What Products Are Made From Injection Molding
Manufacturers all over the world use injection molding to mass-produce all kinds of goods. You can use injection molding machines to make anything from a large object like a garbage can to a small object like a mobile phone case.
The most widespread use of plastic injection molding is to make non-consumer parts used in situations where visual appeal doesnt matterlike mechanical partsbecause the injection molding process often leaves impurities behind on the plastic part. Why? Lets look at the process to find out.
Tire chains made from plastic injection molding
How Do You Make A Plastic Injection Mold At Home
Plastic Injection Molding at Home Using an Epoxy Mold
Vertical Type Injection Molding Machine
Although vertical machines are used in a few specialty applications, such as insert molding, to make use of gravity, the majority of machines are horizontal. Plastic parts that can be affixed to or inserted into other materials are produced by vertical injection molding machines. A clamp is used on vertical injection molders to hold the mold from which the finished product will be manufactured.
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Equipment Used For Injection Molding
Injection molding processes are conducted through special machines that are designed just for that purpose and nothing else. They come in varying sizes and shapes depending on the shape of the product you minted to have at the end of the line, but on a general level, they all work using the same principle. The following are the main machines used in this process.
Type Of Molding Processes
There are three different injection molding processes. These are:
Basic Injection Molding
This is the simplest type of injection molding process. The plastic is injected directly into the mold cavities to create the final piece. Of the three different molding processes, this one has the lowest cost.
Insert Molding
This is a little more complex process than basic injection molding. It involves positioning metal inserts in the mold. Once the metal inserts are in position, the plastic injection molding takes place.
This process creates plastic parts with metal inserts fused directly into them. An example of this is the metal fasteners that you see inserted in plastic components.
The process results in a final assembly with greater strength than mechanically fixing the plastic and metal parts together.
Overmolding
Overmolding is also a little more complex than basic injection molding. In overmolding, an initial part is created using injection molding, let us say Part 1. Then, Part 1 is placed inside another mold, and another plastic injection molding process takes place.
The second process creates Part 2, which contains Part 1. This process is similar to insert molding, with the difference that, instead of a metal insert, both parts are created with plastic injection molding.
An example of this is the soft rubber grip that you see embedded into plastic and rubber products, such as toothbrushes.
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Horizontal Injection Molding Machine
Horizontal injection molding machines are the workhorses of a wide range of plastics-based industries. Plastic parts created on injection molding machines ranging from 10 to 1000 tons are used in consumer products, electronics and telecommunications, food and beverage, medical, automotive, and other industries. Melted plastic is pumped into a mold to make a part in this manufacturing process.
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How To Build A Desktop Injection Molding Machine
Norbert Sparrow | Jan 28, 2022
If youre the type who likes to bring their work home with them, that can be problematic when youre in the injection molding field. Those machines wont easily fit into your average home workshop, let alone through your front door. A couple of hobbyists in Canada have a solution a DIY injection molding machine that can fit on almost any desktop.
The video on the Action Box channel on Youtube describes the step-by-step process for building the Injekto molding machine, with the operative word being simplicity. You wont need a machine shop at home, and you can even build the mold itself using a DIY CNC machine. Instructions for building one also are on the Action Box channel.
Other DIY projects on the channel include a CNC router, spot welder, and you guessed it a Mandalorian-inspired flamethrower. I didnt watch that Action Box video, but I would be deeply disappointed if at some point during the step-by-step instructions, one of the fellows didnt say: This is the way.
The Action Box project apparently came out of the COVID-19 lockdown, when the two hobbyists spent their leisure time building some crazy machines for the home shop. They decided to document their builds and, through their videos, hope to spark ideas in other young and innovative entrepreneurs.
Their channel debuted in July 2020, and it already has 33.1K subscribers and has racked up close to one million views.
Explore Expert Advice For Your Injection Molded Products
Ultimately, this list is only a scratch on thesurface of how many everyday injection molded objects appear in the averagehousehold. What it does show, however, is the versatility and reliability ofthis process. Most people never give a second thought to how or who made theobjects they use, but for manufacturers developing new products, its worthy ofyour attention.
At Reliant Plastics, a Texas-based injection moldingprovider, we have decades of industry experience andcutting-edge equipment available to use for your next production run. Pleaseconsult with our team on designing, fabricating and running the molds that willsupply the products for your next major business push. Contact us to learn moreand get a free quote today.
