What may look like a simple product that you see everyday in streets, yards and places of business where water meters record the delivery of water to a specific address is actually quite involved. For plastic injection molded commercial water meters we start with a single cavity mold weighing nearly 5,000 lbs that has the detail of the part machined into the steel halves of the mold. The “core” is the male side of the mold and forms the inside geometry of the part. The “cavity” is the female side of he mold and forms the geometry of the outside of the part.
The mold is mounted into a 1,000 ton injection molding machine that is the size of a semi-trailer. The machine has 1,000 tons of clamping force to hold the two halves of the mold together when filling the mold with melted plastic resin under very high pressure. In this particular part we inserting a 1″ diameter metal rebar into the cavity side of the mold. The machine closes and fills the cavity of the mold with plastic encapsulating the metal rebar in the part.
The metal rebar adds weight to ensure that the meter cover does not float away when the street floods. In this design, the part requires drain holes to be drilled through the side and ribs of the part and was more cost effective to use a CNC milling machine to drill these holes. The insert molding and machining operations are capabilities that set Texas Injection Molding apart by including in the supply of finished parts. See the attached short video to see the process in action.