Packing Density and Cost Per Part – The Impact of Mass Reduction

When 3D printing a powder bed technology (Jet Fusion, Selective Laser Sintering) one of the most important constraints to consider is the packing density of your build. Packing density refers to the percent of the build volume that is taken up by the printed parts themselves. Depending on your technology and application it is typical to see targets set at 6 – 12%.

For tubes, enclosures, and other larger hollow parts, it is usually not the packing density that limits your print volume but the size of the parts themselves. In this case, you benefit marginally from light weighting your parts. However, the opposite is true for small and/or solid parts.

Take for instance this bracket. When machined, the designer will focus on achieving the functional geometry with as little machine time as possible. Any additional feature will lengthen the machine time in reduce overall output. When printed, 18 of these can be fit into the build volume at a packing density of 10.45%. There is still room to physically fit more brackets but adding more will increase the packing density and risk reducing the overall print quality of our job.

A build like this may cost ~$750 CAD in variable cost. So each bracket is $41.66.

Now for a quick redesign. Keep in mind, the printer will use the same material and speed to run anything inside the build volume. Therefore there is no time cost to adding features to the part.

Now, when we pack the build for a second time we can fit 40 brackets into the build at the same packing density.  This means we have more than doubled the productivity of the printer as well as halved the cost per part. These brackets would cost $18.75

This example is admittedly fairly basic however we routinely see savings that exceed the light weighting opportunity. Feel free to reach out to our team for a part review. With a simple part review and our 3D parts brokerage rates no doubt we can help dramatically improve your profitability