Bending tools wiki

In many cases the decision for new equipment is driven by acquisition of new work and in these instances new bender tooling is part of this process.

While this generally means an additional big ticket item to the bottom line, it further makes it imperative that you cover all the bases with regard to what options are available.

This situation is an excellent opportunity to consider bringing in a tooling system that can be built on later as well as meeting the immediate project needs.

A given bending company more than likely over the years has developed a tooling strategy that they find works for their needs. This can be true whether they make the tooling in house, buy the dies as needed from a given tooling supplier or regularly go out for quote from multiple tooling sources as new projects require.

While each of these directions taken has pros and cons there are many important aspects to consider in this decision. For the most part in house made tooling is advantageous in that the schedule of the tooling design and manufacture is controlled. Most companies that go this route use this fact as the primary reason for the decision and unfortunately the design or quality of the tooling can suffer in the process.

The company in question is generally speaking in the fabrication business not necessarily in the tool and die business. Over the years I have worked with many large companies that have spent an incredible amount of time, money and manpower to develop what they consider to be proprietary die designs specifically to address in house die compatibility issues.

While some of these designs were fairly straightforward, others have been so overdesigned for versatility that they are unwieldy, fragile and problematic especially in high production situations. What was started as an integration strategy to stay in control of the processes can easily become a nightmare. The reality is that when problems develop, parts fail to ship or the quality of them regularly fails to meet the needs, even a qualified and capable outside source has its hands tied to come in and offer more than a quick band aid on the fly.

There is also a more insidious aspect that can develop with this inside integration thinking. Many times the company in question can get so caught up in how proprietary and wonderful the design may be time, money, manpower…remember , that they concentrate so much about keeping their cards to vest that they fail to look to outside sources and notice new technology that could and should be integrated into their processes.

Some of the companies I have seen get to this point over the years, are no longer in existence. Having the die work done outside by a company specializing in the design and manufacture of the tooling to suit the specific machine and the application, ensures that the investment is well placed. While it is always important that tooling cost be considered it should not necessarily be the final determining factor. The most imperative consideration to tooling begins with understanding the bending process, and the various design options of the tooling in concert with the application needing to be fabricated.

Many times these design options will fluctuate the cost radically, whether or not those options are justified or even need to be considered can save or cost you in the long run. As ultimately you may invest as much into the tooling on the project as the equipment, you must develop and maintain a mindset of understanding all of the processes involved. Partnering with a supplier to work with you from the initial application analysis, through installation, set up training and on-site support is a major leg up.

A common problem encountered is that an existing library of tooling is already on hand and a decision will need to be made as to building on the existing die work or to depart from it completely with a new design. The selection of the new machine will have a major impact on this decision, but the first consideration should by all rights be the application itself.

If the new project that is to be manufactured is completely different than the current product being made, the decision is an easy and obvious one new product, new machine, new tooling. Many times however in situations where the new product is similar or even in cases where the new acquisition is to increase the productivity of the same part, this decision still bears more thought than you might think.

It should be noted that most bending machine manufacturers have a specific mounting pattern that drives the die design also. While some of them may be receptive to building a new piece of equipment with a different than their standard mount pattern to for instance accommodate your current die library , others may not.

This fact should not be a deciding factor on selection of the machine manufacturer per se, any more that the decision of die design be based on the bender itself. Once again the first consideration to select the process, the equipment and the tooling design, is the subject application.

Potential tooling incompatibility from the existing dies to additional ones needed for the new project can be more than exasperating, it can cripple the project before it gets off the ground.

Though there are several different methods of tube bending that are used commonly, we will be discussing specifically tooling design using the rotary draw mandrel bending method.

Rotary draw bending is by nature more involved and complicated but subsequently the most versatile. It is the only method that is suitable to produce high quality wrinkle free bends in tight radius thin wall tubes. It is by far the most used for any application where support is needed to control the stretching and compression of material and simultaneously prevent the tube from collapsing. The Clamp Die…Grips the tube against the bend die to prevent slipping. The Pressure Die…Moves forward with the tube forcing it to conform to the radius of the bend die.

The Mandrel…Internal to the tube supports the tube at tangent prevents collapse of the tube. The Wiper Die…Rides between the tube and the bend die controls the compression side on the bend.

In the process of bending the tube we must control its natural reaction to the process of inner wall compression and outer wall thin out. In a very simplistic explanation the mandrel being inside the tube supports it from collapsing in the bend process while the wiper die prevents the inner wall compression from bunching up and forming wrinkles.

In any real world scenario however it is far from that easy. The first step in the process is t0 ascertain the tooling requirement for the subject application. Before this however determining the basic feasibility of the bends required together with the tube material. Simply put, will the material be able to form at the centerline radius needed based on its elasticity or elongation percentage.

Regardless of this fact the limitations are real and failure to research this aspect of the project at the onset of it is a drastic mistake. As we consider the natural reaction of the tube to the bending process is outer wall thin out and inner wall compression, the tooling must provide the support to the tube to control this.

