Printing Air Planes

September 18th, 2011

3D printing is going to change the way all material is produced one day. At some point 3D printers will create the parts for our automobiles, components for computers, our children’s toys, and almost anything else you can think of. A new and exciting prospect for 3D printing is the manufacturing of air drones, unmanned air craft created from a 3D printer. The production of drone components today is very much an assembly process. Robotics and humans work together on creating identical drones today. The 3D printed air drones of the future can be tweaked and perfected for individual tasks with very little effort.

Do you need a drone for information gathering? Perhaps it needs to collect topography information, or measure readings from an active volcano. Just create a design for it, feed it into the 3D printer and it will produce the right tool for the job. Do you need a drone for spraying crops? Just use a design for it. How about a killer flying robot for the military? You know the government already has a design for that. In fact this process is so painless that a design can go from paper to reality within a matter of days. A team from the University of South Hampton is working on perfecting the printing of these 3D unmanned aircraft, and they have already test flown a prototype.

The process the University of South Hampton is using is known as selective laser sintering. They use a 3D printer in conjunction with a polymer powder to create the parts for the air drone. In this process a prototype component is shaved into appropriate layers and then it is melted into its proper form. This is done layer, by ultra thin layer, until the component is the proper shape. Not only can this 3D printer create static parts, but it can also create moveable components in the final design with little assembly required.

This seems like an exciting step in the future of aircraft design. Without having to worry about laborers and delicate hand/robot cut components, designers will be freer in their plans. The mathematics and physics of airflow can be more adventurously tackled as less “straight line” designs are needed. Straight line components are easier to create and keep costs down, when you don’t need to worry about cutting the right curvature of a component that issue becomes non-existent. I can’t wait for us all to have consumer 3D printers (or replicators if you will), so I can make my own aircraft and not have to deal with the TSA.

The Future of Polymer Solar Cells

September 18th, 2011

One of these days our fossil fuel reserves will expire. That is a given. As of today alternative green sources of energy are being researched and experimented with. As long as I have been alive people have been talking about solar panels as a means to power our energy grid. Unfortunately, silicon solar panels are expensive, difficult to adhere to surfaces, delicate, and simply do not capture enough energy from the Sun to be viable. All of these problems make silicon yesterday’s news, it’s time for polymer solar cells to hog the spotlight.

Admittedly today’s polymer solar cells do not retain as much energy as rigid silicon cells. This issue is worked on every day, but that is where the downsides of polymer solar cells end. Polymer solar cells are incredibly lightweight, they can be customized on a molecular level, they have a lower environmental impact, and most importantly they are incredibly flexible; thus making them easy to adhere to surfaces that could not stand the weight of silicon cells.

While a breakthrough in capturing a larger quantity of solar energy is still needed from the polymer solar market, small advancements in other areas of their development have been happening frequently. Recently UK scientists from the Universities of Cambridge and Sheffield have developed a polymer solar film that can be applied to surfaces with ease. They describe the material as a “cling film”, basically a Saran™ wrap that can capture solar power. This cheap, pliable material could be installed onto many things requiring electrical power. Imagine being able to coat your home in this material, soaking up the midday sun could drastically cut down on your energy costs.

Another small victory for the polymer solar market is the advent of thin-film solar. These very small, lightweight solar cells also boast the ability of adhering to surfaces that silicon cannot be applied to. They can stick to handheld devices, oddly shaped objects, and clothing. Recently Mekoprint, a Danish company, has developed a small handheld, solar charged flashlight. It operates by absorbing light during the day, storing that power in a lithium-ion battery, and using a LED as its light source.

One of the most interesting current research projects comes from a solar company in Lowell Massachusetts. Kornarka Technologies is working on a polymer cell that can absorb infrared light. The obvious advantage of this cell is that it can absorb energy all day and night; not being relegate to only daytime use would allow solar cells a large increase in efficiency.

This article is not meant to convince you that polymer solar cells will solve all of our problems tomorrow. Simply put, solar energy in total is just not there yet. Many more research hours and dollars will need to be spent before we can say good-bye to fossil fuels. It is clear however that plastic is making the future look a lot brighter.

MIT Produces Vocal Cord Repairing Polymers

July 24th, 2011

It never fails to astonish me. The minds fostered at MIT always seem to come up with truly incredible things. They have given us Ethernet, perfected radar and even invented those nifty little disposable razors that I couldn’t possibly live without. This summer they are working on giving people with damaged vocal chords back their lost voices. Are they growing new vocal cords in a lab? Are they getting organ donations? Are they giving volunteers small computers that can vocalize for them? Of course not! Obviously they’re using polymers!

