CrazyEddie
Full House
I have a theory about those dots.
Injection molds very often have ejection pins. When the mold halves separate, the part often wants to stick to the mold; ejection pins are designed into the mold to push the part out of the mold half so that it falls down into the collection area. The injection press has a step in its cycle where it pushes the pins forward so the pins can push the part out. It's completely automated; the press operator has controls to tune the cycle so that the pins are pushed at the right time, when the part has cooled and hardened enough to be pushed but without unnecessarily slowing down the operation.
I haven't come across this in my research, but it's conceivable that some compression molds might also be designed with ejector pins. Compression presses are typically much less automated than injection presses, and that includes removing the parts from the molds; rather than being dropped free into a collection bin, press operators pick the parts up and pull them out of the molds. I've seen videos demonstrating this in a variety of ways. However, it occurs to me that some compression molds might have an ejector pin system much like injection molds do, to facilitate the operator lifting and removing the part.
IF that's the case, then those mold ejection pins might be designed such that they could both extrude from and retract into the mold surface (they'd probably need to be able to be pulled backwards and completely out of the mold so that the mold can be disassembled for maintenance and repair).
The fact that these unusual chips otherwise appear to be standard LHC chips exactly like any other, which we otherwise know to be compression-molded and made from standard Paulson materials, suggests to me that these oddball chips were in fact made at the same time and in the same manner as the ones they were found with, i.e. these chips too are compression-molded, made in the normal molds, using the same materials, in the same batch.
BUT! I hypothesize that the dots were the result of a minor failure in the press or a minor error in the press' operation which resulted in the hypothesized ejector pins being partially retracted when the mold was closed! That would leave some space for the plastic to flow into - a space which would have been cylindrical and smooth, leaving behind the perfectly shaped and carefully positioned protrusions we see. And it would have happened on only one side of the chip, since the ejector pins would have been on only one side of the mold.
As usual, this is utter speculation on my part. I wonder if there's any way for anyone to confirm that Paulson molds did or did not have a mechanism like this.
I'm skeptical that the dots are an artifact of an injection mold. Their placement within the debossed hats would make them very difficult to machine smooth; injection gates that leave witness marks like that would normally be positioned someplace unobtrusive or someplace where they can easily be machined away. On the other hand, by the same token, that would also make an odd placement for ejection pins, since those also typically leave witness marks which again would be difficult to machine away in that position. You can see exactly this in the not-Paulson top-hat-without-cane injection molded chips - those "injection points" are actually ejection pin witness marks, which of course the manufacturer didn't bother trying to machine out after molding. So that's an argument against the Paulson molds having ejection pins located there... but the thermosetting plastics used in compression molding might be much harder in the point of the press cycle when they're being removed from the molds than would typically be the case for thermoplastic injection-molded plastics, so leaving witness marks behind from the ejection pins might not have been an issue for Paulson chips.
Maybe someday we'll find out for sure.
Injection molds very often have ejection pins. When the mold halves separate, the part often wants to stick to the mold; ejection pins are designed into the mold to push the part out of the mold half so that it falls down into the collection area. The injection press has a step in its cycle where it pushes the pins forward so the pins can push the part out. It's completely automated; the press operator has controls to tune the cycle so that the pins are pushed at the right time, when the part has cooled and hardened enough to be pushed but without unnecessarily slowing down the operation.
I haven't come across this in my research, but it's conceivable that some compression molds might also be designed with ejector pins. Compression presses are typically much less automated than injection presses, and that includes removing the parts from the molds; rather than being dropped free into a collection bin, press operators pick the parts up and pull them out of the molds. I've seen videos demonstrating this in a variety of ways. However, it occurs to me that some compression molds might have an ejector pin system much like injection molds do, to facilitate the operator lifting and removing the part.
IF that's the case, then those mold ejection pins might be designed such that they could both extrude from and retract into the mold surface (they'd probably need to be able to be pulled backwards and completely out of the mold so that the mold can be disassembled for maintenance and repair).
The fact that these unusual chips otherwise appear to be standard LHC chips exactly like any other, which we otherwise know to be compression-molded and made from standard Paulson materials, suggests to me that these oddball chips were in fact made at the same time and in the same manner as the ones they were found with, i.e. these chips too are compression-molded, made in the normal molds, using the same materials, in the same batch.
BUT! I hypothesize that the dots were the result of a minor failure in the press or a minor error in the press' operation which resulted in the hypothesized ejector pins being partially retracted when the mold was closed! That would leave some space for the plastic to flow into - a space which would have been cylindrical and smooth, leaving behind the perfectly shaped and carefully positioned protrusions we see. And it would have happened on only one side of the chip, since the ejector pins would have been on only one side of the mold.
As usual, this is utter speculation on my part. I wonder if there's any way for anyone to confirm that Paulson molds did or did not have a mechanism like this.
I'm skeptical that the dots are an artifact of an injection mold. Their placement within the debossed hats would make them very difficult to machine smooth; injection gates that leave witness marks like that would normally be positioned someplace unobtrusive or someplace where they can easily be machined away. On the other hand, by the same token, that would also make an odd placement for ejection pins, since those also typically leave witness marks which again would be difficult to machine away in that position. You can see exactly this in the not-Paulson top-hat-without-cane injection molded chips - those "injection points" are actually ejection pin witness marks, which of course the manufacturer didn't bother trying to machine out after molding. So that's an argument against the Paulson molds having ejection pins located there... but the thermosetting plastics used in compression molding might be much harder in the point of the press cycle when they're being removed from the molds than would typically be the case for thermoplastic injection-molded plastics, so leaving witness marks behind from the ejection pins might not have been an issue for Paulson chips.
Maybe someday we'll find out for sure.
Last edited: