Injection techniques in shoe manufacture. (1988)

Documentary №52091, 2 parts, duration: 0:19:03
Production: Centrnauchfilm (CNF)
Director:Brikker Yu.
Camera operators:Yu.Kuznecov


The film shows molding machines of different designs, the process of making shoes and parts via injection. (Part 1 - The production technology of casting soles. Part 2 - Details of the same.)

Reel №1

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Demonstration of new shoe samples.

The main materials for injection molding methods for the production of shoe soles are thermoplastic materials, thermoplastics, rubber compounds and liquid polyurethane compositions.

In the production of shoes and their parts, injection molding methods are used in various ways.

The manufacture of the bottom of shoes, the manufacture of parts, the manufacture of solid shoes.

Production samples.

The technology of production from thermoplastic materials is as follows.

The thermoplastic granules enter the injection molding machine, where it melts and, in a viscous state, is injected into the mold.

Cooling, it hardens and forms a product of a given geometric shape.

The most widely used of thermoplastic materials

polyvinyl chloride.

Its main component is polyvinyl chloride resin.

In addition, it includes plasticizer, stabilizer, coloring pigments and pore-forming agents.

On the injection molding machine, individual parts of the bottom of shoes, heels and pads are made.

The material for the heels is the thermoplastic material acrylic butadione styrene (ABS).

The molten mass of ABS is injected into the mold for a certain time.

The mass in the mold is cooled.

The heel is pushed into a tub of cold water.

The pads are made of a plastic mass of polyamide.

An insole reinforced with a rigid half-insole made of propylene is demonstrated.

The insoles are cut out of the texon.

The heel part of the insole is cut and propylene is injected.

The injection molding machine consists of a carousel table with molds and cells for shoe blanks, an injection and plasticization unit, a hydraulic unit with controls, a refrigeration unit, a control panel.

PVC plastic pellets are fed into the hopper with a suction hose, then through a magnetic separator, the pellets enter a material cylinder with a screw.

A cartoon explaining the sole casting operation.

The amount of material is set for each model separately and is regulated by the control panel.

The process of preparing for the casting of a shoe footprint.

The blank is put on the metal block of the machine.

The thermoplastic mass does not have sufficient adhesion to the upper materials, so a special glue is applied to the shoe footprint using templates.

Every 14-16 minutes, a new half-tank is filled.

However, the sole made of PVC plastic has insufficient frost resistance.

Model with a sole made of PVC plastic.

This disadvantage is deprived of shoes on thermoplastics.

The technology of thermoelastoplast casting is similar to PVC casting.

Various models of shoes with thermoelastoplast molding.

The most progressive method of shoe manufacturing is casting from liquid polyurethane compositions.

This method is called liquid molding.

Key words

Thermoplastic materials.

Reel №2

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The liquid molding machine consists of a turntable, tanks for polyurethane composition flows, a tempering unit, an injection unit, and a control panel.

The composition of the liquid polyol stream "A" includes complex or simple polyesters, activators and coloring pastes.

Polyester is pre-melted at a temperature of 70 degrees for 12-20 hours.

An activator, a foaming agent and a catalyst are added.

The mixture is thoroughly mixed.

The finished stream is loaded into the tank "A" of the liquid molding machine.

A cartoon explaining the preparation for the liquid pressing process and the pressing itself.

In one process, the synthesis and processing of polymer, the manufacture of the bottom of shoes with the required physical and mechanical properties and its strong connection with the workpiece without the use of glue are combined.

To get a high-quality polyurethane shoe bottom, it is important to know the activity of the polyurethane composition.

To do this, before starting work, it is tested by the foam cup method.

The foam structure in the section should be uniform and finely porous.

Polyurethane foam has high adhesion to many materials.

To prevent its adhesion, a layer of separating lubricant is applied to the surface of the molds.

A cartoon explaining the application of separation lubricant.

If the processing process parameters deviate from the set values, the automatic operation mode is interrupted and the alarm is activated.

In a particular case, it is necessary to refuel the tank "A".

The quality of the bottom of the shoe is achieved with a certain ratio of flows "A" and "B".

This ratio can be adjusted on the control panel.

Precise compliance ensures high physical and mechanical performance properties of the material.

Preparation of shoes for casting the sole.

Sealing holes in the insole, ruffling the tightening edge.

After removing the shoes from the tightening pad and attaching the liner, the tightened workpiece is put on the metal pads of the turntable.

When assembling the workpiece by a non-tightening method, a thread insole is attached to the top.

A wooden insert and a supinator are attached to the cardboard insole.

Then glue is applied.

Three workers work on the car.

The resulting polyurethane foam bottom on the shoes almost does not require finishing.

The worker removes abloy and vypressovki.

The advantage of the injection molding method is high productivity, automation of production, a high degree of accuracy, and most importantly, high quality of the product.

Shoppers in front of a shop window, with shoes with molded soles on display there.

Panorama of the store.

Key words

Liquid molding.

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