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FAST, FLEXIBLE & FRIENDLY – Developing a Cost Efficient Tooling Package for Today’s Job Shop

Having a versatile set of tooling is key to press brake productivity.

Purchasing a new press brake can be a pretty daunting task. You’ll have a lot of important decisions to make regarding such things as the length of the machine, the tonnage capacity, the distance between the side frames, the open height and the stroke length. And after you’ve finally selected the press brake that you want, you’ll have to decide which tooling system you’re going to use in your new machine.

Of course, the last thing that you’re going to want to do is to spend a small fortune on a long list of punches and dies. And you shouldn’t have to. So, how can you get tooling for your new machine that provides maximum accuracy, is fast to set up, is flexible in meeting the majority of your needs, provides high quality parts that consistently meet and exceed your customers’ expectations and is friendly to your budget?

The first place to start is to get assistance from someone that has a lot of experience in tooling applications, like your local Wila regional business development manager. He’ll help you to select a versatile set of tooling to maximize your productivity and produce parts of the highest quality using the smallest number of tools possible. For example, if you’re working in a job shop environment, you’re most likely bending materials that fall within a thickness range of 22 gauge to 0.250 in. If so, applying the following guidelines will help you to minimize the number of tools that you’ll need to produce a wide range of parts.

PUNCHES

1. With few exceptions, all punches should be able to be loaded and unloaded vertically. Sliding tooling in and out the end of the machine is time consuming and costly.

2. For air bending applications, use acute angle punches whenever possible for bending materials of 0.120 in. (3.0 mm) in thickness and less. They are fairly strong, have more than adequate compensation for springback with virtually all material types and can bend almost any angle you’ll ever need to produce on a press brake. Some can also be used in hemming applications. They are also lower in cost than gooseneck punches, making them less expensive to replace when damaged or when you need to add additional length.

3. Use gooseneck punches for bending parts that have return bends and complicated bend sequences. Their large relief areas make them extremely versatile and helps to reduce the need to make punch changes when going from one part configuration to another. Heavy duty gooseneck punches are also available for bending materials in the range of 10 gauge to 0.250-in. mild steel and provide tremendous strength and versatility.

4. When the open height allows, always select tall punches (6 in./152.4 mm and taller) when tooling up a new press brake as they are always more versatile than short punches. As a general rule, we recommend that you leave approximately 4 in. (100 mm) of space between the punch and die after the clamping system, punch, die and crowning system, as well as filler block, or die holder (whichever applies), have been installed for part handling. This places a premium on purchasing a press brake with plenty of open height if you are planning to bend boxes and four sided parts.

5. Always purchase punches with hardened working surfaces, and the deeper the hardened zone is the better. Hardened working surfaces not only maximize tooling life and provide a better return on your investment, they also provide maximum long-term accuracy retention. This is extremely important when bending parts on a precision CNC press brake, because, aside from the back gauge, the punch tip and the shoulder radii on the dies are the only surfaces that ever come into contact with the material. It is for this reason that Wila CNC-Deephardens the working surface on all of our punches and dies to HRC 56-60 to a maximum depth of 0.197 in. (5.0 mm).

6. To avoid applying excessive concentrated load, which almost always results in premature wear along the punch tip radii, never allow the material thickness to exceed three times the punch tip radius when bending 10 gauge mild steel and thinner. When bending materials that are thicker than 10 gauge mild steel, never allow the material thickness to exceed twice the punch tip radius.

7. Some applications like bending stainless steel and soft aluminums, for example, may require punches with special tip angles and/or special tip radii. If you are going to need them for your new press brake, try and order them in advance of the delivery of the machine so that you are not waiting for them after your machine arrives. Wila can normally ship punches with modifications to the tip angles and/or radii within ten business days following receipt of order.

Bishop recommends using gooseneck punches for bending parts that have return bends and complicated bend sequences.

DIES

1. When possible, use acute angle dies to air bend everything. Today’s advanced CNC controls accurately determine the proper amount of die penetration that is required to bend practically any material to any angle. It is no longer necessary to purchase dies to match the included angles of all your punches. This will eliminate the unnecessary duplication of die openings, reduce the number of die changes that you will have to make and save you a lot of money.

2. Most parts can be bent with standard dies that are 2.165 in. (55 mm) tall. Parts that have long down flanges require taller dies. While Wila has a full range of standard dies that are 3.937 in. (100 mm) tall, they should only be selected when required, as taller dies are more expensive than short dies.

3. As with your punches, you should always purchase dies with hardened working surfaces. Again, hardened working surfaces not only maximize tooling life and provide a better return on your investment, they also provide maximum long-term accuracy retention.

4. Try and use one die for each two to three material thicknesses that you plan to bend. The following table provides some general recommendations for the selection of a versatile range of dies to bend mild steel in the thickness range of 26 gauge to 0.250 in.

As you can see, in most cases, you can use one die to bend two or more material thicknesses and still get optimum or near optimum results in terms of the inside bend radii, minimum flange length requirements and tonnage requirements. In this case, we would use a total of five dies to bend the entire range of materials from 22-gauge to 0.250-in. mild steel. Of course, you may still need tooling for other applications such as hemming, offset bending, large radius bending, etc.

Bishop also recommends that you should always purchase dies with hardened working surfaces.

As a final suggestion, while it is contrary to the way that things were done in the past, it is actually a good idea to avoid purchasing a lot of tooling with your new press brake. Instead, try and purchase just enough tooling to meet your needs for approximately the first four months of production. This should provide the service engineer with an adequate amount of tooling to set your press brake up and train your press brake operators in the use of the machine and control, and yet allow you to complete the jobs that you need to run in the short term. However, it is almost a certainty that the technology on your new press brake and control combined with the speed of set up, accuracy and flexibility provided by your new Wila tooling system will make you rethink the way that you schedule your jobs and produce your parts. As you do, your tooling needs will no doubt change as well.

Whatever your needs, when you combine Wila’s fast, flexible, and friendly approach to tooling selection, you’re sure to get a cost efficient tooling package that will maximize the productivity of your new press brake and pay for itself several times over the life of your new machine.

Wila