My ‘additive manufacturing’ journey

© Mark Ollig

3D printing, also known as additive manufacturing, creates physical objects from digital files. 

These files can be designed with Computer-Aided Design (CAD) software or found online.

Materials like plastics and metals are used to make physical objects/models, built layer by layer with a 3D printer.

Recently, my two youngest sons gave me a Bambu Lab A1 mini 3D printer as a birthday gift. 

The second oldest son is a 3D printing enthusiast and has printed some models for me, like the NASA Viking 1 lander and the James Webb Space Telescope. 

During the COVID-19 pandemic, he was printing sturdy casings to hold the filter used with N-95 masks. 

He also printed an incredibly realistic miniature of the moon’s surface using artificial moon dust called regolith. This mini moonscape now serves as the landing spot for my model of the Apollo 11 lunar module.

The Bambu printer came out of the box and was nearly fully assembled. The printer fits nicely on the wooden stand that once held my Xerox laser printer, which I had given to my oldest son after purchasing a new HP model.

The Bambu Handy software application allows me to control the 3D printer directly from my smartphone or laptop. 

Today’s computing landscape is all about apps and cloud-based programs, a stark contrast to the floppy disk days of yesteryear.

According to Bambu Lab’s website, their A1 mini 3D printer weighs 12.2 pounds and measures 13.7 inches high, 12.4 inches wide, and 14.4 inches deep. 

The build volume, or maximum size of the object model it can print, is 7.1 by 7.1 by 7.1 inches.

I turned on the 3D printer, installed its app, connected the printer to my internet router’s Wi-Fi, and registered with Bambu Lab.

Bambu Lab’s 3D printers use custom, non-open-source computing firmware, reportedly a Linux-based operating system. Two popular open-source firmware options for 3D printers are Marlin, created in 2011, and Klipper, developed in 2016.

I loaded the Polymaker spool of 1.75 mm (0.069-inch) polylactic acid (PLA) filament onto the 3D printer’s spool holder. PLA is a type of biodegradable plastic. The spool, on which 1,082 ft of filament is rolled, weighs 2.2 lb and is made of recycled cardboard. 

Next, I threaded the Savannah Yellow-colored filament into the polytetrafluoroethylene (PTFE) guide tube, which led to the printer’s hardened steel extruder.

The Bambu Lab A1 has four stepper motors, one of which powers the extruder, which draws the filament into the nozzle within the tool head, where it is heated from 374 to 446 °F. The printer is capable of reaching temperatures up to 572 °F.

Calibration of the 3D printer involves leveling its build plate and adjusting nozzle height, filament flow, temperature, and belt tension to ensure accurate and reliable layer printing at speeds up to 19.7 inches per second. 

The dynamic flow control program ensures the 3D printer dispenses the correct amount of plastic filament.

I used the app to connect to Bambu Lab’s cloud servers, where I chose a digital model from their library. 

To evaluate the printer’s performance, I printed a 3D Benchy tugboat.

This highly detailed tugboat is a standard test for 3D printers. It helps to see how well the printer can replicate complex features like curves, small details, and inclined planes.

I trimmed the filament tip and threaded it through the tube until it reached the extruder, which feeds and controls the flow of melted plastic to build each layer of a 3D print. 

I then tapped the “Load” icon on the color touchscreen at the front of the 3D printer. 

The extruder smoothly pulled the filament through the PTFE tube and into the hotend of the tool head, where it would be melted for printing my model.

I then saw part of the yellow filament emerging from the nozzle, which meant the printer was ready.

The 3D printer began extruding the heated, melted plastic filament, following the digital file instructions to build the tugboat layer by layer on the build plate.

The app provides a live video feed of the tugboat’s construction from the camera attached to the 3D printer. 

The 3D printer performed flawlessly, producing a robust yellow tugboat model with smooth lines and distinct features like a smokestack and windows. 

I was also impressed by how quietly the printer ran from start to finish. 

As this is Halloween season, I also printed a robotic-looking skeleton.

My son proposed a fitting analogy for 3D printing: Building a brick wall involves stacking layers of bricks, while a 3D printer builds objects in layers of plastic. 

