Search results for "Soldering"
showing 4 items of 4 documents
Spatial and thermal measurements using thermography CCD during HF soldering of metallic tubes
2002
High frequency soldering allows high production speed, contactless heating and good quality of the weld. The speed limit of soldering is principally imposed by a good drive of the metal in the profiling machine. To control a HF soldering process, the authors propose a new method and approach which consists in controlling the temperature with a thermal image acquisition system developed in their laboratory. Their computer vision, described in this paper, is based on CCD thermography. This technology brings many advantages and tools in the measurement of thermal and spatial parameters. In fact, high spatial (800/spl times/600 pixels) and temporal resolutions, good relative thermal resolution …
Task scheduling control of BGA solder joint process in flexible manufacturing system
2006
This paper describes an open loop control method of the solder joint process in a rework station for faulty printed circuit board (PCBs) containing electronic components in packages ball grid arrays (BGAs). In particular, a mathematical model describing the solder joint process is, first of all, obtained. Then, the desired thermal profile of the junctions BGA-PCB is determined according to the physical constraints of the rework station framework. The control parameters corresponding to the above desired thermal profile are identified using the above mathematical model. Finally, the open loop control algorithm is implemented on the supervisor interface of the rework station in order to carri…
Electroplated Indium Bumps as Thermal and Electrical Connections of NTD-Ge Sensors for the Fabrication of Microcalorimeter Arrays
2012
We are developing a method to build arrays of Ge-based microcalorimeters for soft X-rays detection using micro-photolithographic techniques. A key element of the process is the electrical and thermal connection between the germanium sensors and the interconnection electrical tracks, that lay on a substrate acting as mechanical support and thermal sink. The geometry of the sensors, that have a square base truncated pyramid shape, makes feasible a connection through indium soldering. We describe a technique, based on microlithography and electroplating, adopted to grow indium bumps of a few tens of square microns of area and several microns high on top of the contact pads patterned on the sub…
The use of three-dimensional oral mucosa cell cultures to assess the toxicity of soldered and welded wires
2007
The aim of the present study was to determine whether there is a difference in toxicity and loss of viability of three-dimensional (3D) reconstructed human oral epithelium (RHOE) cell cultures induced by point-welded (PW), laser-welded (LW), and silver-soldered (SiS) orthodontic wires. Three types of soldered stainless steel (SS) wires: PW, LW, and SiS were prepared ( n = 3) and subjected to multiple end-point analysis (MEA). Six pieces were cut from each wire. Each piece was placed on the triplicate cell cultures (RHOE model based on TR 146 cells). After 24 hours of topical exposure, the cell cultures were cut and stained with haematoxylin/eosin. Toxicity was assessed by evaluating the mor…