Q: What are the differences between extrusion and injection moldinding ?
A: Extrusion is done by pushing a pliable material (naturally or through heat) through a die (essentially a cut-out, simple or complex, in a solid material) so that lengths of the material take the form of the die. It can then be heat treated, cold worked, or cut as needed.
Injection molding begins with a mold (the three-dimensional form desired). Liquid silicone rubber or thermopalstics and thermosetting polymers, often in the form of pellets, are meltal and injected into the hollow space of the mold. Additionally, another mold may be inserted into the liquid to create hollow space and/or textures after cooling.
Q: How much does a simple mold for plastic injection molding cost?
A: It's depends on your country and how many parts you want to put in the mold.
There is a base cost for an injection so that the more part you put in the mold the more you divide this price.
The less costly injection mold I have ever seen is more than 5000 USD but the margin of the molder was reduced to a minimum.
Basic injection molds are usually between 5000 and 10000 USD . These are big enough to put a dozen of your parts.
It may be less in foreign countries (Asia…) but if you do so I would suggest you get the contact trough an experienced subcontracting management agency near where you live because subcontracting in asia involves many risks for someone not experienced..