Aluminum extrusion press selection – 3
When choosing equipment for the production of aluminum profiles, the most important stage – selection of extrusion press.
- Press layout
- Press manufacturer
- Spare parts and technical documentation
Press layout
Currently, there is a noticeable shift towards presses with a short stroke (removable ram) and the so-called compact (with front loading of the workpiece), especially in Europe. Both of these types, together with the usual layout, are shown in Fig.. 1.
Fig. 1 – Three types of extrusion press layout: traditional, short stroke front loading [2]
Both types of presses – and short stroke, and "compact" - reduce idle time of the press, as the distance decreases, which must be passed through the stamp compared with the maximum length of the workpiece. These types of presses are much more rigid in construction., with shorter columns and less overall deflection of the front cross member. Both types require less space and fewer foundations., than ordinary presses.
Short-stroke presses reduce the stroke of the stamp by, that they move it to the side or down immediately after it leaves the container.
In a “compact” press or a press with front loading of the workpiece, the container moves back along the stamp and they both move back, to make room for loading the workpiece. The blank is loaded in front of the container and the container “swallows” it, when moving forward to the matrix.
Both of these new types of presses, understandably, more complicated than usual and require, Need to think, high production culture.
Press manufacturer selection
When choosing suppliers to receive specific offers for a new press, you should never justify the choice of their objective characteristics only. Most buyers take experience into account., reputation, reviews and comments from other buyers, scope of service and technical support offered.
Press suppliers are "ranked" from the most branded and most high-tech companies (and the most expensive) to companies from the so-called developing countries with a low technical level (and cheaper). "Top" presses offer high efficiency, performance and reliability, short idle cycle, latest design solutions, greater rigidity, better alignment, the best hydraulic system and latest generation computer control system. However, these "top" presses are not always the right choice for everyone.. When making a decision, the following points must be taken into account..
- Is this the only press in the company or are there other presses, to complete an order, if this press suddenly breaks?
- Is there money to buy a "top" and expensive press?
- Is the market ready to appreciate the benefits of higher quality products and pay for it? Depends on, how quickly the funds will pay off, invested in a “top” press.
- Is there a highly skilled workforce available and are you willing to pay for it? How will this affect the profitability of production?
- Will the press remain modern and competitive for the foreseeable future, or will its technological advantages soon become obsolete?
Spare parts and technical documentation
Spare parts for the press
- Near 5 % cost of the project should be earmarked for spare parts.
- Spare parts for the press must be negotiated simultaneously with the delivery of the press itself and this should be done as part of the supply contract..
Technical documentation for the press
- The supply contract must include the transfer of detailed drawings, especially press tool, which will be part of the delivery.
Annex
Extrusion Press — Recommended Spare Parts List [2]
Mechanical
- Complete set of packing, “O” rings, and gaskets for main ram, crosshead cylinders,
container cylinders, butt shear, and die change cylinders - Container cylinder (one) (very important: it is not unusual to bend or break a container cylinder rod)
- Crosshead cylinder (one)
Hydraulic
- Main pumps (complete set); or rebuild kits for all pumps if plant is equipped and trained for in-house rebuilds. (A complete set is recommended because failure of one pump often
releases particles which then damage the other pumps.) - Coupling for main pump
- Auxiliary pump(s) (one spare for each pump)
- Complete servo-valve (one)
- Filters — complete set
- Spools for valves — complete set
- Solenoid coils
Electrical
- Container heating elements — complete set
- Motor for main pump
- Temperature controller
Tooling
- Container with liner (one)
- Stem (one)
- Fixed dummy blocks (3 to 5)
- Die carrier (for Unistation or Rotostation die changers)
Sources:
- Seven Steps for Selecting An Extrusion Press /Al Kennedy, ET 2008
- Extrusion Press Maintenance Manual / Al Kennedy – 2022
