摘要:
A method for making a disposable model for a precision investment casting, which comprises casting a naphthalene or para-dichlorobenzene-containing modeling material into a pattern mold at a temperature of 150.degree. C or less, preferably 80 to 150.degree. C and further preferably at a casting speed of 5 to 0.1 kg/second; the modeling material being optionally admixed with a resin selected from the group consisting of polystyrene, polyethylene, polyvinyl acetate and a mixture thereof as a reinforcing material or comprising a mixture of naphthalene or paradichlorobenzene (preferably 80 to 30% by weight), a wax (preferably 20 to 70% by weight) and the resin as mentioned above (preferably 0.5 to 15% by weight on the basis of the whole weight of the modeling material).
摘要:
A method of working thermoplastic sheet materials employs a pair of high frequency electrodes for heating the materials, one of the electrodes having a cutting edge which is lightly applied during the heating operation to bond the sheets together, after which force is applied to sever the sheets by means of the cutting edge. Apparatus is disclosed comprising a pair of rams operative in one direction to press the pair of electrodes together initially under light force, then under pressure stored up in a compression spring and finally to sever the sheets by means of pressure exerted by one of the rams.
摘要:
METHOD OF MOLDING A CAPILLARY DRAIN CONSISTING OF A FLAT BUNDLE OF CAPILLARIES MADE FROM HYHDROGELS AND SUITABLE PARTICULARLY FOR TREATING GLAUCOMA IN OPHTHALMOLOGY WHEREIN THE DRAIN IS MANUFACTURED SO THAT A SYSTEM OF PARALLEL FIBERS OR FILAMENTS IS LAID BETWEEN PARALLEL PLATES SEPARATED FROM EACH OTHER BY FLAT THIN SEPARATING INSERTS OR GASKETS. AN INITIATED MONOMER MIXTURE SUITABLE PRODUCING WATER-SWELLABLE CROSS-LINKED HYDROGELS IS FILLED INTO THE MOLD OBTAINED AND THE MONOMER MIXTURE IS POLYMERIZED UNDER CROSS-LINKING CONDITIONS. THE MOLD IS DISMOUNTED AND THE FIBERS OR FILAMENTS ARE REMOVED BY DISSOLVING OR MELTING OR PULLING THEM OUT.
摘要:
The invention relates to a device and method of using the device and plastic injection molding processes. A mold is provided utilizing a core inside the injection cavity of the mold. The core is prior to insertion of the mold subjected to a sub-freezing atmosphere. The core is then placed in the mold cavity wherein is injected the plastic material to mold the plastic part substantially surrounding the core. A thin film of air is formed around the "core" at the time of the injection of the plastic material thereby providing a substantial increase in surface finish to the plastic molded part. The core is made from a material which when heated will melt prior to the melting of the plastic part so that the core and part are removed from the cavity and subjected to a heating step thereby enabling removal of the core from the part.
摘要:
A method of manufacturing a heat exchanger comprises temporarily suporting a number of tubes in a first mould using a plurality of removable tube plates. The first mould is then filled with a molten, low melting alloy. After the alloy has set, the assembly is removed from the first mould and the tube plates are disintegrated by solvent or chemical action. The assembly of tubes supported by the set alloy is then inserted into a second mould and plastic material is injected into the mould to form a thin shell around the tubes and alloy and may also form header tanks of the heat exchanger. Finally, the whole assembly is removed from the second mould and the alloy is melted out to leave the completed heat exchanger. The method is also applicable to the manufacture of other hollow articles having a complex internal configuration.
摘要:
Molded polyurethane objects are prepared from rapid-setting polyurethane compositions employing molds prepared from foamed polymers of vinyl aromatic compounds. The molds retain their shape and dimensions sufficiently for the polyurethane composition to solidify and then the mold distorts and shrinks away from the molded object.
摘要:
A method for molding one piece seamless contoured structures. The mold consists of a hollow, cylindrical mold member whose internal surface area defines the external surface of the piece to be molded, that is adaptive to receive a piston having a reservoir containing a fluid plastic and a mandrel mold member of low melting alloy whose shape defines the internal surface of the molded structure. The piston is forced upward to cause the fluid plastic to flow into the interstices and allowed to cure. Heat is applied to the mold assembly to melt the alloy to allow removal of the contoured structure when the mold assembly is disassembled.
摘要:
An exhaust gas purifying apparatus comprising a secondary combustion chamber composed of a combustion cylinder enclosed by heat insulating material with an air gap therebetween, said insulating material being enclosed and supported by an outer casing. In manufacturing the exhaust gas purifying apparatus, the combustion cylinder is coated with easily combustible materials, to a predetermined thickness, and subsequently disposed within the outer casing with a predetermined gap or space therebetween. Heat-insulating material in a form of sludge is poured into said gap or space and solidified. Thereafter, the combustible material is burnt away and removed.