SMT Guidelines. Module de-soldering and rework_ugd_v1.01

Transcription

1 SMT Guidelines Module de-soldering and rework_ugd_v1.01

2 Document Title: SMT module de-soldering and rework Guidelines Version: 1.01 Date: Status: Document Control ID: Release Module de-soldering and rework _UGD_V1.01 General Notes Simcom offers this information as a service to its customers, to support application and engineering efforts that use the products designed by Simcom. The information provided is based upon requirements specifically provided to Simcom by the customers. Simcom has not undertaken any independent search for additional relevant information, including any information that may be in the customer s possession. Furthermore, system validation of this product designed by Simcom within a larger electronic system remains the responsibility of the customer or the customer s system integrator. All specifications supplied herein are subject to change. Copyright This document contains proprietary technical information which is the property of SIMCOM Limited., copying of this document and giving it to others and the using or communication of the contents thereof, are forbidden without express authority. Offenders are liable to the payment of damages. All rights reserved in the event of grant of a patent or the registration of a utility model or design. All specification supplied herein are subject to change without notice at any time. Copyright Shanghai SIMCom Wireless Solutions Ltd

3 Contents Version history Scope of the document Manual soldering tools Manual soldering tools introduction Preparation before manual soldering Manual de-soldering process PCBA with Single side components placement PCBA with both sides components placement Basic considerations for manual de-soldering

4 List of Figures FIGURE 1: MANUAL SOLDERING TOOLS...7 FIGURE 2: CUSTOMIZED SQUARE HOT AIR TIP...7 FIGURE 3: HOLDING IN REVERSE...8 FIGURE 4: DE-SOLDERING WITH PREHEATER...9 FIGURE 5: HEATING THE MODULE WITH HOT AIR SOLDERING GUN...10 FIGURE 6: CHECK WHETHER THE SOLDER IS MOLTEN...10 FIGURE 7: REMOVE THE HOT AIR SOLDERING GUN...10 FIGURE 8: PICK UP THE MODULE WITH A PAIR OF TWEEZERS...11 FIGURE 9: COOL DOWN

5 Version history Date Version Description of change Author Origin 5

6 1 Scope of the document This document is intended for the following versions of the SIMCom modules: SIM300DZ SIM340DZ SIM300W SIM340W SIM700D 6

7 2 Manual soldering tools 2.1 Manual soldering tools introduction NO Manual soldering tools type 1 HAKKO 850 Hot air soldering gun 220~300W 50/60Hz 2 Surface thermometer 3 Customized square hot air tip 4 Tweezers 5 Anti Electrostatic discharge wristband 6 Smoke absorber HAKKO Repairing board cradle 8 PCB pre-heater Figure 1: Manual soldering tools Figure 2: Customized square hot air tip 7

8 3 Preparation before manual soldering Assemble the customized square hot air tip on to the HAKKO850 and tighten the screw to assure it is immovably. Power on the hot air soldering gun and the smoke absorber, keep a distance about 15cm between the smoke absorber and PCBA. It is recommended to set the temperature of the hot air to about 400 ± 20, the volume of the air flow to 4.5 ± 0.5. Caution should be taken for the ESD protection. The operator should take the anti electrostatic discharge wristband for avoiding damage by static discharge when contact to the components on PCBA. If there are some big size DIP package components nearby the SIM300DZ module such as electrolytic capacitors, potentiometers which intervenes the SIM300DZ module to be heating by hot air soldering gun. They can be removed by soldering iron in advance. In addition, if some components are not heat resistant, they can be screened from the hot air. The correct posture of holding the hot air soldering gun by hand is shown as following figure Figure 3: Holding in reverse 8

9 4 Manual de-soldering process Recommended operation for manual de-soldering: Hot air heating the pads of the SIM300DZ module Check whether the solder is molten Remove the nozzle of the hot air soldering gun and remove the SIM300DZ module with a pair of tweezers Put the SIM300DZ module on the smoke absorber for cooling down 4.1 PCBA with Single side components placement If the PCBA is designed with single side placement, it is recommended to preheat the bottom of the PCBA. Course of preheating the PCBA can permits lower soldering reflow temperature and reduces thermal stresses to the PCB substrate when localized reflow is made with hot air nozzle. The illumination of the operation for manual de-soldering: Fix the position of the PCBA on the adjustable board cradle Preheating the PCBA with the temperature about 150 handle the hot air soldering gun and take equably heating to the pads of the SIM300DZ module Hot air soldering gun SIM300D module Make example for PCBA PCB preheater Figure 4: De-soldering with preheater 4.2 PCBA with both sides components placement If the PCBA is designed with both sides placement, it is recommended to change the soldering tip for customized square hot air nozzle for heating with a pair of tweezers. The illumination of the operation for manual de-soldering: Handle the hot air soldering gun, make the square nozzle cover the SIM300DZ module and 9

10 take equably heating to the pads of the module for 2 or 3 minutes to melt the solder Make the hot air soldering gun is held vertically to the PCBA Assure the square nozzle can totally cove the module Figure 5: Heating the module with hot air soldering gun Check whether the solder is molten. Check whether the solder is molten with the tweezee Figure 6: check whether the solder is molten On the condition of the solder is molten, remove the hot air soldering gun reposefully and vertically. Care should be taken that the pads of module and other components are not damaged during remove the hot air soldering gun. Figure 7: Remove the hot air soldering gun At the moment when the solder on all pad is molten, the module can be removed by a pair of tweezers. Firstly, insert one tip of the tweezers into the gap between module and the PCBA, then pick up the module carefully. 10

11 Figure 8: Pick up the module with a pair of tweezers Let the unsoldered SIM300DZ module cool down in the environmental temperature. Assure the module can not be swashed and overturned during the whole process of cooling down. Otherwise that may introduce the risk of artificially destruction such as components out of the position or BGA bridges connection. Figure 9: Cool down 11

12 5 Basic considerations for manual de-soldering Basic considerations for manual de-soldering: Immobility: Do not allow the parts to move during solidification of the solder. The end of the period of solidification of the solder can be observed by a sudden change in the appearance of the solder surface. Overheating: The bodies of the components positioned in the stream of gas are often heated more rapidly than the terminations to be soldered, so that for this reason also overheating may be encountered. Removal of excess solder: Removal of solder may be performed at various stages of the repair operation. Sometimes it is useful to remove as much as possible of the solder before the module is taken out of or off its place; in other cases the module has already been removed and then excess solder must be taken off the solder lands before the repaired module or a new one can be replaced and resoldered. 12

13 Contact us: Shanghai SIMCom Wireless Solutions Ltd. Add: Building A,SIM Technology Building,No.633,Jinzhong Road,Changning District, Shanghai,P. R. China Tel: Fax: URL: 13