What is the difference between injection and blow molding?

In Injection moulding we melt the plastic theroplastic material and inject the same in Required shape of Mould  , While in Blow Moulding we use air to blow the heated preform to take required shape as per mould such as bottle etc.

injection to build prismatic shape and blowing to build bottles

le moulge par injection pour mes piesse plin et le moulage par souflage ce pour le piece creu 

In Injection molding we inject matterial to make object . and in blow molding we blow preform to make bottle or other job

La differérence entre les deux c'est le moule

BLOW MOLDING FOR CONTAINERS (HOLOW ARTICLES) INJECTION MOULDING FOR VARIOUS ARTICLE

l injection se fait via une vis qui injecte la matiere à travers une buse avec une pression dans les parties du moule en y epousant la forme.par contre dans le blowing (soufflage) la paraison sortant d une tete est enfermée par les 2 parties du  moule creux (forme de l article) un apport d air comprimé est necessairevia une soufflette pour donne à l article l aspect de l empreinte

Injection Molding: Is to inject plastic melted material in the gap between the two halves of a cold mold with such high pressure (normally 30 to 1000 bars depending upon product) to form a smooth surface of a product.

Blow Molding: Is to blow compressed air (normally between 4 to 6 bars) in a parison of plastic between two halves of a cold mold.  

• Blow molding, by its nature, makes parts whose wall thickness will vary from place to place, based on how much the material has to stretch as it is being blown. An injection-molded part’s thickness is determined by the mold and core relationship.
• Injection molding makes solid parts, like a Frisbee, while blow molding makes hollow parts, like a soap dispenser.

injection molding process takes material from pellets or powder status and melt it then mold it while blow molding uses readymade preforms then blow it to whatever mold.

the other difference is injection has more molecules orientations and mechanical strength than blow molding. also, injection molding has long parting line while blow molding usually has like dot at the bottom.

The main difference between injection molding and blow molding is

Injection Molding- produces a part that is solid such as reusable coffee cup lid.

Blow molding-produces hollow part such as water bottles.