SU133219A1 - Method of making hollow nylon parts - Google Patents

Description

Methods for manufacturing die-cast hollow nylon parts are known. However, the complexity of the technological processes of manufacturing by these methods and the need to use special equipment hitherto hinder the widespread use of nylon.

The described method of manufacturing hollow nylon parts (rings, sleeves, cuffs, etc.) differs from the known ones in that the starting material is melted "directly through the form that undergoes rotation, with the formation of hollow products under the action of centrifugal forces, is easy to learn, does not require natural equipment and can be used in industry in workshops where there is a heating device and a lathe or other tool for turning the forms.

In addition, the proposed method does not require pretreatment of raw materials, allows the use of wastes from the production of nylon products, manufactures large-sized (with an axis of symmetry) parts and is promising for applying thin anti-friction layers of nylon to the inner surfaces of the sliding bearings.

The process flow diagram for the manufacture of caprone bushings by the described method is depicted in FIG. 1, 2, 3, 4 and 5.

Grind out the form of iron or steel, taking into account the shrinkage of nylon (Fig. 1) .-- f

Capron is loaded into the mold cavity and closed with a lid with a hole with a diameter of 5-6 mm for the gas to exit during the melting of caprone (Fig. 2).

The nylon-loaded form is heated to a temperature of 240-260 to prevent overheating of “April,” as well as the mechanical and anti-friction properties are lost.

The heated mold is installed in a chuck, lathe or fixture.

The shape is supported by a rotating center and a gas outlet and rotated to cool it to a temperature of 50-70 °.

The number of revolutions is set depending on the diameter of the form, for example, when the diameter of the internal form is up to 100 mm, it is equal to 1200– 1500 rpm; when the diameter of the inner form is up to 200 mm, 800-1000 rpm (Fig. 3).

The cooling sleeve is removed from the mold and normalized in boiling water or oil (FIG. 4).

Aging time in oil is 5 minutes per 1 mm of the thickness of the part at a temperature of 140-150 °.

Aging time in boiling water is 15 min per 1 mm of the part thickness.

Normalization in the engine is subjected to products with a wall thickness of up to 2 mm.

Further, the sleeves, if necessary, are subjected to conventional machining.

The installation of the nylon bushings on the equipment is carried out in two ways: by direct pressing into the boring hole (Fig. 5) and pressing into the sleeve of cast iron or steel, followed by machining the seats (Fig. 6).

The mating of parts from nylon. With metal (movable and stationary), as well as the recommended thickness of the walls of the sleeves are shown in the table.

Clearances and tensioned landings of nylon bushings

The gaps and tensions are established empirically. At speeds of rotation more than 2 m / s and with insufficient heat removal, the gaps should be increased by 25-30%.

Subject invention

A method of manufacturing hollow nylon parts, characterized in that, in order to intensify the process of manufacturing and using nylon wastes without prior processing, nylon wastes are heated to a temperature of 240-260 ° and subjected to rotation in the form to form a hollow product under the action of centrifugal force; after which the product is kept in oil at a temperature of 140-150 °.

five

S

Fig j

777 /// 7 /////// Л V

Otkoy kapron

Fig 2

Centre

/////// 77 //// 77 / / Kapronova mijfm