Aluminum extrusion: heating and billet feeding

Accessory extrusion press

In addition to proper extrusion press any line for extrusion of aluminum profiles includes about ten units of different auxiliary equipment. Usually distinguish between auxiliary equipment BEFORE the press and auxiliary equipment AFTER the press [1, 2]. to press equipment includes, including:

Table loading ingots or billets in the heating furnace
Oven heating of ingots or billets
Scissors hot cutting pillars
Loader heated preform in a press
Apparatus lubricant end of the heated preform.

Sometimes accessory to the press can also include

Machine for cleaning pillars.

Table load of ingots and billets to the furnace heating

Equipment for the continuous supply of raw press for pressing the blanks may have a different structure and configuration depending on, what is the starting material at the entrance to the press:

pillars – typically 6-meter round ingots or cheroots
blank - segments pillars, cut to a predetermined size, for example, length 600 mm, for direct loading into container.

Often the loading table columns and blanks has a slight slope to facilitate their movement to the loading axis in the oven. Hydraulic system traversing poles avoids strikes poles against each other and on the hardware elements. The longitudinal feed of the posts into the furnace is carried out using a chain conveyor (Figure 1).

Figure 1 - feeding table pillars and pillars loading conveyor to the furnace heating
manufactured Tecalex [3]

The oven heating billet pillars and

Gas heating furnace preheated pillars or preform to a predetermined temperature. The main task of these furnaces - is to ensure accurate and constant temperature blanks for feeding in their immediate press container.

Most furnaces heating pillars used direct heating flame burners. Hot products of gas combustion are then directed towards the incoming pillars (workpieces) for their preheating. This provides significant energy savings [2, 3]. In each heating zone of the furnace set contact thermocouple, which control the heating temperature of the column (workpiece) (figure 2) [3].

Figure 2 - Furnace for heating aluminum pillars (billets). A number of contact thermocouples are visible for controlling the heating temperature in the zones of the furnace [3]

Scissors hot cutting pillars

hot shears cut from the preform post optimal length, which depends on the compression parameters, including on the type of matrix and profile design (figure 3). When loaded into a furnace pre-cut blanks is achieved precedence feeding blanks of different lengths.

The cutting system of heated billets has special cutting matrix, which provide a minimum distortion of the column from the effects of cutting effort. After that, the preform is cut a predetermined length, Post residue was returned to the furnace, where it is heated up to the next pillar cutting cycle. Typically, the remaining short end of the column is connected to a shortened work piece from the next column, that would get given the full length of the workpiece. Due to some difficulties in the processing of short pieces pillars usually try not to leave residues shorter column of a minimum length. This is achieved by means of special programs for programmable logic controllers.

Figure 3 - Shears for hot cutting of aluminum posts [3]

Transmitter heated preforms in the press

supply system the heated billet from the heating furnace directly to the container, equipment is very critical for high performance media. The object of these systems is to feed the workpiece exactly at the axis of the container, to ram press could without problems and without the participation of the operator to load it into the container.

The applied supply system the heated preform depends on the structural arrangement of the press, for example, Usually it is the press or short-stroke. A classic example of loader heated preforms is shown in Figure 4 [3].

Figure 4 - A device for feeding the heated workpiece to the press [3]

Movement of the workpiece from the hot shear is produced by an electric drive and a polyurethane toothed belt, reinforced with steel cord. The accuracy of displacement is provided by a precision programmable decoder. Transfer to a container preform made two movable gripper with hydraulic drive. The system allows you to work with a composite preform.

Device for lubrication on the ends of blanks

To prevent adhesion of the workpiece to press the washer on the end of the workpiece has traditionally applied a special lubricant. Currently, the aluminum industry uses three methods of applying a lubricant to the surface between the workpiece and the press washer [2]:

flame application of carbon black;
spray application of special liquid formulations;
elektrosticheskoe spraying powder of boron nitride.

Flaming coating the soot preform end remains the most common and, Unfortunately, the most reliable, convenient and cheap method (figure 5). Harvesting is delayed in its position prior to loading the container for a few seconds. Acetylene torch lights on 3-4 seconds with a flame, directed at the workpiece end. combustion mode acetylene - with a maximum allocation of black smoke. Generally, this procedure was subjected to each preform. The main problem of this method is the problem of air pollution in the working area of the press [2].

Figure 5 - Device for applying acetylene soot to the end of the workpiece [2]

Machine for cleaning aluminum pillars

Sometimes, especially in the manufacture of high-precision aluminum profiles with high demands on the quality of their surface, the equipment for feeding billets includes a machine for cleaning the surface of the ingots-pillars before loading them into the heating furnace (Figure 6).

Figure 6 - Machine for cleaning aluminum ingots-pillars [3]

Poles on its way to the heating furnace pass through the rotating wire brushes, which remove oxides and other contaminants from the surface. In many cases, the surface of the pillars is removed large quantities of dirt, oxides and other contaminants. It contributes to the quality of pressed aluminum profiles, especially the quality of their surface [2, 3]. This system requires additional effort to clean up and disposal of dust, which occurs when cleaning poles.

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