injection molding: a mainstay.

by:INDUSTRIAL-MAN     2019-08-28
Now that the injection molding has a history of more than 150 years, it is still one of the most reliable manufacturing processes used today.
Can other processes compete?
Injection molding has been around for a long time as a manufacturing process.
Alexander parks created the first man in 1861 --
He named it commercial plastic made by Parkesine.
This polymer is made of cellulose, just like modern plastics, which can be heated, shaped and maintained in the selected shape once cooled.
However, it is expensive, not very strong and flammable.
Over the next few years, the materials of John Wesley Haite, an American inventor-what he calls the celluloid-improved the polymer.
Hyatt and his brother Isaiah first applied for a patent for injection molding machines in 1872, using which they produce simple objects such as buttons and combs.
Due to the incredible demand for cheap, large scale, the injection molding industry grew rapidly during World WarII in 1940
Produce products.
In 1946, James Watson Hendry, another American inventor, made a spiral injection molding machine.
When hyatts\'s machine works like a large subcutaneous injection needle, the plastic is injected into the mold using a piston through a heated cylinder, and Hendry\'s new and improved version uses a screw-in motion, allows for more accurate control of injection speed and product quality.
This machine also allows mixing materials before injection in order to add colored or recycled plastic to the original material and mix thoroughly before injection.
In the 1970 s, Hendry continued to develop the first gas --
The auxiliary injection molding process allows the production of complex, hollow fast cooling items.
This greatly improves the flexibility of the design as well as the strength and finish of the parts manufactured, while reducing production time, cost, weight and waste.
The spiral of Hendry continues today.
Screw injection molding machines account for the vast majority of all injection molding machines.
Jared Sunday, engineering director at Pa Latrobe, explained: \"The injection molding process is to first load the original plastic resin, usually in the form of particles, into the loading bin or hopper . \". -
Based on classic industry
A plastic injection molding company for medical devices.
This is gravity-
Put into a long heating barrel with a reciprocating screw.
The heated barrel, combined with the friction of the rotating screw, converts the original plastic resin into a uniform melt.
When the crew returned, it built a melted reservoir at the front of the barrel.
Under the Controlled high pressure and speed, the spiral advances forward, pushing the melt into the mold. Production-
Grade injection molds are usually made of two and a half or more of high-strength steel.
However, they can be constructed by events with softer steel, aluminum or plastic for shorter runs or prototyping.
Inside the mold contains the reverse geometry of the predetermined shape of the part being manufactured.
When meltis pushes into the mold, it flows into the inner opening area of the mold.
Cool the melt through a controlled process until it is solidified.
The mold is then opened and the cooling part is popped up or removed by the robot.
\"Today\'s machines have very strict tolerances and repeatability.
Because of its ability to produce a large number of products, injection molding is still one of the most cost-effective manufacturing methods.
Tight tolerances, repeatability and cost-effectiveness provide a Holy Trinity advantage for medical equipment oem customers.
\"Tight tolerance\" is a term that often revolves around [loosely]manufacturing]
\"Industry,\" Ken Glassen, vice president of engineering at kaysun Corporation, plastic injection molding, wrote in the manufacturing industry.
Net article last year.
\"However, if the tight tolerances are not completed properly, the parts and products will perform poorly or may fail, resulting in unsatisfactory customer satisfaction and resulting in overhaul of tools and/or processes. Othertight-
The benefits of tolerances may include eliminating secondary operations such as machining, making it easier to obtain fit parts and allowing metal parts to be converted into plastic parts-
All of this helps to reduce costs.
\"Tight tolerance\" is simply the ability to produce components with minimal changes.
According to Glassen, injection molding is usually performed under [tolerance]+ or -]0. 002 inches.
Ali\'s tight tolerance is [+ or -]0. 001 inches.
Part design and complexity, materials, tools, and process design and control play an important role at the tolerance level.
