Essay, Research Paper: Injection Molding

Technology

Free Technology research papers were donated by our members/visitors and are presented free of charge for informational use only. The essay or term paper you are seeing on this page was not produced by our company and should not be considered a sample of our research/writing service. We are neither affiliated with the author of this essay nor responsible for its content. If you need high quality, fresh and competent research / writing done on the subject of Technology, use the professional writing service offered by our company.


Injection molding is a process used to form products from plastic. The process
requires a mold, clamping component, injection unit, and some sort of plastic.
As time has advanced so has injection molding by developing new techniques and
new products to aid in the manufacturing of the injection molded parts.
Injection molding was used as early as the 1860’s. It can be used to form many
different products. Whether the products are small, large, complex, or simple
they can be produced. Injection molding has derived from metal die casting.
However, the polymer can’t just be poured into a mold, it has to be forced
into the mold cavity. The polymer is forced into the mold and pressure is held
on it to avoid shrinkage in the mold cavity as it cools. Injection molding is
capable of producing a large number of parts with very high precision. All
thermoplastics except polytetraflouroethylene (PTFE), polyamides, and some
aromatic polyesters can be used by the injection molding machine. Some
thermosetting plastics can also be used. The typical fabrication process can be
done by one of two different types of injection molding equipment. Either a
plunger, or reciprocating screw type machine can be used. The process starts by
melting the polymer resin. Once the resin is melted, a mold is placed in the
clamping unit. The clamping unit is to hold the mold together. The plunger or
reciprocating screw then force the polymer resin into the mold. In the plunger
operated machine, the plunger is hydraulically operated. This forces the plastic
through a heated area, where it is then spread into a thin layer by the torpedo.
Then the melt comes to the nozzle and is injected into the mold. The
reciprocating screw rotates, this moves the polymer resin forward for injection.
As the screw rotates it acts to melt, mix, and pump the polymer to prepare it
for injection. The reciprocating screw machine is the most widely used of the
two machines. Once the polymer resin is injected into the mold cavity, the mold
is allowed to cool. The mold has a gate, which limits back flow and directs the
flow of the melt into the mold cavity. Once the mold has cooled and the polymer
has solidified the mold can be removed and the part can be ejected. When the
gate freezes, the screw begins to rotate again and the part is ejected. This
completes the cycle time. Cycle times range due to the amount of time the
polymer needs to cure or solidify. This is called the hold time. Some advantages
of injection molding are high production rates, design flexibility, low
tolerances, can process wide range of materials, low labor, little or no
finishing, and scrap is held to a minimum. However, some disadvantages are high
startup and running costs, part must be designed for effective molding, accurate
cost prediction is difficult, and machine cost is very high. The high tooling
costs come from the molds being built to a high level of precision. The molds
are usually constructed of hardened tool steel, and aluminum or other soft
metals when tooling life is not an issue. Tooling costs can range from $5,000 to
$100,000. However, there are some parts that can not be formed by any other
method of processing except injection molding. These parts typically become
feasible around 1,000 pieces. To go with the high tooling costs there are a
large number of variables that go along with it. Injection molding machines may
require special plant services that other equipment does not. As technology
advances so must the industry to keep up production. One way injection molding
is keeping up is by becoming automated. Usually, operators are placing parts
into molds, and then taking the parts out. Now, robotic devices are being used
to place inserts before molding and remove parts after molding as well as a host
of other operations as well. Not only does the robotics speed up the process,
but makes it much more cost effective. Another way industry is trying to keep up
with technology is by using computer software. The software is called “Mold
Adviser,” which is a mold design and analysis package that can be used to help
speed up operations while reducing tooling costs. Using the past standard
operation of designing molds a company could easily waste six to twelve weeks
and anywhere from $30,000 to $40,000 on fixing a mold that has a problem with
filling correctly. The new software will detect these problems up front before
production begins. It is used with a CAD program, and is really divided into two
parts. The Part Advisor and the Mold Advisor. The Part Advisor can test the
parts design and analyze the part to see if it will fill correctly. Once the
part has been analyzed, users begin the Mold Advisor. The Mold Advisor will help
setup gates and runner systems, predict plastic flow, shot size, and cycle time.
Users of the new software have reported that the software is easily learned and
user friendly. Injection molded products include TV, VCR, CD’s, CD players and
computer housings. So, one can see the impact that the products of injection
molding have on our every day life. Injection molding has been used since the
1860’s. Products of all sizes and shape have been produced. However, with
advancing technology and the high cost of molds it will be interesting to see
how much further injection molding will advance and how it will advance in the
future.

BibliographyHarris, Laura. “Injection Molding.” 30 Nov 1999. http://www.engr.uconn.edu/cheg/polymer/injmold.htm
“Injection Molding.” 30 Nov 1999. http://www.endura.com/injmold.htm
Mapleston, Peter. “New approaches show promise in large-part molding.”
Modern Plastics Nov 1999. Snyder, Merle R. “Automation is gaining in vertical
infection molding machine market.” Modern Plastics Aug 1996. Taylor, Gerry.
“One-two punch knocks out injection-molding problems. Machine Design 17 June
1999: 80.
0
0
Good or bad? How would you rate this essay?
Help other users to find the good and worthy free term papers and trash the bad ones.
Like this term paper? Vote & Promote so that others can find it

Get a Custom Paper on Technology:

Free papers will not meet the guidelines of your specific project. If you need a custom essay on Technology: , we can write you a high quality authentic essay. While free essays can be traced by Turnitin (plagiarism detection program), our custom written papers will pass any plagiarism test, guaranteed. Our writing service will save you time and grade.




Related essays:

0
0
Technology / Internet And WWW
The “Internet” and “World Wide Web” Defined In recent years the Internet and World Wide Web (WWW) have become more and more popular as an information resource. Many people believe that the WWW is the...
3132 views
0 comments
0
0
Technology / Internet History
In 1973, the U.S. Defense Advanced Research Projects Agency (DARPA) initiated a research program to investigate techniques and technologies for interlinking packet networks of various kinds. The obje...
3744 views
0 comments
1
0
The history of the Internet traces its roots to the United States government. The original use of the information system was to maintain communication during the cold war, with the Soviet Union in 19...
3616 views
0 comments
0
1
Technology / Internet Surfing
The internet can be a huge and scary informational jungle for a non-expert. Given the enormous amount of information that the internet contains, this is no surprise. There are things that one can do ...
3214 views
0 comments
0
0
Technology / Internet Tech
The Internet links people together via computer terminals and telephone lines (and in some cases wireless radio connections) in a web of networks and shared software. This allows users to communicate...
3269 views
0 comments