Plastic flow simulation can help manage the complexity of plastic injection molding when an experienced engineer performs and interprets the analysis. Proper analysis can eliminate unplanned costs.
Plastic injection molding is much more complicated than it appears to the untrained eye. The resin choice, mold design, process parameters, and part design must work harmoniously to produce a quality part that meets specifications and will function as intended. Plastic flow simulation, also called mold flow analysis (MFA), helps skilled and experienced engineers ensure all process components work together correctly. Choosing the right partner can reduce your frustration and save you money.
The Complexity of Plastic Injection Molding
Your injection molder must consider many variables when manufacturing your product. Having a clear and comprehensive understanding dramatically reduces the risk of part defects. Plastics used in injection molding are vast and can be categorized as thermoplastic or thermoset plastics, depending on how the chemical bonds react. Between them, there are hundreds of polymers and combinations of polymers. The engineer must be familiar with the material and flow properties (melt point, viscosity, shear flow, elastic effects, shrinkage, and more) and how process variations and mold design influence the flow. Any additive and material modifications can affect how the resin will react.
The process parameters can also impact how the resin reacts (e.g., the temperature may affect viscosity, crystallinity level, or final product strength). The injection molding process involves control of temperature, pressure, fill cycle times, and other variables, which can be impacted by the material choice, mold design, and product design.
The mold design (gate placement, venting, injector pins, etc.) is critical for the proper flow of resin into the chamber and release of the product, directly influencing product success or failure. The part design (e.g., wall thickness, bosses, undercuts can impact, etc.) plays a crucial role in product outcome as well.
Plastic flow simulation provides a computerized depiction of how molten plastic will flow into each mold cavity while considering all the interactions occurring simultaneously. Issues such as short shots, bubbles, warpage, and other consideration, such as knit and meld lines, may be predicted and corrected by controlling the gate position, injection speed, and other processing conditions.
Plastic Flow Simulation Reduces Unexpected Costs
There are many benefits to mold flow analysis, and catching errors early on can pay off considerably in the long run. Author and design for manufacturability expert Dr. Davis Anderson says that at the design stage, only 8 percent of the budget has been spent, but the design determines the part’s manufacturability, which makes up 80% of the budget. He explains the “Rule of 10,” which states that it costs ten times more to fix defects at every successive stage of manufacturing. This means if the part costs $X, the cost to find and repair a defect is $10x at the next stage, $100x at the next, and so on.
Of course, these numbers aren’t exact for every situation, but they demonstrate how quickly costs can accumulate if issues aren’t resolved early in development. Changing a design is much less expensive than reworking a mold or performing secondary operations at assembly if parts don’t fit as intended. By performing plastic flow simulations, engineers can fix issues early in the development stage, preventing substantial costs later. However, it should be pointed out that mold flow analysis can also help solve problems with an existing mold. If your current molder is struggling to get good parts, transferring your molds to a molder skilled with simulation can also save you money.
Who is Performing the Simulation Matters
The simulation is only as good as the engineers performing it. They must be proficient at analyzing the data to drive design choices. Choosing the right plastic injection molder to do these simulations is critical.
The analysis of a simulation is sometimes accurate and sometimes not. A good simulation model requires good inputs. An experienced engineer will understand the inputs required to properly model the part and mold geometry, the processing conditions, and the material properties, which could have up to 10 sets of inputs.
A skilled engineer will understand the limitations of the data and the simulation analysis. For example, is there accurate rheology data (flow properties) for your resin with additives? Using data from a similar material may not provide the expected results. Uncertain or improper inputs will lead to an analysis that looks nice on paper and parts that can’t be manufactured.
Your Experts In Plastic Flow Simulation
At SEA-LECT, our expert engineers, mold makers, and analysts use MOLDFLOW® software for mold flow analysis. Our experts lean on years of experience to optimize your part. In addition, we can offer advice on design and the best technology and materials to ensure your product can meet your expectations. We want to reduce your frustration and find ways to save you money.
Our expertise in plastic injection molding has allowed us to provide solutions when others have failed. Whether that is developing a bioplastic luggage tag, creating professional musical instruments, or problem-solving color matching for an existing product, we deliver next-level solutions for challenging problems.
Many companies will hold their knowledge tight to their chests, but as experts in plastic injection molding, we believe that sharing this knowledge strengthens our community. Our experts are teachers. We have initiated an apprenticeship program to pass on our expertise to the next generation and are also involved with local middle and high schools. We also support continuous learning for teachers through our STEM externship, giving them firsthand insight into 21st-century skills needed in the modern STEM workplace.
We also want to help those just getting started with designing plastic products. Volunteering our expertise through the NW Innovation Resource Center to problem-solve design challenges, identify flaws, source materials, and customize solutions to get new start-ups ready for the investor stage, gives those starting out a leg up.
If you are ready for a partner with proven results that is confident in its mold flow analysis and injection molding expertise, connect with us to learn how we can help with your current plastic injection molding challenges.