Design and Manufacturing of Injection Molded Products

In this interview with Martin Solina, director of product management, manufacturing at Altair, we explore how to assure robust design and manufacturing of injection molded products. To learn more, download the “Eguide to Injection Molding.”

Injection molding is an established manufacturing technique used across numerous industries, so what competitive advantages do simulation technologies offer to the design and manufacturing of injection molded products?

  1. Better decision making – In general, when it comes to questions about design and manufacturing, simulation helps customers make better decisions because as a designer you have to consider not only structural performance but also the manufacturability of the part. Applying simulation early in the design stage leads to better products that are also easy to manufacture and defect-free. By making these better decisions early can only help you save time and money, leading to better products.
  2. Robust design with lower reject rates – Across most manufacturing industries, not only injection molding, component reject rates tend to be around 5% to 10% but can be even higher in some complex shaped parts. Using simulation technologies can effectively reduce reject parts to considerably lower values. By detecting defective parts at an early stage, changes to the part or processes can be made easily, whereas if companies only detect these defects very late when they are already in production, it becomes very expensive situation to recover from both in terms of time and cost. That’s why reducing reject rates is so very important.
  3. Faster products to market – Using simulation techniques can significantly reduce the number of iteration loops between design and manufacturing teams which is important because, in so many cases, it’s these loops that are responsible for delaying the time to market. If we design a part and send it to be manufactured, but the production team says we cannot make this part as it is, then it has to be redesigned. That doesn’t only involve manufacturing, it can involve revisiting other analyses that also cause delay. Using simulation to check a part can actually be manufactured before sending it to be produced saves a lot of time.

How important is design for manufacturing?

For me it’s a key point. To implement simulation early into the design stage is putting these technologies directly into the hands of the designers. It is really important to avoid iterations loops between design and manufacturing, as I said, to help reduce the time to market. But it also gives designers the opportunity to learn how to design for manufacturing to reduce time and costs by understanding more about the manufacturing processes and constraints. We’ve seen that many companies’ designers are beginning to use simulation techniques not only to check manufacturability but also to modify the design. “Think manufacturing” early in design adds in quality and part performance factors that can improve manufacturability.

Analysis software is often thought of as virtual testing, can you explain a little more about how simulation reduces cost and drives better decisions?

Traditionally simulation has been used as virtual testing to answer, for example, “what if” I change this? Virtual testing consists of creating the whole system – the part, the entire mold with runner system and cooling lines, with everything defined exactly as we have been doing in the real life. Then, simulation is performed to check if the part has any problems, if the cooling system works fine, etc., and this is what we call virtual testing.

To test exactly the same things that we do in real life, but in a digital world brings huge benefits because it is so much faster and cheaper to make a mold in the virtual world. And the real benefit can be observed by bringing together different teams, the customer, the designer, the manufacturing process people, and getting them all using simulation tools early cuts through time wasted on iterations.

It lets everyone work together to predict problems and resolve them at the start of processes and not find them in late stages. We are changing how design and manufacturing work and have many use cases where integrating simulation in the early stage of structural component design is becoming a key step in their design stage.

We reduce costs by basically applying simulation techniques earlier to avoid having to duplicate processes and redo things when we make a change. The idea is simple: identify and make changes as early in the design chain as possible.

You work with customers in many different industries. Have you developed a standard workflow that translates across different organizations?

Over the last 10 to 15 years, I’ve been working in different industries with different processes, not only polymer injection molding but also metal casting. We realized that although designers and CAE analysts have different goals, but both require easy-to-set- up and use simulation. Originally, say 10 years ago, simulation was only for specialists, only people who knew about simulation techniques and had that type of expertise could use simulation. Today, we are putting advanced simulation technologies in the hands of designers who don’t need to be experts in simulation techniques. We’ve been changing the way we design our simulation software so that users no longer need to know about complex parameters, meshing and this kind of thing. What we have created is a 5-step simulation workflow that leads the user to easily define, set-up and run a simulation.

What our injection molding technology offers is two different flavors of simulation: We can run a “fast” simulation, or a quick analysis to let the user understand the basics of the injection molding process or a “detailed” simulation, which provides much more information from a more complex analysis.


What is the one take-home message you want everyone to consider when embarking on an injection molding manufacturing project?

First off, I’ve probably said this many times already, use simulation as early as you can. Whereas in the past it was used only to virtual test or to validate, now simulation has really become my new “workplace buddy” that’s there to help when we have a design for a part and when we ask: Where do I put the gate so it fills properly? What and where will my part have a possible defect? How can I change my design to avoid these types of defects? Can my part be manufactured? How can I change my design to improve the manufacturability, reduce cost, etc.? All before we get to the factory floor.


Integrating simulation in our end-to-end full workflow design process, or within the entire life of the part, is very important for the future. Having the means to connect optimization, motion analysis, with manufacturing is already being applied in some forward-thinking industries to create really robust, high-performance components

One final thought: Don’t be afraid of simulation! Some people still have the idea that it’s complex, hard to use, something that they don’t know enough about, don’t know how, or lack the confidence to use. Today simulation can be used by anyone dealing with real parts, be they a designer, manufacturer, QA, structural analysts, estimators, or sales teams.