An ironworker can be an important and versatile machine in a metal fabricating shop. Quite often ironworking is the first step in the manufacturing process, and one ironworker typically can provide enough fabricated material to keep up to seven welders or assemblers busy.
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Since its invention in the late 1800s, the ironworker's main
strength has been its ability to perform a variety of operations. It can punch
a range of materials with punches of various sizes and shapes. It also can
shear rod, flat bar, angle, and channel. In addition, it can notch angle iron,
pipe, channel, and flat bar. Many ironworkers are available with special
tooling to bend, stamp, and form too.
As versatile as the ironworker is, however, it is possible to purchase the wrong machine—or at least not the best machine—for your application. Important considerations for selecting a machine include its capacity, versatility, safety features, and quality.
The material thickness you process will indicate whether to use an ironworker or a turret punch press. An ironworker punches plate up to 25mm, and sometimes even thicker. Typically, turret punch presses are used on sheet material 6mm. and thinner. Ironworkers usually are used for shorter production runs and applications for which tolerances are not as critical.
Determining Capacity
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Ironworkers typically are rated by tonnage at the punch station. A 45-ton ironworker should punch a 38mm hole in 8mm material; a 60-ton machine should punch a 25mm hole in 16mm material; and an 90-ton machine should punch a 30mm hole in 20mm material (see Figure 1).
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Figure 1 |
The first step, therefore, is to determine the maximum material thickness so you can establish the tonnage range needed for your punching application. Examine the steel rack and the product that you are fabricating. Determine the maximum hole diameter to be punched; the maximum thickness of the material to be punched; and the maximum thickness and width of the channel, angle, and rod to be sheared or bent.
The material or part width plays a part in your ironworker selection. The throat depth of an ironworker punch station should be greater than half of the part or material width. Material length, however, really is not an issue. An ironworker can process almost any material or part length.
Because many different types of steel and ranges of hardness in mild steel exist, it is advisable to get a machine that is at least 20 percent larger than you think your everyday use requires to avoid getting a machine that is too small. Most machines are rated for material with tensile strengths between 60,000 and 65,000 pounds.
Many mild steels have tensile strengths between 50,000 and 70,000 lbs. or higher, and your machine may not have the power to punch the material at the higher end of the hardness values. When punching hard steel, such as stainless steel, it is better to increase the estimated tonnage by 50 to 100 percent, depending on the grade of steel.
Be sure to compare the rating of the machine not only in tons, but also the diameter of the hole and thickness of material it can punch. Ironworker tonnage ratings can vary from ironworker to ironworker.
Assessing Versatility Needs
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Ironworkers are available with different designs to enhance versatility. For example, the stations on some machines are permanently built in. These machines offer punching stations, angle shears, rod shears, notchers, and short flat bar shears.
If you are a structural steel fabricator, you may prefer these machines because the stations cover the majority of the materials you process and do not require tooling changes.
If you are a general welding, fabrication, maintenance, and structural steel fabricator who does not know what a customer will bring in the door tomorrow, you may want an ironworker that offers the capability to adapt to all customer needs. Tabletop tooling concepts, which provide a wider variety of tooling, may suit your needs.
In addition to angle shears, rod shears, notchers, and flat bar shears, tabletop ironworkers offer options such as larger press brake bending attachments, tube shears, channel shears, pipe notchers, V notchers, picket tools, square tube shears, and a variety of special tooling. Although these machines can use a larger variety of tooling than those with built-in stations, time is required to switch from one operation to the next.