Shear vs. Saw

Choosing the Best Method for Your Operation

For your operation to run at peak efficiency, your equipment needs to be just right for your needs. The decisions made during the initial selection phase will impact your bottom line for years to come.

One component that’s key in keeping costs under control is delivering the right length billet to the press. Here, we take a look at the considerations involved in deciding whether a hot log shear or a cold billet saw better suits your operation’s billet-cutting needs.

Precise Control

Determining the billet length needed to produce the correct amount of extruded product is vital to efficiency. Overcompensate, and create costly scrap. Underestimate, and lose a cut length at the saw (more scrap)—another costly mistake in both time and money.The cold saw operates on the entry end of the furnace, while a hot shear operates at the exit of the furnace, immediately before the billet is deposited in the press loader. “For this reason, a hot shear can provide a correct length billet every time,” says David Jenista, Systems Engineer at Granco Clark. “A cold saw requires a decision about the billet length numerous billets in advance—cutting begins well before the corresponding die has been placed in the press.”

Scrap Management

Aesthetically, the two methods produce somewhat different billets. The saw delivers a clean-cut, sharp-edged billet. The shear deforms the material somewhat, creating a billet with a slightly rounded edge.

Although smooth and straight, each cut with the saw will convert a “slice” of aluminum into small chips. This scrap—typically collected by a vacuum collection system attached to the saw—must be recycled, adding to the cost.

A log shear offers improved metal management. With its selectable “no scrap” mode, 100 percent of the log can be consumed.

Minimized Maintenance

When it comes to cost, the saw offers an advantage over the shear with a lower purchase price. Its operating costs also tend to be lower because it’s less complex than the shear—the shear has a number of hydraulic motions that must occur on each cut; the billet saw has only two.

In addition, the saw operates at room temperature, while the shear processes 900-degree logs, applying more heat to the components. Over time, the cool-running saw will see less wear on the mechanisms, therefore minimizing maintenance.

Accommodating Special Requirements

In some circumstances, the deciding factor may come down to plant or production constraints:

Production Cycle Time. With a press line capable of extruding more than 60 billets an hour, a saw will likely be the better equipment option. The hot shear moves the log through multiple steps outside the furnace—requiring more than 20 seconds to complete a cycle—so the log must be brought back up to temperature before the next billet can be sheared. The cold saw can more easily meet the demands of faster cycle times because the billets are cut first, and then wait in the furnace to be discharged directly to the press.

Space Availability. Space constraints and the layout of your plant may point you toward the best choice. Although a saw requires slightly more floor space, it can be installed to accommodate the building layout. The furnace/shear system uses less floor space, but must be installed in a straight line.

The choice between the saw and the shear comes down to which piece of equipment best meets the demands of your extrusion line. Choosing the method that’s right for your operation’s specific needs will help to increase efficiency and decrease costs. Let us help.