I like this printer and consider it an incredible tool for exploring the possibilities of 3D printing on a personal scale.

Forty years ago, while working for the Winsted Telephone Co., I clearly remember unrolling copper-paired cable from a heavy wooden spool mounted on a trailer hitched to the company’s yellow 1965 Ford F-100 service/utility truck. 

These days, I am threading thin plastic filament from a lightweight recycled cardboard spool attached to a 3D printer.

 Perhaps tackling a 3D-printed model of that old ‘65 Ford telephone truck will be my next project.

Thank you for the great birthday present, boys.

Finished tugboat and robotic skeleton 3D printed and placed on the build plate of
the Bambu Lab A1 model printer.
(Photo by Mark Ollig)

Bambu Lab A1 mini 3D printer building the tugboat.
(photo by Mark Ollig)

‘Air Mail’ within a tube network

© Mark Ollig

From 1889 to 1893, John Wanamaker served as US Postmaster General and strongly advocated pneumatic mail delivery.

In 1892, Congress appropriated $10,000 to Philadelphia to build a two-and-a-half-mile network of eight-inch pneumatic mail tubes beneath the city streets.

In 1893, the Philadelphia Post Office became the first US high-speed delivery mail transport system.

This system used air pressure to propel a cylindrical capsule or container (sometimes referred to as a carrier) through a network of tubes between post office substations and the main post office.

Capsules were made of gutta-percha (similar to rubber but harder and less elastic), leather, wood, durable fibers, steel, and a mostly brass shell casing.

The Philadelphia Times wrote the new pneumatic tubes were a “conspicuous success” Feb. 19, 1893.

“Postmaster General Wanamaker and Philadelphia Postmaster Field inaugurated the pneumatic tube, and after dedicating it to piety and patriotism by the Bible and the flag [included inside a container], sent mail matter through it with such speed as to obliterate time,” the article said.

The sound made by a capsule rushing through the tubes was described as “whoosh!”

The capsules varied in diameter depending on the size of the tubes, typically six to seven inches for the eight-inch tubes and around five inches for the six-inch tubes.

To return capsules, the system removed air from the tubes, creating lower pressure that pulled them back, allowing two-way travel within the same tubes.

The pneumatic tube system used electric motors, rotary blowers, and air compressors to create air pressure (3 to 8 psi) that pushed capsules through the tubes.

Although the capsules could reach up to 100 miles per hour, the turns in the tube network limited their average speed to 30 to 35 mph. Reaching their destination, the mail containers emptied onto a cloth-aproned catch.

A majority of the pneumatic tube network was located underground and within buildings.

The tubes usually connected with each other using flanging, which widened the tube ends, which were secured with bolts and a gasket to the next tube for an airtight connection.

Lead-based soldering was used for junction points where tubes branched off or changed direction.

Due to high costs and fabrication challenges, steel wasn’t commonly used for pneumatic tube construction until the early 1900s.

“Mail Matter Cut in Pneumatic Tubes” was the Philadelphia Inquirer newspaper headline March 5, 1893, describing “an accident in the service that destroyed many letters.”

The article mentioned a “serious hitch” that temporarily disrupted mail delivery between postal substations and the post office’s pneumatic tube system.

The lid of a mail carrier capsule wasn’t properly fastened. As it traveled through the tube system, it detached, spilling mail parcels that were then shredded by another speeding capsule, “cutting them to pieces,” as the newspaper put it.

The Pneumatic Transit Company operated the Philadelphia mail tube system.

The Philadelphia Inquirer published “The Pneumatic Tubes Facilitate the Handling of Post Office Business” on May 2, 1893. The article stated that the pneumatic tube between the main post office and the East Chestnut Street substation was operational, and that the new system would deliver mail much faster. It also noted previous problems, likely referring to the “serious hitch” described in the March 5 article.

New York City started using a network of pneumatic mail tubes Oct. 7, 1897, mostly made of cast iron with an inside diameter of eight and one-eighth inches buried four to six feet below the ground.

