Skip to main content

Clean and low distortion accurate welding for micro assembly

Objective



Objectives and content:

Industrial companies manufacturing miniaturised electrical, mechanical and optical components suffer from the restrictions of today's major micro-assembly techniques for metal parts, like laser micro-welding and micro-arc welding.

The problems are related to contamination and distortion:
Contamination: The present art of micro-welding leaves some debris on the products with typical dimensions of microns. With ever-decreasing dimensions of the parts the contamination gives rise to malfunction as a result of electrical leakage currents and corona discharges in electrical and electron-optical parts, and to scattering of light in optical components;
Distortion: Distortion of the parts arises due to handling of the parts and due to thermo-mechanical deformation resulting from the heat input necessary for welding. The order of magnitude of these distortions can be expressed in (several) microns. Distortion impares the dimensional accuracy of the parts, and therefore the functionality. The debris can be removed to some extent by mechanical or chemical cleaning methods. These methods will not be adequate for future products, where delicate parts will have to be assembled that will not survive cleaning. This is a severe limitation in product design.

Contamination and distortion are symptoms of an uncontrolled welding process. Particles are generated during the process originating from a turbulent, fiercely boiling melt where a keyhole is present in the molten material. The subject of CLAW is to prevent as much as possible any particle generation at the source by putting just the exact amount of energy in the metal part so as to obtain a quiet melt. Laser micro-welding and laser-guided micro-arc welding will be investigated. Research indicates that new equipment and new process parameters are needed for this. Based on this approach a novel, well-controlled micro-welding technique is to be developed, which gives virtually no contamination of micro-parts, and at the same time little thermo-m.
%The industrial issues are:
- to prevent product contamination during micro-welding, such that subsequent leaning is not necessary;
- This is achieved when the contamination levels are sufficiently low and the particle sizes are in the sub-micron or nanometre range;
- to handle and manipulate micro-parts with sub-micron accuracy in an industrial production line;
- This is achieved when the (delicate!) parts can be gripped and positioned with sub-micron accuracy within a cycle time of 2 seconds, without leaving a permanent deformation of the parts;
- to join micro-parts by laser micro-welding or micro-arc welding processes with sub-micron final accuracy;
- This is achieved when a novel, industrial scale micro-welding process is available with low distortions in the range of 0.5 m and 1 mrad in angle ,respectively and when a total assembly time of 2 seconds is realised(including handling and manipulation).Within the scope of this project the complete process chain will be investigated consisting of novel micro-part gripping and handling tools, the novel micro-welding processes, and computer support for part-design and process control. The developed process will be tested through demonstrators, these being defined by the 4 industrial end-users participating in this project. The project tasks will be accomplished through joint efforts by an interdisciplinary team of 12 project partners from 5 European countries, with expertise in the areas of process engineering, energy sources, handling systems, process control and simulation, thus covering the complete process chain of parts assembly. BE97-4855

Coordinator

SIEMENS AG
Address
6,Otto-hahn-ring 6
81739 München
Germany

Participants (11)

Cheval Frères S.A.
France
Address
Rue Des Bosquets
25045 Besançon
Commission of the European Communities
Netherlands
Address
3,Westerduinweg
1755 ZG Petten
ETA S.A. - FABRIQUE D'EBAUCHES
Switzerland
Address
11,Maienstrasse 11
2540 Grenchen
FRAUNHOFER GESELLSCHAFT ZUR FORDERUNG DER ANGEWANDTEN FORSCHUNG E.V.*
Germany
Address
Steinbachstrasse 15
52074 Aachen
GROUPEMENT D'ETUDE ET DE RECHERCHE POUR LES APPLICATIONS INDUSTRIELLES DES LASERS DE PUISSANCE
France
Address
16Bis,16 Bis Avenue De La Prieur De La Côte D'or
94114 Arcueil
HAAS-LASER GMBH & CO. KG
Germany
Address
39,Aichhalderstrasse 39
78713 Schramberg
Loughborough University
United Kingdom
Address
Ashby Road
LE11 3TU Loughborough
MC. GREGOR WELDING SYSTEMS LTD.
United Kingdom
Address
69,Fred Dannatt Road 69
IP28 7RD Mildenhall
Nederlandse Philips Bedrijven BV
Netherlands
Address
1A,kastanjelaan
5600 MD Eindhoven
RWP GmbH
Germany
Address
11,Am Münsterwald
52159 Roetgen
Swiss Center for Electronics and Microtechnology S.A.
Switzerland
Address
1,Jaquet-droz
2007 Neuchâtel