- To bring water up to a boil, Adam uses a 2000 watt immersion heater running off a 120 VAC power outlet.
- For his birthday, Carmen has asked for the Arduino starter kit from Adafruit.
- Brian mentions an Arduino + LabVIEW bundle that is available from Sparkfun.
- Carmen references an episode of The Amp Hour that describes how companies buy up old equipment to make out-of-production IC chips.
- At one time, NASA was buying up out-of-stock Intel 8086 CPUs from eBay to maintain their supply of spare parts.
- Entire CPUs can be programmed into FPGAs these days.
- Adam describes the slow advancement in traffic signal controller technology over the past several decades.
- Brian asks Jeff if autonomous vehicles are robots.
- Without using the “singularity” term, Jeff hints at the coming intermingling of humans and machines.
- Brian ponders future robots declaring that certain problems “do not compute.”
- The group gets into an extended discussion about the economic effects of technology, especially with regard to the number of jobs being automated each year.
- Marc Andreessen has famously declared that “software will eat the world.”
- Jeff recounts the central plot to Fredrick Pohl’s short story from 1954, “The Midas Plague,” in which the rich consume less, while the poor are forced to consume the glut of goods and services produced by robots.
- Rodney Brooks has started a company, Rethink Robotics, which is selling an adaptable robot for less than $25,000.
- In a discussion about people resisting change, Jeff recalls the story of John Henry, a “steel-driving man” who raced a steam-powered hammer in tunneling through a mountain.
- Jeff asks the group to consider the economic effect of Chris Gammell‘s hypothetical “chip printing machine.”
- A relatively small firm in England, ARM Holdings, designs the instruction set architecture used in the popular ARM processors.
- Carmen points out that small companies and advanced hobbyists can fabricate their own chip designs using the MOSIS foundry service, which is operated by the University of Southern California.
- Brian notes the recent interest in solar-powered roadways, although not everybody thinks it is a good idea.
Thanks to Steve Snodgrass for the photograph titled “UH-1N Cockpit.” Podcast theme music by Paul Stevenson.