Beyond Bending: Press Brakes Can Do Much More
It might come as a surprise that the press brake you walk by on the shop floor each day can do a lot more than make flanges. When considering how to get from product drawings to finished goods, keep in mind that your press brake can do so much more than just bend.
Posted: April 11, 2018
The press brake is one of the oldest types of fabrication equipment that is still in everyday use today. Before lasers and plasma machines cut parts with heat, and before computers were connected to electric drive motors to create CNC machinery, there were press brakes making bends in sheet metal. And despite the fact that the technology of bending has progressed tremendously over the last decades, the advanced press brakes of today would still be recognizable at a glance to a metalworker from the 1940s. Indeed, the press brake has been around for so long and is so ubiquitous in metal processing that there is a strong tendency among fabricators to feel like it’s old news. The particulars such as accuracy, speed, safety, and ease-of-use might change over the years and from model to model, but the work is still the same: it goes up and down; it makes bent parts.
It might come as a surprise that the press brake you walk by on the shop floor each day can do a lot more than make flanges. The press brake is not merely a bending machine: It is a machine for generating pressure in a controlled way, and there are a lot of applications for such a device. In fact, you may already have multiple manufacturing processes in your production that are all doing jobs which could be done by a single press brake with the right tools. One great example is bracing of sheet metal parts. A variety of different types of stiffening braces can be applied using press brake tools. Beading bars are small sections of tooling intended to be placed between normal punches and dies in a press brake setup. When a flange is bent over the beading bars, the bar creates a diamond-shaped rib right through the bending radius that is perpendicular to the direction of the bend. This has the effect of greatly stiffening the bent flanges, making the part more rigid overall.
Beading bars are highly flexible in that they can be freely positioned between segmented press brake tools, allowing the user to make stiffening ribs in various types and thicknesses of material and at any position desired along the bend. Stiffening braces can also be added to flat areas of a part with a different style of tool; this has the effect of making large, flat panels more rigid, and is commonly seen in ductwork, for example. Longitudinal braces not only make thin sheets stronger, they also prevent large panels from flexing when, for example, air pressure around the panel is changing. Stiffening braces formed on a press brake can be used to eliminate gussets that have to be added to products for strength; to reduce the noise caused by vibrations in a sheet metal assembly; or to allow products to be made from thinner material than would otherwise be required for the application.
Various formed structures that are found everywhere in sheet metal products are easy work for a press brake. Louvers are sheet metal features which may be functional (facilitating airflow through an assembly) or strictly aesthetic. Other commonly formed metal features include tread patterns, card-guide slots, extruded holes, and countersinks intended to receive fasteners. These types of features are most often formed by stamping presses or punching machines, but stamping presses are not well-suited to flexible manufacturing, and punching machines are not available to every fabricator, especially if the lion’s share of that shop’s work is geared toward laser cutting.
In cases where you need to form features in small quantities, investing in machinery expressly for those products might not make sense. Purchasing a press brake tool set, on the other hand, can be a fairly inexpensive to way to add these features to a product. And because they are press brake tools, they can be used to make forms in different locations on different parts in a much more flexible way than would ever be possible with dedicated stamping dies. Rapid prototyping or other products that experience frequent revisions benefit especially from the flexibility of the press brake as a forming tool.
From forming metal structures like those listed above, an obvious next-step is the embossing of sheet metal parts. The embossing of company or product logos is a great way to give components a distinctive look and feel, and embossed metal features resist wear and tear in a way that etching or stickers cannot. If traceability is a prime concern for the product, the embossing of batch or part number information can provide durable tracking of a part through its entire lifecycle, even after paint has covered it over. Press brake tools can be purchased which allow for alphanumeric inserts that can be rearranged as needed, just like block letters in an old printing press were rearranged to make different words and phrases. This kind of modular typeface tool allows you to emboss strings of letters and numbers on your products in a highly flexible and cost effective way.
Press brakes can also do jobs which would typically fall to specialized machines. Press brakes can, for example, form rods and tubes that are raw materials that are not often associated with sheet metal bending machines. Press brakes can also be used to add press-fit hardware of various kinds to sheet metal parts. Weld nuts, stand-offs, sleeves, and threaded rods can all be inserted into sheet metal parts using press brake tools that are specially designed for the purpose. There are dedicated machines that are intended to do this type of work, but if the production quantities are smaller, adding a dedicated machine (not to mention the machine operator) might not be economical. Likewise, if the part requires flanges to be bent and hardware to be inserted, bringing those operations together onto one machine can represent an efficiency gain compared to using two separate processes and handling the part multiple times.
At the end of the day, fabrication is really not so much about the right tool for the right job as it is about adding the most value to a sheet metal product at the lowest possible production cost. When considering how to get from product drawings to finished goods, keep in mind that your press brake can do so much more than just bend.
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