Injection Molding & Extrusion

Plastic injection molding
Plastic injection molding is a method of manufacturing products by injecting liquid plastic under pressure into a metal mold and then curing it. It is the most commonly used and cost-effective technology for the mass production of plastic products. The process itself requires sophisticated equipment and serious technical training. However, under the supervision of experienced professionals, all costs justify themselves, and the result is a product of excellent quality at a bargain price.
Scope of injection molding technology
This method is the most popular for the production of almost any plastic product. It should be borne in mind that this method is used in mass production. In case you need to produce from several thousand to hundreds of thousands or several million products. The method is not suitable for the production of units or dozens of products, since the development and manufacture of molds is quite expensive.
We present an incomplete list of products that can be produced using this technology:
  • cases for radio-electronic equipment;
  • automotive components;
  • plastic lids and caps;
  • cases for medical equipment;
  • details of household appliances;
  • Kids toys;
  • plastic packaging, etc.
Benefits of using injection molding technology
Injection molding is economically and technically much more profitable than the seemingly cheaper method of molding into silicone molds.

Why is injection molding recommended for large batches?
  1. The production process results in higher quality products. The supply of liquid plastic under pressure allows it to be evenly distributed over the mold, filling even the smallest holes.
     
  2. Possibility to obtain a part of any complexity, incl. with very thin walls. For the production of products, a metal mold is made, the design of which takes into account all the small details of the future product. As a result, you can get both a simple and a very complex product, with many holes and bends.
     
  3. No need for mechanical processing of the product. The finished product does not require additional processing. The exceptions are very complex products, however, in this case, the improvements are minimal.
     
  4. Ability to reuse forms. The metal mold, which is created before production, will last a very long time, with its help you can make any number of products.
     
  5. Low cost, subject to the production of a large batch. The more products are made, the cheaper the cost of one copy will be, the process is mechanized - there is no need for labor costs.
However, this technology has its drawbacks:
the high cost of preparatory work, and, accordingly, the unprofitability of manufacturing a product in one copy or a small batch.
The main stages of the production of the product by injection molding
The process of manufacturing plastic products by injection molding includes several stages. All stages can be divided into two groups: preparatory work and direct casting.
We propose to consider all the stages in more detail.
Preparatory work
  1. Creation of a 3D model of the future product. A 3D model, as a rule, is created according to drawings, descriptions, or photographs in a special program by an experienced specialist.
  2. Making a prototype. After the approval of the 3D model, a prototype is created, i.e. sample of the future product. Most often this is done using 3D printing. A prototype is needed to evaluate and test a future product. If any inaccuracies are found, it is necessary to return to the first stage and refine the 3D model.
  3. Mold design. This process is carried out on the basis of a 3D model of the future product. At this stage, it is important to take into account all the smallest details and subtleties.
  4. Mold making. The finished 3D model is divided into several parts. Each part is made separately, after which they are assembled into a mold.
  5. Test casting. Next, the first copy is made, which is subjected to careful study and testing. If inaccuracies or flaws are found in the process, the mold is finalized.
Preparatory work lasts from several weeks to several months. This is the most important stage, which needs to be given enough time, because. the quality of future products depends on it.
Injection molding process
  1. Melting and feeding plastic into the mold under pressure. The heated plastic is fed into the mold under high pressure.
  2. Uniform distribution of plastic in the mold. Due to the pressure, the plastic is evenly distributed over the shape, filling even small holes.
  3. Mold cooling and plastic solidification. The cooling time depends on several parameters: type of plastic, mold temperature, etc. For small items, this is usually a few seconds.
  4. Release of the finished product. After the mold has cooled, it opens to dispense the finished product.
The cost of manufacturing a product by injection molding
As a rule, the manufacture of products by this method requires serious financial investments at the stage of preparatory work. However, the more pieces will be produced in the future, the lower the cost of one item. At the same time, the quality does not change and remains at a high level.

The production price is calculated individually, based on all the features of the product. As a consequence, the final cost is dynamic.
Consider the main pricing indicators:
Product complexity. The higher it is, the more expensive the mold will be, and, accordingly, each product.
Plastic type. The material is selected based on the requirements for the final product.
The number of pieces in a lot. The more of them, the cheaper each product, and other significant factors.
An example of calculating the cost for the manufacture of a plastic case
The term "extrusion" comes from the late Latin word "extrusio", which literally means "pushing out" and quite accurately characterizes the feature of the process. Extrusion is a technology for the production of any product, in which molten material is forced under pressure through a forming device, taking the desired shape. As a rule, extrusion is used to obtain products or blanks with a cross section of the desired shape. In fact, the length of the finished product can be unlimited, and the limit of the diameter is determined by the diameter of the outlet.

With the help of this technology, films, pipes, profiles, sheets, shells are obtained, that is, solid extrusion billets and molded products. The main advantage of extrusion is the low cost of the process; it is one of the cheapest ways to produce products from polymeric materials.
Extruder
An extruder is a machine for molding plastic materials by shaping them by forcing (extrusion) through a profiling tool (extrusion head).

The extruder consists of: body with heating elements; working body (auger (Archimedes screw), disk, piston) located in the housing; loading unit of the processed material; power drive; systems for setting and maintaining the temperature regime, other control and measuring and regulating devices.
Our company has an extrusion line with which we produce various hoses and pipes from soft PVC, both single-layer and multi-layer with fiber reinforcement. We also produce flexible profiles that can be used in furniture production to mask various gaps, such as masking tapes for stretch ceilings, handles for cardboard packaging.
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