Inventor to Entrepreneur: Plastic Injection Molding

Plastic is a wonderful, versatile material that can be used for producing nearly anything! The great thing about plastic and injection molding is that it makes mass-production for products more accessible. It’s no longer necessary for every item you buy in the store to be meticulously handcrafted.

What makes plastic injection molding even better, is that entrepreneurs can come up with an endless amount of new ideas for products that will improve our daily lives. Everything from technology to basic toys have some plastic-molded parts. And while we don’t think of the injection molding process often, it’s part of our daily lives. Even the device you’re using to browse the Internet, has some plastic molded parts!

But if you, like the average person on the street, have no idea where to begin in making your product idea a reality through injection molding, there are some simple steps to take.

Is Your Idea Worth It?

The first, most important question to ask yourself before having a product mass-produced, is whether or not the product will truly be profitable. Unfortunately there’s no way to know for sure, and as with any new business venture, there will always be some risk involved.

But that shouldn’t stop you from doing your research.

When thinking about whether or not the product you want to make will sell, you can ask yourself some basic questions like:

• Does my idea solve a problem?
• Does my idea improve upon an existing product?
• Will there be a large enough market interested in buying my product?
• Can I explain the benefits of my product simple and succinctly?
• Can my product be manufactured at a realistic cost?

You’ll have to answer the first few questions for yourself by doing some market research. But the last one will require you to get quotes from product designers and plastic injection mold manufacturers.

Where to Start?

If you have a good idea that you believe will sell, your first challenge will be to get it on paper. Draw your design using some pen and paper. Don’t worry if you aren’t good at drawing, the important part is for your drawing to clearly show what you expect the finished product to be like.

You can also make some basic prototypes illustrating your idea using things like clay. Although it’s unlikely that a clay prototype would be functional, this will help designers understand what your product should look like in 3D. Apart from your clay prototype, you can also build a functional prototype using anything you can find around the house. This prototype will help you explain your idea more effectively.

Once you have proper designs and product examples, it’ can be a good time to venture into having it made in plastic. When you start out, getting your idea 3D printed can be an excellent way to make a realistic prototype of the end product.

3D printing is a wonderful technology for producing small amounts of plastic parts without the upfront investment of having a plastic injection mold made. For this reason, some products never go further than the 3D printing stage. An example of an innovative for 3D printing is in the manufacturing of prosthetics for amputees. Because every amputee has very specialized individual needs, 3D printing is now used to manufacture low-cost, custom-made prosthetics.

However, most products have to be mass-produced in order to be profitable, so for the purpose of your product design, you’re likely to use 3D printing only during the prototyping phase of design.

Once you’ve got a basic, 3D printed prototype of your final product, you’re ready to take the idea further. If there’s anywhere you were hoping to pitch your product idea, the prototype is sure to come in very handy!

Let’s Talk CAD Designs

This is where you hand your ideas over to the professionals. Computer-aided design – or CAD, for short – is a process where professional designers take your idea to the next level.

CAD designers know more about the injection molding process and the manufacturing of plastics products in general, so their designs will usually be made considering different aspect of the manufacturing process. This is essential for successful product design, seeing as a plastic injection mold will have to be designed and made specifically to produce parts for your product. The professional product designers will draw the final product design, not only thinking about the functionality of your product, but also how the molds producing parts for your product will function.

Some of the things a professional CAD designer will keep in mind while designing the final product include:

• What material will be used to make each part of the final product?
• How easily can each part of the final product be molded?
• Where should the gates be placed on the mold to ensure the part has no molding defects?

Chances are, your designer will take an example of their design to a plastic injection mold manufacturer in order to decide how the molds should function. Plastic injection mold design and quality in the manufacturing of the mold itself will play a huge role in the quality of your final product.

If the gates feeding molten plastic into the mold aren’t placed correctly, for instance, the plastic might not fill the whole mold cavity and your parts could all end up being defective.

For this reason, your mold designer and manufacturer will be just as important in getting your product idea on the shelf as your designer.

