How to Choose New Pressbrake For Metal Bending.
Is there any ways to choose the right pressbrakes for your sheet metal bending? The answer is positive, the following items you need to consider when you plan to buy one new pressbrake:
While a press brake bending machine is a simple machine in its principles, it’s highly flexible and many accessories are available. The endless variety of sheet metal thickness, length, and shapes demand for a great customization of size, tonnage, and tooling. For this reason it’s important to analyse in depth your production needs, so as to choose and buy a machine able to do its job perfectly.
You don’t know how to choose and set up a press brake? The most important factors to be kept into consideration are:
Length
Tonnage
Daylight and stroke
Throat
Tool clamping and tool adapters
Back gauge
Compensation systems, anti deflection table
Energy saving systems
Front support arms and sheet followers
Angle control systems
Optionals and accessories
Choosing a press brake won’t be easy, but with this 4-part tutorial you will be able to pick the right press brake for your metal bending job. In this first part, we will focus on how to choose length, tonnage, daylight, stroke, throat, tool clamping, and tool adapters.
1 — Max metal bending Length
It depends on the maximum length of the workpiece to be processed. If you bend by stations, i.e. with multiple working stations on a single press brake, you will need to add up the length of the individual stations. For example, take a 700×1800 mm panel. You can bend all the short sides first, retool the machine, and then bend all the long sides. This way it would take a 2000-mm long press brake, but efficiency would be pretty low. On the other hand, you could choose a 3000-mm machine equipped with two working stations, one for the long side and one for the short side. So you don’t have to take up work again and processing times are reduced.
2 —Max sheet metal bending Tonnage
It’s the bending capacity of a press brake. 5 main factors come into play:
material: softer materials like aluminum require less tonnage with respect to stainless steel or high-strength steel
thickness
length
die opening: smaller Vees result in higher tonnages
process: air bending requires less force with respect to coining or hemming.
Choosing the bending force of a press brake is clearly one of the most important variables when you purchase your new machine. If you want to know the tonnage required by your job, use our free online bending force calculator.
Don’t forget you should always oversize the press brake by 20/30% compared to the theoretical data, to be able to manage the variability in the characteristics of the material and for not working to the limit of the capacity of the machine.
Furthermore, if the load is concentrated in a very small area (for example with thick but short pieces), it is better to choose a bigger machine size to avoid deforming the ram.
3 – Working area: daylight, stroke, and throat
What do we mean by daylight and stroke a press brake? Together with throat, they are part of the dimensioning of the working area.
The daylight is the front opening of the press brake. Increased daylight version is equipped with tool holders and allows to easily bend boxes without using special tall punches.
Versions with extended stroke allow for easier extraction of formed pieces.
Throat is the C-shaped aperture in the side frames. It varies according to total dimensions of the press brake. An increased throat is useful to extract pieces from the sides or for machines in tandem.
4 — Pressbrake Tool clamping and adapters
Different clamping systems allow to change and rearrange tools. The more fragmented your production lots, the more important are shorter setup times. Remember that a press brake is paying for itself only when it’s bending parts!
Tool holders are adapters to be inserted between ram and punches. They allow to make deep boxes without the need for tall punches, which are often more expensive and more fragile. Tall punches can nevertheless be installed directly on the ram.
