DETAILED STUDY

As part of the sites environmental policy a study was conducted by The Humber Resource Efficiency Centre to ascertain whether we were managing our production of waste materials so as to have the minimum impact on the environment,and having produced the waste were we fully conversant with all the various methods of disposal.

As dross formed a large part of our waste material it was decided to measure the impact of the Solder Recovery System on our waste levels.

The recovery system was used on one of our three solder machines so that a comparison between solder usage with and without the EVS could easily be made. The trial was run over a period of one month and the figures collected were:

1. New solder added
2. Weight of recovered solder
3. Weight of waste dross
4. Number of boards soldered

For the purpose of the results, machine 1 used the EVS.

OPERATION

The operating of the EVS is very simple and basically consists of adding hot or cold dross into a heated chamber,compressing the dross with a heated piston,collecting the usable solder squeezed out in an ingot tray and at the end of the cycle discharging the waste dross down a chute directly into a bin for disposal. Maintenance is minimal and easy and each unit has the ability via supplied software to monitor the machine operation and feedback any fault details.

In our experience it was found that a better return was achieved when small amounts of dross were processed often rather than one or two large amounts. No major problems have been encountered with the machine and all of our minor problems have been addressed by the manufacturers and remedial improvements incorporated into their latest machines. Spares, technical back-up and support were also of a high standard.

RESULTS

Results were collected and collated on a daily basis but for the purposes of this report they have been totalled and averaged.

CONCLUSIONS

As can be seen from the above results a number of different conclusions can be reached. We were particularly interested in:

1. recovery rate
2. saving on solder usage

The average recovery rate was 59%,the highest achieved was 79% and the lowest 31%. This difference can be explained due to two main factors.

1. As was mentioned earlier in the report,the greater the amount of dross loaded into the machine for processing in general produced a lower return in terms of reusable solder.
2. It is also possible to process the dross more than once to extract solder so therefore it is...
3. obvious that the higher the solder content the higher the return,the reverse also holds true. It would therefore appear that the sample that produced the 31% return was very low in solder content. The experience of the operators can also,when combined with the above mentioned factors affect the results and during this study period a number of new and different operators were collecting the results.

For the reduction in solder usage the following calculation was used:

    ______recycled solder_______    x 100 = 35.5%
    recycled solder + new solder

These figures are not that far removed from the manufacturers claims and we are confident that higher returns can be achieved.

The immediate effect can be seen from the table above,the solder machine with the SRS averages ·0143 kg/brd whereas with the other two machines the average is ·0265 kg/brd a difference of ·0122 kg/brd. This difference is purely the amount of usable solder being thrown away with the dross. In this instance it equates to putting 80% more solder / board.

If we could recover all of the usable solder in our dross then the returns and hence savings would be higher than those achieved during the trial period and could even surpass the manufacturers claims.

If we then also project using the figures achieved on machine 1 we would have recovered a further 378 kg from machines 2 and 3. This would have given us a total of 610 kg recovered solder in one month.

If we then assume the same levels of production for the year we would expect to recover 7,320 kg of usable solder. Based on £4.54/kg this would give an annual saving of £33,232.