There are still fabricators that do not place much emphasis on leveling. Some suppliers, such as in the machine construction or engineering sectors, even think that leveling just means flattening or straightening sheets, a process characterized by manual flattening methods such as hammer and flame, press brake or bending machines. The problem with these traditional methods is that the parts are more or less flat, but the stress within the material has not been eliminated. Cutting sheets with laser or plasma cutting machines leads to distortion within the material, where it becomes bowed and stressed. The results are clear: bowed and stress filled sheets and parts will then have to be subjected to time-consuming rework or are rendered completely useless for downstream processing.
As their products are relatively interchangeable, sheet metal fabricators are under immense competitive pressure. In addition, their customers do not want to assume the costs for sheet leveling; they simply assume the sheets are already flattened. Without the aid of precision levelers, the tight flatness tolerance of today’s sheet metal customers is only attainable with large overhead and know-how. Manual flattening is hardly economical due to cost and lack of expertise. If the price no longer includes flattening, the supplier is forced to forego the leveling process and the customer will complain about a possibly lower quality product in the end.
Contract manufacturers can position themselves in the market by being able to meet high demand for quality at more affordable prices through implementing modern leveling processes. This is a reason why you should perhaps reconsider purchasing a precision leveler.
Roller leveling is the technique used when using a precision leveler to flatten sheets and parts. A roller leveler works by feeding the part through the offset rollers with a gradually decreasing alternating bending motion. Finally, the alternating bending motion and gradual decrease in the leveling process produces a stress-relieved, flat part.
Many laser or flame-cut parts have unique shapes or cutouts that result in a varying cross-section throughout the part. These material variations, as well as any such inconsistencies at the beginning or end of the part cause strong fluctuations in the force applied during the leveling process. One of the challenges in roller leveling consists of delivering a consistent leveling process despite the rapid changes in applied forces. For optimum leveling results, the gap between the upper and lower leveling rollers should remain constant during the process. Changes in the distance between the rollers can negatively impact the final results.
Modern precision levelers are increasingly becoming the standard for many of today’s sheet metal fabricators. The sheet metal levelers are equipped with a servo-hydraulic leveler gap control. The servo hydraulic cylinders can measure any deflection to the machine which affects the leveling gap and within a fraction of a second react by applying a counteracting force. Maintaining the geometry of the leveler and keeping the leveling gap constant is paramount to the effectiveness of the leveler. This same feature allows hydraulic precision levelers to detect an overload, an important feature since excessive leveling forces can cause damage to the machine’s components. For non-hydraulic machines, the machine stops automatically if the load exceeds the machine’s capacity.
Producing flat and stress-free sheet metal not only adds value for suppliers but also for customers. Investing in sheet metal levelers also pays off for contract manufacturers, in particular those who deliver large, complex assembly components to OEMs. Sheet metal fabricators report that after utilizing machine leveling, downstream sheet metal processing becomes easier and faster. They also report 70 to 80 percent less inconsistent bend angles had to be corrected during the subsequent bending processes. The leveled parts also fit better in the welding fixtures and it takes much less time to place them in the fixtures. In addition, the flat and stress-free parts reduced the time it took during the robot welding process and delivered cleaner welding seams faster.
As a supplier, you should strongly consider incorporating sheet metal leveling into your manufacturing chain. Adding significantly more efficient processes to your manufacturing chain will allow you to meet the highest customer demands in terms of part quality. For many fabricators, sheet metal leveling constitutes the bottleneck in their manufacturing chain, and many are not aware of it. It mostly becomes evident when flattening sheets manually, which requires a lot of time and skilled operators. Even an experienced operator might take an hour per part for complex assembly parts.
Customers who still rely on manual flattening methods can save significant costs and resources by using a sheet metal leveler as shown in this sample calculation: an operator takes 20 minutes on average using a hammer and flame. To flatten 10,000 parts by hand, the business must spend nearly $250,000annually on machines, employees and time. Using a modern precision leveler, on the other hand, an operator takes less than one minute per part and can also be occupied in other manufacturing areas during the time saved. According to this example, a contract manufacturer can save well over $120,000 per year. It doesn’t take long to justify the cost of purchasing a precision leveler.
Flattening sheets using a roller leveler is an excellent solution for meeting the demand for precise and reliable parts. Contract manufacturers who supply individual sheet metal parts can differentiate themselves in the market with stress-relieved and flat parts. Therefore, suppliers of complete assembly components save time and money by requiring less rework and producing less scrap. Purchasing a precision leveler is a wise investment for all suppliers in the sheet metal fabrication industry.