A question was asked if Mitsubishi - Matsuura Machinery had a closed-loop system:
http://www.makrum.fi/wp-content/uploads/2012/...-82012.pdf
Not even close. These cameras, similar to Arcam LayerQam, that claim to have some "feedback" or "continuous quality assurance" is not IPQA. IPQA is "in-proces". Any manufacturer can use any sort of verbiage but to claim "in-process" feedback the function must affect the welding process while it happens at the exact moment in time. This is why acoustic energy was studied in weld pool heat uniformity:
http://jjsigmalabsblog.blogspot.com/2013/12/a...nergy.html
"in-process" functioning is described in PrintRite3D patent:
“The frequency sensor can directly detect the variation in weld pool volume on account of a frequency shift. [0056] i. Once a shift is detected, the real-time controller 14 can have an internal logic table that analyzes the nature, sign and magnitude of the change. Based on pre-determined rules that can be determined by a distillation of multiple modelling runs or an expert system or otherwise generated based on experimental data, the controller 14 can decide which machine variable will be the best choice for adjustment so that the weld pool volume will return to its target value . These so-called "response vectors" can define a desired control strategy for a given change in weld pool characteristics. [0057] j. The controller 14 can then make changes to the process variables welding machine tool 15. [0058] k. New measurements can be made with the sensing system and steps above can be used to recalculate the weld pool volume, and the process continues indefinitely as long as the welding process 10 is in progress .”
The cameras may be looking at porosity. But porosity is the end result of unmelted / incorrect weld pool heating. When buried in the additive process, subsurface pores are not correctable by hot isostatic pressure (heat + pressure treatment):
SUBSURFACE porosity
http://www.industrial-lasers.com/articles/pri...ation.html
The pictures on the last page of standard materials by Arcam have microscopic pictures to access density. Notice the use of "melt pool". Look at the recommendations for pressure, heat quantity, and time for hot isostatic pressure treatments for each material. The camera takes picture of cuts sliced in longitudinal and transverse sections of errors and results after post-process correct.
http://www.arcam.com/technology/electron-beam...materials/
I say errors because:
"The nature of the rapid, localized heating and cooling of the melted material enables near-forged material properties when proper heat treating is applied."
http://www.industrial-lasers.com/articles/pri...ation.html
Thus, the melt pool was not uniform and unmelted metal powder was left to be buried beneath the surface.
http://www.makrum.fi/wp-content/uploads/2012/...-82012.pdf
Not even close. These cameras, similar to Arcam LayerQam, that claim to have some "feedback" or "continuous quality assurance" is not IPQA. IPQA is "in-proces". Any manufacturer can use any sort of verbiage but to claim "in-process" feedback the function must affect the welding process while it happens at the exact moment in time. This is why acoustic energy was studied in weld pool heat uniformity:
http://jjsigmalabsblog.blogspot.com/2013/12/a...nergy.html
"in-process" functioning is described in PrintRite3D patent:
“The frequency sensor can directly detect the variation in weld pool volume on account of a frequency shift. [0056] i. Once a shift is detected, the real-time controller 14 can have an internal logic table that analyzes the nature, sign and magnitude of the change. Based on pre-determined rules that can be determined by a distillation of multiple modelling runs or an expert system or otherwise generated based on experimental data, the controller 14 can decide which machine variable will be the best choice for adjustment so that the weld pool volume will return to its target value . These so-called "response vectors" can define a desired control strategy for a given change in weld pool characteristics. [0057] j. The controller 14 can then make changes to the process variables welding machine tool 15. [0058] k. New measurements can be made with the sensing system and steps above can be used to recalculate the weld pool volume, and the process continues indefinitely as long as the welding process 10 is in progress .”
The cameras may be looking at porosity. But porosity is the end result of unmelted / incorrect weld pool heating. When buried in the additive process, subsurface pores are not correctable by hot isostatic pressure (heat + pressure treatment):
SUBSURFACE porosity
http://www.industrial-lasers.com/articles/pri...ation.html
The pictures on the last page of standard materials by Arcam have microscopic pictures to access density. Notice the use of "melt pool". Look at the recommendations for pressure, heat quantity, and time for hot isostatic pressure treatments for each material. The camera takes picture of cuts sliced in longitudinal and transverse sections of errors and results after post-process correct.
http://www.arcam.com/technology/electron-beam...materials/
I say errors because:
"The nature of the rapid, localized heating and cooling of the melted material enables near-forged material properties when proper heat treating is applied."
http://www.industrial-lasers.com/articles/pri...ation.html
Thus, the melt pool was not uniform and unmelted metal powder was left to be buried beneath the surface.
Now, the conflict between the statement that SUBSURFACE porosity is not correctable by HIP stated here:
http://www.industrial-lasers.com/articles/pri...ation.html
and Arcam showing microscopic pictures of sliced metals:
http://www.arcam.com/technology/electron-beam...materials/
Arcam only describes the result of HIP as "finer grain" .
So, which source are we to believe? Should we believe Indutrial-Laser.com or Arcam?
The article submitted to Industrial-Laser was written by GE Aviation engineers:
Todd Rockstroh: http://www.linkedin.com/in/toddrockstroh
David Abbott: http://www.linkedin.com/pub/dave-abbott/a/763/a
Ken Hix: http://www.linkedin.com/in/kenhix
These GE engineers say that porosity is corrected by:
"Subsurface porosity can be compensated through machine calibration, settings, and tool-path programming ."
They specifically stated, "... unfused powder near the surface of the component, which occasionally breaks through the surface and therefore cannot be healed by the HIP process ."
It's the welding machine correction by a controller to ensure the welding process that will create near-forged material properties. Hence, PrintRite3D, the closed-loop process controller.
http://www.industrial-lasers.com/articles/pri...ation.html
and Arcam showing microscopic pictures of sliced metals:
http://www.arcam.com/technology/electron-beam...materials/
Arcam only describes the result of HIP as "finer grain" .
So, which source are we to believe? Should we believe Indutrial-Laser.com or Arcam?
The article submitted to Industrial-Laser was written by GE Aviation engineers:
Todd Rockstroh: http://www.linkedin.com/in/toddrockstroh
David Abbott: http://www.linkedin.com/pub/dave-abbott/a/763/a
Ken Hix: http://www.linkedin.com/in/kenhix
These GE engineers say that porosity is corrected by:
"Subsurface porosity can be compensated through machine calibration, settings, and tool-path programming ."
They specifically stated, "... unfused powder near the surface of the component, which occasionally breaks through the surface and therefore cannot be healed by the HIP process ."
It's the welding machine correction by a controller to ensure the welding process that will create near-forged material properties. Hence, PrintRite3D, the closed-loop process controller.
