Hi,
You can use
hikaserial::increasePerf();
in order to ask PHP to remove his 30sec limitations ; but it might not work with all servers.
The issue is not coming from HIkaSerial or from the ean generation ; it's just that you're asking to generate a lot of data and for sure it will take some time.
Activating the "fast random" setting in HikaSerial will use another function to generate the random data ; which will be "less random" but faster. The Joomla function to create random data are very secured but time consuming.
Regards,