Metal powder bed additive manufacturing apparatus and methods
A powder bed fusion apparatus includes a build platform movable in a build sleeve, the build platform for supporting a bed of metal powder, a powder layer formation device for forming layers of metal powder to form the bed, a scanner for directing an energy beam to selected regions of each layer to consolidate the metal powder and a radio-wave generator arranged to surround the metal powder and generate radio waves to heat the metal powder that forms the bed.
1. A powder bed fusion method comprising
lowering a build platform in a build sleeve,
forming layers of metal powder to form a bed,
operating a scanner to direct an energy beam to consolidate the metal powder at selected regions on each layer and heating the metal powder within a radio wave generator that surrounds the metal powder,
heating the metal powder within a radio wave resonator that surrounds the metal powder using radio waves at a resonant frequency of the radio wave resonator, and
sweeping a frequency of the radio waves across a range of frequencies to identify and/or track the resonant frequency.
2. A powder bed fusion method according to claim 1 , wherein the radio wave generator is controlled to generate resonant frequencies between 100 MHz to 500 MHz.
3. A powder bed fusion method according to claim 1 , comprising altering the frequency of the generated radio waves to track changes in the resonant frequency of the radio wave resonator as the bed of metal powder is formed.
4. A powder bed fusion method according to claim 1 , comprising setting a frequency of the generated radio waves in response to a signal generated by a sensor.
5. A powder bed fusion method according to claim 1 , wherein the radio wave generator comprises a radio-wave cavity containing the metal powder.
6. A powder bed fusion method according to claim 5 , wherein walls of the radio-wave cavity are formed by walls of a build chamber, a build sleeve and a build platform of a powder bed fusion apparatus.
7. A powder bed fusion method according to claim 1 , wherein the radio wave generator is controlled to generate resonant frequencies between 30 MHz to 500 MHz.
8. A powder bed fusion apparatus comprising
a build platform movable in a build sleeve, the build platform being configured to support a bed of metal powder,
a powder layer formation device configured to form layers of metal powder to form the bed,
a scanner for directing an energy beam to selected regions of each layer to consolidate the metal powder, and
a radio-wave generator arranged to surround the metal powder and generate radio waves to heat the metal powder that forms the bed, wherein
the radio-wave generator comprises a radio-wave resonator that surrounds the metal powder and the radio wave generator is arranged to operate at a resonant frequency of the radio wave resonator when containing a bed of metal powder,
the radio wave generator comprises a signal generator and a controller configured to carry out the powder bed fusion method of claim 1 .
9. A powder bed fusion apparatus according to claim 8 , wherein the radio-wave generator is arranged to generate radio waves between 30 MHz to 500 MHz.
10. A powder bed fusion apparatus according to claim 8 , wherein the controller controls the signal generator to set the frequency of the generated radio waves in response to a signal generated by a sensor.
11. A powder bed fusion apparatus according to claim 8 , wherein the radio-wave generator comprises a radio-wave cavity containing the metal powder.
12. A powder bed fusion apparatus according to claim 11 , wherein walls of the radio-wave cavity are formed by walls of a build chamber, the build sleeve and build platform.