Overview

This part of the IEC 62739 series provides an evaluating test method for the erosion of the metallic materials without surface processing intended to be used for lead-free wave soldering equipment as a solder bath and other components which are in contact with the molten solder. The specimen is mounted to the rotation block of the test equipment which is driven by the motor (may include gear unit) then immersed into molten lead-free solder and rotated to simulate solder flow in the wave soldering equipment. The erosion depth is measured after the block is rotated for a designated period of time. Test equipment shall include equipment that realises the test conditions. Component materials of the test equipment which come in contact with molten solder shall be erosion resistant or processed to be erosion resistant. The test equipment consists of a pot unit, rotation unit, and control unit. The pot unit consists of a heater to melt the lead-free solder alloy and a pot in which a specimen can rotate. The rotation unit consists of a motor which rotates the specimen and a rotation block to which the specimen is attached. The control unit has functions to control the heater, using a temperature sensor, control mechanism and motor rotation. Since dross spreads during the test, it is preferable for the test equipment to have a ventilatory function with an exhaust air duct. Other test equipment can be used if its configuration and functions meet the afore-mentioned requirements. Normative Annex A contains specifications of test equipment and the measurement equipment described. The test equipment described in this standard contains a pot unit, rotation unit and control unit, every unit having the following characteristics. Since the specimen rotates during the test, the dross and hot air would diffuse into the ambient air. Therefore it is necessary that the test equipment has an exhaust air duct for ventilation. The ventilation rate does not need to be given if it does not influence the solder temperature. The measurement equipment described in this standard contains an optical microscope, a digital indicator, a CCD camera as well as a TV monitor. Informative Annex B describes the method of estimation of maximum erosion depth by extreme value statistical analysis. The measurement ranges of the same quality on the specimen shall be determined. The maximum erosion depth of the specimen is measured experimentally using the Gumbel distribution and the most probable erosion depth of the specimen is assessed using the Gumble distribution. The responsible committee is DKE/K 682 "Montageverfahren für elektronische Baugruppen" ("Electronics assembly technology") of the DKE (German Commission for Electrical, Electronic and Information Technologies) at DIN and VDE.

Document: references other documents

Responsible national committee

DKE/K 682 - Aufbau- und Verbindungstechnik für elektronische Baugruppen