Compare this with additive manufacturing (Also known as 3-
D. print or rapid prototype)
, The parts of which are recreated by laying thin layers of material a little bit.
According to Quickparts Inc.
A manufacturing service company that provides additive manufacturing and injection molding, the standard tolerance of most additive manufacturing processes starts from [+ or -]0.
As the design size increases, 005 inch and compounds start there.
This is an important consideration for OEM customers, bearing in mind that the success of the project depends on the degree of Assembly between different components.
Additive manufacturing as a manufacturing process due to a variety of 3-
Printing art and technology.
When only a small number of devices or components are needed, the process provides a great advantage in terms of cost.
This is also the standard process used to make prototype components during the design and development phase of medical devices, as it is both fast and cheap.
\"Additive manufacturing is excellent in the early stages of product development ---
Come up with a design, print it out and see if it works from a formal and functional point of view, \"Ryan Case, sales director, N Orchard ParkY. -
Headquartered in polymer conversion company, Medical Plastic injection mold company
Was told to outsource medical products.
\"It really reduces the cycle of development, so you can get closer to your device faster.
However, many industry experts believe that injection molding is still the best option once the equipment enters mass production.
Additive manufacturing is a younger process (
About 30 years)
And it is developing rapidly, but it has not yet reached the point where it can produce durable parts in large quantities like injection molding.
Material considerations confirm Glassen\'s position, and Classic told mpo dmpo on Sunday that the tolerance was strict to 0.
001 inch \"not uncommon\" in injection molding \".
\"This can be done by using a wide variety of off-the-
\"Shelves and custom plastic materials and colors,\" he said . \".
\"The injection parts can be very soft, the touch is soft, or almost as strong as steel.
\"The ability of injection molding to produce extremely robust components with strict tolerances facilitates the transformation of some OEMs from metal to plastic.
According to Mark Fuhrman, sales and marketing director, C & J Industries, C & J Industries is a plastic injection molding company based in Pa Meadville.
The company saw many customers coming to the company seeking to switch from metal to plastic for the same equipment. C&J uses PEEK (
Ethereum ketone)
In addition to being very strong, it can be reused for high pressure sterilization, stability, and limited shrinkage.
Although peeping is an expensive polymer, injection plastic is still more effective for some devices than processing metal.
\"In plastic injection molding, the secondary operation that metal parts usually need is free,\" explains Fuhrman . \".
\"A metal part may require it to have multiple operations such as machining, adding a tread, adding a bite edge, etc.
The machined parts usually have multiple settings, and then the parts must be treated twice, whether it is anodized or painted.
Some secondary processing is required to make the metal part look attractive.
These processes are inherent in plastic injection molding and are free of charge.
\"In fact, the main constraint for a month --
D. printing is a process in which a polished surface cannot be provided on a printed metal device.
Direct metal laser sintering, 3-
The printing process of the metal produces a granular finish, which makes the printed hair of the device larger than required, so that it can be polished to the Mirrorlikefinish.
If the metal is completely abandoned, this is no longer a problem, because molded plastic parts can come out of the mold without further surface treatment.
But is it possible for most devices to simply replace the metal with plastic?
Fuhrman told MPO that there was a customer who came to C & J with a very solid stainless steel part and wanted to convert the polymer to save money: \"We have a medical device, it is a very high impact force component that can be placed on a medical/surgical tool for processing the femurs.
\"It is very strong and strong,\" Forman said . \".
\"The customer is converted from stainless steel to plastic injection molding, which provides them with some additional features that, without welding and processing, are actually not able to be created in steel ---
The process does not at all drive out an attractive and cost-effective device.
Therefore, due to the elimination of these secondary processes, converting to plastic injection molds is a considerable cost savings for them.
\"At present, the choice of materials for injection molding is more extensive, but this situation is changing rapidly as additive manufacturing technology advances,\" classic said on Sunday.
\"Additive manufacturing is also able to produce components using plastic, ceramic or metal.
