Facts About Injection Mold Builders

There are several facts about injection mold builders. This article will discuss the process, materials, costs, side-action cores, and side-action molds. To find out which one is best for your project, continue reading! Also, we’ll discuss the advantages and disadvantages of each option. This article will also discuss how the process of side-action cores can reduce your costs. Besides, we’ll cover the pros and cons of each type of injection mold.


Injection molding is a process that allows you to produce a specific product. The molten plastic flows into a mold where the injection unit is located. The machine’s motor controls the molten plastic’s speed and dwell pressure. The machine changes speed control to pressure control when the screw position reaches a specified value. Once the molten plastic has solidified, it is forced out of the cavity image by an ejector bar.

The plastic or rubber mold is designed to resemble the part to be produced during the molding process. Once this is complete, the mold is built to approximate dimensions. After rough machining, steel is reserved for precision machining. The mold is then assembled and tested, and the parts are sent to a mold maker. Injection mold builders should carefully follow all design guidelines to produce high-quality products. A mold must have multiple runners of the same dimensions to facilitate the injection process.


You must choose the right materials if your company plans to produce plastic parts. Most plastic injection molds are steel, aluminum, or beryllium-copper alloy. These materials cost less than other types but are unsuitable for high-volume production or parts with very tight dimensional tolerances. CNC machines or Electrical Discharge Machining are excellent choices for making aluminum injection molds. Copper alloy inserts are used in the molds in areas that need to remove heat quickly. In addition, copper alloy inserts reduce cycle time and improve aesthetic quality.

Other materials used for plastic parts include PP and PMMA. PBT is an engineering polymer and can be filled with glass fibers for dimensional stability and strength. PP is also resistant to warping and is difficult to paint. High crystalline polypropylene (HIPS) is stiffer and less brittle than regular polypro. PPE/PS is a blend of polyphenylene ether and polystyrene. It provides excellent dimensional stability and a low degree of mold shrinkage. Polycarbonate plastics are also lightweight and exhibit excellent optical properties. However, they require higher processing temperatures and are not scratch resistant.


There are three major costs that you’ll encounter when hiring an itar-registered injection mold builder. First, there are the material costs. These include the cost of raw materials, processing fees, and mold cores. Once you’ve chosen the raw materials, you’ll need to select a thermal treatment process for the mold core. The cost of processing varies depending on the mold’s complexity, but the processing fee ratio to mold base material price is usually 1.5 to 3. Another major cost is the machining cost. CNC machining and electrical discharging (EDM) processes are used for most types of molds. These processes are typically the most time-consuming and expensive, and their costs are usually reflected in the hourly rate.

When choosing a mold builder, you need to determine whether the price will match the quality of the finished product. An injection mold built in the USA will typically last longer, require fewer repairs, and lower your overall cost of ownership. Injection molds are also classified according to SPI class (formerly the Plastics Industry Association) standards. By choosing the correct “mold class,” you can save considerable costs by avoiding the most expensive supplier.

Side-action Cores

When designing an injection mold, the side-action core is an important component. These cores enter and exit the mold on opposite sides. They are ideal for manufacturing parts with overhangs but increase the mold builder’s cost and complexity. In addition, they require the cylinder to move perpendicularly, and any angle other than 90 degrees is more difficult to manufacture and increases lead times and cost. Therefore, to design this type of core, the designer must incorporate draft angles.

Injection mold builders must be aware of the possible interference of side-action cores with the ejection mechanism. When these two parts are set to collide in the opening direction, the ejector mechanism will be activated and must be reset. Side-action cores should be used only when the projections of the slide and the ejection mechanism coincide in the opening direction of the mold. The ejection mechanism must be reset if the two cylinders are aligned in the opening direction of the mold.

First Article Inspection

If you’re considering using a third-party injection mold builder, you may want to consider the first article inspection (FAI) process. An FAI is a comprehensive quality control process that involves examining the first piece of the mold before the mold is used in production. It consists in checking a wide range of factors, including the quality of the mold, the equipment, and the process itself. Many companies are not familiar with the process, but it’s crucial to the overall quality of your product.

The benefits of first article inspection are numerous. It reduces waste and can save you a lot of time by catching problems in the production process before they become large problems. But some clients feel that it isn’t necessary for all applications. For example, if you’re only producing a small batch of parts, you may not be interested in FAI. On the other hand, if the mold builder is already familiar with having a specific part, they may not want to invest in an inspection process.

Environmental Impact

The environmental impact of an injection mold can be measured. While it’s difficult to predict the exact environmental impact of a specific product, a life cycle approach can give an idea of how mold affects the environment. This study uses a life cycle assessment model to predict the environmental impact of a plastic injection mold throughout its life cycle. The life cycle assessment model explains the inputs, variables, and algorithms involved in calculating the environmental impact of a plastic injection mold. The model is then applied to a case study to isolate the environmental impact of mold production.

While reducing embodied energy is crucial for sustainability, the environmental impact of an injection mold builder is also an important consideration. Injection molding produces waste that must be recycled. However, different processes have varying degrees of recycling. For instance, many companies recycle the excess plastic produced during injection molding. This excess plastic is remelted and reused, or it can be sent externally for recycling. Moreover, many companies are pursuing ways to reduce plastic waste in their manufacturing processes. Advanced technology and improved production methods will help reduce plastic waste.

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