Modern aluminum extrusion pullers

Modern extrusion press for aluminum and its alloys are used with special pockets matrix and feeders, which provide continuous production of the lash welded together at the ends of the profiles of the individual blanks. On saw cutting this continuous hot whip lash cut into a length of 50 and more meters for further straightening and cutting-to-length. Movement and direction of aluminum profiles at the exit of press systems provide modern pollers, are often combined with hot-cutting saws.

Ordinary puller - a pulling device, which directs effluent from the press profile as it moves along the outlet table press for subsequent transfer to a cooling table and further the tenter.

Output table extrusion press

Pullers work on the output table press. For greater certainty of the output section will describe the structure, since some of its sections are named differently. Output table press usually comprises a receiving table, and an output roller conveyor. Reception desk is directly adjacent to the press. He usually has a non-driven rollers, thereon disposed tunnel water or water-air cooling and, usually, stationary hot saw cutting. Just behind the reception desk starting off roller table with driven rollers. The output roller extends parallel to the entire length of the cooling section. Since the output roller table sections traversing system is transmitted to the cooling table, and further - to tenter.

The functions of the puller

Puller extrusion press should perform, how miniumum, следующие четыре функции [1]:

  • Adopt and maintain profiles on the receiving table for the entire length of the roller output in each cycle press unattended
  • Give a signal to the press to stop pressing, is achieved when the predetermined length of the profile
  • To provide a tensile force in accuracy sufficient for, all profiles mnogoochkovoy matrix were identical length
  • Promote hot cut saw cutting profile exactly in the space on the outlet roller conveyor, where they will be sent further to the cooling table.

Чтобы иметь возможность выполнять эти функции пуллер должен быть:

  • reliable - have a probability of failure of not lower than, чем других частей прессовой линии;
  • быстрым – выполнять свои задачи и возвращаться за время технологической паузы пресса на исходную позицию;
  • smooth - operate without damage profiles.

types pollers

Various pullers may differ from each other as intended, and a separate design specifications.

A single puller

Most of the early pollers were single. However, understandably, that a single puller difficult to keep coming back to the starting position on the output table during the waiting time of the press when changing workpiece. The duration of the pause is usually not more than 20 seconds, and the output length of the table, which is necessary to have time to pass Puller, often it is about 50 m. It should be noted, that at an excessively large rate of movement of the puller decreases its reliable operation.

double puller

To reduce the non-productive downtime media have been developed various types of double pollers, that provide the, что в начале каждого цикла прессования один из пуллеров всегда находится на исходной позиции возле пресса:

  • two puller, front and rear, первый передает профиль второму в ходе цикла прессования;
  • Параллельные пуллеры (пуллеры-близнецы), who work in the press cycle turns, то есть через цикл;
  • The combination of the main and auxiliary puller puller. The main puller pulls the profile during the press cycle, and the auxiliary puller drove the profiles already cut more by the output roller conveyor for transfer to a cooling table.
  • A combination of a saw-puller and conventional puller. Puller-saw cuts the profile of the track welding and helps ordinary puller spending profile for the output table.

Location puller

Pullers are moving along the guide rails, which can be placed directly on the output table or next to it.

drive puller

Обычно применяются следующие типы приводов пуллера:

  • cable,
  • chain,
  • a linear motor and
  • rack.

The supply of electric power to the puller

Энергия для приведения в движение захватов пуллера (и пилы горячей резки, когда она установлена на одном из пуллеров) может подаваться:

  • on cable suspension,
  • on the supply rails or
  • in the form of compressed air to the air cylinders, are charged after each working cycle.

Types of seizures and their actuators

Захваты пуллера могут быть в виде тисков или состоять из нескольких сегментов (пальцев). The grippers are opened and closed by pneumatic cylinder, springs, hydraulic cylinders or linear electric actuators.

Pullers with servo-drives

Modern pullers require precise positioning on the output table and the rapid discharge of their functions. Последним достижением в развитии систем пуллеров для экструзионных прессов для алюминия явилось применение на них сервоприводов для приведения в движение различных устройств [2].

Leading manufacturers of pressure equipment already offer these pullers. In figures 1 and 2 shows the different types of pollers Tecalex с применением сервоприводов [3]:

  • одиночный пуллер с сервоприводом захвата (далее – «пуллер») и
  • пуллер со встроенной пилой горячей резки (далее – «пуллер-пила») с сервоприводами захвата, moving the saw blade and saw rotation.

Figure 1 – Пуллер компании Tecalex с сервоприводом захвата [3]

Figure 2 - Puller Saw Company Tecalex
c servo capture, перемещения пилы и вращения пилы [3]

Work pollers system with servo-drives

on pullerah, who work for servo, Each actuator is controlled by its own controller. Управляющий шкаф программируемых логических контроллеров (ПЛК) соединяется с сервоприводами через токопроводящие шины на монорельсе, by which drive pullers. specified parameters, for example, speed and acceleration are transmitted through the controller to the servo control system.

EXAMPLE pollers system operation - without puller puller with saws and saw -Shows, What challenges must perform pullers when processing profiles, выходящих из пресса [3].

Пуллер без пилы работает в основном в пределах выходного рольганга (рисунок 3). When the puller reaches the end of the profile roller conveyor, puller-saw arrives at the last traces of welding, which was formed when stopping the press for loading a new workpiece. Пуллер-пила отрезает профиль точно по следу сварки (рисунок 4).

Figure 3 - Puller with a profile exits with a reception desk
на выходной рольганг [3]

Figure 4 - Puller-saw on the receiving table
пресса отрезает профиль по следу сварки [3]

After cutting the profile puller reaches his roller conveyor for transferring the cooling table, and further stretching machine. Puller-saw pulls along the following profile of the output table so far, пока пуллер без пилы не вернется и заберет его у него (рисунок 5). Then puller continues to pull the profile of roller conveyor, а пуллер-пила возвращается к прессу и ждет следующей порезки профиля (рисунок 6).

Figure 5 – Передача профиля от пуллера-пилы к пуллеру [3]

Figure 6 – Пуллер-пила возвращается к прессу после передачи профиля [3]

The advantages of servo

Servo systems technology for compressing lines pollers aluminum profile has the following advantages as compared to conventional drive systems, most often, гидравлическими [3]:

  • Servo system provides a more precise execution of a predetermined movement cycle components pollers.
  • movement cycles of various actuators can be accurately monitored and then sync within the overall system pollers.
  • Servo have increased reliability.
  • Maintenance of servo systems, less time-consuming.
  • Elimination of hydraulic oil increases fire safety equipment.
  • In view of the life cycle of servos are the best investment performance in comparison with other, lower costs drive, for example, hydraulic.

Sources:

  1. http://pressmaintmanual.com/files/52490270.pdf
  2. Jürgen Sturm and Jaume Amoros, Servo-Drive Applications in Aluminum Profile
    Extrusion Equipment, Aluminium Extrusion Technology Seminar, Chicago, 2016
  3. http://www.tecalex.net/image/noticies/tecalex_2015-MayServoDriveFlyingPuller.pdf