Appendix I
ZCast Design Guide - 18
6.10 Wall Thickness Guidelines
As indicated in the section 6.3 ‘Shelling Your Mold’, thinner sections bake quicker and more
efficiently. Maintain the following guidelines for modeling your mold with thin walls:
• Any mold wall that is in contact with metal should be no less then 0.5” (12mm) thick, and
no more then 1” (25mm) thick (with exceptions below).
• The mold should be able to sit square on a base for pouring.
• Ribs should be added where necessary to provide rigidity (typically in the drag, where a
supporting surface is being built up). Ribs should be about 0.5” (12mm) thick.
• Maintain large enough areas for clamping.
• Use off the shelf pouring cups and risers
6.11 Pouring Sleeves & Risers
A pouring sleeve is a tapered cylinder made of a refractory material with a ceramic filter at the
base. The filter is removable, so the pouring cup can be used as a riser as well. There is no
requirement to use Sleeves, but the convenience is an advantage.
Pouring sleeves are inexpensive, come in several sizes, have a variety of filters available, and
work well with ZCast molds. A conical seat should be printed in the mold to accommodate and
position the Sleeve. The Sleeves should be attached to the ZCast mold with a foundry adhesive
or core paste. For safe measure they can be clamped or wired in place to prevent shifting during
pouring.
Additionally, you can design a pouring sleeve to be integral as part of your ZCast mold. Be sure
to make allowances for filter insertion to help alleviate impurities when pouring.
6.12 Chills
Chills will be familiar to experienced foundrymen. The purpose of a chill is to help rapidly solidify
the molten metal in a portion of a casting. Controlling the solidification rate in this manner helps
to control the grain structure; keeping a tight, fine structure. The result is a sound casting with a
uniform distribution of the alloying elements.
Chills can be used in ZCast molds in much the same way they are used in traditional sand
casting. While they can be complicated, externally cooled components, they are often as simple
as steel or iron blocks which can be inserted into cavities designed (or cut) into a ZCast mold.
6.13 Printing
For general printing techniques, you should refer to the User Manual for your printer and the
ZPrint System Software Manual.
• When choosing your powder type (in “3D Print Setup”), simply select ZCast
500 from the
powder list (it will show up on the list for any printer that is capable with the proper
upgrade). The proper settings for saturation, layer thickness and scaling factors are
already set for you.
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