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What Is Injection Molding
Injection molding is basically a manufacturing method that involves injecting molten material into a mold. Injection molding plastics at home can be carried out using various materials. They include metals, glassware, elastomers, confections, and, most typically, thermoplastic and thermosetting polymers. The parts material is first supplied into a heated barrel, mixed, and then injected into a mold cavity. That is where it cools and hardens according to the cavitys configuration.
Molds are usually manufactured by an injection mold-maker from metal, usually steel or aluminum, and precision-machined. That is done so as to form the features of the required part after a product is conceived. The process is usually done by an industrial designer or an engineer in a company that provides a plastic injection molding service. Injection molding is a popular method used for producing a wide range of parts, from minor components to whole bodies.
What Is The Best Material To Make A Mold
Because of their flexibility and capacity to replicate exceptional detail, the majority of mold manufacturing materials are manufactured from natural or synthetic rubber.This is because rubber can be molded into virtually any shape.On the other hand, certain molds are constructed using more durable materials like gypsum plasters.Natural latex, polyurethane, epoxy, and silicone are the types of mold rubber that are most frequently used.
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Benefits Of Making Injection Molds On Your Own And On A Large Scale
There are several benefits to making injection molds on your own. First, its cost-effective. You can make as many molds as you need without spending a fortune. Second, its a great way to produce large quantities of products quickly and easily. And finally, its a great way to customize your products exactly the way you want them. You can control the shape, size, and design of each and every mold. Youre limited only by your own imagination!
Tips To Consider When Trying Diy Injection Molding At Home
The specific strategy to DIY injection molding will differ depending on the intended design and volume but the following pointers can help you improve your chances of success.
- Consider utilizing a water bath to cool your part more quickly and reduce warping.
- Details that are embossed or engraved should be offset from the surface by at least 1 mm.
- Add 125 mm to the back of the mold plates when designing for an aluminum mold frame so as to accommodate compression forces and to ensure a full seal.
- Print the mold with a decreased layer height in order to limit the visibility of print lines on the finished product. It’s worth noting that this will lengthen the printing process.
- Add two to five degrees of airflow on surfaces that are perpendicular to the draw direction to make it easier to remove the part and reduce possible mold damage.
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What Plastic Is Used For Injection Molding
Plastic part manufacturers most commonly use are thermoplastics for injection molding. Thermoplastics are polymers that turn molten under high temperatures and solidify under cool temperatures. Unlike thermoset plastic material, which burns if it is reheated, you can heat and cool the thermoplastics multiple times before it degrades beyond use.
Youll most often see thermoplastics in plastic pellet form for injection molding purposes. You can mix plastic pellets with colorants, recycled material, and even glitter or other specialty additives.
The most common types of thermoplastics are:
- Polyethylene is one of the most versatile plastics to use for injection molding. Polytheylenes high ductility, tensile strength, impact resistance, low moisture absorption, and recyclability make it an ideal material for plastic containers and bags.
Make Your Own Injection Molding Machine
Tried, true, and totally doable. Start cranking out solid thermoplastic parts.
Sometimes theres a tool you want to buy, but you cant justify the cost. In that case, why not make it? For me, a plastic injection molding machine fell into that category and it turns out theyre not hard to make.
I wanted to make solid plastic parts for some of my amateur science experiments. There are a number of ways to make things out of plastic, each with its advantages and disadvantages. Often just cutting raw material to the desired shape works best. Some plastics can be cast by pouring a liquid resin with hardener into a mold . Vacuum forming works well for making things out of thin sheets of plastic . I considered making a 3D printer, but for the few plastic parts I envisioned needing, it wasnt worth the time and money.
Plastic injection molding has been around since thermoplastics were invented. Its a great way to make many copies of a part quickly, and what I like best is that its easy to reuse old plastic objects to make new ones.
So I built an injection molder based on the plans in Vincent R. Gingerys book Secrets of Building a Plastic Injection Molding Machine. David Gingery could be considered a forerunner of the Maker Movement he and his son Vincent have written a whole series of books on building tools for the machine shop.
My Build
Making Molds
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Home Plastic Injection Molding
I had been thinking about giving one of the Gingery injection molding machines a try for a long time. I was hesitant to try because I didn’t know how well it would work . I also didn’t have a good method of creating molds for the machine. After I purchased my CNC milling machine I had a tool to produce molds of significant complexity to make it really interesting so I decided to give it a try.