A capsule carrier pierced with holes and filled with oil would occasionally be sent through the tubes to keep them lubricated.

Due to the fast speed of the mail carriers traveling through the pneumatic tubes, the New York City postal workers operating them were nicknamed “rocketeers.”

In time, New York City was using 27 miles of tubes connecting 23 post offices.

Pneumatic mail tube systems began in Boston (1897), Brooklyn (1898), St. Louis (1904), and Chicago (1898).

The 1909 US Government Printing Office report “Investigations as to Pneumatic-Tube Service for the Mails” notes, “The contract speed of 30 miles an hour between stations is in strong contrast with the contract rate for mail-wagon service, which would range from three to five miles per hour.”

The same report states the US Congress’ post-office appropriation bill for the fiscal year ended June 30, 1909, provided “for the transmission of mail by pneumatic tubes or other similar devices, $1,000,000.”

By 1915, six US cities used pneumatic tubes: New York, Brooklyn, Boston, Philadelphia, Chicago, and St. Louis, according to the United States Postal System.

In the years that followed, more economical mail transport methods led to the decline in use of the mail tube system.

In late 1953, the US Post Office Department ended its use of tube systems for mail delivery, citing tube capacity limits due to expanded mail volume, high costs, and maintenance.

I found no record of Minnesota ever having used a pneumatic tube system for delivering the US mail.

Today, pneumatic tubes are being used in hospitals, manufacturing facilities, industrial facilities, and bank drive-throughs.

The pharmacy where I pick up my prescriptions has a drive-through pneumatic tube system.

RCA’s ‘All-Shook Up’ journey

© Mark Ollig

The Wireless Telegraph and Signal Company was established July 20, 1897, the world’s first wireless electronic communications enterprise.

It was founded to market the inventions of Italian inventor Guglielmo Marconi, who pioneered wireless telegraphy.

Headquartered in England, it was renamed Marconi Wireless Telegraph Company in March 1900.

The company’s American subsidiary, the Marconi Wireless Telegraph Company of America (later American Marconi Wireless), was established in 1899.

The US had also been pioneering wireless technology.

In 1900, Nikola Tesla was granted US Patents 645,576 and 649,621 for a wireless power transmission system that included technologies enabling wireless communication.

Tesla’s innovations laid the groundwork for many of the wireless technologies we use today.

From 1899 to 1900, the US Navy conducted experimental wireless telegraphy technology trials.

American inventor Lee de Forest developed the three-electrode Audion vacuum tube in 1906, which significantly improved radio signal amplification and detection.

The General Electric Company (GE) began the Radio Corporation of America (RCA) Oct. 17, 1919.

RCA would assume the radio rights of GE and was initially established with involvement from several companies, including Westinghouse Electric Corp., to take over the assets of American Marconi Wireless.

General Electric (GE) acquired the Marconi Wireless Telegraph Company of America for $3.5 million Nov. 20, 1919, along with the US rights to Marconi’s wireless technology.

Reportedly, the US Navy pressured Marconi to sell its American subsidiary to ensure that the transatlantic radio technology would be under US control, ultimately leading to GE’s acquisition of Marconi Wireless Telegraph Company of America.

RCA gained control of radio-related assets and patents from various companies, including American Marconi Wireless, General Electric, Westinghouse, AT&T, and the Wireless Telegraph and Telephone Company.

By 1926, vacuum tube technology had rapidly advanced, along with the growing AM radio presence in the US.

That same year, RCA established the National Broadcasting Company, pioneering the formation of national radio networks.

In 1929, RCA acquired the Victor Talking Machine Company, known for its “Victrola” phonograph record players and the iconic “His Master’s Voice” logo, with the dog Nipper listening to the speaker attached to a gramophone.

It was renamed the RCA Victor Division of the Radio Corporation of America. RCA Victor was a leading record label that signed iconic artists such as Elvis Presley.

In 1932, the US government sued General Electric in a federal antitrust lawsuit for monopolizing the radio industry. As a result, General Electric had to sell RCA to allow for more competition, which enabled RCA to grow independently.

