Production apparatus for forming plastic molded articles
An apparatus and method for making plastic molded articles generally having a double-skinned configuration with a foamed interior extending between the two skins. Such an article can be produced with a double beauty finish, and various inserts can be placed within the foamed interior between the two skins. The apparatus of the present invention includes the machinery used in order to make such a plastic article. The heated mold configurations can be made of inexpensive aluminum, compared to the traditional stainless steel production mold, and therefore will help the manufacture of large molded plastic articles.
1. A plastic forming apparatus for making plastics from at least two different particulate plastic materials, comprising:
at least two complementary open bare surface molds, each mold being mounted on a rolling cart, where said molds are capable of being moved along a trunion track and capable of being heated;
said molds having at least one open bare surface with a sealing edge for ultimately mating with the other open mold, said open bare surface being disposed for receiving the particulate plastic materials;
at least one hopper for dumping a first particulate plastic into each of the open molds individually, said hopper having at least one distributor arm with a downwardly facing distributor tube including louvers for opening and closing the louvers to distribute the particulate material into each of the individual open molds, said hopper being capable of being recharged with surplus particulate plastic material after the molds are used;
a supply of heat for separately heating the complementary molds;
a second hopper for dumping a second particulate plastic into at least one of the molds, said second hopper also having a distributor arm with a downwardly facing distributor tube including louvers for selectively opening and closing the louvers to distribute the particulate material into the at least one mold, said hopper being capable of being recharged with surplus particulate plastic material after the molds are used;
a means for rotating the molds to remove excess particulate plastic material and a means for bringing the two open molds together to form a cavity therebetween,
a cooling station for cooling the heated molds;
a track for rolling the two carts from under the first hopper to a position under the second hopper and then into the cooling station; and
a means for moving the closed cavity molds into said cooling station.
2. The apparatus of claim 1 , wherein the at least two complementary open molds are made of aluminum and further comprise heating plenums attached to the back of the molds to heat the molds.
3. The apparatus of claim 1 , wherein the heating plenums include a propane fired heating unit capable of being tipped over after the particulate material has melted onto the mold, in order to discharge any remaining unmelted particulate plastic.
4. The apparatus of claim 1 , wherein the at least two complementary open molds are designed to be held apart at a predetermined distance to allow for a resulting article having a sandwich configuration with a foamed center.
5. The apparatus of claim 1 , wherein the molds rotate on a horizontal axis on the rolling cart, such that after the desired melted skin has been formed on the mold, the mold can be tipped over to discharge excess plastic before the next step.
6. The apparatus of claim 1 , further comprising dump trays under each of the hoppers for receiving the discharge excess plastic.
7. The apparatus of claim 1 , further comprising a vacuum mechanism for transferring the excess particulate plastic contained in the dump trays back up into the hopper for further distribution into subsequent molds.
8. The apparatus of claim 1 , further comprising water spraying nozzles in the cooling station for cooling the molds after the desired article has been formed.