How to manufacture the photocell,Iwould to make factory advic me

Let me understand this right... you don't have a factory, much less one for manufacturing electronic components... and you don't have any idea how to make this particular component much less any others... and you are asking here how to do everything?

You do realize you can't do this in your spare bedroom, and you aren't going to learn all the details on a help forum, considering there are a large number of trade secrets involved with anyone who DOES make these.

Come on Smoothy. How else do you expect someone to establish a new factory?
The internets are a perfect place to gain all sorts of knowledges. :D

Yeah... pretty soon someone is going ot hot-glue wires to a "Sweet Tart" and call it a capacitor.

Hell, I've got an Engineering Degree in Electronics... and while I know how it works... basically how they are made (theoretically), I don't have a clue how one would even begin to manufacture them, but I know it takes a crew of PHD's with lots of experience in the field, cleanroom manufacturing facilities... and a lot of highly toxic materials. Not to mention funding measured in Cubic yards of Dollars to set the operation up.

Here is a basic circuit:
Circuits Controlling Relays page

I would research existing photocells and the variations(Intermatic is a good source of what's available).
Then you need to design and have built, an enclosure, and circuit board, buy components in Bulk(cheaper) and assemble yourself(unless it is cheaper to pay someone else).
Will need UL or some type of approval, More money.
Marketing.

Problem is he asked how to make a photocell, not how to use a photocell. HUGE difference there

Smoothy, The link I provided DOES show how to make a photo detector circuit with a parts list and everything.

It didn't even occur to me he wanted to make the actual part, I thought he wanted to make one for use to control exterior lighting.
To make the component would be futile, thinking I could out do Sylvania, GE and the rest. They already make proven reliable sensors?

THAT is exactly what I read his question to ask.