This magical polymer is known as PEG30, which is a modified polyethylene glycol. It actually mimics the elastic properties of vocal chords. The technical term for the pliability of the vocal cords is viscoelasticity. PEG30 is flexible, durable and responds effortlessly to the movement of air. Simply put, normal lung power causes PEG30 to form the shapes needed for proper speech to be achieved.

PEG30 will mostly be used in individuals who have vocal cord scarring. This ailment is more common than you think. Vocal scarring generally occurs in children who have been intubated. In an emergency situation, where a child needs oxygen quickly, gentle treatment of the vocal cords is not at utmost priority. The British Singer/Actress Julie Andrews is likely the most famous example that comes to mind. In 1997 she underwent surgery to remove non-cancerous lesions from her throat. The subsequent vocal cord scarring that she suffered has never healed to this day, and has left her unable to sing.

Ms. Andrews plays a role in the current research being done into PEG30. Andrews approached the professor of laryngeal surgery, Steven Zeitals of Harvard University, concerning her dilemma. He had been developing a material that could be injected into scarred vocal tissue to lessen rigidity. When his research hit a wall he sought help from Robert Langer, a professor of chemical engineering for MIT. Together, they and their team have produced this wonderfully responsive vocal gel.

PEG30 is not yet in use today. It has however been found safe by the FDA. The hope is to use PEG30 in some injectable capacity. Human trials will begin in 2012, with a goal of having 10 test subjects. If PEG30 is found to be acceptable for mainstream use, %6 of the US population will have the ability and a reason to sing. I’m sure they won’t sing as well as Julie Andrews, but at least plastic helped to bring forth from them, the sound of music.

Plastic On the Frontlines of Anti-Counterfeiting

July 24th, 2011

Since the death of barter and the birth of monetarism, a war has raged; a war between those who would earn (or steal) legitimate legal tender, and those who would counterfeit. This issue has gone on since before Cleopatra stamped her face onto bronze coins and continues on to current day. With no end in sight, what will save us from these thieves, pretenders and usurpers? Why, polymers of course!

The forefathers of plastic currency find their roots in the land down under. The University of Melbourne first developed notes composed of polymers in 1988 and the Reserve Bank of Australia were first to adopt them. These notes are made of biaxially-oriented polypropylene (BOPP) and are currently used in 32 countries around the world today. Australia took on the task to create these difficult to counterfeit bills, when in 1967 they noticed a spike in fake notes in circulation, with the advent of the color copier they feared this problem would increase drastically.

The practice of creating legal tender out of plastic heralds many advantages over paper threaded currency. For one, it is far more durable than paper; not having to replace destroyed currency has its obvious benefits. The notes are water proof; freeze proof and easily recycled into other useful items once they do finally wear out. This longer life cycle also reduces the environmental strain of manufacturing new bills. Besides durability and recyclability, plastic cash boasts security against counterfeiting which paper can never pretend to achieve.

The newest participant in the production of plastic notes is The Bank of Canada. In late June they unveiled their new $100 and $50 polymer notes. These notes will be in full circulation by March 2012, and they plan to create $20, $10 and $5 polymer notes by the end of 2013. Why the sudden switch to a completely plastic note system?

Much like the challenges Australia faced in 1967; Canada, starting in the early 2000’s has seen a dramatic spike in the circulation of counterfeit bills. In 2004 The Bank of Canada found that out of every one million paper notes in circulation, 470 of them were fakes. It may seem to be a small fraction of bogus notes to you or me, but it’s serious enough to raise alarm and devalue a currency. Whatever was The Bank of Canada to do?

When all hope was thought to be lost, a hero emerged from a newly upgraded mint, deep from within the reaches of The Bank of Canada. Equipped with the powers of raised lettering, embedded barcodes, large transparent windows with a portrait of the Tower of Peace etched upon it and an image of Prime Minister Robert Borden; the ability to change color when tilted at different angles and the most sophisticated holograph ever created. This hero came to save the Canadian monetary system and discourage and destroy the counterfeiters. This hero’s name is plastic, and plastic is so valuable that it can print its own money.

The Progress of Biopolymers

July 11th, 2010

For any reader who isn’t aware, most of the world’s plastic is currently made from crude oil. The process involves several steps, depending on the polymer that one is creating, but the total cost is still a fraction of the cost needed to create biopolymers of the same quality. Biopolymers are created by having a culture of bacteria consume large amounts of biomass. When the bacteria are mature, the culture is sterilized and the biopolymer is extracted directly. Many factors are now causing chemical and plastic companies to consider possible ways to reduce their reliance on crude oil, so reducing the cost of biopolymer production has become a greater priority. Since the polymer-using world cannot simply pay double or triple for things like plastic bags, plastic bottles, and plastic tubing, achieving this cost reduction is the missing critical factor to wide scale use of biopolymers.