Although there are many general materials to choose from, there are limited options for custom materials specifically adjusted.
Injection molding will be a wise choice if the expected product is a pipe connector, filter, syringe or standard device.
But if you are creating a stand, plaster or a custom fitting that can be implanted for a person, additive manufacturing will meet your needs.
\"Injection molding, mold, repeat repeatability are key attractive features of injection molding.
The nature of this process itself enables it to produce the same precise devices over and over again, with very strict tolerances and precision.
However, if the equipment is made by thousands of people, the process is only cost-effective.
For smaller runs, 3-
D. printing makes more sense because, unlike injection molding, new tools (mold)
You don\'t have to create each time you make a new device.
Usually, the same printer can be used.
\"The main advantage of any molding process is replication, which is the ability to produce millions of the same products that fit the shape and size of the mold,\" said Thomas Hicks, director of product development at Volkswagen Charlton. -
Micro-styling based on MTD.
\"Replication is the foundation of manufacturing, and interchange is the key to mass production.
However, not all applications require mass production, and some implants are examples.
They may only need a very limited number. The time-
Consumption efforts and costs associated with creating a permanent mold that can be manufactured do not meet these limited needs.
Similarly, in the process of developing high-production components, some steps themselves do not use hard tools. The main example is rapid prototyping, which usually includes a series of iterative design changes.
On the other hand, the main advantage of the additional process is the speed at which physical parts are created and the ability to create physical parts at low cost.
Compared to molding, the disadvantage is usually that compromise is required in terms of part design (
Resolution of characteristic geometry, clarity of transparent material, smooth surface finish, Micro
Tight dimensional tolerances, usually the appearance of any desired feature)
And the choice of materials.
\"Repetitive conversion to volume saves costs.
\"The cost-effectiveness of molding may depend on volume,\" explains the case of the polymer converter . \".
\"Additive manufacturing is great when you run very small in dozens or even hundreds of places.
When you start expanding to thousands, you can make multiple
An air eclipse tool, you can make multiple parts at a time.
Each time you double the number of parts you make, you will cost about 25%.
\"Repeatability is an important consideration for medical devices, because sterility and precision are indeed the most important.
Therefore, process verification and control are an important part of the feasibility of injection molding.
Injection molding manual (
Rosato and others, 2000)
Pay attention to several factors that affect repeatability, including the filling time of the movable material in the mold and the screw design.
Consistent melting quality is an important factor in ensuring injectionto-
For this reason, the geometry of the screws that inject the movable material into the mold must specifically match the polymer being used.
This is just a small understanding of the many details that need to be considered in order to achieve precision and good repeatability.
\"Everything is for control,\" Case said . \".
\"Are you ready to make sure that the products you deliver are repeatable not only from a manufacturing perspective, but also in a wider manufacturing environment, to ensure that the right resin enters the parts every time;
And the operator processes the parts in exactly the same way each time;
The rigor and culture you are involved in can handle the repeatability of the process, not only in the molding process, but also in the acquisition of materials and the processing of products through the printing machine, and so on.
\"These mechanical details cause injection molding to be very expensive for a prototype or small molding --Run production.
If only a few hundred devices are needed, it is not worthwhile to create the right mold and calibrate the parts of the machine.
This kind of operation will be more appropriate on 3-
Printing machines that can be calibrated through software rather than hardware.
Mike Borst, global project manager at SMC Limited, added: \"The need for tools in the molding process may be the biggest drawback compared to additive technology . \"
Medical device contract manufacturer based in Wis Somerset.
\"Relatively Speaking, it takes more time and money to produce molded parts.
However, when these parts are produced, it is usually possible to have thousands of parts.
Knowing where you are in the development process and what you need for the \"test\" section will determine which technology to use. \" Micro-
How small can molded parts be?
Not as small as amicron, says Foreman.
But in C & J, components can be molded small enough to fit on Roosevelt\'s ears. But amicro-
Molded parts do not necessarily mean a small part.
