The industry uses Injection molding widely as a manufacturing process. And, it already has a long history. In addition, the process is constantly being refined and improved with new technological improvements. Therefore, we give you an overview of the top 5 advantages and limitations of injection molding.
Benefits of injection molding.
- High-volume manufacturing of plastics: In brief, a mold is a tool to produce one or multiple and identical plastic parts in a repetitive way.
- Wide range of materials: Different components are made of specific raw materials. More specific, there is a wide variety of materials each with its features and specification (cfr. strength, hardness, UV-resistance, temperature range, cost)
- Very high productivity: Average, we have 2000 or more molding cycles per day. Depending on the number of cavities in the mold we produce components following the number of molding cycles or multiplication.
- Great repeatability and tolerances: With each molding cycle we produce identical plastic components. And, this hundreds of thousands times in a row.
- Excellent visual appearance: There are numerous ways to nicely design plastic parts. For instance, different surface textures or coatings improve the look and feel of plastic parts.
Limitations of injection molding.
- There is a relatively high start-up costs for tooling.
- Design changes are costly.
- You may expect longer lead times than other technologies when you count the manufacturing of the mold.
Look around you. I am sure you see a plastic part. To recognize them, look out for these 3 things: a parting line, witness marks on the hidden side and a relatively uniform wall thickness throughout the part.
What is injection molding?
After explaining the top 5 advantages and limitations of injection molding, let’s talk about the process. We use injection molding as a manufacturing process for the mass-production of plastic components. More specific, each part has the same shape and tolerances after molding. First, we melt polymer raw material granules. Next, we inject them under pressure into a mold. Once in the mold, the liquid plastic cools down and solidifies. In injection molding we use thermoplastic polymers that with the possibility to be colored or filled with other additives.
It has to be said, injection molding is the most common manufacturing process for plastic components. Examples are: Electronic enclosures, parts for automotive and home appliances.
The industry uses plastic injection widely as a manufacturing process. Specifically, it is popular because of the very low cost per unit when manufacturing high volumes. Though, low volume runs of 1000 – 5000 parts are possible. However, it is more profitable when a mold produces from 100K to 1000K cycles. As a reference, the cost of a plastic part varies from 0.01$ to 0.5$ for small components, to 10$ for large parts between 0.5 to 1 kilogram. As a result, injection molding offers high repeatability and flexibility in product design.
Restrictions of the mold.
The main restriction on injection molding is the high initial investment for the mold. In addition, you need to count the manufacturing time of the mold. Therefore, we count a minimum production time of four weeks. Nowadays, the startup cost is a lot lower than in the early days of injection molding. Thus, plastic injection is now accessible for most business. To give you and idea, molds cost vary between 3000$ and 100K$. More specific, the cost depends on the size and complexity of the product and the number of cavities in the mold.