The difference in cost between standard polymer production and biopolymer production is not caused by any one factor. Since the world uses such a large amount of plastic, existing polymer production facilities are huge, whereas biopolymers are mainly produced by small specialty groups and laboratories. Several companies are now considering the construction of large scale biopolymer factories, but they are waiting on the researchers to bring down the other areas of cost first. At present, it requires 3 times the weight in biomass to create a unit of biopolymer. This is because the bacteria being used are only able to consume certain nutrients from the biomass, leaving the rest behind as unusable waste material. Efforts are underway to find or engineer a more efficient bacteria for this task. The other side of the coin is to more effectively process the biomass such that a greater portion of it is consumable by the bacteria. Many different areas of research are currently being conducted toward this achieving this end, because labs and universities know the impact of these discoveries will be felt for centuries to come and the shorter-term breakthroughs could easily lead to a Nobel prize.

Understanding Radiopacifiers

May 17th, 2010

In many custom tubing applications, it is desirable to manufacture the components such that they can be seen with fluoroscopy or x-ray imaging. Typically this is done by blending the polymer with another material, the radiopacifier, which is chosen because it has a higher radiopacity. With many different radiopacifiers available, it is useful to understand the strengths and weaknesses of each before making a selection.

Barium Sulfate(BaSO4) – Barium Sulfate is the most commonly used radiopacifier for almost all medical applications where imaging is an issue, including catheters and other types of tubing. While BaSO4 does not have the highest level of radiopacity, it remains moderately priced compared to the alternatives. Because it is not as dense as other radiopacifiers, a high volume of barium is needed to achieve a high level of radiopacity and typically the barium begins to affect the strength of the polymer after it exceeds 20% by volume. BaS04 also tends to mix more easily with elastomers than the other alternatives.

Bismuth(Bi) – Several different bismuth salts are commonly used as radiopacifiers, all of which have a higher density than Barium Sulfate. The high density creates a higher weight-to-volume ratio, which means that the resulting polymer can be more radiopaque with a lower volume percentage of the bismuth salt. While bismuth fillers have been growing in popularity, the fact that they are much more expensive than Barium Sulfate still precludes their use for certain applications.

Tungsten(W) – Tungsten is considerably more dense than the other alternatives, providing the highest weight-to-volume ratio of any commonly used radiopacifier. Because of this, polymers made with tungsten can be extremely radiopaque without a significant change in mechanical properties. Though raw tungsten is also relatively inexpensive, its other properties ultimately make it a more expensive choice for many applications:
1. Tungsten is highly flammable
2. Tungsten is black and extremely difficult to change the color of
3. Tungsten is abrasive, causing accelerated wear on processing equipment and surface roughness in the end result

Preserving Our History with 3D Printing

March 16th, 2010

Beyond the manufacturing advantages, the combination of 3D scanning and 3D printing has led to an incredible way of preserving rare artifacts from the past. For many collectables, the primary reason they have dwindled in number has always been the extreme cost of having the original molds remade from scratch. With a 3D printer, the physical molds are replaced with digital instructions, provided by a 3D scan of the original object, or created carefully with design software. This process has been used to recreate tools, toys, machine parts, forgotten oddities and even some more ancient artifacts. Using 3D print materials based on clay or ceramic powder, it is possible replicate very old pottery. This will eventually make it less expensive for museums to exhibit a wider variety of history.

Here at AP Extrusion, many of us share an interest in recreating old automobiles, especially the muscle cars of the 1960s. 3D printing makes it possible to replicate the plastic components that have long since passed out of market. This enables us to restore a complete vehicle without spending years hunting down parts. We are always interesting in talking to anyone who shares our passion and in many cases, we may be able to help with your custom restoration efforts. Consider 3D printing as an alternative to any custom molding project and you will likely find the time and cost are greatly reduced.


Plastic’s Place in the Biosphere

March 16th, 2010

Since it first came into wide-scale industrial use in the mid 1930s, polyethylene has been chosen as the preferred material for many applications. Most of these applications came about because polyethylene is low-cost, heat resistant, acid resistant, insulant and slow to biodegrade in nature. Among these properties, the last has proven to be more of a double-edged sword as each year we continue to produce 80 metric tons and the environment breaks down far less. Recent progress on biodegradable polyethylene has presented a partial solution, but many of the most common applications simply weren’t intended to rot under natural conditions. Most forms of tubing and cables only function effectively so long as they remain completely intact. The same can be said for most plastic car parts, electronic casings, food and drug containers, and many others.