This fact means that the tooling in the case of the mandrel and the wiper die are in a fixed position while the tube is drawn across and over them. This in turn crates drag to the tube compounding the prevalence of outer wall thin out. In the case of materials with low elongation, the yield point is reached and the tube fractures.

The balance point then becomes how much support to offer the tube so as not to go so far as to induce enough drag to fracture the tube. Even with material types with low elongation there are strategies that can be effectively employed to achieve success. The bender selected for the project will need to have all the effective options possible for this.

The obvious goal is to effectively form the tube without fracturing and with the least deformation possible. The discussion of these bender options and their implementation fall outside of the scope of this paper, but suffice it to say are an integral part in the success of any bending project. Let us assume then that the homework has been done and the machine selected for the project is equipped as outlined and the best platform possible to get the job done.

We then move to the process of dialing in the tooling itself based on production of the application at hand. To begin it is best to gage the severity of the application. This will determine whether a wiper die will be needed and will further allow the decision of how many balls will be required on the mandrel to support the tube. Again, we must provide the amount of support needed without crossing the fine line of too much drag induced in the process.

We will then calculate the Wall Factor of the tube. Wall Factor. This must then be further considered with the D of Bend. The bend centerline radius divided by the tube O. Once again these aspects must be then weighed with the tube material elongation percentage as well. The benefit of providing an interchangeable tooling system is immediate to the project at hand but also provides a game changing platform to build on as needs change.

The implementation of tooling that can readily interchange pieces of a die set, be repositioned easily in a stack of die sets to accommodate change overs is an incredible time saver. While in some cases it will mean more individual components the setup and die change over time reduction alone is more than worth it.

There are other further benefits as well. Our goal will be to produce perhaps forty different part configurations in three different tube sizes. It is entirely possible that some of the subject parts may have bends of different radius dimensions in the same piece of material.

This will by necessity be stacking multiple sets of dies on the bender. The CNC machine will then position the tube automatically to the correct die set in the stack for each bend moving it forward and rotating it between the bends based on the XYZ coordinate data programed in for each part.

There will be certain parts in the project simple enough to require a straight forward single die set, and in those cases the machine will go through the same motions as noted but with no need to transfer up to a different level in the stack.

Here is a visual example of a tube that will represent parts typical to our hypothetical project. It stands to reason that if we look simply at one tube size in this scenario that we will require a different bend die for each bend radius needed. Each of these bend dies might need multiple gripping lengths dependent upon the part configuration needed. The system we will build will then have the ability for each bend insert to interchange into each bend die in a common tube size.

Every bend die insert will have the same bolt hole pattern allowing for a minimal number of hand tools and time to change to a different length or surface finish. All the bend dies will be exactly the same height with the machine mount provided on both the top and bottom so that they will all sit on the machine the same or in any position in the die stack regardless of tube size or of centerline radius.

It will be possible to preset certain die stacks if needed to load on the machine as one unit to further facilitate quick die changeover for part changes in production. All the mandrels will be made where possible with the same length of shank and thread size.

And all wiper dies with a uniform mounting pattern. Die sets or stacks could be pre-assembled based on tube part number prior to the machine operators shift based on the daily production requirement for the job. The benefit for the long term building on this foundation is substantial as well.

In an all too familiar scenario of part dimensional changes in production and additional parts thrown into the mix, the interchangeability of the die system is obvious.

Now assume that your customer or a new customer entirely needing an emergency prototype etc. The additional dies needed by your tool supplier will simply and quickly be a new bend die body and a wiper die rather than an entire new set. The ability to have this versatility work for you is an immediate return on investment. The long term benefit can be the start of an entire new direction of thinking for production problems far too familiar to many.

For obvious reasons the type 6 die shown on the previous page is in most cases the best to consider for the versatility of the removable grip design. This is also a beneficial design for tooling strength as the grip insert bolted in is fully supported by the body of the bend die itself, rather than in the design of the type 1 die inserted spool where the grip is left unsupported for a portion of its length. Either of these bend dies offer greater versatility in that the grip area can be exchanged with one of a different length or even a different surface finish.

The grip can be made with directional serrations to aggressively grip the tube even on the shortest gripping length. These serrations can be made with different peak spacing and height to make them finer and thus minimize the amount of surface marking to the tube.

An alternative tube groove finish that can provide even the shortest grip with the ability to firmly hold the tube is a tapered knurl finish. While this has the impression and appearance somewhat to a typical knurling process. While this will still mark the tube surface in the bending process, the marks are less noticeable and it is possible through a secondary operation to reduce them to even less of an issue. As we discussed, the bends get more severe as the tube OD increases, the bend radius decreases and the wall thickness of the tube gets thinner, all of these aspects draw on the decision of the bend die design.

The grip length and surface finish being simply one of them. The break point on when to change from a relatively simple design of the type 1 to the type 6 is based on the amount of grip insert that will be unsupported. As the radius of the type 1 die gets tighter the amount of material that will fully support the grip area is reduced. If that reduction means more than a third of the length of the grip insert has no backing the grip can in extreme situations weaken, deflect or even break.

