This is Volume 2 of a 3 part blog series regarding part orientations when 3D Printing in FDM. In Volume 1 we covered Build Speed and Surface Quality. If you missed my last post please start with 3D Printing Orientations Guide Volume 1. This Volume we will focus on Airflow and Support Removal.
All Stratasys FDM Printers have an enclosed and heated build chamber. The goal with this is to keep the part at a uniform temperature and fairly hot for as long as possible All plastics shrink when they cool. We want our parts to cool at the same rate (uniformly) after we remove them from the build chamber. To accomplish this, Stratasys has circulation fans on all FDM printers. On the old 360mc, 400mc, and 900mc, Air circulation flowed from left to right inside the machine. We want to expose as much surface area as possible towards the sides of the machine. That is, a long part, would lay in the Y direction (front to back). If a large part was placed in the left side of the machine, the airflow would never reach parts on the right side. This would cause the parts on the right to shrink as they were built causing warpage, and could eventually come in contact with the head. In these machines we would want taller/larger parts on the right.
On the Dimension line and newer Fortus machines the Air flow moves in from both sides. We still want to expose as much surface area of our parts to the air flow (in the Y direction) but in these machines, we need to keep larger parts in the middle so the flow is no blocked.
When printing in layers we need a support structure to hold up any overhang. The support structure is one of two types, either Break Away or Soluble. Which type of support is determined by the machine and the type of material we want to run. Soluble is dissolved away in a hot Sodium Hydroxide solution (which I call the Hot Tub) for easy hands free removal. The Break Away needs to be removed manually. Looking at the images below, Orientation 1 would be good for Soluble support. Most people would navigate to this orientation simply because it would use the least amount of material. Orientation 1 would be difficult to remove if it were Break Away. Orientation 2 would be the best choice for Break Away support. Since it is one solid chunk of support, removal should be quite easily.
Still have questions? Ask them in the comments section below and stayed tuned! Next month we will be posting Volume 3 of this Guide.