Until recently, recycling remained our first and only effective strategy for sustainable use of “non-biodegradables”, but in 2008 it was discovered that a variety of bacteria called Sphingomonas can degrade polyethylene molecules. Since polyethylene does biodegrade very slowly in nature, a Canadian science fair student named Daniel Burd was able to isolate and eventually concentrate the specific microorganism(Sphingomonas) responsible for the breakdown. Though the right concentration does not exist in nature, high volume Sphingomonas can break down plastic in a few months instead of the 1000 years it takes now. It should also be noted that this organism is unaltered at present, though many companies are now proficient at bioengineering bacteria for specific purposes. In the future it may be possible to breed varieties of Sphingomonas that are even more effective at breaking down polyethylene and other types of plastic.


The Future of 3D Printing

March 16th, 2010

Since the early days of science fiction, people have known that eventually our path of technological evolution would lead us toward machines that could create any physical object based on specified parameters. The birth of 3D printing in 1986 was our first real step toward achieving this vision and as companies realized the tremendous savings when compared to traditional prototyping techniques, many new branches of research quickly opened up. Though the first 3D printers could only use one particular type of plastic, the demand for other materials led to techniques for rapid prototyping with metal, glass, and clay, as well as other types of plastic and hardened resin.

The first commercially available 3D bio-printer was recently announced by a company called Invetech as being capable of printing tissue and organs at the cellular level. One of the most exciting spin-offs of 3D printing is a project called RepRap, which is open-source, meaning that all its blueprints and results are publicized and can be used by anyone freely. RepRap is the first known attempt at building a self-replicating machine, the ultimate goal being to have RepRap print more RepRaps. Having undergone several revisions already, RepRap can now print all of its own plastic components and the research is currently being targetted at the printing of whole circuit boards.

Part of the project’s stated goal is to “enable the individual to manufacture many of the artifacts used in everyday life” for “a minimal outlay of capital”, so it’s not that difficult to see where a few more decades of research could lead. With the right supply of power cells and raw materials, a single RepRap could concievably be given the blueprint for an entire building and then print up as many copies of itself as were needed to construct the building blocks and put them in place. Some have even speculated that advanced versions of RepRap will eventually be able to improve their own design, essentially beginning a path of AI evolution.


The Most Widely Used Plastic in the World

March 16th, 2010

With so many varieties of plastic tubing to choose from, a design engineer has many difficult choices to make when prototyping a new medical device. Of all the materials used for such applications, polyethylene most often leads the way.

Introduced to the world of manufacturing at the time of FDR, polyethylene has since made many applications easier to manage, safer for consumers(compared to earlier metal counterparts), and cost-effective enough to mass-produce.

When choosing a type of polyethylene, mechanical factors always come first, because they are the basic requirements needed for a design to function. Fortunately, polyethylene is extremely versatile and most mechanical requirements can be met with many possible formulas. Cost must also factor into the decision, as all consumer products have a price point which limits their allowable manufacturing cost. Understanding the properties of the different grades can assist a design engineer in the selection of thermoplastic materials for products that use custom plastic tubing.

LDPE(Low Density Polyethylene) – The first invented grade of polyethylene, LDPE remains the most commonly used density. In addition to being useful for plastic tubing, LDPE is also used for plastic bags, food storage, computer/car components, general purpose containers, and many other things. While it has a lower tensile strength than the higher density grades, it has a higher resilience(maximum energy per unit volume that can be elastically stored) which makes it very flexible.

HDPE(High Density Polyethylene) – While it has many of the same applications as LDPE, it is harder, more opaque, and somewhat more resistant to heat and chemicals. It is often used for outdoor scenarios where there is a large temperature range as well as containment scenarios where chemicals need to be isolated from the environment over a wide area.

LLDPE(Linear Low Density Polyethylene) – Slightly harder to process than normal LDPE, LLDPE has higher tensile strength, impact resistance and puncture resistance. Basically this means that a thinner layer of plastic can remain intact under flexibility testing. Its primary use is in flexible tubing, but it is also used for plastic wrap, toys, lids, cable coverings and more.

UHMWPE(Ultra High Molecular Weight Polyethylene) – More expensive than most other grades of polyethylene, UHMWPE has the highest impact strength of any thermoplastic presently made. It is often referred to as high performance polyethylene and is typically reserved for “unbreakable” scenarios like artificial bone replacements, bulletproof vests, etc.

VLDPE(Very Low Density Polyethylene) – Because VLDPE is characterized by even lower heat resistance than LDPE, it is often used in packaging for frozen food and ice. Some tubing and stretch wrap is also made from VLDPE and it is commonly blended with other polymers as an impact modifier.

PEX(Cross-linked High Density Polyethylene) – PEX is almost exclusively used for long-term tubing scenarios. Many thermal properties of the plastic are improved by the cross-linking process. It maintains strength at a higher temperature and reduces flow. Under low temperatures, impact resistance, tensile strength and scratch resistance are improved. Cross-linking also improves the chemical resistance.