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Injection molding is one of the most popular methods of mass producing identical plastic products. It is fast, highly efficient, with the ability to produce an incredible amounts of parts per hour.

It has many benefits compared to other manufacturing processes. For example, once the initial costs have been met, the price per unit is actually extremely low compared to processes like CNC machining. This is in part because it is easier to mass produce products with injection molding, as well as reduced waste. Injection molding is also incredibly fast, almost entirely automated, and highly reliable.

In this week’s blog post, we will go over the many benefits of injection molding, and why it might be the manufacturing process your business needs!

How it Works

Injection molding works by using a screw-type plunger to heat and inject molten plastic material under pressure into a closed metal mold.

With thermoplastics, pelletized raw material is fed through a hopper into a heated barrel with a reciprocating screw. This melts the pellets into molten plastic, which is then poured into the mold.

When the material is cooled, it is removed from the mold, where it can be cleaned and inspected.

Benefits of Injection Molding

Fast Production

Injection molding is one of the fastest means of production out there, especially when compared to other methods. This makes the process highly efficient and cost-effective. While speed depends on the complexity and size of the mold, there are typically 15-120 second pass between each cycle time.

Furthermore, automation, see Low Labor Costs below, allows for making incredibly precise and accurate injection molds. Computer aided design (CAD) and computer aided manufacturing (CAM) allow close tolerances during the making of the molds, which in turn also enable fast production of products.

Complex Part Design

Another benefit of injection molding is that it can handle extremely complex parts. In addition, it can create large quantities of uniform parts, virtually indistinguishable from each other.

In order to achieve that level of uniformity, however, the mold must

High Precision

A huge benefit of injection molding is its ability to create complex part designs requiring tight tolerances. In fact, with injection molding, the designs can be as accurate to within +/- .005” or even closer depending on part design.

This is particularly important for industries such as the medical device industry, where parts need to be as accurate as possible to function properly.

Stronger Products

Thanks to the process used, injection molding can create incredibly strong products. With the molding, it is possible to use fillers in the material, which reduces the density of the plastic while it is being molded and adds greater strength to the completed part that other processes do not offer.

Flexibility

Since the molds are subjected to extremely high presser, the plastic is pressed harder and allows for a larger amount of detail than other methods of manufacturing. Injection molding can be used for complex or intricate shapes.

And with choosing fluoropolymers, there are a lot of materials to choose from. It is easy to find the material to suit your needs.

Low Labor Costs

Because injection molding is an automated process, with the majority of the process being performed by machines and robotics that can be controlled and managed by a single operator, the overhead cost is greatly reduced. With a lower overhead, the manufacturing is significantly lowered.

Product Consistency

As stated above, the process of injection molding enables manufacturers to mass produce identical products. With an accuracy rate of a 100^th of a millimeter, injection molding is a great choice if you need to mass produce products.

Ability to Use Multiple Plastics at Once

The ability to use different types of plastic simultaneously is another benefit of injection molding. This can be done with the help of co-injection molding, a process in which a second component (core) is injected into the first component (skin).

This can save costs by filling a material with a cheaper material such as regranulate, and it can also enhance the quality of a component by giving it a more reinforced core.

Reduced Waste

Since part repeatability is so high with injection molding, there is very little plastic waste involved. Compared to traditional manufacturing processes like CNC machining, which cuts away substantial percentages of material, injection molding produces very low scrap rates, and what excess material is left over can be re-used.

This makes the process a good choice for companies wanting to reduce their environmental impact.

Some Considerations for Injection Molding

• Design Considerations
  1. Design the part with injection molding in mind. While injection molding can make complex parts, simplifying 3D geometry early on will save time and money in the long run. Other things to keep in mind:
     • Keep walls thin, typically between 132” and 110”
     • To strengthen parts, use additional structures such as ribs instead of thicker walls
     • Round corners and edges whenever possible
     • If possible, add a slight taper to the sides to allow for easy release of the part from the mold.
• Production Considerations
  1. Try to minimize cycle time as much as possible. Using machines with hot runner technology will help.
  2. To keep production fast and easy, try designing your part specifically to minimize assembly. This can save on overhead!
• Financial Considerations
  1. While injection molding will save you money in the long run, preparing a product requires a significant initial investment.
  2. Be sure to determine the number of parts you need to produce to be the most cost effective beforehand.

In Conclusion

Injection molding is one of the best manufacturing processes for producing high quality products on a massive scale. With its high accuracy and repeatability, as well as it’s reduced waste, it can save manufacturers money. It is also great for producing stronger products with more complex designs, perfect for complex parts for complex machines.

If you are looking for injection molded polymer parts, contact Advanced EMC Technologies today and we will be happy to help you!

