Metal drop ejecting three-dimensional (3D) object printer with a thermally insulated build platform translational mechanism
A three-dimensional (3D) metal object manufacturing apparatus has a thermally insulative layer between a platform on which an ejection head ejects drops of melted metal and a X-Y translation mechanism on which the platform is moved within an X-Y plane opposite the ejection head. The apparatus also includes a housing having an internal volume in which the platform and X-Y translation mechanism are located. In one embodiment, the thermally insulative layer is a plurality of spheres made of a thermally insulative material such as a ceramic made of zirconium dioxide or zirconium oxide. The thermally insulative layer protects the X-Y mechanism while the housing helps keep the surface temperature of the object being formed on the platform in an optimal range for bonding of the ejected melted metal drops to the object's surface.
1. A metal drop ejecting apparatus comprising:
an ejection head;
a platform positioned opposite the ejection head;
a heater configured to direct heat toward the platform;
a translation mechanism configured to move the platform;
a housing that encloses an internal volume in which the translation mechanism and platform are located;
a first actuator operatively connected to the platform, the actuator being configured to operate the translation mechanism to move the platform within the housing; and
a plurality of thermally insulative members positioned in a portion of the internal volume of the housing between the platform and a floor of the housing.
2. The apparatus of claim 1 wherein the ejection head is configured for fluid connection to a source of melted bulk metal.
3. The apparatus of claim 2 wherein the translation mechanism is a X-Y translation mechanism configured to move the ejection head in an X-Y plane parallel to the platform and positioned between the ejection head and the platform.
4. The apparatus of claim 3 wherein the housing has at least one wall, the wall and the floor of the housing encloses an internal volume in which the X-Y translation mechanism and the platform are located.
5. The apparatus of claim 4 further comprising:
a second actuator operatively connected to the ejection head, the second actuator being configured to move the ejection head bidirectionally along an axis perpendicular to the X-Y plane within the internal volume of the housing.
6. The apparatus of claim 5 further comprising:
a controller operatively connected to the heater, the first actuator, the second actuator, and the ejection head, the controller being configured to:
operate the first actuator to operate the X-Y mechanism to move the ejection head in the X-Y plane within the internal volume of the housing;
operate the heater to direct heat toward the platform; and
operate the ejection head to eject drops of melted bulk metal to form a metal object on the platform.
7. The apparatus of claim 6 , the controller being further configured to operate the heater to maintain an upper surface temperature for the object being formed on the platform within a temperature range of about 400° C. to about 550° C.
8. The apparatus of claim 7 further comprising:
a temperature sensor configured to generate a signal indicative of a temperature within the internal volume of the housing; and
the controller is further configured to compare the signal generated by the temperature sensor to an upper temperature limit and a lower temperature limit to operate the heater and maintain the upper surface of the object being formed in the temperature range of about 400° C. to about 550° C.
9. The apparatus of claim 8 wherein the heater is an infrared heating tube.
10. The apparatus of claim 8 wherein the heater is a convective or ceramic heater.
11. The apparatus of claim 1 wherein each thermally insulative member has a spherical shape.
12. The apparatus of claim 1 wherein each thermally insulative member has a thermal conductivity in a range of about 1.8 W/m·K to about 2.2 W/m·K.
13. The apparatus of claim 1 wherein each thermally insulative member has a diameter of about 1/16 of an inch to about ½ of an inch or about 2 mm to about 6 mm.
14. The apparatus of claim 13 wherein each thermally insulative member has a diameter of about 5 mm.
15. The apparatus of claim 1 wherein each thermally insulative member is formed of a material including a ceramic that includes zirconium dioxide or zirconium oxide.
16. The apparatus of claim 15 wherein each thermally insulative member has a spherical shape.
17. The apparatus of claim 16 wherein each spherical thermally insulative member has a diameter in a range of about 2 mm to about 6 mm.
18. The apparatus of claim 1 wherein the housing is formed of a material including quartz glass.
19. A metal drop ejecting apparatus comprising:
an ejection head configured for fluid connection to a source of melted bulk metal;
a platform positioned opposite the ejection head;
a heater configured to direct heat toward the platform;
a X-Y translation mechanism configured to move the platform in an X-Y plane parallel to the platform;
a housing having at least one wall and a floor that encloses an internal volume in which the X-Y mechanism and platform are located;
a first actuator operatively connected to the platform, the actuator being configured to operate the X-Y translation mechanism to move the platform in the X-Y plane;
a second actuator operatively connected to the ejection head, the second actuator being configured to move the ejection head bidirectionally along an axis perpendicular to the X-Y plane within the internal volume of the housing;
a plurality of thermally insulative members positioned in a portion of the internal volume of the housing between the platform and the floor of the housing; and
a controller operatively connected to the heater, the first actuator, the second actuator, and the ejection head, the controller being configured to:
operate the first actuator to operate the X-Y mechanism to move the platform in the X-Y plane within the internal volume of the housing;
operate the heater to direct heat toward the platform to maintain an upper surface temperature for the object being formed on the platform within a temperature range of about 400° C. to about 550° C.; and
operate the ejection head to eject drops of melted bulk metal to form a metal object on the platform.
20. The apparatus of claim 19 further comprising:
a temperature sensor configured to generate a signal indicative of a temperature within the internal volume of the housing; and
the controller is further configured to compare the signal generated by the temperature sensor to an upper temperature limit and a lower temperature limit to operate the heater and maintain the upper surface of the object being formed in the temperature range of about 400° C. to about 550° C.
21. The apparatus of claim 20 wherein the heater is an infrared heating tube.
22. The apparatus of claim 21 wherein each thermally insulative member has a thermal conductivity in a range of about 1.8 W/m·K to about 2.2 W/m·K.
23. The apparatus of claim 22 wherein each thermally insulative member has a spherical shape.
24. The apparatus of claim 23 wherein each thermally insulative member is formed of a material including a ceramic that includes zirconium dioxide or zirconium oxide.
25. The apparatus of claim 24 wherein the housing is formed of a material including quartz glass.