Posts Tagged ‘plastic extrusions’

The Progress of Biopolymers

Sunday, 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.

Plastic’s Place in the Biosphere

Tuesday, 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 Most Widely Used Plastic in the World

Tuesday, 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.


3D Printing is an automatic “Hole-in-One”

Tuesday, March 16th, 2010

What does 3D printing and golf have in common?

If you’re TaylorMade and pro golfer Mark O’Meara you can equate it with success — affecting both game performance and sales performance.

When TaylorMade was looking to produce a new set of irons, they turned to O’Meara and 3D printing. While the story is not recent, it is relevant as to the beneficial use of 3D printing.

O’Meara was getting ready for the 1998 Skins Game and asked TaylorMade to have the irons ready in time for him to use during the tournament. TaylorMade had limited time to test and develop its new set of clubs, but because of the availability and expediency of 3D printing, they were able to create 50 wax patterns on a 3D printer, which were then sent to a foundry for casting and finishing.

The end result: The prototype of the Firesole Tour Irons were developed on time using 3D printing, which also provided for tremendous cost-savings—and of course, O’Meara won the Skins Game.

While not every manufacturer has a pro golfer at their disposal to test new products, it does have access to 3D printing technology that can assist its design engineers throughout the product development process.

3D Printing has provided innovative solutions to companies like TaylorMade, but also has been utilized for manufacturers who develop medical equipment for people with disabilities, and 3D printing has also assisted EOIR technologies with the development of a camera mount for the M1 tank and Bradley fighting vehicle.

From the frontline to the golf course, 3D printing technology takes the guesswork out of prototype development to ensure a product’s performance under all “stressful” conditions.


Extruded Profiles…of Courage

Tuesday, March 16th, 2010

What defines courage?
Short list: strength, confidence and taking action despite the conditions that threaten your success. While the definition of courage is subjective, for those who work in the medical industry that have to demonstrate courage at every turn—it requires those attributes and many more. But believe it or not, one of their single most important tools to assist them is extruded profiles.

Extruded profilesare utilized in a variety of applications from medical device components, processing aids and medical instruments. Something as simple as a PVC plastic tube acts as a conduit to sustain life in many cases; such as that used as a catheter that’s inserted into a patient’s heart. And having high quality PVC extruded profiles provides this life-saving equipment with the versatility, flexibility and durability it needs to assist medical personnel to do their job.
So when custom tubing manufacturers and design engineers are in the development phase of extruded profiles, they take into consideration the end user of the product and the extruded profile application. It’s not just a matter of ensuring that profile extrusions are cost-effective to satisfy the bottom line, but they also need to take into account particular parameters during the design of the extruded profiles to ensure it will perform during any mission-critical application.
Characteristics such as, will the PVC profile extrusion:

  • Perform reliably
  • Be resistant to chemicals
  • Demonstrate UV and heat stability
  • Maintain rigidity

After all, it’s these parameters and more that medical professionals rely upon to ensure that the extruded profiles they are utilizing, whether made in urethanes, PVC, or custom compounds will facilitate the success of any medical procedure.