At Quality Mold Shop, we pride ourselves in producing precision molds for any industry. We’ve successfully designed and maintained injection molds for the technology, medicine and the automotive industries. Talk to us about mold design, maintenance and manufacturing.

How to Mold Living Hinges

Living hinges are popular in low-cost containers, like the ones you see on Tic Tac or floss containers. But the use of living hinges can vary widely, and so the molding technique is also often used for producing medical instruments such as hemostats.

As you could expect, molding living hinges would be much more difficult without modern plastic injection molding technology. Especially seeing as the hinge itself relies on the plasticity of the material to last longer.

What Are Living Hinges?

Don’t know what a living hinge is? Well, actually it’s quite simple.

Like a normal hinge you’d expect to see somewhere like on a door, living hinges can be used to make things like swinging container lids. The only difference is that, unlike normal hinges, living hinges don’t have loops and pins to make up the hinge mechanism. A normal hinge typically merges two different parts together in this way. However, living hinges are more like a line where the plastic bends to allow movement. Basically, it’s a “seamless” hinge, because there aren’t two parts merged together by a hinge. Instead, the hinge in molded into a single-part product.

What this means is that living hinges have to be able to flex constantly without tearing. This is what makes plastic a good option for molding living hinges, seeing as metal would break as a result of metal fatigue if one were to make a living hinge from it. Materials such as wood, on the other hand, aren’t even bendable. By the time wood is thin enough to bend, it would simply splinter if it were to be flexed so much.

But just because plastic is a good material for molding living hinges, doesn’t mean that all living hinges molded out of plastic are perfect. On the contrary, products that have living hinges typically have a lifespan that lasts as long as the living hinge is functional. After a certain amount of time, even a plastic living hinge can grow weak and tear along the hinge line.

For the most part, living hinge failure isn’t such a big problem, seeing as living hinges aren’t usually molded into products that need to have a long lifespan. However, living hinge failure can become a problem if the hinge doesn’t last long enough to fulfill its purpose. This can be especially true in the case of something like a container that breaks before its contents is all used. So even though living hinges don’t have to last forever, they at least need to last long enough to fulfill their purpose.

To mold durable living hinges will take some careful consideration on your behalf.

How to Mold Durable Living Hinges

To mold a living hinge that lives up to your expectations, every step of part creation is important, from the actual design of the part to the material used to make it. Different plastics have different uses, and not all plastics are a good choice for molding plastic hinges into a part.

So, although molding a hinge into a part might seem like a challenging task, it’s much like molding anything else, as long as you plan everything properly and pay attention to detail during every step of part creation, you’ll get the results you were hoping for.

For the most part, experts tend to recommend homopolymer PP for molding living hinges. However, your molding will also have a big influence on the quality of your final part, so don’t neglect checking the ideal molding temperatures and processes, seeing as you’re likely to get better results molding hinges at lower temperatures.

Mold Design and Construction

When it comes to molding any plastic part, the design and construction of your mold is just as important as what polymers you use and the process itself. Unfortunately, plastic molding isn’t a simple process. There are many things that can go wrong along the way, and a bad mold could very well be one of them.

Things to consider in mold design and construction include where to place gates and understanding how your material will flow through the mold once it’s entered. This might seem like a small things, but the flow pattern of the molten plastic in your mold can have a potentially huge impact on the quality of the parts a mold can produce, and unfortunately some molds with faulty designs are simply incapable of producing parts that live up to their intended purpose.

Of all the steps in molding a part with living hinges, having your mold designed and made will usually be the most costly, and so it’s important that the mold delivers as you hoped it would from the start.

The first step in getting your mold made would be proper part design, of course, so don’t neglect proper part design and prototyping. There’s simply no sense in having a high quality mold made for a part that was poorly designed to start with.

However, once you have a good part, your mold’s ability to accurately produce the part becomes the next most vital step in molding a proper part. Because unlike with selecting your polymer, changing your mold and experimenting with it won’t be as simple.

To get a mold that you can rely on, be sure to contact us at Quality Mold Shop. We’ve produced a large number of molds for almost every industry, and our precision equipment allows us to manufacture high quality molds for creating even the most detailed parts.