Don't forget balls hitting balls. Before electricity we made magnets by banging steel to steel.

LTG : )

Any ball that has ferrous metal as a component can be magnetized to some degree.

Let's start with what I'm SURE of:

Operating current is DC in modern games for all coils, including magnets. You can make a magnet/coil with windings of wire using either AC or DC, but DC produces a stronger magnetic field or "flux", because it's a steady state, as opposed to switching between two peak voltages at different polarities. Think of it this way: For a very extremely brief moment, the magnetic field generated in a coil is exactly the same in AC as it is DC. But as the polarity starts to change, the field changes. This isn't an issue with DC, and frankly, it's hard to notice as a human being without tools at 120hz. But we can tell because it's enough to have a stronger effect on a solenoid, or electromagnetic coil. It's why EM games can feel 'mushy' and solid state games feel 'snappy.'

How much variation these days is largely up to the coder. They pulse the magnets to do different tricks, like throwing the ball or holding it, or like on the new GOTG where it circles around the magnet a little bit. The duration and frequency of the pulses is altered to control the action as well as to ensure the coil itself doesn't overheat.

Transformers: All games from EM to non-Spike DMD games use transformers with multiple windings built into them to provide multiple voltages. Spike/Spike2 uses a regulated power supply instead of a transformer.

From what I could gather with my relatively uneducated brain, there is something specific about the different types of chromium oxides and the way they're physically structured that gives them the propensity to retain a magnetic charge.

From wikipedia: "Chromium(IV) oxide (CrO2) is a magnetic compound. Its ideal shape anisotropy, which imparts high coercivity and remnant magnetization, made it a compound superior to the γ-Fe2O3. Chromium(IV) oxide is used to manufacture magnetic tape used in high-performance audio tape and standard audio cassettes.[56] "

Does this relate to pinball, and how it would relate specifically...I have no idea. I don't know how the balls are manufactured.

TBH I think you're obsessing a bit much over something that doesn't really need a solution, or explanation. Certain metals retain magnetism more than others, and chrome is one of them. The 'solution' is to use the other balls, or things like plastic inserts in the trough. Cheaper, easier, and just as effective as engineering a different type of 'pinball' or finding out the why if you HAVE to use chromed balls. /shrug

I just like science, so I'll keep an eye on here if someone with deeper knowledge has something more valuable to offer, but so far doesn't seem like anyone else cares...and I hardly blame them.

I think it’s a valid topic and worth investigation. Ball baron wants to sell the best balls possible and be able to say they won’t or will magnetize with certainty. They shouldn’t just randomly magnetize- there’s a reason and I’d be interested if anyone came up with something scientifically. Maybe the government will fund a study?? Lol maybe not. stern?

If a ball "won't magnetize" then it equally won't be attracted to a magnet, or coil. This kind of makes this type of ball useless in games WITH magnets.

If you are that concerned just buy a degaussing wand and demagnetise your balls every so often.

On a related note: I used to run induction furnaces at a steel mill. When you're running 250-4000 kilowatts through the coil, nearly everything becomes magnetic. So balls of any material becoming slightly magnetized does not surprise me.

I wonder if you could use any of these magnets to demagnetize balls?
https://www.amazingmagnets.com/sf-sphere-magnets.aspx

I'm not sure if this was supposed to be smartassed or not, TBH.

All good, man. It's just difficult for me to determine what people mean in text sometimes, and I'm trying to be better about not flying off the handle without asking first.

Leaving a ball on a magnet won't change its magnetic properties much. It's the repeated movement of the magnetic field that rearranges the atoms on the non-magnetic object, eventually magnetizing it.

Take a look at this experiment: https://www.education.com/science-fair/article/demagnetize/
Heating your balls in an oven may demagnetize them. I have removed hard drive magnets from their mounting plates using a heat gun. The magnet was extremely weak afterwards.

I was wondering if using my demagnitizing "ring" that I use on arcade CRT's would work well. I'm going to have to dig it out and give it a try. Now where did I put it?