A Quick Overview of the Injection Molding Process: Molding 101

Injection molding is an essential process used by many different companies to create outstanding products, and this process is often a mystery to the end user, but as the manufacturer or designer, you know just how involved it can be.

Whether it’s rubber overmolding or injection molding, you know it’s a complex process, but just how complex is it? What does it involve? There are a few things you need to know, and we’re going to cover some of the basics so that you can understand a bit more about how the injection molding process works.

Beyond Overmolding: Injection Molding Basics

Plastic injection molders help you to determine the size of the machine required for the molding process in question, allowing you to easily source an injection molder that will meet your needs. There are several different types, each one given a rating or classification that corresponds to the type of project or need. These classifications will include:

  • 3- 68 Ton Press
  • 5- 123 Ton Press
  • 5- 154 Ton Press
  • 5- 202 Ton Press
  • 5- 233 Ton Press
  • 4- 400 Ton Press

The injection molding presses used by any facility in the industry are based on tonnage, which is related to the clamping force exerted by the machine. Presses have a rather wide range, from 5 tons of pressure to more than 4000, and the higher the press ton rating, the bigger the machine is going to be.

Injection Molding Process

A Closer Understanding of Tonnage

Let’s say you have an injection molding machine in your possession that is rated for 70 tons. In that case, it would deliver a clamping pressure of 70 tons, and it would maintain the pressure in question during the entirety of the injection molding process. Keep in mind that choosing the right pressure is essential, as too much or too little will significantly effect the quality of the end product. Pressure has an effect of the viscosity of the product being formed, and too much will in fact cause excess material to appear on the part edge; a phenomenon known as flashing.

Figuring out Pressure Requirements

Pressure requirements are a critical factor in the process whether you’re doing plastic overmolding or plastic injection molding, and there are of course several factors that go into making the determination. First of all you have to consider the safety factor which helps to avoid defects in the final product. Secondly, you will calculate the size of the plate along with the mold/part size.

Plastic molding injection professionals, like us, generally use the rule of 2.5x the surface spare inches of the part being produced, meaning a product or part measuring 42 square inches would call for a press that is able to exert 105 tons of pressure. The safety factor, assuming it is at 10%, would call for 115 tons of clamping force. That being said, you would be looking for a press that is capable of exerting 120 tons.

Finding the Right Company – An Even more Essential part of the Molding Process

plastic overmolding

The items that we mentioned above are an essential part of the injection molding process, but so is making sure you find the right company to get the job done for you. There are a ton of companies out there that provide injection molding services, as you’ve probably figured out by now, but making sure you have one that will get the job done, and done right? That’s a challenge in and of itself. With all of that being said, you want to choose us, and you want to make sure you’re asking the right questions.

Let us help you figure out the scope of your project and let us provide you with a functioning prototype. It’s time for you to make sure that your company is ready to serve customers with products pieced together in the finest facilities that money can buy. Don’t worry, we have your production well in hand.

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