How ancient forging still shapes modern engineering

Welcome back! This month’s Mechanical newsletter explores how ancient forging still shapes modern engineering, how membranes make aluminum recycling cleaner, and what rodent silk can teach us about strength.

Plus, we spotlight Judith Resnik, the forever young NASA legend. Take a peek at the world’s most advanced warship, and recommend some offbeat space movies that deserve your attention.

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INDUSTRY UPDATES

• US unveils world’s most advanced warship with 1,150-mile range, 44-ton payload

  This autonomous vessel has a top speed of more than 50 knots and a range of 1,000 nautical miles.
  

• Student-built HydraJet from recycled parts swims over water with air power

  A sleek, agile hydroplane that skims the water, with the help of a top-mounted 70-mm Electric Ducted Fan (EDF).
  

• US: World’s largest six-lane wildlife crossing takes shape in California 

  A $92 million, ambitious five to six lane wildlife crossing bridge project, which started in 2022, will be completed in 2026.
  

• Biofuel could become hydrogen carrier

  An international team of scientists has developed a novel method for storing and releasing hydrogen that involves lignin-based jet fuel
  

• Spider silk stretches for strength

  Cutting-edge computational study reveals why spider silk becomes stronger once stretched.

SPOTLIGHT

Forging Ahead – How an Age-Old Process Still Powers Modern Engineering

Forging is an ancient yet remarkably versatile metalworking process, dating back to Mesopotamia around 4000 BC. It shapes metals through hammering, pressing, or rolling, typically after heating them to temperatures where they become malleable. 

Historically, blacksmiths utilized this method to craft tools, weapons, and agricultural implements. Modern forging, however, has evolved significantly, incorporating electrically powered presses and advanced tooling to achieve high precision, strength, and durability in manufactured parts.

Today, a variety of metals such as steel, aluminum, brass, copper, titanium, and stainless steel are commonly forged, as these metals withstand compressive forces without becoming brittle. However, materials like cast iron or high-carbon steel, prone to cracking under impact, are unsuitable. Forging provides critical advantages, including improved grain structure, superior mechanical strength, and absence of defects like porosity and cracks.

The forging process involves several key stages. Initially, dies—special molds designed for shaping—are prepared. Metal billets or ingots are then heated in furnaces to precise temperatures, often between 850°C and 1150°C for steel, making them easily deformable. Next, the heated metal is pressed or hammered into the desired shape, possibly requiring multiple passes and reheating to reach exact dimensions.

Subsequently, components undergo heat treatment such as annealing or tempering to refine mechanical properties, followed by controlled cooling to optimize strength. Final finishing steps, including machining and surface treatments, prepare the parts for industrial use.

Forging methods are classified by temperature into hot, warm, or cold forging. Hot forging, performed above the metal’s recrystallization temperature, requires lower force but yields less precision and a rougher finish. Warm forging, conducted at intermediate temperatures, provides improved precision and smoother surfaces, whereas cold forging at room temperature offers high dimensional accuracy but demands significant compressive force.

Different specialized forging techniques, like drop forging (using hammer impacts), press forging (continuous pressure), upset forging (expanding bar ends), roll forging (using opposing rollers), and precision forging (near-net shapes at controlled temperatures), cater to diverse industrial needs. 

Due to its reliability and strength advantages, forging remains essential across critical sectors, including aerospace, automotive, and oil and gas, for components like gears, crankshafts, valves, and bearings, continually advancing through innovative materials and simulation technologies.

MechTech Innovations

Optimized recycling method recovers aluminum from smelting waste

Aluminum smelting plants often discard valuable aluminum along with contaminated cryolite, a practice that drives up costs and environmental waste. To address this, MIT researchers, in collaboration with Japanese manufacturer Nitto Denko, have developed an innovative nanofiltration membrane designed to recycle aluminum from spent cryolite efficiently. 

The membrane uses a thin, positively charged coating to selectively capture aluminum ions, effectively blocking 99.7% of aluminum while allowing contaminants like sodium, lithium, and potassium ions to pass through.

The filtration method splits the waste stream into two solutions—one easily disposable, and another rich in recyclable aluminum ions. Lab tests demonstrated the membrane’s remarkable durability and chemical resistance, performing consistently after prolonged exposure to harsh acidic conditions. 

The researchers have also integrated an energy recovery system, utilizing a high-pressure pump and a pressure exchanger, slashing energy consumption by up to 80%. The spiral-wound configuration of the membrane further ensures compactness, cost-effectiveness, and reduced fouling.

As global aluminum demand continues to soar, this innovative recycling technology offers a sustainable, energy-efficient solution for aluminum production, reducing both environmental impact and operational costs.

MOVIE RECOMMENDATIONS

Coherence (2013)
A dinner party turns surreal when a cosmic anomaly creates parallel realities. Smart, low-budget sci-fi that plays with quantum mechanics and identity.

Europa Report (2013)
A realistic, found-footage-style space mission to Jupiter’s moon Europa uncovers potential alien life. A quiet, scientifically grounded thriller.

Love (2011)
An astronaut stranded on the ISS grapples with isolation and the nature of human connection. Produced by rock band Angels & Airwaves, it’s philosophical and haunting.

The Vast of Night (2019)
Set in 1950s New Mexico, a switchboard operator and a DJ uncover a possible extraterrestrial signal. Slow-burn suspense meets retro sci-fi charm.

Ikarie XB-1 (1963)
This Czech gem predates 2001: A Space Odyssey, exploring a deep-space mission and psychological strain with eerie Cold War undertones.