Trained staff make the difference
The full potential of a modern aluminum extrusion line can only be achieved if, when it is driven by professionally trained personnel. Very important, people, who work on it:
- not only understood how extrusion and other equipment works,
- but also understood bases extrusion technology of aluminum alloys,
- knew how to manage it and
- How can they influence her?.
The performance of most press lines could greatly improve, if their operators understand fully all the factors of the extrusion process of aluminum. They should know the factors, which impose restrictions on the press-process, and understand, what their press control capabilities, increase compression rate and, thereby, shorten the cycle time pressing.
That is why it is important to conduct regular training for operators of the press line. Many plants operators pressed aluminum extrusion line almost do not receive any training, Moreover, that they were in the beginning of the show which buttons they have to press and when. Even the foremen and masters, who presided over the press, spotters matrices and quality controllers often do not possess the elementary concepts, for example, of metallurgy of aluminum alloys.
Most often, all training is to press on the job training. Usually it conducts training work, who himself studied at the same workplace. At the same time, obviously, that the various press line workers need to have different amounts of knowledge and skills depending on the job, they perform. It is therefore important, that all personnel must press a regular professional training held, which would highlight specific aspects of the production of extruded aluminum products - bars, bands, profiles and pipes.
Plant management must clearly understand the purpose of these training programs. Ultimate their goal - to get trained workforce, which is capable of performing complex manufacturing operations in full. Production problems will always occur, but many of them can be easily addressed by staff, if he owns the basic principles of technology and metallurgy of aluminum alloys.
Typical training courses for staff lines for aluminum extrusion are as follows.
“A introduction to metallurgy of aluminum alloys”
- Chemical composition of the aluminum alloys, which are used in the plant
- Effect of different alloying elements on properties of pressed parts made of aluminum alloys
- The aging of aluminum alloys
- The structure for pressing aluminum ingots
- Structural changes during the homogenisation of ingots of aluminum
- Structural changes in the ingots during heating before compression
- Structural changes during extrusion
- Effect of cooling rate extruded profiles on the press to their final mechanical properties
- Structural changes during aging operation, artificial and natural
Press cooling and aging
The need for rapid cooling at the outlet of the profiles of the matrix alloy 6xxx series, such as 6060/6063, often restated operators extrusion presses.
Another kind of problems arise during the artificial aging of profiles:
- Soft, enough strong material, usually the result of insufficient cooling at the press, differences in exposure profiles before aging, underaging or overaging.
- Low mechanical properties can be corrected again aging, but only if the profiles were nedostarennymi.
- If the cause of low strength was insufficient cooling or overaging, it is no longer possible to do anything.
“The basic principles of extrusing aluminum”
- Typical "extrusion force - ram travel" curve per press cycle
- Extrusion cycle stages: simple, the breakup of the ingot, the beginning of expiration, extrusion, end of extrusion
- Influence of the maximum force of the press on the speed of extrusion
- Temperature change during extrusion
- Relationship between extrusion speed and force
- Relationship between extrusion force and temperature
- Methods for measuring the temperature and the typical measurement accuracy
“An extrusion press”
- Description of the hydraulic press and its control system
- Control of the furnace for heating ingots (billets) and other furnaces
- Proper application profiles for the transmission system of the press line
- Correct setting drinking hot and cold cutting
- The types of matrices used
- the passage of metal through a matrix management
- Typical problems in the pressing profiles
- factors, that affect the service life of the matrices
- matrices for the care and support of the pressing tool
Short, essentially, informally
- Staff training should not be limited to classroom activities based on the principle “teacher – student”.
- Press operators often have many years of practical experience and can bring a valuable contribution to the discussion of issues under study.
- The training itself should not be too long.
- Two hours, along with the discussion is the limit for most people trained.
- Short periodic sessions with frequent repetition of the main provisions are the most effective.
Source: Alan F. Castle, Aluminum Extrusion Technology Seminar, 2000