How do I use the results of Gas Assist Analysis to save money?

Moldflow Corporation introduced Gas Assist Analysis to its suite of software modules about 15 years ago. In the last two years, this module has evolved dramatically with the introduction of Gas 3D. Even with the increased capabilities, a question remains for tool builders: How do I use the results to save money?

Inputs

Before we get into the results, we need to address what is required to perform an analysis. If you have had any analysis performed in the past, you know that you need a CAD file and a specific material to get started. For Gas Assist Analysis, you will also need to define the gas injection process method - whether the molder is using gas volume control or gas pressure control. The analysis gives us the flexibility of where to gate the part and where to inject the gas. We also must define when to inject the gas based on the percentage of the cavity volume filled.

Results

With so many inputs to control, getting useful results really depends on what you want out of the analysis. We, as a company, spend a lot of time upfront working with our customers to define the objectives of the analysis. If we know what success looks like, we can save time by focusing on particular needs. Very few projects have the exact same needs, but there are some common themes among gas assist projects.

Optimizing gas injection locations is the most frequent objective for tool shops. We can adjust the number and location of gas injection points to achieve a particular wall thickness or part weight. The gas injection pressure and timing have a tremendous impact on the shape of the gas penetration.

When the gas injection location is fixed by the part design, a common objective is defining the gas injection process to minimize part weight. We can also define the point at which blowout occurs.

Savings

As with most simulation tools, the cost savings comes in the form of minimizing cycle time and material usage. For tool builders, you have the added savings of knowing you won't have to change gating for the plastic or the gas after the tool is built. With the wide range of results available, it is essential that you know what you want out of the analysis before you start.