Category Archive: Uncategorized

Roll Forming Vs. Press Braking

In a previous blog post, we discussed the differences between roll forming and stamping, and specific advantages roll forming presents over the stamping process. Here we will take a look at roll forming versus brake forming—the difference, advantages, and distinctions.

Also known as pressing or press braking, brake forming has some similarities to roll forming. However, brake forming has several limitations that make it the right choice only for specific situations. The tools only produce parts in low volumes, so while it can be economic if the required volume is kept to a minimum, it is a highly labor-intensive process with a longer lead time.

Automated brake forming

Additionally, press brakes are limited to the length of the part they can form—it is very difficult to find press braked parts that are very long. While some automated braking is now being seen, in general, it is still a much more expensive process.

Roll forming also has closer tolerances on the profile than brake forming. When it comes to hole punching and end flare, however, brake forming has better location tolerances. In simple terms, roll forming is done in a linear fashion, while brake forming is done in width.

What are some other differences and advantages of roll forming over brake forming? The profiles with roll forming are often so complex that they simply may not be able to be brake formed. Additionally, historical-style brake forming in many different operations leaves more room for error (and profile dimensions are much worse, and brake forming leaves a lot of gauging)—while roll forming is quicker and can do mostly anything, as opposed to brake forming, which is more limited. Brake forming, for example, can’t do sleeves, as the radius of a sleeve is too large.

Production automated brake forming may be used for higher volumes, but it is especially needed for items very difficult to roll form, such as ones that are not formed in a linear fashion only. Tooling and setups can be expensive, but tolerances are very repeatable for things like hole punching and lengths. It is the only high production option for some parts, and the use of these are growing, taking away more manual brake pressing in many operations than in the past on higher volumes. Roll forming has not seen much business loss from that style of brake forming, but it is a factor today.

As you can see, the only time brake forming is preferable to roll forming is when the volume is very low, the run is short, and the shape needed is compatible with the press brake.

Tips on Becoming a Government Supplier

As the government is large in size, it is constantly in need of new suppliers for any number of different goods. This is especially so with the Defense Department. According to the Congressional Budget Office, for the fiscal year 2014, the DoD’s budget is an impressive $607 billion. In this blog, we will point out some of the better ways on how to become a supplier for the U.S. government and what you need to know about military contracting.

  • The first step is to sign up for the System for Award Management (SAM). According to their website, SAM is a free program that “consolidates the capabilities” of the Central Contractor Registration/Federal Agency Registration (CCR/FedReg), Online Representations and Certifications Application (ORCA), and the Excluded Parties List System (EPLS). SAM allows government agencies to review a vendor or subcontractor’s qualifications when they are in the process of awarding contracts.
  • Once you sign up for SAM, you can head over to the Federal Business Opportunities website. The site, which has helpful videos to guide you through the process, claims that there are more than 23,300 active federal opportunities available.

Now that you have a general idea of how to get started, there are few specific tips for working with the military.

  • As you might expect, confidentiality is major part of any military contract. At Johnson Bros., many of our military projects require us to keep secret a wide range of information including materials, sizes, and even packaging.
  • Versatility is a must. Military projects often require low quantities and very specific turn-around times. Production delays or faulting products will hurt your chances for future jobs.

If you want to learn more about how to become a supplier for the federal government, you can visit the SAM website or you can also drop us a line today.

Roll Forming Vs. Stamping: Differences and Advantages

We have found that oftentimes, current and potential clients in need of metal fabrication want to know the difference between roll forming and other processes and which is best for them. Many wonder if processes such as stamping, brake forming, or extrusion are the right choice, and how they differ from roll forming.

Roll forming versus stamping, for instance, presents a number of differences, as well as certain distinct advantages. We will identify the differences between roll forming versus stamping by going over some common fabrication factors considered in both: length, labor, material, and fabrication processes.