In 1936, RCA conducted experimental television broadcasts in the New York area, using a limited number of television sets primarily for its employees.

One of the main attractions at the 1939 New York World’s Fair was RCA’s “The Magic Brain,” a large display resembling a radio with lights illuminated in sequence. The display showed how a TV signal traveled from a camera to a transmitter and a TV screen, and a narrator explained the process.

In 1940, developers at RCA supplied six CXAM radar systems to the US Navy, marking the first radar deployment on US naval vessels.

CXAM: C represents the Navy classification, X refers to the X-band frequency range, A indicates air-search, and M stands for microwave.

Four years earlier, RCA manufactured the VT-138 vacuum tube, a round electron-ray indicator tube commonly used in radios as a tuning aid with a glowing green indicator.

During WWII, miniaturized versions of these electron-ray indicator tubes were adapted for use in military proximity fuses attached to ordnance, such as bombs.

NBC’s New York station, WNBT (now WNBC), began airing regular commercial television broadcasts July 1, 1941.

Manufacturing and public sales of RCA’s CT-100, the first commercially available color TV, began March 25, 1954.

In November 1955, RCA Victor purchased Elvis Presley’s contract from Sun Records for $35,000 (about $411,000 today) and began selling what turned out to be many millions of vinyl records.

In 1968, the RCA Victor Division was renamed RCA Records and continued to release Elvis’s music on records, eight-track tapes, cassette tapes, and compact discs (CDs).

In 1986, General Electric acquired RCA Corporation for approximately $6.28 billion, gaining control of NBC’s television network holdings (then known as NBC, now NBCUniversal), along with other RCA assets.

In 1987, GE focused on core areas like broadcasting (NBC) and financial services (GE Capital), selling some RCA assets, including its consumer electronics manufacturing operations, to Thomson-Brandt, S.A., a French multimedia and electronics manufacturer.

GE retained ownership of NBC until 2011, when Comcast acquired a 51% majority stake in NBCUniversal, with GE holding a 49% stake. Two years later, Comcast obtained GE’s remaining 49% portion.

RCA was founded 105 years ago, and though the company itself may be gone, its trademark name and logo, now owned by Talisman Brands in Houston, TX, live on through licensing agreements for various consumer electronic products.

RCA Records remains an exclusive label under Sony Music Entertainment, and its history is one which seems to echo Elvis’ recording of “All Shook Up.”

My music collection contains the 1972 RCA Victor label (with Nipper) stereo LP record album of “Elvis as recorded at Madison Square Garden,” and an Elvis Presley 1973 RCA eight-track tape cartridge.

The early days of Minnesota television

© Mark Ollig

“The managing director of the British Broadcasting Company, J. W. Reith, says that television, the transmission of pictures as well as the voice by radio, is theoretically quite possible,” the Minneapolis Journal reported May 7, 1924.

Around 1923, Minnesotan Stanley E. Hubbard organized WAMD (“Where All Minneapolis Dances”), a 1,000-watt radio station at the Marigold Gardens Ballroom. He had a small studio and a transmitter there.

The Minneapolis Star newspaper announced Saturday, Feb. 21, 1925, “The station [WAMD] will broadcast on 234.8 meters [1,277.7 kilocycles] and will operate between 2:45 and 5:30 p.m. Sunday.”

WAMD began broadcasting live music Feb. 22, 1925, from inside the Marigold Gardens at 1336 Nicollet Ave. in Minneapolis. In July, the station moved to the downtown Radisson Hotel at 35 S. Seventh St.

Hubbard started KSTP radio March 29, 1928. In August, he became interested in experimental radio picture broadcasts, employing a mechanical scanning system that used optical still images transmitted via radio signals.

Mechanical scanning utilizes rotating disks, drums, and mirrors to capture and display images, then breaks them down into horizontal lines for transmission and reconstruction.

KSTP broadcast still images over its radio waves four times a week, but only a few people had a mechanical scanning television set (called a televisor) to see them.

