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An Insider's View - American Injection Molding Institute (AIM) Certificate Program

by Administrator28. March 2016 14:03

My name is William Allen. I have been around plastics injection molding my entire life. My parents actually met while working in an injection molding facility as young adults and I can remember recognizing the sounds and smells of a plastics plant as early as five years old. When I found myself on the hunt for a job in 2005 I made my way into the plastics world as well. Starting out as an operator I was able to see plastics manufacturing from many angles as I worked my way up through the ranks. My first formal training in the realm of processing came in the form of a two day class and a one month crash course from a newly hired engineer on staff at Nampac (North American Packaging) which, at the time, was located in East Cleveland Ohio. That was in 2007. At the time, I was strictly working with polypropylene making one product – buckets - in several sizes and colors on the 11 presses we had in house. It wasn’t until midway through 2008, when Nampac closed its doors, that I joined the Thogus Products family as a process technician. I immediately started to realize just how many different plastics there were, and how much processing variation could exist in a facility that ran so many custom jobs.

Over the course of the next six years I enrolled in three additional technical training programs and gained a great deal of invaluable experience. My experience expanded across many different machines, several types of robots and automation, and of course multiple types and grades of plastic. Fast forward to March 2015, I was then offered an opportunity to be among the inaugural class of the AIM Institute in Erie Pennsylvania - an opportunity I will be eternally thankful for and know I will benefit from for the balance of my career. 

Upon taking the entrance test for the AIM Institute (strictly for the sake of gauging current level of knowledge) I realized two things. First, this was not going to be a walk in the park. Second, I simply did not know nearly as much as I thought I did in the realm of injection molding. I was a fair mixture of nervous and excited. But, since I only had a week’s notice before the first of the four classes I was not able to do any research on what exactly I had signed up for; and therefore possibly less nervous than I would have been. Previously, I had read many articles both written by and written about John Beaumont, Mike Sepe and John Bozzelli and recognized them as leaders and pioneers in their respective corners of the plastics world. Little did I know that they would be among the instructors that would be teaching the AIM institute classes. I was a bit star-struck to say the least when I first entered the classroom and saw their name tags on the desks. I remember thinking “I might be out of my league here.” Turns out the mix of students in that class ranged from product design, to tooling, to processing and even quality control. The class, thankfully, is designed to work for anyone in the plastics world.

Throughout the next year I learned plastics - starting at the molecular level and working all the way through tool design, processing and even part review and design. The classes, while very challenging (even for the Thogus, degreed plastics engineer who was taking the class as well), were not the usual “take your information and go” type of classes. There was an enormous amount of support not only during the class and on the homework assigned between classes, but on any day of the week at any time. The instructors were just an email away and their responses were always prompt and informative. They want the students to succeed and their passion for the plastics industry was always evident. I admittedly had rough patches in some areas, but I was never completely lost. When I needed help it was always available.

In addition to the support from the instructors at the AIM Institute, the time allotted to me by my workplace to complete the WebEx classes and homework assignments was pivotal in my completion of the certification as well. Without Thogus’ support and encouragement throughout the program I may not have done as well or even have been able to complete and pass the classes. Their investment in me made an enormous difference in my ability to do well and directly impacted how much I was able to digest and retain the information. 

After my grade for the final test came in and I received my certificate in the “Plastics Engineering and Technology” program I had a great sense of pride. I finished the class tied for the top grade, and while the class was not very large, I felt very accomplished. More importantly, I had a measurable increase in confidence. I was able to step up at work and take on a new role with new responsibilities. I bring a new understanding of troubleshooting to every situation and find myself narrowing in on a particular problem so that I can quickly investigate solutions. I am able to look at new designs and recognize potential issues before products are launched, which can make a world of difference once the steel is cut and processing begins. The lessons and education I was afforded by this program have made a world of difference for me in my day-to-day work. Learning real world applications from experts in a professional setting and having the homework and reinforcement between classes made the information stick. It was an experience I will never forget, and the confidence to challenge the industry standards, ask questions and strive to solve problems will be a staple in my career. 

AIM Certificate

 

Which plastic processing method should you choose?

by Administrator17. March 2016 09:23

 

Plastic products are everywhere and the processes in which to make them are many. Knowing which process to choose for making a plastic part is key to making a quality part, and also to finding a supplier that can help you achieve your production goals. 

So, how do you choose? Let’s look at some of the most common processes used to make a plastic part:

1. Blow molding

Typical Use: Blow molding is typically used in the making of hollow parts, like bottles, that have a uniform wall thickness.

Overview of the Process: The first step in blow molding is the creation of a resin parison or a preform. A parison is a tube-like shape of plastic with a hole in one end that allows pressurized air to pass through. The parison is then clamped into the machine and air pressure is used to inflate the material which fills up the mold and creates the desired shape.