High-performance automobiles require seals that must face even more rigorous constraints and provide reliable performance in operating environments where standard seal designs would fail. In this blog post, we’ll review the various categories of seals used in automotive applications, discuss how high-performance automotive seals differ, and what sealing solutions are currently being used.

Automotive Seal Categories

Seals can be used for multiple purposes with the primary ones being the exclusion of contaminants, reduction of friction, leak prevention, and the containment of pressure. That said, there are several different categories of general automotive seals that also apply to high-performance automobiles.

Driveline seals are key to a smooth, reliable transmission and not only aid in reducing power losses but help to better optimize fuel consumption. In addition, driveline seals are critical to the overall performance of the transmission system. As a category of seals, they include axial seals, transmission seals, and bonded pistons.

While comfort is not typically a major concern for high-performance automobile drivers, braking capacity and the ability for the vehicle to hold the road certainly are–making high quality, reliable suspension seals essential to both safety and control in racing environments.

Keeping the oil or grease lubricant contained and uncontaminated in wheel bearings reduces friction and power losses. That happens to be the job of wheel-end seals, which must be able to withstand a wide range of temperatures and exposure to some extreme conditions, whether on a paved race track or in off-road competition. 

Engines seals include those for camshafts, crankshafts, valve stems, and auxiliary shafts. There are also seals required for spark plugs, valve stems, and injector tubes are well. Engine seals need to be extremely low friction to minimize power loss and provide the ability to integrate with sensors to track engine performance. Needless to say, the materials need to be rugged enough to withstand the heat and be compatible with all media involved, including fuel additives that can damage materials.

The purpose of bearing seals is to keep the lubrication in and contaminants out of the critical bearings in a vehicle. Because the bearing seals contribute to reducing friction, they also reduce power losses. If a bearing seal gives out during a race, it will result in serious power loss and one failure after another as related systems are impacted.

Sealing Challenges in Performance Motorsports

While there are challenges in the specification of seals for any automobile, the challenges are more complex and constraints far more stringent in the design of high-performance automobiles. When the ability to shave off a fraction of a second could make or break a successfully competitive design, weight becomes a major factor: every ounce counts when trying to maximize speed and minimize losses for Indy Car, Formula 1, NASCAR, Rally, and CART vehicles.

Reliability is extremely critical for racing: when a car is moving at extreme speeds, small problems can lead to massive disasters and potential death. And reliability is just as vital for endurance and off-road races where the ability to survive in rough conditions is part of the competition.

When vehicles are moving at the extremely high speeds involved in racing, everything becomes more intense and that includes vibrations and shock loadings. And for off-road competitions, the impact loadings are even more intense. Racing seals must be able to also retain their ability to exclude contaminants and retain media (whether its fuel or lubricant) even in the presence of these extreme loads.

Dynamic seals must also be able to handle continuously higher speeds than an average automotive seal, which can make the choice of materials even more challenging. The coefficient of friction and ability to dry lubricate (as is seen with materials such as PEEK and PTFE) becomes even more important. There are also extremes in both pressures in temperature that require seals with dimensional stability, often requiring spring-energized or labyrinth seals.

Chemical inertness is also vital, especially as some newer fuel additives for racing cars have proven incompatible with rubber hoses. Materials like PTFE and PEEK are chemically inert, but it is very important to check material compatibility before moving forward with a seal design.

Another challenge faced when designing seals for high-performance automobiles lies in available space: to keep weight down and ensure that the vehicle is aerodynamic, compact sealing solutions that take up a minimal amount of space are required. 

Solutions for High-Performance Automotive Seals

When designing seals for high-performance automotive applications, advanced polymer seals should be seriously considered. Polymer seals weigh a fraction of their metal counterparts and less than elastomeric seals. They involve far less friction and can be just as rugged and durable as well. Because materials such as PEEK and PTFE are dry-running and self-lubricating, they can sometimes eliminate the need for a bearing. Performance polymers also include additives that enhance the properties of a polymer, increasing its stiffness, impact resistance, and dimensional stability as well as reducing friction. 

Polymers are far less susceptible to corrosion than their metal counterparts and, when the right polymer is chosen, are less susceptible to chemical attack than elastomers. Polymers also lend themselves more readily to manufacturing with complex geometries than metals and offer more freedom as far as manufacturing methods than elastomeric materials. 

Engineering polymers also provide the resistance to wear, strength, and stiffness needed in the rugged environments and demanding operating conditions of racing. And the use of polymer seals as opposed to metal seals reduces problems with metal-to-metal contact such as galling and abrasion. Note, however, that in many instances, the seals required for high-performance automobiles must be custom-made to achieve the necessary level of performance while staying within design constraints. 

Conclusion

The design of high-performance automotive seals can be extremely challenging and many engineers are turning to polymer seals to effectively meet those challenges. Engineering polymers such as PEEK and PTFE, including the variety of grades and fill options available, are an excellent solution to many seal designs.