Gingery publishing has two books on plastic injection molding:Plastic Injection Molding MachineandPlastic Injection Molding Attachment for the Drill Press.The first book details the construction of a full injection molding machine including the mechanism used to push the ram into the injection cylinder. The second book features a smaller machine that relies on an existing mechanism from a drill press to push the ram. Using the drill press attachment design reduces the complexity and space required for the project. For these reasons, I decided to build the drill press attachment injection molder. The temperature control for the heater is also different in the two books. The drill press attachment book uses a purchased PID controller, thermocouple and purchased cartridge heaters. I do not know the details of the other controller because I do not own the book.
A Note Regarding The Tooling Process
Despite the clear advantages of injection molding, the process is not without drawbacks. Namely, the upfront tooling costs and significant lead time required are obstacles for many manufacturers. While tooling might be considered the first phase of the injection molding process, for our purposes were considering it separately because its a heavily-involved undertaking that need only be completed once for each product.
Tooling requires product design teams to design and prototype a part often via 3D printing and then to create a mold that can be used to reliably make the part. This requires extensive testing and optimizing, but once the mold is complete, the same injection molding process can be completed thousands of times to create identical parts.
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Pros And Cons Of Handling Plastic Injection Molding In
If youre considering plastic injection molding for your product or products, the accessibility and relative ease of the process can make it seem appealing to invest in an in-house solution. Given the high volume of parts that can be efficiently produced, the path to recouping your initial investment in in-house plastic injection molding can look clear and relatively painless. Before jumping feet first into an in-house custom injection molding solution, however, its important to consider the cons along with the pros and there are several of each.
As a process, injection molding advantages are readily visible for most applications. If youve settled on the process but are deciding whether or not to invest in in-house, be sure to carefully consider each point below.
Pros:
Cost-efficient production: Injection molding is, in general, a cost-efficient production process. While material choices, part complexity and part design can affect pricing, injection molding will typically offer a favorable price point when compared with other processes, all other factors being equal . An in-house solution can further boost the cost-efficiency advantages by cutting out shipping costs and the built-in overhead costs that would otherwise go to your supplier. Of course, that overhead cost is then shifted to you, which can attenuate some of the advantages detailed here.
Cons:
What Are Ideal And Minimum Quantities For Injection Molding
There is no universal rule for minimum quantities when considering injection molding. Generally, with tools costing at least $10,000 for the smallest and simplest parts, production volumes of a few dozen parts or even a few hundred parts can rarely carry a proportion of the capital cost of the molds. It is not uncommon for injection molds to cost between $50,000 and $500,000. In this range, it is expected that production volumes would be at 10,000 units and up.
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Pull Down Handle To Inject Plastic
Pull down on the handle with a quick, but steady motion. You will feel a solid resistance when the mold cavity is full. Hold the handle there for a few seconds, and then lift it back up until it locks place.NOTES:The downward force on the handle causes the injection nozzle to press down tightly against the top of the mold, allowing the molten plastic to flow directly into the sprue hole. The time it takes to pull down the handle will vary, depending on how much plastic you are injecting. A small part may only take about 2-3 seconds to inject . A larger part may take 10-15 seconds or longer to inject .
Shuttle Type Injection Molding Machine
This method allows you to use two bottom mold halves with one top half. While one bottom half is molding with the top half, the other bottom half is available for insert loading. The bottom half of the press is filled with inserts and shuttles into position with the top half, while the bottom half molding shuttles out for part ejection and insert reloading when the press opens.
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Case Study: Using A Plastic Injection Mold To Create A Gutter Cleaning Tool
Recently, we had an entrepreneurial client come to us with an idea for a plastic part. He had jury-rigged an innovative gutter cleaner from parts he bought at a local hardware store. On his own, he produced about a dozen gutter cleaners. But he needed to scale his production to make the product commercially viable. He came to our team at Rex Plastics to find out whether plastic injection molding was right for his design.
After reviewing the hand-made prototype, we recommended that he use injection molding for the following reasons:
- The plastic part was smaller than 40g.
- The client needed to manufacture more than 1000 plastic parts per year.
- The plastic parts wall thickness was uniform.
- The plastic part could be made from a thermoplastic material.
- The function of the plastic part was more important than its aesthetics.
- The client could wait several months before starting mass production.
We were able to design a mold for the gutter cleaner, build a prototype, tool the mold, and begin production in just a few months.
Today, the client purchases thousands per year, and order quantities for his gutter cleaner are climbing steadily.
Check out our other case studies to understand how this process can work for you:
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