Variations of the Technology: Within the technology there are three types; extrusion blow molding, injection blow molding, and injection stretch molding.

 

2. Thermoforming

Typical Use: Within thermoforming there are two categories: Thin-gauge and thick-gauge. Thin-gauge thermoforming requires sheets less than .060in thick (1.5mm) and thick-gauge, the sheets are greater than .120in thick (3mm). Trays and packaging for medical, food, and retail are created using thin-gauge and larger items like plastic pallets, bumpers, refrigerator lines are made using thick-gauge thermoforming.

Overview of the Process: A plastics sheet is heated until it is pliable and placed over or between a steel mold of the shape to form customized plastic products. Typically thermoforming is done in a continuous, high-speed process where thousands of parts are made each hour.

Variations of the Technology: Vacuum forming, compression molding, pressure forming

 

3. Rotational plastic molding or roto molding

Typical Use: Rotational molding is typically used when making hollow parts that require uniform wall thickness such as tanks or kayak bodies. 

Overview of the Process: A mold is filled with a polymer resin – typically in powder form; the resin is then heated to a molten state while the mold rotates bi-axially so that the resin coats the inside of the mold cavity in a uniform fashion. Once cooled the part is removed from the mold.

Variations of the Technology: Much of the variation in rotational molding lies in the production equipment itself. There are a variety of methods used to actually rotate the molds: Rock and Roll, Clamshell, Carousel, Vertical, Shuttle and Swing Arm machines to name a few. Rotational molding often times is confused with rotational or spin casting which have slight variations that make them different than rotational molding. 

 

4. Extrusion

Typical Use: Extrusion is used to make products that have linear and fixed cross-sectional profiles such as pipe, hose, and fenestration products; and is the reason why extrusion is often times referred to as profile extrusion.  Extrusion is also one of the most common processes used to make compounded plastic pellets for extrusion or injection molding.

Overview of the Process: Either plastic compounded pellets or a dry blend of chemicals are placed into the material hopper and then loaded into the barrel of the extrusion machine where they are heated and worked along a screw to the end of a machine where they exit through a die. The die shape dictates the ultimate dimensions of the profile coming out of the machine. The shape or profile is then cooled and cut to the desired length. Because of the length requirements, often times extrusion equipment can take up an extensive amount of space on a shop floor.

Variations of the Technology: Often the screw does the majority of the work to extrude the product through the die, but in highly filled polymers such as fiber-reinforced profiles sometimes a method of pulltrusion is employed where the extrudate is pulled through a long die. 


5. Injection molding

Typical Use: Injection molding is the most common method of manufacturing plastic parts and is ideal when production of a single part is of high volume. Injection molding allows for a fast rate of production, the ability to have many textures, finished, colors and complex parts.

Overview of the Process: Similar to extrusion, plastic compounded pellets are loaded into the barrel of a machine where the material is melted and worked down the length of a screw. Unlike extrusion, however, instead of exiting the machine through a die, the material is pushed through a runner system into a closed mold made of steel in the shape of the desired part. The mold goes through a heating and cooling cycle and once the desired temperatures and time settings are achieved the mold opens and the part can be removed.

Variations of the Technology: Much of the variation that exists in injection molding has to do with the way in which the injection molding machine itself is positioned (vertical or horizontal) and also the way the tool is designed. Tooling and the machine are always dictated by the complexity of the part and the volumes that need to be achieved while optimizing manufacturing efficiencies.

Now that you know the processes let’s refer to a chart for advantages and disadvantages of each as it relates to potential applications.

 

Technology

Types of Parts

Advantages

Disadvantages

Blow molding

Disposable containers for packaging liquid consumer goods (soda bottles) 

Produce a one-piece hollow part

Best suited for mass production of small containers

Higher productivity than rotational molding

Limited to thermoplastics

Limited to hollow-forms

Wall thickness hard to control

Thermoforming

Tables, trays, liners, bumpers, packaging

Make parts quickly

Large and small parts can be made

Material is higher in quality and durability

Tool costs are less than other processes

Material costs can be as much as 50% higher than other methods

Uses more plastic than other methods

Rotational Molding


Tanks and other large, hollow parts 

Very little material wasted

Best suited for making large hollow parts

Not fast-moving process

Material costs are high

Extrusion

Drinking straws, pipes, tubes, hoses, optical fibers, fenestration products, deck boards

Low initial setup cost

Low production costs 

Limited precision

Restricted to only parts with a uniform cross section

Injection Molding

High volume, complex shapes

Most versatile

Many types of resins & additives

Fast production

Low labor costs

Design flexibility

High initial tooling cost

Part design restrictions

Accurate Part design required at initial stages 

 

 

Hopefully this information will help you when you have to decide what process to use when making a plastic part! 

 

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Manufacturing | Plastics

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