The length of a part is one of the most important factors when trying to decide between roll forming and stamping. In most cases, stamping parts longer than 10 inches will have more expensive tooling. A 36” to 48” stamped part may be double or more what roll forming dies would cost. Roll forming tooling, on the other hand, has no restriction on length other than the size of the facility producing the part and the weight-handling capabilities there.

Stamping will get even more expensive if there are multiple lengths of the same profile. To produce parts at multiple lengths, completely separate multiple stamping dies would be required. The more lengths you add, the greater the stamping die cost. With roll forming, no additional tooling is usually required. A simple adjustment can be made on all roll forming machines to produce parts of different lengths, typically using a digitally-controlled computer.

Another operation cost is labor. One way stampers attempt to create longer parts is through secondary assembly. Secondary assembly does reduce the tooling costs, but it increases the labor costs to join the two parts together. As we already learned, roll forming can adjust part lengths on the machine on the fly, which is much less labor intensive. Stamping short parts is also more labor intensive when including holes, trimming, or complex notching and multiple stamping press stations that may be required then. Most stamping dies don’t include advanced fabrication options, so a secondary operation is required, which can be conveyorized and automated, also at extra expense and setup cost. With roll forming, many advanced fabrications, such as holes, trimming, or notching, can all be done inline, reducing secondary fabrication costs, though additional fabrication conveyorizing can also be done in roll forming. There are also many ways to post fabricate roll formed parts automatically in conveyorized stations as we do at Johnson Bros. For example, as a reduction of allowed end flare, roll forming can produce that; stamping and brake forming do not.

The metal options between stamping and roll forming are very different. Both can handle light-strength steel, such as carbon steel, but when it comes to working with high-strength steels, roll forming has the upper hand. High-strength steels are very difficult to stamp because of springback, galling, and scratching. The harder the steel, the more likely the steel will bounce back to its original shape after stamping. Even if stamping is successful in forming high-strength steel, there will be evidence of galling and scratching on the finished shape. In roll forming, there is a gradual bend as steel moves through each bending pass. This gradual bend reduces springback, galling, and scratching when high-strength steel is used.

For the right applications, roll forming has many advantages over stamping. Roll forming can offer the lowest tooling and maintenance costs with the assurance of quality metal fabrication.

Now that we are in the new facility, which doubles our size, stampings will also be offered at Johnson Bros. (with some already produced!).

Putting a Curb on End Distortion

Roll forming is a time-honored manufacturing process, performed by bending a flat metal strip continuously and progressively by tandem sets of roll tooling. Many customers use roll forming in place of press braking, stamping, and extruding because it allows for longer lengths, higher tolerances, sweeping, hole punching, and the use of high strength materials. It is safe to say that customers who want high quantity parts will save money, production, time, and will have more options when roll forming is used.

There is a problem that occurs occasionally with customers moving from other fabrication techniques. Having not dealt with this problem, they don’t understand one of the primary complications of roll forming. The problem is end distortion. End distortion, better known as end flare, is the deformation at the ends of a roll formed part. Roll formed parts with end flare may have one end bent slightly inward and the other end bent a little more than that, but outward (Type A in image), or a more likely result when both ends are bent outward (Type B), with one end slightly less than the other. Each type is caused by the release of residual forming stresses after the part is cut.

End Flares

In order to reduce end flare, it is important to consider the causes and what steps can be taken to prevent and correct them as much as can be possible.

The forces exerted on the metal strip during roll forming are not the only sources that can cause distortion. The distances between the forming regions is also instrumental in this process. A greater distance between the ends is likely to have less end distortion than a shorter distance. Pre-notched materials can be another source of distortion. The back edges of the notches can hit the rolls during the rolling process, causing them to toe in, which results in more distortion than a normal end, unless the distortion is corrected within the die set up and design. The cutoff process is the main potential source for flaring, with the die potentially causing distortion at both the leading and the trailing ends of a roll formed profile. The cutoff die will produce more distortion from its leaving side, as more clearance is necessary to allow the part to move out of the die and the entry end to move through without getting snagged. Another consideration of distortion from the cutoff die is when the orders are in very high footage quantities. On high quantities, if tolerances are allowed to be greater, adding more clearance so parts can run through the die faster, providing lower prices and helping to prevent any potential downtime.

