[JJ_SO]

photonius, on 15 Jan 2014 - 15:05, said:

"separation aid" (in German "Trennmittel")". Excellent point, that may be the reason that it streaks? This could or should be cleaned off?

Those first parts out of the mold will normally be thrown away. Especially if the parts are complicated. Later on, if production works regularly and all temperatures, times and pressures at the injection machine are set, that chemical is not needed, otherwise the mold design has a flaw.


Also, who says the smears are from the cushion - and not from the parts this person had between cushion and sensor? Try with a tiny piece of candle wax between your finger and a hard surface, then move your finger to the side instead of lift it away from the surface.

photonius, on 15 Jan 2014 - 15:05, said:

"There must be at least two molds. " Yes, I am aware that such molds are quite expensive, so that you make a run for several thousand sticks, and those would not be made on a kitchen table. I think it's made of two parts, the stick/handle, and the rubber top. If my guess is right, the way the two are merged is by hanging the stick/handle into something that does look like ice-cube molds, and the rubber is poured into the molds and solidifies around the stick.

Alternatively, since rubber is soft, if the rubber is made with the hole, the stick could just be pushed into the rubber, and pops into place.

No. The corners of the cushion can't be lifted of, so therefore it's either glued or injected in another process. That might be the reason of it's design, be pulled off the mold by hand or robot. Otherwise the points of the ejector pins would be visible.

photonius, on 15 Jan 2014 - 15:05, said:

It should be possible to source some type of stick from China, either already on offer, or from a factory that makes these sticks to specification, example http://www.alibaba.com/product-gs/848600...esale.html

You can try, I have one and it works which is what counts at the end.