Injection molding is often the manufacturing process of choice for companies that require mass-produced plastic parts, as it is cost efficient to manufacture thousands or hundreds of thousands of parts. In fact, plastic injection molding is continually looked at as an alternative to machined metal parts when feasible, as long as part functionality is not compromised. Injection molding is used worldwide to mass produce various parts and critical components for a wide variety of industries including:
- Automotive
- Aerospace
- Medical
- Pharmaceutical
- Consumer Goods
- Consumer Electronics
Engineers in these industries, and many others around the globe, are continually researching ways to improve their plastic injection molding process for improved quality and cost reduction. There are basically two areas for evaluation of implementing cost-effective efficiencies; the injection mold itself and the injection molding process.
As an experienced injection mold making and plastic injection molding company, QT Manufacturing offers the following considerations when optimizing your injection molding process for maximum cost effectiveness.
Injection Mold Design Considerations
The key to a quality part begins with a quality tool. To anyone with experience in injection molding or mold making, this is rule number one. The largest expense of an injection molding project is typically the mold. Be sure to begin with a well-thought-out constructed mold, designed to save money while meeting all customer specifications.
Some of the most important points to consider for mold design entail:
Part Design
– Carefully evaluate all critical part dimensions, such as thin walls that may succumb to underfill or complex part designs that require cams and lifters during the molding process. Understanding the best method of tool construction for critical areas prior to cutting steel can save a lot of money in tool adjustments later.
Molding Environment
– The molding environment includes the press the tool will run in, the orientation of the clamping system, the location of water fittings for the cooling system, and the location of electrical connectors, to name just a few. An experienced mold designer will consider these and all other environmental considerations prior to beginning mold construction.
Ejection System
– The ejection system is of critical importance in mold design, as the location of ejector pins is crucial to proper ejection without damaging the part. Some complex part designs require the use of lifters to aid the ejection process for quick and efficient ejection without causing part damage. The most effective ejection system should be designed prior to mold construction.
Plastic Resin
– There are literally thousands of plastic resins to choose from, each with specific properties for viscosity, melt flow, strength, durability, elasticity, shrink rate, surface finish and many more. The type of resin specified is critical information for mold design as different polymers have varying shrink rates, which changes the dimensions of the part upon cooling. Construction of the mold cavities must always account for shrink rate to end up with a component that meets customer specifications.
Resin properties play a vital role in part quality and must be a top consideration when designing your injection mold. An experienced injection molder will have the knowledge of how particular resins melt and fill cavities during the molding process.
Consider a Hot-Runner Tool
A hot-runner tool is typically more expensive to construct, but can save a considerable amount of money over the long run, especially when an expensive thermoplastic resin is required in the molding process. The elimination of runners with a hot-runner tool can provide significant savings on high volume requirements. Doing the math to compare a cold-runner to a hot-runner tool proves beneficial in many injection molding applications.
These are only a handful of the most important considerations when designing your injection mold. QT Manufacturing utilizes a thorough checklist with these and many more design considerations as part of our Advanced Product Quality Planning (APQP) procedures incorporated into our Quality Management System.
As an ISO9001:2008 and AS9100C registered mold making and injection molding manufacturer, we conduct a thorough review of your injection mold design to ensure maximum productivity and profitability prior to cutting steel. Knowing the best answers to all these considerations is key to saving money when constructing your tool.
If you are unsure of the best part design, or require assistance with reverse engineering for new projects, let us assist with your design considerations or with a prototype tool.
Consider a Prototype Tool
For new projects or those requiring a new material, design or function, constructing a prototype tool can provide valuable insight into requirements for a production mold. QT Manufacturing offers prototype services with quick turn-around from our master toolmakers and machinists. We explore all options for you and assist with the most beneficial mold design for your project.
Once you have the best tool design, you can optimize plastic processing techniques for even more cost efficiencies.
Improvements in Cycle Time
As the saying goes, time is money, and that surely applies to plastic injection molding. For high-volume programs, shaving even a few seconds from your cycle time reaps big benefits in the bottom line. QT Manufacturing employs a team of highly skilled design and processing engineers with experience in optimizing the molding process for maximum efficiency. We are experienced at improving cycle times without jeopardizing part quality or functionality.
Faster cycle times equate to higher profitability, quicker lead times and on-time deliveries.