As we are building a system to ensure optimal compatibility we are going a slightly different route. It has been found that using the attributes of both these dies in a hybrid design can bring about the most versatile and strongest platform This will be the first design point we will build on.

First however we need to get some other basics considered. There are several schools of thought regarding Interlocking dies that should be factored in as well at this point. Reverse Interlocking Non Interlocking The most obvious advantage of interlocking tooling is that it self-aligns to a degree but most importantly the alignment of the tooling to itself once the hangers are adjusted and locked down , is consistent set up to set up.

These hangers for the clamp and pressure dies respectively once set should not be removed from the tooling, ensuring that every time they are put into the tooling set the alignment is there. This makes any adjustment or tuning of the tool set changing from one to the next minimal if needed at all. In the event that you are bending a thick piece of sheet metal, you can apply heat from a blowtorch along the seam of your bend line to facilitate your bend.

Keep in mind that many kinds of fabricated metal have extremely high melting points, and applying your torch injudiciously could cause damage or do harm to your sheet metal or equipment. I want to bend aluminum by hand to make my own mobile phone case.

What is the minimum thickness I need? There isn't really a minimum. Thinner aluminium bends easier, just like steel, but you also want structure so it holds its shape. So your best bet is to buy something like 0. However, thicker sheets are more prone to cracking, and then there are different grades of aluminium, so you will need to buy the right grade for the job too.

Not Helpful 2 Helpful 8. I have a bending machine and am working on a door frame. Most of the time, my sheet size is wrong when I bend it. What should I do?

Did you size the sheet of metal to take into consideration the stretching of the metal at the bend? If you do a degree bend, the metal will stretch and shrink the thickness of the metal. Not Helpful 5 Helpful 7. Not Helpful 3 Helpful 3. That depends on how you want to bend it. If you want to bend it, in an elbow like a piece of pipe, that isn't going to work as the wall of the can is too thin.

The can will collapse under any kind of bending operation. Unlike a pipe which derives its strength from the thickness of its wall, aluminum cans actually get their strength from the non-compressible liquid sealed inside them. However, an aluminum can could be cut into pie wedges and welded back together in the form of a segmented elbow like those used for vent pipe if you really, really need one. There's plenty of welding videos for aluminum cans on YouTube. Not Helpful 2 Helpful 2.

Apply an equal amount of force used to create the crease in the opposite direction of the crease. Yup, easier said than done. Once a piece of sheet metal is creased, its well neigh impossible to take the crease completely back out of it.

In smaller pieces, I've had success tinkering out a crease with a hammer and a dolly, or on a hydraulic bench press sandwiched between two pieces of flat bar.

In a large sheet, a long piece of flat bar could be used as a dolly and some careful tinkering, but the crease will almost always be noticeable. I used a forklift once to flatten out a piece of sheet with mixed results. Next time I'd want to sandwich the sheet between some flat bar first. Not Helpful 3 Helpful 0. Include your email address to get a message when this question is answered. By using this service, some information may be shared with YouTube.

To remove irregularity or improve uneven bends, place a hardwood piece lengthwise along the bend and hit the bend with increased strength using a heavy-duty hammer or mallet.

Helpful 0 Not Helpful 0. In some cases, as with thicker sheet of metal, you may need to use a sheet metal brake to apply your bend. Manual sheet metal brakes for hobbyists and small or mobile businesses are available at affordable prices at most hardware stores. Hydraulic, computer controlled sheet metal brakes are very expensive and used for high-volume industrial or construction use. Submit a Tip All tip submissions are carefully reviewed before being published. Make sure you have correctly solved the bend allowance equation before attempting to bend sheet metal.

If the equation is solved incorrectly, your sheet metal bend will be incorrect and your sheet metal could be ruined. Helpful 1 Not Helpful 1. You Might Also Like How to. How to. More References 2.

Co-authors: Rugged printing materials have the potential for longer service life, but they are also more costly. In any case, on low-tonnage small bending machines, even cheap printing polymers can last a long time, which is of commercial significance. Imagine a small electric bending machine with standard tools. All tools can be conveniently stored in adjacent drawers. Next to it is a set of steel seats, all of which can be connected to the printed die and punch. The remaining jobs will be printed out, either sent to the Additive Services Bureau, or printed in an internal 3D printer library adjacent to the project in the headquarters office.

Considering that they usually only need a part of the printing tool instead of the base, the printer does not need to take a long time. The printing plant also produces forming aids such as inspection gauges, customized backstop fingers and pins. These tools and auxiliary tools are printed, and because most tools and auxiliary tools are destined to be small machines for short bends, they are usually small and light enough to slide into working travelers.

All of these effectively make the smallest bending machine in the factory have the greatest flexibility and the highest productivity. Shops that try printing tools cannot learn from decades of tool design experience. In this sense, early adopters have found the tip of the iceberg. Unknown things abound, but so are possibilities. Reprint Statement: If there are no special instructions, all articles on this site are original.

Please indicate the source for reprinting. Skip to the content Home Sponsored Content 3D printing tools can make low-tonnage bending machines more flexible. Sponsored Content. Flexible electrical Imagine a small electric bending machine with standard tools.

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