Quality control method for regulating the operation of an electromechanical apparatus, for example an EBM apparatus, in order to obtain certified processed products

Patent metadata

Field	Value
Publication number	US-10488852-B2
Application number	US-201615557415-A
Country	US
Kind code	B2
Filing date	Mar 14, 2016
Priority date	Mar 12, 2015
Publication date	Nov 26, 2019
Grant date	Nov 26, 2019

Abstract

The invention relates to a method for regulating the operation of an electromechanical apparatus ( 1 ), for example an EBM apparatus, in order to obtain certified processed products, wherein it is provided an initial calibration step that is intended to check the proper functioning of all the component parts of the apparatus ( 1 ) structured to ensure the complete functionality and a subsequent quality control step carried out on the obtained products by the carried out working process. The method entails the following steps:
defining a plurality of measurement parameters relating to the component parts of the apparatus; measuring at least some of said parameters by means of sensors and/or measurement indicators related to said parameters during at least one processing phase performed by the apparatus; performing a quality control step on the obtained products after the working process obtaining data on any deviation from the expected quality; comparing the detected measurements of said parameters and data on any deviation from the expected quality with corresponding values of reference parameters available for that specific apparatus and for those products; detecting any deviations in one or more of said parameters or said data with respect to the values of the reference parameters; computing, on the basis of such differences, a total correction and regulation value; applying said total correction and regulation value preferably to only one of said parameters prior to the subsequent process, for example to the generation energy of the electrons beam ( 3 ). Basically, the method of the present invention allows obtaining semi-finished products free from structural defects by means of a primary check of the correct functioning of the various component parts of the apparatus (calibration procedure), a secondary check of the operational effectiveness of the process itself (operational qualification procedure) and a further final check of the process stability and repeatability within a process window (performance qualification).

First claim

The invention claimed is:

1. A method for regulating an operation of an electromechanical apparatus in order to obtain certified processed products, of the type in which it is provided an initial calibration step that is intended to check the proper functioning of all component parts of the apparatus structured to ensure the complete functionality and a subsequent quality control step carried out on obtained products by a carried out working process, the method comprising:
defining a plurality of measurement parameters relating to component parts of the apparatus,
wherein the parameters are set in a predetermined interval between a series of maximum and minimum values;
measuring at least some of said parameters by means of sensors and/or measurement indicators related to said parameters during at least one processing phase performed by said apparatus, wherein the sensors and/or measurement indicators are coupled to an apparatus control unit;
performing a quality control step on the obtained products after the working process, and obtaining data on any deviation from an expected quality;
comparing detected measurements of said parameters and data on any deviation from the expected quality with corresponding values of reference parameters available for that specific apparatus and for those products;
detecting any deviations in one or more of the measured parameters or the data with respect to the values of the reference parameters;
computing, on the basis of the detected deviations, a total correction and regulation value;
applying said total correction and regulation value to a generation energy of an electron beam of an EBM apparatus; the generation energy of the electron beam being obtained from correlation formulas between the parameters associated to the component parts of the apparatus based on the following relations:

T
∝

E
A

E
∝

t
·
I
·
V

wherein:
T is a temperature of the molten layer;
E is an energy applied to the electron beam;
A is a fusion area;
t is a time of the fusion;
I is a current of the correlation filament of the electron beam; and
V is a potential across the filament;
the control unit of the apparatus being able to compute on the basis of said formulas, and by means of an automated procedure, a type of energy to apply to the electron beam to realize processed products corresponding to a predetermined quality level,
wherein the maximum and minimum value for each parameter is set according to said formula, and
wherein the definition of the plurality of measurement parameters relating to component parts of the apparatus is modifiable during the useful life of the apparatus and also after an application of said total correction and regulation value.

2. The method according to claim 1 , wherein the regulation of said generation energy of the electron beam is realized by means of an adjustment of an electric potential and/or current applied to a generation system of said electron beam.

3. The method according to claim 1 , wherein a possible drift of just one parameter related to a mechanical structural part of the apparatus provides for a correction and adjustment of that one single structural mechanical part.

4. The method according to claim 1 , wherein the step of quality control of the obtained products by means of said at least one working process provides for a predefined series of dimensional, chemical-physical and resistance controls.

5. The method according to claim 4 , wherein said quality control provides at least the following tests on specimens of the obtained products from the working process:
Test about the dimensional correspondence L;
Tensile tests in the z direction;
Tensile tests in the directions x and y;
Complete chemical analysis;
Porosity, discontinuities or micrograph evaluation;
Visual, adhesive and compression analysis of the structural network.

6. The method according to claim 1 , wherein a measuring phase of at least some of the parameters is performed by means of sensors and/or measurement indicators mounted on the same apparatus.

7. The method according to claim 1 , wherein measurements of said parameters and the values of the reference parameters are stored in a memory portion associated to a command and control unit of the apparatus.

8. The method according to claim 4 , wherein said quality controls on the obtained products can be regulated by sampling at a fixed rate or on first production lots.

9. The method according to claim 4 , wherein for a pre-heating phase the following correlation formula is used:

Theme
Equation

Pre- heat- ing

E
=

V
·

current
speed

·

(

line
⁢

⁢

offset
·

(

number
⁢

⁢
of
⁢

⁢
repetitions

+

line
⁢

⁢
order

)

)

Assignees

• Limacorporate Spa

Inventors

• Pressacco Michele
• Regis Marco

Classifications

• G05B19/41875 Primary

  characterised by quality surveillance of production · CPC title

• B22F12/90

  Means for process control, e.g. cameras or sensors · CPC title

• B22F10/85

  for controlling or regulating additive manufacturing processes · CPC title

• B22F10/38

  to achieve specific product aspects, e.g. surface smoothness, density, porosity or hollow structures · CPC title

• B22F10/362

  for preheating · CPC title