Ram Tube End Forming
Ram end forming is one of the most common forms of tube end forming. This process is completed by loading a tube into a set of clamp dies. Depending upon the application, these dies will have cavities cut within them for the tubes to rest in, and the end form profile will also be cut out for the tooling to move the material to. When the end forming cycle is initiated, these dies will close and statically hold the tube in place. Then a shuttle with either a tool or a set of tools will move forward to form the end of the tube. As the tool forms the tube, it causes the metal to creep, otherwise known as cold flow. The metal will follow the path of least resistance and it moves until it’s formed into the profile cut within the tool and the dies, resulting in a complete part.
Pros & Cons
Ram end formers have many benefits. Due to their hydraulic power, some ram end formers are powerful enough to form wall thicknesses as large as 0.500”. As much as 250 tons of forming force can be supplied with some models. This hydraulic power drastically increases their expansion and reduction range capabilities compared to rotary or segmented method. In terms of expansion range, for standard diameters and wall thicknesses, a ram end former is only limited to the deformation that the material can handle before it reaches a failure point. Because the material is moved into a tube cavity cut within the dies, ram tube end forming is a very accurate process that it capable of producing tubes with critical tolerances, concentricity, and offsets. Ram end formers are an ideal machine platform for tube and pipe that requires multiple kind of end forms to be produced in one machine/operation. Some ram machines are progressive tube end formers with the ability to be equipped with multiple tools to complete various forms on one tube. Aside from their power, they also have to the capability to progressively expand or reduce a tube, colloquially known as progressive ram end forming. Proto-1 has accomplished progressive tapered reductions from 4.5”-2” and 3”-1.5” with our line of ram end forming machines.
While ram end formers have many benefits that make them ideal for various applications, they do possess certain drawbacks as well. Depending on the material type, beads with tight or radical radii can be hard to form since it’s difficult to move material into the radii profiles cut within the dies. This can lead to washed out/flatter radii within the final part. Some bead applications that are ram end formed may require a rotary end forming process after to iron out the bead into specification. Free forming, where the material doesn’t have a cavity or profile to form against, can be difficult and lead to less accurate parts. Tooling for ram end forming can be heavy and costly depending on tube size and wall thickness. This heaviness can also increase tool changeover times. If a part is bent, it may require compound dies that are heavier and take up more space. Ram end forming tools are specific to the tube wall and diameter being formed. Tooling allows for little to no change of the wall thickness and diameter of the supplied material prior to end forming. Should tube suppliers change, be sure to verify that the newly supplied material matches the specifications of the previous. For larger applications (4”+), the footprint of the equipment is larger than the other 2 end forming methods.
Ram end forming is practical method for many types of applications. Complex expansions or reductions that may require progressive end forming are best suited for ram end forming. As aforementioned, their expansion and reduction range is the best in class out of the 3 methods. Small beads and 37° & 45° are easily achieved via ram end forming. Larger beads, like Marmon beads are possible but the front of the Marmon is free formed. For better results on Marmon beads, we recommend a segmented end forming method. Offset expands, for applications such as fuel funnels, are best suited for ram end forming.
* Proto-1 is an OEM of tube cut-off and end forming equipment for the tube and pipe industry. We have full line ups of ram, rotary, segmented, and tube deburring machines. We also strive on custom application and adding automations to help with difficult applications. If you have any question regarding tube end forming, please contact us today. *
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