After a long time.... How are you doing? Welcome back to ROBOT.LK!
There is nothing called "Electronic Device manufacturing" in Sri Lanka and I'm wondering whether your real assignment is to find such places. If you ask a question from electronics lecturers, why all these electronic engineers are moving to software industry, I guess that has the practical answer.
Anyway, since you are one of our senior members, I'll give you this guidance. You will find it very hard to find such a place. Two big companies who maintains some standards are Motorola and Zone24. Unfortunately those are 99% in to firmware which made them also software companies. If you take MIT, there is a small team who are making displays for their stock market application. You may call them and check.
Hitech Solutions is a company formed by several engineers from UoM. So far they made several nice products to the industry automation field. But I suspect you will be able to see a proper process there as no local manufacturing company can maintain that huge cost to maintain standards. Another big issues is that local customers are not willing to pay a reasonable fee for their automation requirement. But they are ready to pay millions for foreign consultants. I'm not sure this will change in the recent future. Hitech Solutions is now moving towards buying and selling of spare parts required for factories, etc... and they have been able to acquire few valuable partnerships.
Nikini automation is another company who are in to industry automation. Lot of students are going for their industry training there especially electronics and mechanical engineering students. Again I suspect proper industry standards are practiced by them. Please call them and pay a visit on an initial meetings.
Dialog lab at UoM was doing some good projects during recent past. They received few awards as well. Since it is within your parameter, you might have a look too.
Arther C. Clerk center can be considered. They have rectified few French made locomotives which were almost retired for not having DSP knowledge. Those people have took it as a challenge and finally made the engines to work fine. In addition to that, they have so many other projects as well.
There was a company called Tandon Lanka. I'm not aware of the current situation of them.
TOS Lanka is a Japanese based assembly plant. Please contact them to see whether you can pay a visit.
There could be some more firmware guys in World Trade Centre, Colombo. But I'm not in touch with them for a long time.
Could be some more BOI export manufacturing companies. I was told that all Seagate hard disks are made here and export to Singapore. But I wasn't told about locations, etc...
Places like Sri Lanka Railways has electronic workshops where you can see repairing process of circuit boards.
I hope this would give you some idea.