Go With the Flow

PMF Industries leads the way in precision metal forming

By Karla Sexton, Industrial Modernization Center

Many Pennsylvania manufacturers would be satisfied to offer a specialized, quality service that’s in high demand in the world market, such as flowforming or flowturning, but for PMF Industries of Williamsport, it’s the Plus that makes them unique.

The combination of flowforming with state-of-the-art processes, in-house manufacturing, design flexibility and overall project management is what PMF Industries calls “FlowformingPlus.”

Flowforming, an advanced form of metal spinning, has been used for years in the military and aerospace industries that required precise, thin-walled, seamless components such as seen in rocket motor and missile casings. However, the process has found increasing demand in other commercial applications for the aerospace, filtration, food, electronics and defense industries that demand hollow symmetrical shapes with relatively close tolerance control, variable wall thickness and profile, improved tensile strength and superior inside surface finishes. Flowforming also allows for the P (in Plus) to stand for “precision,” since it controls tolerances to within the same range as many traditional machining operations and often provides for one-piece construction of parts, eliminating many of the extra welding or “hogging out” that many other traditional fabrication methods require. The process is based on a predetermined reduction of the thickness of a start blank or preform. The reduction is closely controlled, which results in a very uniform or precisely varied thickness in the finished part.

FLOWFORMING VS. METAL SPINNING

Traditional metal spinning utilizes a relatively thinner piece of starting material and produces the shape of the finished part similar to deep drawing. With traditional metal spinning, no reduction of the wall thickness is intended, but tight tolerances or variances are difficult to maintain.

Flowforming is a cold metal forming process for the manufacture of rotationally symmetrical, hollow components. The process uses rollers to extrude and therefore thin or reduce the cross-sectional area of the wall thickness of the blank or preform, which is engineered to produce a cylindrical, conical or contoured hollow shape. This preform is extruded over a rotating mandrel.

The process starts with the creation of a preform using a number of processes, including deep drawing, forging or machining. The preform is engineered to ensure that exactly the right amount of material is present to form it into the final shape, taking into account the varying requirements of the design for wall thickness and conical tapering. PMF pioneered the development and expert use of computer modeling of flowform shapes and the analysis of the factors involved in the flowform process. Utilizing this scientific approach, PMF has been able to reduce development, setup and material costs for its customers.

Once the actual flowforming process begins, the preform is spun and pressed against the rotating mandrel to give it the desired shape. In a manner similar to rolling dough, the material is “pushed ahead” to allow a larger finished product to be created from a smaller preform. The thickness of the finished part is determined by the gap that is maintained between the mandrel and the rollers during the process. This gap can be changed or remain constant anywhere along the length of the part. Flowforming is the only metal forming process that allows the flexibility to vary the wall thickness to produce thicker and thinner sections in any combination almost anywhere the design requires.

MOVING FORWARD PMF

Industries has been a participant in a significant part of the industrial heritage of Williamsport for many years. However, in 2001, the company was poised for dramatic growth when the former family owned business was bought out as part of an employee stock ownership plan (ESOP), and is now managed by the team of President & General Manager John Perrotto and Executive Vice President & Director of Engineering Ken Healy. In recent years, the company has more than doubled its revenues and grown its workforce to more than 80 employees.

“PMF is growing all segments of its business – aerospace, micro-electronics, food processing, commercial filtration, nuclear contaminates/fuel housings and defense,” said Perrotto. “This growth can be attributed to several factors – change in management philosophy to adopt a more aggressive approach to its marketing efforts to penetrate into new industries, improvements such as ISO 9000 certification with the help of the Industrial Modernization Center (IMC), our local industrial resource center that opened new doors for us, new Web site strategies brought to us by MoJo Active and new market penetration overseas.”

PMF’s capabilities in precision metal forming are at the company’s hub. PMF is growing not only revenue, but also in capacities and capabilities. In the last several years, PMF has added an additional 30,000 square feet of facility for manufacturing processes, such as advanced CNC spinning machines, hydroforming and electromagnetic forming to name a few. In the near future, nickel brazing will also be added to their capabilities.

The Plus is also people. “We have a core group of employees who know the business and the technology. We would not have been able to realize this growth without our staff, and it would not be possible to reach higher without them,” stated Healy. “We are positioned well to achieve our vision for the future. With the kind of culture that has everyone rowing together, and with people who are willing to learn and work hard, we can achieve the impossible.”

In addition, Perrotto stated that they understand it will take further investment to reach new heights. “We try to pay a good starting wage and provide good benefits. But what keeps people here is the challenge and diversity of the work, creating new productions. We encourage teamwork and communication.”

“PMF is not about another P – price,” said Perrotto. “Which is trying to be a lowcost job shop. It is about responsiveness and agility. We can adapt to bring together the processes that can provide a better product through engineering and speed to market. We get a lot of repeat business because we are willing to work together with our customers to help them with experimental designs. Often we partner with our customers to co-develop their new products by contributing research and engineering time. We are willing to take a risk on our customers’ success, and it has paid off for us.”