The Marmon bead has become a commonplace tube end form throughout many areas within the tube and pipe industry. Today, this application can be seen daily from diesel particulate filter canisters (DPF) on heavy trucks to bi-cone exhaust connectors in the automotive industry. Our machines that we build at Proto-1 have been forming Marmon beads for over 15 years but as the Marmon bead evolved so did our machines and processes.

Past Solutions Meet Future Problems:

In the past, Proto-1 used a rotary or spin forming method to produce Marmon beads on our RFM-6 tube end forming machine. The process proved to be sufficient when it came to Marmon beads composed of mild steel. However, as years progressed, so did the Marmon bead and its tolerances. Proto-1 began seeing new specifications come in with tighter tolerances and different raw materials. Beads that were made with mild steel, now had to be produced on stainless steel. Our first attempts at rotary end forming a Marmon bead on stainless steel proved to be a learning experience. When our rotary machines formed the bead on stainless steel, the material would thin and move out from the bead, so much that it was enough to shear through the bead itself. Armed with this knowledge and learning experience, our engineers went back to the drawing board. Proto-1 devised a new method to form stainless steel Marmon beads on our RAM end forming line of tube end forming equipment. The first process utilized a RAM machine with a progressive end forming tool set to end form the bead. The ram process proved to be a good foundation as wall thinning was reduced greatly versus the past rotary process. However, the radii and angles of the bead were not as defined as the rotary process. Proto-1 then devised a second process to be utilized on our rotary end forming machine. The second process would iron out the bead to produce more profound radii and iron out the angled surfaces. We could now produce tighter tolerance Marmon beads on stainless steel, however, the beads required 2 separate operations and 2 different machines.

Problems Lead to Innovation:

Fast forward to 2012. Proto-1 is still using the same two-step process to produce stainless steel Marmon beads on our RAM-70 and RFM-6. New Marmon specs were coming in with tighter tolerances and new surface profiles. The tooling to produce more accurate beads had become expensive to produce. Proto-1 decided to take a step back and look for a new solution from a different perspective. Using our segmented end forming machines as a base, our in-house engineers envisioned a new segmented machine rather than a Rotary or RAM end forming machine. The creation of the ISM-6, or Indexing Segment Tube End Forming Machine, became that vision. The ISM-6 was built to form a variety of applications that include: Marmon Beads, Flares, Expansions, Spherical Beads, and Reductions. The ISM-6 can produce end forms on tube and pipe from 1.5” – 6.0” in diameter (marmon beading from 2.0” – 6.0”), with critical tolerances and concentricity. The 4 outer jaws clamp and hold the part in place while the inner segments expand, retract, and index. This process allows the segments to move the material into the end form cavity cut into each jaw. The indexing between expand cycles prevents the material from thinning/stretching between segments. This capability makes the ISM-6 ideal for end forms such as Marmon beads, where surface profiles are critical to the performance of the end form. Compared to Rotary or RAM end forming, this new segmented process produces beads with minimal wall thinning, more profound radii and more accurate profiles. Being able to produce a better product, eliminated the need for a second tube forming machine/process. Not only was the ISM-6 able to eliminate an entire process, but the tooling costs are lower. A servo-controlled version of the ISM-6 offers even more capability. The servo-controlled version can be used to swage/reduce the front lip of the Marmon bead before the segments expand, retract, and index. This capability yields even better tolerances especially for the front portion of the end form. The ability to control all the individual axes with servo accuracy allows for multiple combinations of control and form types.


Overall, the ISM-6 became the solution to a compounding problem. Not only does the ISM-6 offer better quality and accuracy but it also provided a cost-effective solution for customer who possibly couldn’t justify the cost of two machines for the older process. The ISM-6 was a product of innovation but the machine as a whole reflects Proto-1’s thought process behind every tube end forming problem; to build the most cost-effective solution while providing utmost quality and service to the customer.

*The ISM-6 is the featured machine from now until the end of April 2020. During that time, the ISM-6 will receive a 10% discount. *

Proto-1 Manufacturing is an OEM of tube cutoff and end forming machines for the tube and pipe industry since 1997. Our machines specialize in tube cutoff, deburring, beading, flaring, expanding, and more.

For more videos regarding the ISM-6 and its capabilities please go to our YouTube page at this link.