Explanation of Technology
ExOne offers the very latest in additive manufacturing technology. The digital part materialization process produces complete sand cores and mold packages or fully functional metal parts directly from CAD files. It utilizes a layering technique to “print” items one layer at a time from powdered material.
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While our printers all share the same base functionality, our material processes do differ in the post-printing steps, which are explained below.
ExOne’s sand printing process uses conventional foundry-grade materials to digitally create molds & cores for sand casting, without the need for a physical pattern.
- It all starts with a CAD file provided by you or created by us.
- ExOne Systems' built-in software slices the CAD file into very thin layers (0.008 – 0.015 inch) (0.2 – 0.50 mm).
- A binder catalyst is coated on the sand which is then spread in a layer in the build box.
- The printhead jets a second component of the binder system selectively onto the spread sand layer (according to the design for that layer). When this component meets the catalyst coating on the sand, a polymerization reaction occurs which bonds the sand particles together. Curing occurs in the air without the need for external heat.
- The build box is lowered slightly.
- A new layer of sand is spread, repeating this process until all layers have been completed.
- The build box now contains a fully printed and bound mold/core, surrounded by loose sand (which acts as a support).
- The molds/cores are then depowdered, and are fully ready to be sent to the foundry to complete the casting process.
ExOne’s metal printing process creates fully functional metal parts – both for prototypes and short run production - in a matter of days.
- The process begins with a CAD file provided by you or created by us.
- ExOne Systems' built-in software slices the CAD file into very thin layers (0.004 – 0.006 inch) (0.1 – 0.15 mm).
- The machine spreads a layer of powdered metal in the build box.
- A printhead moves across the layer, depositing liquid binder according to the design for that layer.
- The layer dries and the build box is lowered slightly.
- A new layer of powdered material is spread, repeating this process until all layers have been completed.
- The build box now contains a fully printed and bound part, surrounded by loose powder (which acts as a support). The part is considered in a “green state” at this point and very fragile.
- The printed part is depowdered and goes into a furnace for sintering, which burns out the binder and fuses the metal molecules making a hardened part, approximately 60% dense.
- Metal parts are now strong and can be handled but still contain tiny internal gaps. Therefore, infiltration (a second thermal process) is required to bring parts up to full density. ExOne Materialization Systems typically utilize a bronze infiltrant.
- Thermally-processed metal parts are near 100% density and can be used functionally – not only as prototypes. A variety of finishing options are available, including protective coats and plating.
ExOne’s glass printing follows a similar process to Metal (see above), eliminating the infiltration step.