Much has been written about 3D printing.  For those who fit hearing aids, especially custom-molded types, or earmolds, many of us have been told that the shells have been 3D printed.  But, what does this actually mean?

 

What is 3D Printing?

This is known also as desktop fabrication, or additive manufacturing.  It is unique in that actual objects are created based on a 3D blueprint design.  To many, 3D printing appears to be magic, appearing to build something from essentially nothing – and right before your eyes!  Additive manufacturing is the opposite of subtractive manufacturing processes where objects are ‘carved out’ using numerous tools.  Additive manufacturing builds an object layer-by-layer without the use of any particular tools and offers much higher levels in shape complexity.

 

Most 3D printers (3DP) methods use a layer-by-layer process to fabricate objects.  The general process for all types of 3D printing is as follows:

  1. A solid 3D computer model is created from medical imaging data or by computer aided design (CAD).
  2. The 3D model is sliced into consecutive two-dimensional (2D) slices.
  3. Each of the 2D slices is then fabricated by a computer-controlled layer-by-layer process.
  4. Post processing, which may include heating, removing powder, etc.

 

Is 3D Printing New?

Yes, and no.  It was first introduced in 1986, but began to draw serious attention in the 1990s.  The first machine having this capability was produced by 3D Systems, and was named the Stereolithographic Apparatus.  The reason for this name was because it used stereolithography as the process for printing 3D models.

 

So, What is Stereolithography?

Stereolithography (SLA or SL; also known as Stereolithography apparatus, optical fabrication, photo-solidification, or resin printing) is a form of 3D printing technology used to create models, prototypes, patterns, and production parts in a layer-by-layer fashion using photopolymerization.  Photopolymerization is a process by which light causes chains of molecules to link, forming polymers.  The polymers then make up the body of a three-dimensional solid (Wikipedia, 2015).  The object is manufactured layer by layer, curing the part on each level. When the build is complete, the platform raises above the vat, draining the excess resin away from the part.  The process of stereolithography is illustrated in Figure 1, and a video showing the process can be viewed at this link.

 

Figure 1.  Stereolithography employs an ultra-violet laser beam to cure liquid photo polymer in layers.  A platform starts one layer depth below the surface of the polymer material and the laser cures the first layer based on thin data slices of the object from a computer.  The platform is lowered by one-layer depth and the next layer is cured.  The process is repeated until the object is completed.  This image shows the top down process, but the build can be reversed, pushing the product up and out of the resin, or bottom up process.  In the latter procedure, the laser and mirror are placed below, and not above.

 

As mentioned previously, 3D printing technology falls within the boundaries of additive manufacturing, which is the opposite of subtractive manufacturing processes where objects are ‘carved out’ using numerous tools. The former, on the other hand, builds the object layer-by-layer without the use of any particular tools. This enables designers to devise even the most complex of designs without having to worry about how they will actually be created; 3D printers can generally print out complex designs with no problems at all.

 

Different 3D Printing Processes

The term 3D printing technically refers to the development of any object that is made from the ground up. Different processes are used to help accomplish this job, and some of these will be described in that which follows.  However, regardless of the process used, the concept behind the creation of objects using 3D printing technology remains the same.  The production of a 3D model starts from using a computer-aided design (CAD) software to set up the SL machine.  It is from this point on that the actual process used to create the physical object varies.

 

Four different types of 3D printing processes likely to be encountered are:

  • Stereolithography (SLA)
  • Selective Laser Sintering (SLS)
  • Fused Deposition Modeling (FDM)
  • Multi-Jet Modeling (MJM)

 

 

3D printing will be continued on the next post, in which the different types of 3D printing will be explained.

 

Featured image is from file:///Users/waynejstaab/Desktop/3D%20printing/Stereolithography%201.webarchive.

 

 

Reference

Wikipedia.  Stereolithography. (2015).  https://en.wikipedia.org/wiki/Stereolithography.

A recent trip to the city of Chengdu, China (home of the giant panda), provided an unexpected experience – the practice of ear-picking, or what some might refer to as ear cleaning or ear scraping.


Ear Picking and Giant Pandas – Chengdu, China

Most tourists who travel to Chengdu, China go to see the giant pandas.  However, another attraction is the traditional teahouse.  Traditional teahouses have largely disappeared in most of China, but they are still a thriving part of life in Chengdu, considered the city of leisure in China.  On nice days, you will find people sitting in teahouses, parks and along the rivers, whiling away the day sipping tea, playing chess, visiting with friends, or just snoozing.  But, you will also find some individuals of a special profession roaming around carrying a set of weird instruments – the ear-pickers, as they are called.  For many Chinese, teahouses are the perfect place to get your ears cleaned while sipping tea (Figure 1).   Every day, hundreds of residents and tourists in the city go to visit ear-cleaning masters, who usually provide their service in tea houses and parks.

Figure 1.  In Chengdu, China, you get to pick.  Teahouses are a perfect place to get your ears cleaned by ear-pickers, while sipping tea.  Or, you can have the giant pandas entertain you.  Actually, you can do both.

Ear cleaning is not just a hygiene issue in Asian countries, it is an important part of Asian history and culture.  It is a social procedure often performed by friends or loved ones, and usually in the home.  Our young female guide of 27 indicated that ear picking was a part of her normal life, as it is for many others.  In fact, many Chinese believe that regular ear cleaning is one of the three traditional practices – along with bathing and foot massaging – to help people live a long and healthy life. 


Ears and Senses

Ear pickers claim that acupuncture points along with nerve endings in your ears correspond to the internal organs of the body, and that earwax removal with Asian tools can be a soothing and stimulating experience.  They claim that it relaxes people’s nerves and makes them feel comfortable.  The ear-picking process is often described as an ‘ear massage’ in China as the movements of the tool stimulate acupressure points inside the customers’ ears.