Crop or slugless cutoff dies generally produce more end distortion, but they allow for less downtime than slug type cutoff dies. The slug type cutoff dies typically require more downtime because they wear more quickly than the crop or slugless dies. With additional wear, the slug type cutoff dies require more sharpening to prevent burs. Slug cutoff dies do allow for less flare or end distortion and can even be designed to provide the least flare possible or to spank the end of the parts on the sides to remove most of the flare. The more complicated the die, the more maintenance and downtime that will increase the part cost.

Fortunately, other steps can be taken to troubleshoot this problem. A downhill roll die design helps minimize end distortion, with less longitudinal elongation and forming than conventional uphill designs. Another method during the design stage is using a longer length profile region during manufacturing, or by spreading the forming out over more stations. When using more stations, there is less angle increment per length, less forming movement, and less end distortion than on less end stations used to make the same part. Mounting a pair of side rolls before a forming pass is another common method for preventing end distortion, as these reduce the surface stresses in the forming zone, and are particularly effective when dealing with notched rolls, but can be much less exact and can form with more variance or be less accurate between stations. Sleds or solid fixtures from one roll station to the next will also help keep away distortion, especially when pre-punching, but these can wear quicker than roll dies do, creating more downtime.

When distortion has already occurred, a number of post-treatment options are available, including counter-forming, straightening, and a combination of the two. With proper design and post treatment options, the problem of end flaring can be dealt with safely and effectively. One example of post-treatment options is a secondary conveyor-fed operation may be used to remove the end flare by spanking the sides of the part at the ends. This secondary operation typically allows faster production with a less complicated die design, and can be added if the current flare is not acceptable. With proper design and post-treatment options, the problem of end flaring can be dealt with safely and effectively.

Roll forming has many advantages over the other fabrication techniques, but if end distortion is overlooked, especially during the design phase, it will be very costly. It is imperative that any potential roll forming customers know about end flare and work with a roll form manufacturer who understands how to avoid it.

High Dollar Tooling at Johnson Bros

As the economy improves, so does the American manufacturing sector. At Johnson Brothers, this exciting rebound has been noticeable and we couldn’t be more thrilled. As each month has passed, the number of higher-dollar value tooling orders has increased.

Perhaps the most interesting part of this recent boom is that people are not just demanding more tooling, but also tighter tolerances due to the fact that customers no longer need to compromise quality to lower cost. This movement towards more exacting custom tooling means that we have moved away from pre-punch technology in favor of inline fabrication done by the same inline die that also cuts off the part or an inline press die. Whether it is for slot-to-slot, hole-to-hole, or holes-and-slots-to-ends, customers don’t just want higher volumes, but also higher levels of consistency and quality. When it comes to both, nothing beats inline fabrication compared to expensive secondary fabrications.

While we also offer outstanding pre-punch services, with lower die costs and lesser tolerances, there are some projects that demand inline fabrication in the same die as the inline cutoff die. This avoids stretch, making tolerances greater with less distortion of holes, slots, notches, etc. when done in the pre-punch die. At Johnson Brothers, we have highly trained tooling design and construction experts that can handle the extra demands of tighter tolerances.

As with any good news, our ability to handle larger orders and incredibly tight tolerances has spread around the country. Leading makers of furniture, partitions, displays, racks, solar panels, and filters (just to name a few!) have come to rely heavily on Johnson Brothers for custom tooling along with a wide variety of other services.

If you need custom designed and constructed tooling, and you demand the industry’s tightest tolerances, then contact one of Johnson Brothers’ tooling experts today!