Press Brake Operator Should Be Know
Operating a metal bending press brake is one of the most important factors to overall metal sheet fabricating success. Although there are many factors that also play into a fabricators success, proper press brake operation is essential to the goal. A press brake operator should know many things not only about the product they are producing, but more importantly, the process in which they are producing them in. As many factors go into making successful accurate and quality parts, we have selected a few of the very most important to highlight for press brake operators to remember when approaching a press brake forming application.
Know Your Metal Bending Machine - Before attempting to form some metal parts successfully, every press brake operator should be completely familiar with their tool. In this case, the machine the are using. Know the press brake control. Know the press brakes maintenance history. Know and understand how to safely use and operate it correctly. Know how to turn it on, warm it up, program it and set it up. Press brake operators should also always know how to adjust it for inaccuracies and any issues that may prevent your forming operation from being a success. The most dangerous operator you can have is the one that knows 'just enough' to make the ram go up and down.
Know Your Press brake Tooling - Press Brake Tooling is usually the single biggest cause for incorrect parts (aside from press brake operator error) that can be corrected easily and in advance. A good press brake operator knows that tooling breaks, deforms and just plain wears out and that at some point machine adjustments need to be made for the wear and eventually the tooling should be replaced. A good press brake operator also knows that there are a variety of types of press brake tools forming operations that can vary from basic, soft cheap tools to hardened and ground precision tools that can last 5-10X longer. A press brake operator should know his tooling just as he knows his machine and applies the appropriate tools for the forming job in hand.
Know Your Sheet metal Bending Material - What material a press brake operator is working with is just as important as knowing the machine and tooling being used. 1mm SS reacts different then 2mm Gauge SS. Springback is different, tensile and yield strength is different, dwell time at the bottom of the bend is different and the tooling used is different. Although the materials may chemically be identical, the added thickness reacts differently when in the hands of the press brake operator. Knowing your material, and what to expect out of it is vital to a successful press brake operation.
Forming on a press brake used to be pretty simple. Take a V-Die in the angle you desire and run the punch into the material forcing it all the way down to the bottom of the die and go just a little more, 10% of the material thickness or so. This overstroke effect was called “coining” and eliminated the need for material thickness adjustments, springback, etc. It was an accurate way to form 1 bend in 1 part, and even though it took an enormous amount of force/tonnage to do that the mechanical press brakes of the day delivered. However the limitations of 1 bend in 1 part per setup presented enormous limitations on production to valuable time AND samples to get the forming just right. Fast forward to today….
With the introduction of CNC Controls and much more accurate forms of controlling the ram depth. As the CNC controller technology developed, manufacturers begin to incorporate more and more “logic” into them thus simplifying the layout and setup process. Today's Press Brake bending is inherently more accurate, faster and much more reliable. Controllers are packed with information on bending variables and sequences and perform much of the fabricators layout and design for them simply by their input of the desired formed shape results.
But these press brakes still are only as good as the material and tooling your put into the machine. Here are some basic steps you can perform to ensure successful bending on any press brake.
Material Type: Make sure you have defined the correct material type in your machines controller. It means a lot to the controller as it calculates tensile strength, yield strength, springback and a myriad of other factors based off of the material type. For example if your bending A36 (a recycled combination of steels and very common) yet are programming your controller with “Mild Steel” your likely be getting poor results and having to overly compensate accordingly. The correct material type your forming is paramount to a successful brake bending application
Material Thickness: Just as important as material type, material thickness is equally important to your press brake forming success. Sheet Metals are known by “GAUGE” thickness and the gauges can vary in thickness from suppliers by as much as 5% and still be acceptable and “within range.” However 5% in bending +/- 1/2° over 10’ can have a massive impact on your press brake bending success. Measure your material and input the decimal of the materials actual thickness to ensure your getting the right results from your press brake, the first time.
Tool It Right: Many Press brake bending issues can be directly related to inaccuracies in tooling. Often we find that customer complaints of bending issues are directly related to worn, broken or simply inaccurate press brake tooling. If you want the best results from your press brake put the most accurate tooling you can buy into it. Premium tooling is more expensive BUT it last far longer, is extremely repeatable when removed/replaced into the press brake and is very flexible as it is segmented allowing for any side flange forming possibility. You’ll invest in premium press brake tooling 1 time and it will last you 3-5X longer than the cheap stuff while providing you years of reliable bending.
Crowning: If your still shimming your dies, it’s time to stop and quit wasting your valuable time and money. Press brake crowning devices compensate for the inherent “flex” of the bed downard in the middle against the tonnage forces the ram is applying. Whether you have a manual or CNC Crowning device you will enjoy the capability to quickly and accurately adjust for
Press brakes Axes of Control
A press brake can have numerous control axes depending on the model. When looking at a press brake, be sure to check which of the following control axes it has:
Y Axis. The standard up/down motion every press brake should have. This is the typical control axis for a single cylinder hydraulic and most mechanical brakes.
Y1/Y2 Axis. A machine with a Y1/Y2 axis designation can control up and down motion for either side of the machine—sometimes allowing it to compensate for worn tooling.
X Axis. This typically refers to the machine’s back gauge or motion stop that is used to keep a part in place for a bend. Allows the back gauge to move forward and back as needed.
X1/X2 Axis. Some brakes may have different “fingers” to act as backgages that are independently controllable—typically useful for complex part flanging.
R Axis. Refers to a back gauge that can be moved up and down. Useful for forming parts with downward-formed flanges.
R1/R2 Axis. If a back gauge consisting of multiple “fingers” has up/down motion, this is how that will be marked.
Z Axis. Marks a back gauge that can move left and right in addition to other movement axes.
Z1/Z2 Axis. If individual fingers can move left/right, this is how that movement is labeled.
CNC Crowning Table(Anti deflection table). A machine with a CNC system can control or “pre-bend” the bed of the machine to correct for worn tooling or flexing of the press brake.
Sheet Lifters(Bending aids). Additional mechanical support for holding large, heavy sheets of metal in place during the down stroke of the press brake’s ram. This lets a single person operate the press brake when bending large or heavy pieces of sheet metal.
Robotic Interfaces. Robotic loading, operation, and unloading systems for a press brake that may allow it to operate almost completely unattended in some circumstances.