In 1928, amateur radio hobbyists experimented with constructing television receivers. One example had a housing measuring 23-by-26-by-12 inches, featuring a 1.5-by-1.25-inch glass screen, with its internal mechanical scanning system powered by five 45-volt B (dry cell) batteries.

In 1933, Dr. George A. Young obtained a license for Minnesota’s first experimental television station, W9XAT, which used mechanical scanning-disc broadcasting equipment.

The picture quality was reportedly “subpar,” and the audio was transmitted over his WDGY radio station on 780 kHz until 1934, then on 1130 kHz until he ended his experimental television broadcasting in 1936.

In 1938, 100 experimental television sets were reported to exist in the country, mainly in the possession of corporate executives and manufacturing engineers testing this new visual medium.

In August 1939, Hubbard arranged a public demonstration of television viewing of an American Legion parade via a closed-circuit broadcast on six television sets at the Radisson Hotel.

Minnesota’s first commercial television station, KSTP-TV, began broadcasting Tuesday, April 27, 1948, on channel five with a test pattern, followed by a Minneapolis Millers baseball game at 3 p.m. and narrated newsreels.

The Radio Manufacturers Association, which tracked radio and television statistics, reported that more than 6,000 television sets were in operation in the Twin Cities area Aug. 3, 1948, with many of them in hotels, bars, and restaurants.

WTCN-TV (now KARE-11) started broadcasting on channel four July 1, 1949.

During the 1940s, TV sets were expensive and primarily found in affluent homes and businesses. RCA, Zenith, General Electric, Admiral, Emerson, Andrea, Philco, and DuMont were the leading manufacturers of televisions.

Decreasing prices, the growing number of television programs, and the wonder of the new technology drove people to purchase TVs.

The Twin Cities joined major television networks Sept. 30, 1950, via coaxial cable and radio relay transmission towers.
NBC, CBS, and ABC provided the majority of national programming during the 1950s. The DuMont Television Network also offered national broadcasting from 1946 until 1956.

In 1952, WTCN-TV’s channel four license was sold and used for the broadcast frequency of WCCO-TV.

In 1953, WTCN-TV reappeared with WMIN-TV in a time-sharing arrangement on channel 11 using its VHF frequencies of 198 to 204 MHz.

In 1955, WMIN-TV sold its share of channel 11 to WTCN-TV, allowing WTCN-TV to begin broadcasting full-time.
In January 1953, KSTP-TV became the first television station in Minnesota to broadcast at the maximum allowed 100,000 watts by the FCC, reaching viewers in Brainerd and Duluth.

NBC’s color broadcast Jan. 1, 1954, of the Tournament of Roses Parade in Pasadena, CA, marked the first time such a transmission was available nationwide.

It is estimated that around 100 color television sets, likely prototypes or early production models, across the country received the broadcast, as manufactured models only appeared a few months later.

An April 26, 1954, Minneapolis Star newspaper ad showed the RCA Victor CT-100 color television set with its Tri-Color Picture Tube and a 15-inch screen selling for a pricey $1,000 ($11,746 today).

In 1957, Twin City Area Educational Television from the University of Minnesota’s St. Paul campus began broadcasting on channel two.

KSTP-TV made history Jan. 1, 1961, by becoming the first station to broadcast its entire program schedule in color.

In 1954, WTCN-TV channel 11’s children’s program “Lunch With Casey” was hosted by Casey Jones (Roger Awsumb) with Roundhouse Rodney (Lynn Dwyer). The same year, WCCO-TV began “Axel and His Dog,” featuring Clellan Card as Axel Torgeson and Mary Davies as Carmen the Nurse.

In 1960, “Romper Room,” hosted by Mary Betty Douglass, known as “Miss Betty,” aired on WTCN-TV and moved to KMSP-TV channel 9 in 1962.

By 1966, many programs were broadcast in color. I clearly remember hearing, “The following program is brought to you in living color on NBC.”

Each week, from 1966 to 1969, I watched “Star Trek” on KSTP-TV channel five.

And yes, the program was brought to me in living color on NBC.

A Minneapolis Star newspaper ad for the RCA
Victor CT-100 color television
 (published April 26, 1954)