| Re: Why are some molds no longer available?
This is a long post, and I apologise for it's length, but it may help understand how the molding process takes place and why molds are no longer used.
I once worked at a injection mold factory, and I believe the molding process for chips is very similar to what I did and let me try to explain the process.
You first have to design a mold, it can be made out of several types of materials; steel, brass, aluminum, and a few others, but steel is the most popular. Next you will need to know what size of part your making and how many you want to process and feasible to make per cycle. This means if you have a small part, I've seen molds that can make 48 parts per cycle (small spacers) to one part (large battery body). Then of course, the more parts and the larger part you want to produce will effect the price. The main body of the mold could easily cost you the 40K mark as was mentioned earlier, but I know of molds that cost a couple 100K. Then for each part you want to produce, you need to have a die made, these are engraved with a negative and depending on the complexity, each die could almost cost you the price of the mold. These dies though are removable from the mold for maintenece/upkeep reasons.
Next you need to find out what material you want to make your part from. There are so many different types of plastics alone that you can chose from that will fit your purpose, or in our case, clay composites to make our chips. You purchase this plastic in the form of pellets in 200-1200# and even larger "gaylords" of media. Your charged buy the pound, ranging from under a dollar for you basic materials, to mucho denero for your specialty media. But this media only comes in basic colors, so if you want to do something fancy, you have to by color die to add to your media. This could also come in a wide arrange of amounts, but the cost is around 10-100X your cost of the basic media per pound.
Now you need your press, you can shell out 250K to prolly a mil for a used press, or several mil for a new press. These presses need a high amount of energy to run, and usually are water cooled. And like in your car, you need that water cooling to goto each cylinder, or in our case, die to make sure you do not damage the die and or part during the process. So your processing needs to be able to accomedate all of this. Or another option is that you find a company that I worked for that you bring in your mold, you buy the media, and we would use one of our machines to make your parts, and we charged per part for the production.
The process to make the part is done in a cycle (there was a link to this earlier in the thread). It's basically three parts, your heating, molding, and cooling. It starts with a high pressure press to hold your mold close (yes, this is where the 10000 pounds of pressure comes in, and you will understand why in a few minutes). Your media will go through a series of heaters to melt it and combine it with your color die to around 300-500 degrees. Then this molted media is injected into the mold and each die at pressures reaching 1000's of psi (you want that media to get into the mold as quick as possible to fill the die evenly before the cooling process). Then media will be held in the die for a few seconds to achieve equall molding and then cooled evenly to make sure it will not be brittle. Finally the mold halves are split apart, the peices fall out or pushed out with pins, the mold closes and the process starts over. This complete process takes seconds to complete.
So when taking in the above info, you can see why some parts are made then never seen again. The cost to make the mold and the individiual die is high, and they can be damaged very easily. If you do not set up the machine correctly and have too much pressure too quickly, your faces of the mold and die will impact each other and cause damage. While you inject the media at to high of pressure and it seeps out of the die, this can cause permanant damage (these are your two main reasons for flashing). All molds and dies will wear out over thousands or millions of cycles, and when this point is reached, you have to decide to make the same mold over again, or go with something a litle new and updated (makes people like us collectors buy more stuff).  | 
Re: Why are some molds no longer available? 
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