Browse Prior Art Database

Surface-Mounted Component Desoldering Tool

IP.com Disclosure Number: IPCOM000059957D
Original Publication Date: 1986-Feb-01
Included in the Prior Art Database: 2005-Mar-08
Document File: 3 page(s) / 54K

Publishing Venue

IBM

Related People

Lawrence, JG: AUTHOR

Abstract

An arrangement is described to safely desolder and remove surface mounted-components with many pins from substrates. The tool, as shown in Fig. 1, consists of the following major features. A compliant head 1. An automatic lifting device 2 capable of supporting an inert gas atmosphere and component ejection. A combination Hot Gas Director/Heat Shield/Heat Sink 3. A Hot/Cold Gas Manifold 4 and a Heat supply 5 including a heating coil with sensor and controller. Due to assembly variations, the components are not in exact locations from card to card. In order to minimize alignment time, the compliant head 1 allows the grippers 2g to go down over the component 10 without precision alignment. If the tool is to be used for manual desoldering only, this is adequate.

This text was extracted from a PDF file.
At least one non-text object (such as an image or picture) has been suppressed.
This is the abbreviated version, containing approximately 52% of the total text.

Page 1 of 3

Surface-Mounted Component Desoldering Tool

An arrangement is described to safely desolder and remove surface mounted- components with many pins from substrates. The tool, as shown in Fig. 1, consists of the following major features. A compliant head 1. An automatic lifting device 2 capable of supporting an inert gas atmosphere and component ejection. A combination Hot Gas Director/Heat Shield/Heat Sink 3. A Hot/Cold Gas Manifold 4 and a Heat supply 5 including a heating coil with sensor and controller. Due to assembly variations, the components are not in exact locations from card to card. In order to minimize alignment time, the compliant head 1 allows the grippers 2g to go down over the component 10 without precision alignment. If the tool is to be used for manual desoldering only, this is adequate. If an automated rework station is desired, the compliant head can be sensored using force sensors. The output of the sensors can be fed to a tool control microcomputer which drives an X-Y table to zero out misalignment of the tool and component. A replacement surface-mounted component (SMC) device can then be positioned and resoldered in the same location as the one which was previously removed. The important feature of this tool is to lift the device being desoldered at the instant that the last solder joint is reflowed. Typical desoldering equipments on the market rely on visual or pre-timed methods to detect when reflow has occurred. Since thermal mass of components and substrates differ, this often results in over or under heating and much guess-work as to correct times. It is important to lift devices straight up to avoid smearing solder. Available desoldering equipment does not provide a way to do this. The lifting device is shown in Fig. 2 and comprises the following parts: A. Ejector/Pressure Rod for closing grippers (H) B. Compression spring to drive pressure rod (A) up to close grippers C. Washer to compress spring D. Wedge to drive washer up and compress spring (B) E. Hollow tube-assembly for A, B, C, D, H F. Outside...