I need to know if it’s possible to have an electromagnet that can stick to steel of around 600-1000 microns thick with a very strong holding force.
The magnet head needs to be around 5-20 mm diameter.
Without a weight or force value, it’s pretty hard to recommend something. There are simple calculators online for steel plate of a given thickness and given magnet grade, however, these tend to be for neodymium, rather than electromagnets.
What’s the strongest electromagnet you sell?
Can an electromagnet gain strength from increasing the length of the core?
I forget most of the theory now but the term “ampere turns” comes to mind. It is a number obtained by multiplying the number of turns by the current (DC) through the windings and has a direct relationship to the magnet strength.
Everything is reliant on everything else. For instance the current is directly proportional to the wire resistance which is largely controlled by the cross section area and wire length. The number of turns will dictate the length. But in practise it is not all that easy. If for instance you want to modify an existing magnet to say double the strength. You could halve the resistance thus doubling the current but you would have to retain the number of turns. But now your wire size has increased and the same number of turns will not fit on the bobbin but your wire length would decrease so the current would be more than half. So it goes on. All too hard to do that.
In a nutshell you purchase (or build) a magnet which will do your job and don’t even think of going down the modification path.
To answer your question, I don’t think so. This would come under the modification category mentioned above.