Uncategorized | CA Machine Tools - Metalworking Blog

A Guillotine Shear vs A Swing Beam Shear

Guillotine

The most important factor in providing a precision cut, is the manner in which the upper blade cuts though material from beginning to the end of the cut A Guillotine drive system insures that the upper blade crosses down in a straight line from directly above the work piece. From the beginning of the cut all the way to the end of cut, the relationship of the upper blade to material never changes.

Swingbeam

In direct opposition to this a swing beam pivots from the side of the end frames and brings the ram down in an arc of a “swing” (like a welding helmet coming down over your face). This causes the relationship of the top blade to the work piece t change throughout the entire cut. Because the blade comes down in an arc, the cut is distorted from the beginning of the cut all the way through the cut.

Comparison of major cutting processes:

Waterjet machines — fast speed, able to cut thick material, good accuracy and finishing surface. Cuts virtually anything with no heat affected zone(HAZ). Some burr occurs near cut. Waterjet is widely used as metal cutting machine, glass cutting machine, ceramic tile cutting machine, marble cutting machine, and granite cutting machine. Waterjet cutting machine typically can cut as much as 4″ thick of steel (100mm).

Wire EDM — slow cutting speed, but able to cut very thick material. EDM has very high accuracy and excellent surface finish. No burr, a little HAZ. Only electrically conductive materials can be cut with EDM. Also there must be a way to drill a hole for putting through the wire for cutting.

Laser — good speed and precise cut when cutting thin material. Laser yields little burr, a little HAZ. Laser is suitable to cut non-reflective mild steel. A 6kw laster machine can cut as much as 25mm (1 inch) steel. Laser cutting machine is also very expensive.

Plasma — cuts at high speeds and generates heat that leaves rough edges. Accuracy is not very high with plasma cutting. Plasma cutting Can cut electrically conductive materials, up to 6″ of aluminum. Process yields HAZ. Special gas need to assist the process.

How Does Water Jet Cutting Machine Work

A water jet machine has essentially two components: a high intensity pump that pressurizes water to 40,000 — 90,000 PSI , and a cutting head assembly mounted on a frame that can move along the x-y-z direction over the material being cut. Pressurized water is forced through a tiny nozzle hole to create high energy density stream that can erode and tear the surface of materials to achieve a cutting affect. Pure water ca alone can cut plastics, foam, wood, resilient floor coverings, rubber and similar soft substances. In some cases, water is mixed with a garnet abrasive to cut harder materials such as metals, stone, ceramics, glass and dense composites.