Inch large parts can be from Micro
Formed on the thin wall of 0.
For example, 004 inch thick, or 0. 008 inch hole.
C & J has created a suture ring for eye surgery, which is small as can be imagined. \"Micro-
Molding is a special subset of injection molding, and while in general theory it is described in the same way, the final part is now much smaller (
Some of the size of rice, or smaller)
\"The size is naturally much smaller,\" said Hicks of MTD . \".
\"This change in size requires a special understanding of the behavior of plastic materials in these smaller sizes, which requires special techniques for making molds, and handle, measure, and package the finished product.
Hicks talked about a common misconception.
Moldingactually means.
This process is not about making a special tinmold.
According to another micro-modeling expert in Ankney, Iowa --basedAccu-
Micro mold Co. , Ltd.
Molder is not just sorted by hardware.
Combination of innovation, processing and expert tools
Building together constitutes a real Micromolding.
It takes years of experience to master this process, and a good media will only be as good as its previous technology.
What about additive manufacturing?
This process has become very advanced in its short life cycle.
Last year, a research group at Harvard University and the University of Illinois at UrbanaChampaign 3-
Printed a small lithium battery about the size of a grain of sand (
Less than 2000 microns).
In order to make a micro-cell, the team printed a bunch of staggered micro-cell electrodes, each of which is less wide than the width of human hair.
Of course, this battery makes it available as a medical device of the same size.
Researchers are even printing live tissue, and a team from the past university of connecting to print artificial kidney may work with the University of ofOxford to create a printer that can print synthetic skin tissue.
Although these innovations are exciting, 3-
D. printing cannot match the molding in strength and durability.
Although the molding may not be able to make a delicate organization, it can certainly produce solid parts.
\"About Micro
The size of the part, usually the only machining of the production part is through the micro
Molding. \"Said Hicks.
\"With the introduction of compromise and the change of design, the change of materials.
As the part becomes more and more the real \"micro part/created object may be similar to the original design, but it will not be the real prototype, it will be as likely to test and execute as the desired part.
This part becomes more like a \"model\" than a \"prototype\", not even the part that was originally wanted.
\"Case compares the whole process to cooking pasta ---
It makes everything clearer.
\"One of the main advantages of molding compared to additives is-
Beyond Tolerance--
\"This is also the strength of the components,\" Case said . \".
\"In additive manufacturing, you build it layer by layer, and in molding, you are made at once.
The polymer itself is composed of a series of molecules.
Imagine if you cooked a whole bunch of pasta, put it on a platform and let it cool, all the pasta wrapped together to form a part, this is like a model;
However, if you put your glasses on each other, it would be easier to separate ---
This is like manufacturing materials.
Thus, while additive manufacturing has the ability to add thin layers and make subtle components, it can be said that its \"strength\" is elsewhere.
From prototype to final product, and additive manufacturing has proved to be the ideal choice for prototype manufacturing. -
So the name \"rapid prototype--
Mike yurkewicz, engineering manager at C & J, warned that the equipment designer should still be very clear about the impact of moving equipment production from additional manufacturing to injection molding.
Something that works in one process may not work in another.
As MPO points out in MPO, \"The closer the component design is to the end, the more attractive the molding is as a manufacturing option.
\"A design that can be made,\" says Yurkewicz.
\"Product designers can use 3-
Additive process that may not be formed.
So once you have exceeded the initial quantity required for 510 (k)
Application or research, etc. , and then transfer the process to the injection molding, design features such as a certain Wall thickness will cause tolerance problems.
If your volume justifies jumping into the injection molding, if you design in this way during the rapid prototyping phase, you may draw yourself into a corner.
\"Molding is the main force of manufacturing.
This process can create evolume like other processes, which is a reliable, repeatable process.
When molders praised the cost efficiency of their process, 3-
Dprinters do the same in their own process, and the cost-effectiveness actually depends on the volume.
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