CNC press brake machine types by the type of parts they make
Metal fabrication shops depend on a CNC press brake machines to make things out of metal by mechanical, hydraulic or forging force. Press brake machines can also do the cutting, but everything is by applying force instead of removing chips. So, press brakes are generally broken into four main types – press brake, roller press, forging machine and punch press. You’ll find a wide range of available types of press machines. Some top machines include Mitsubishi Diamond Eline CNC press brake, which is valued over $150,000, press machines like the 60-tonnage 1999 Auto-Sert Flyer, 350 ton Cincinnati CB II-10 or a 4-way roll press brake like the Sahinler 4RS-10-640 from 2012 that can make 122” long 24” rolled parts.
Press Brake Machine
The CNC press brake machine uses dies that are secured in place with two plates. An operator put the stock on the bottom die and activates the CNC to press the metal between the dies which forms the material. Press brakes may be hydraulic press, hydra-mechanical press or use a mechanical-friction clutch. Press brakes are sold with a certain number of tons which indicate the load the machine can deliver to form parts. Press brake tonnage can be calculated using material type, the vee dies opening, bend length and material thickness. To give you an idea of scope, a 30-ton press is fairly small and may be good for starting, while a 600-ton hydraulic CNC press brake can handle steel so large it requires fork-lift loading.
Roller Press Machines
Though both press brakes with bump forming can make cylindrical shapes, roll plates, or roller press machines are specially designed to form cylindrical or radius parts well. Plate rolling press brakes are faster and better suited to high-volume production. The material’s yield and tensile strength, minimum and maximum diameter of finished parts and the overall length of the parts also determine whether using a press brake or plate rolling machine make the most sense. Rolling press brakes generally form thinner materials and press brakes can form much thicker materials.
Hybrid Press Brake Machine
A hybrid press brake machine like the Evolution hybrid press brake uses the precision of CNC precision along with the strength and stability of a press brake ram and rolling capabilities of a plate roll. The plate roll may have top support with rigidity like a press brake ram to counteract upward forces pressing on the top roll. It can swing away with the cylinder is almost complete to prevent interference with small-diameter parts. With a hybrid, a fabricator can form parts that are longer and have thicker walls and tighter diameters than a traditional plate roll could handle.
Press forging machines apply gradual pressure on a die holding a workpiece. This can be applied either in an open die or closed die forging process. In open die forging, metal is surrounded by the die on one side only, vs. closed die where the workpiece is completely enclosed in the die. Press forging is often used to make coins and other parts that require complete deformation of the material.
Punch press machines are used to cut holes in the material using dies, often in series, until the desired shape is attained. Punch presses are characterized by frame types, mechanism delivering the power, size of the working area, the force rating, tooling capacity, speed or productivity, maximum weight of the workpiece, and more. Die sets consisting of male and female punches are used on the punch press to form the holes. CNC punch presses are known for high-volume production capacity with cycle times often in the milliseconds.
How are press machine sizes determined
The press size is determined by the maximum capacity to apply load on a piece of blank stock. It’s expressed in tones. The bed areas are also considered the press size. Presses may be manually operated or powered. Manually operated presses only work on thin sheet metal where little pressure or force is needed. All CNC controlled machine presses are powered.
Frame Types for CNC Press Machines
There are four main types of frame designs, the inclinable frame, straight side frame, adjustable bed, gap frame and horning, and open-end frame design.
The inclinable frame can tilt back up to some angle. It can be locked into a particular inclined position. If the back is open to drop scrap, it could be called an “open back inclinable press.” Presses that have a larger frame opening with a wide gap between the base and ram to accommodate large workpieces on long beds are often called gap frame presses or C-frame presses. These may be OBI – open-back inclinable or OBS, open-back stationery.
Straight side press
A straight side press will have straight side frame for a large bed area that can accommodate high tonnage, great rigidity, and longer strokes. The frame has vertical and straight sides which is why it’s called a straight side press. Some press machine frames have adjustable bed type frames. These are sometimes called a column and knee type press because its bed (knee) can be adjusted to different heights by moving it up or down with power screws.
An open-end press has a solid vertical frame with all the sides open. The driving mechanism is in the back and the ram controlling mechanism is in the front. Typically, these are considered light duty press machines. If the machine press has a vertical frame with a top that hands towards the front which houses a driving mechanism and ram control, the front face which looks like a work table can be called “horn,” giving the machine the name “horning press.”
Power Sources for CNC Press Machines
CNC press machines are powered by three main mechanisms, leading to the names Hydraulic Press, Machine Press, and the Pneumatic Press. Here we discuss common uses for each type of machine.
The hydraulic press, which has been around for a long time, uses a hydraulic cylinder to generate compression force required to shape the metal. Common applications for hydraulic presses include forging, clinching, stamping, vacuum and laminating, transfer pressing molding, blanking, punching, deep drawing, and metal forming. Hydraulic presses are efficient power presses that deliver a level of force that mechanical and pneumatic presses can’t duplicate.
A machine press uses mechanical features to generate force. This is similar to when a blacksmith uses a hammer to shape metal. Typical applications for the machine press include the punch press, stamping press, capping press and the press brake which bends metal into shape. Of course, there are many more applications for this common type of machine.
A pneumatic press is powered by compressed air or compressed gas. They are often a low cost, more flexible and safer alternative to eclectic motors and actuators. Many shops already have pneumatic systems like air brakes, air compressors and vacuum pumps which makes adding a pneumatic press an attractive idea if the part application fits.