 

Ear-Picking is Alive and Well in Chengdu

This ancient practice of ear-picking is dying, but is alive and well in Chengdu, capital of Sichuan Province of southwestern China, where the process is considered by many as an enjoyment – thanks to the city’s professional ear-pickers.  It is especially a popular pastime in the People’s Park in central Chengdu, and the charge for the service is about 10 yuan (about $1.50 US) and takes about 15 minutes.  Ear-picking was originally just one of the services offered by Sichuan’s itinerant barbers, who you still see occasionally on the streets of Chengdu, but it’s now mostly a specialist trade.


Tools of the Trade

Traditional ear-pickers are said to use up to eight tools, including wires, copper tongs, goose down, and wooden scoops, many of these self-made (Figure 2).  They also wear headlights while working to help them see better.  Figure 3 shows some of the tools up close.

Figure 2.  Traditional ear-pickers use up to eight tools, including wires, copper tongs, goose down, and wooden scoops, many of the tools being self-made.  The tools are all held in one hand, that bracing against the head.   I am not certain what the Exacto blade is used for, but was held by our ear-picker.  The headlamp light is washing out the tool being used in the ear canal in the right image.

Figure 3.  Some of the tools used for ear-picking.  The long object held in the right hand is a tuning fork and comes into play at the end of the session.

While many tools can be used, the traditional ear cleaning tool is the ear pick (being used but with the end not not shown in the photographs because it is in the ear canal).  This is a small spoon-shaped instrument used to remove earwax, not unlike a cerumen spoon used by otolaryngologists.  Another tool includes an ear hair cutter to trim long hair at the opening of the ear canal or on the lobule.  A down puff is used as the final touch – rotated as it sweeps the ear’s surfaces clean.  What is surprising is the distance from the head that the tools are held for wax removal.  One might assume that his is because if the hand were closer to the ear, the light from the headlights used would be blocked.


Ear-Picking Procedure

The ear-picker uses an eight-instrument technique.

  1. The skin around the ear is stroked with a small blunt knife, intending to send shivers of pleasure all over the body.
  2. A thin file is run along the ear lobe and outer edges of the ear canal to remove hair.
  3. A thinner file, consisting of a flexible metal strip, is used to gently loosen the wax.
  4. Larger pieces of wax that come loose easily are removed with a pair of pincers.
  5. Smaller pieces of wax are scraped out using a bamboo stick with a small scoop at the end.
  6. Down feather brushes were twirled around in the ear canal to remove any wax flakes.

From this point onward, it appears that what follows is more icing on the cake, intending to provide some kind of pleasurable sensation in the ear.

  1. A hair-thin piece of wire is slid into the ear canal and is tapped around.
  2. Then a thicker piece of wire, having a loop at the end, is also tapped around in the ear canal.
  3. A metal rod or bamboo stick with down feathers is inserted, and a tuning fork is gently snapped against the rod, causing the feathers to vibrate inside the canal.

Ear-Pickers are said to have nearly two years of training, much of which involves practicing holding their instruments without twitching or shaking.  For some, this involves holding a pair of chopsticks for six hours a day.

 

Warning

The ear pick is an effective tool for removing the dry, flaky wax common to East Asians. It is not as effective on the tougher wet wax common to those of European and African descent. People with gooey cerumen-laden wax should use irrigation or have a hearing health professional remove the wax.

The art of ear cleaning is extremely delicate as incorrect pressure or angles could cause damage to the customers’ ear canal and/or hearing.  The job requires full attention to avoid damage to the customer.

Although the thought of ear-picking can be scary, the experience is apparently enjoyable because it has grown to be one of Chengdu residents’ favorite leisure activities in the past two decades.   There is an effort being made by a group of ear-pickers in Chengdu to help preserve their skills so that the time-honored trade can carry on benefiting many Chinese generations to come.  Unfortunately, difficult training of the trade has deterred many young generations from entering into this practice.  Additionally, more glamorous and profitable industries are preferred by Chinese youngsters.

Note:  This article is not a recommendation for ear-picking.


Personal Experience

Figure 4.  Article author having his ears “picked”.

Having a background in new, and often unusual product development, I have been known to have been involved as a subject so that I can experience first-hand different products/practices. This was no different, so I volunteered to have my ears picked.  Actually, I volunteered a couple of days earlier, but did not know what it was for – and volunteering was performed in military style: you and you.  I was one of those selected. So, my “volunteering” for ear-picking was a total surprise, and before I had time to think, I was in the bamboo chair in the middle of a Chinese teahouse to have my ears picked, or scraped (Figure 4).  And, all we were doing was walking through the teahouse.

I was curious, but somewhat hesitant when I saw the parcel of tools to be used. They all looked as if they would have an unimpeded route from one ear to the other. Instrument disinfecting was identified by a small plastic vile of clear fluid and a piece of cotton taken from a cigarette packet in the shirt pocket. I could only assume that the vial held alcohol or cigarette lighter fluid.  Having been in China for almost two weeks at the time, either was OK since my hygiene standards had already been lowered.

I am used to having objects in my ear, including those for cerumen (wax) management, which I frequently perform.  There was no discomfort in the procedure used on me, but I had minimum earwax and it had not affixed itself to the canal walls. Still, I could feel a gentle nudging along the edges to loosen what was there, but no discomfort. The artisan probed and scraped inside my ear canal with his scoops, copper prongs, and twirled around inside with a series of down brushes, removing a small amount of wax.  Actually, the twirling of the feather down brushes felt good.  However, the most intriguing sensations occurred when he placed a tool in my ear and then touched its handle several times with a humming tuning fork of very low frequency.  It felt rather good.  Not exactly orgasmic, but nice.