Managing the Injection Molding Process
A lot of rigid plastic box manufacturers use the term “quality” to define and distinguish their products from their competitors’. “Quality” can be a subjective term and as a customer, do you know what quality translates to for your rigid plastic box manufacturer?
At Alpha Rho, we make premium quality rigid plastic boxes, and when we say quality, we are referring to two distinct parameters:
- Ensuring defect-free products
- Maintaining consistency in our product
To us, both these approaches are equally important. Every time you receive your order of rigid plastic boxes from us they should be identical to the ones you ordered before and of the same high quality.
Achieving high quality comes down to precise control of our injection molding process. This process involves melting polystyrene and injecting it into a mold where it cools and solidifies. After ejection, we remove the sprue, and send the boxes to assembly and packaging. On the surface this process may look straightforward but if you look closer you’ll discover a host of process parameters that need precise control.
Two key factors need to be paid meticulous attention – temperature and pressure. They separate out into a whole series of measurements, and each one needs careful control.
Unlike some liquids, polystyrene’s viscosity varies with temperature. The hotter it gets, the easier it flows. A screw turns solid polystyrene through a heated barrel and into the mold, heating it as it goes. How hot the polystyrene gets depends on how quickly it moves through the barrel and the temperature of each zone.
Mold temperature is critical too. If it were at room temperature, the polystyrene would freeze the moment it touched the cold metal. In order to avoid that, the mold is both heated and cooled to keep it at the optimal temperature.
Injection pressure determines how quickly the liquid polystyrene fills the mold, and also influences temperature. Once the mold is full we hold the pressure for a few seconds while the polystyrene solidifies. At the same time, we also need pressure to keep the mold closed as it fills (molds are made in two parts so we can get the boxes out.)
Our injection molding machines are packed with instrumentation to monitor each aspect of the process. Sophisticated controllers optimize each step of the cycle to ensure complete consistency.
Having said that, we do acknowledge that sometimes a product with a quality issue could go out to a customer because, despite all the monitoring, machines might drift from settings on occasion. We strive to minimize that error and ensure that every box you get from us is of the same high standard by having external and internal audits in place.
You work hard to create your product—proper, high-quality packaging shouldn’t be seen as an extra step, but an integral part of producing your product and delivering your brand. Contact us at Alpha Rho to discuss your packaging needs, your target audience, and how you want your product and packaging to be perceived. Odds are, we can improve your branding and your profits through custom-printed plastic boxes and containers!