Enough of theory. Let’s see how a typical workflow of Figure 4 Direct Digital Molding looks like in real life. Here are a couple of parts loaded into 3D Sprint, the part preparation software for 3D Systems plastic 3D printers.
Using high-density vertical stacking we are able to pack 45 sets of these parts on a Figure 4 Modular platform. That’s a total of 90 parts.
These take a total of 5 hours and 14 mins to print.
Post processing involves 10 minutes of washing, 3 minutes of drying and 2 mins of curing.
After 15 mins of post processing, the entire stacked build is ready to broken out and supports removed. This picture shows the minimal number supports used while building the parts. Notice the tiny pieces connecting the parts. Those are the supports. They are intelligently designed so that parts support each other other than relying on the build platform to be supported.
Lesser the supports, lesser will be the time and effort required to remove them. But our San Francisco based team of advanced application engineers who were working on this were hard pressed to print a really large number of these parts in time for Formnext 2019. So they came up with a really ingenious way of cleaning supports. They dumped the entire build in a cardboard box and spun it around for 20 minutes in a cement mixer which they were using in their lab to mix new and used powder for their SLS 3D printer.
The result was 100% of all supports were removed automatically without any need for human intervention. This picture shows the parts and supports separated out.
When I heard them mention the cement mixer for the first time I thought they were joking. But then I saw the pictures. Of course, this isn’t a scientific way to doing things. But it just goes to show how much efficiency can be squeezed out of the workflow if you need to.
The supports are designed to be broken off easily by hand without leaving any remnants on the surface. Vaccum casting and injection molding also need some manual work to remove the extra bits from the parts. But I doubt you can toss the parts around in a cement mixer and expect them to come out clean.
In the next part of this series I’ll discuss part quality and cost per part.