In 2006, the CPSC announced that it had received 170 reports of recalled toy magnet drops, of which 3 serious injuries were children swallowing no less than one magnet, all 3 of which required surgery. It is important to pay attention to the design of magnet products with the characteristics of small objects in toys for children over 3 years old.
"Polly Pocket" doll series and magnetic accessory set
An important technical factor for such toys with magnets is how to stick the magnet stably and permanently to the product. This seemingly non-technical problem is the biggest problem in production. One of the reasons, of course, is that the strength of the bonding cannot be tested immediately, that is, it is sent to the certification line for testing, and it cannot fully prove that the bonding method used in production is reliable. Even large companies like Mattel have not been able to think of a good, reliable, and stable test method to guarantee such testing.
Usually in the toy industry, the following methods are more used:
Several common methods
Glue bonding
If you use A-glue, or other super adhesive glue. Usually, because the magnet is relatively small, glue will be used to glue the magnet to a plastic plane. This is not a very reliable method, because over time, this adhesion decreases or gradually loses its adhesion, causing the magnet to fall off. Please note that toy products may take 1 year from production to end user, and some may take at least 3 months.
Tight fit design
That is, to design a hole of the same shape that is smaller than the size of the magnet, and then use external force to force the magnet into this hole, using the principle of tight fit to achieve this purpose. But it's also not a design that can be trusted completely. The reason is related to the characteristics of plastics, whose plastic parts will bend in the opposite direction when subjected to pressure in a certain direction for a long time. That is to say, as long as the time is long enough, the hole in the plastic will eventually become as large as the magnet, thus losing the tight fitting force, and the plastic aging process also promotes the gradual loss of this tight fitting force
Embedded design
That is, the magnet is treated as an insert, so it is molded together in the mold. In the process of injection molding, because the plastic as a variant will "wrap" the strong iron well, so as to achieve the use of mechanical principles to play a fastening role. This is a very reliable method, of course, if the iron can have a little concave and convex dots into a knot, it can be wrapped a little tighter. Of course, the cost of this method is relatively high, and the injection molding cost is different, and the structure that could have been automatically demolded has become semi-automatic or manual, but it is also missing a process, that is, no other processing, and it is very assured.
Accessories clamp tightly
An additional accessory is mechanically made to sandwich the magnet between two plastic parts. Of course, if it is the bonding of plastic to plastic, there are many ways to do it, such as ultrasound, glue, etc., because the bonding between plastic and plastic has been well proven to be reliable and has been used a lot. But if you add a small object in order to convert the bond between magnet and plastic into a bond between plastic and plastic, it is not a good way. One more small object is twice as dangerous, unless there is really no way.
Experienced manufacturers usually use more than two methods to achieve multiple safety designs, such as adding some glue to the tight design to make it safer, but it is doubtful how much the two unreliable methods can play a role. We sometimes consider whether we can add a bitter taste to the magnet so that the child will spit it out as soon as it is put in the mouth, but this is not a fundamental solution.
Puzzle solving suggestions.
The size in the picture shows that the magnet is small and easy to fall off
How to solve the problem, the author suggests:
1 Use insert molding, so that you can also feel safe after shipment (of course, the best thing is to insert the molded parts after the magnet and not small objects.) )
2 Use other mechanical methods to fix, such as from the design point of view, hands and feet can be designed into two halves, and then the magnet is sandwiched in the middle. Of course, this two-halves of siblings can stand up to the plausibility destruction test.
When the above two methods cannot be used, the use of tight matching and glue at the same time can still play a little protective role to some extent.
If you can, reduce the number of magnets and reduce the suction power a little more. If the suction force is small, the danger can also be reduced.
Plastic magnets are also a good choice, after all, the bonding of plastic and plastic is very mature.
