3D Printing: A New Era for Valve Manufacturing?

A Quick Recap

Additive manufacturing is basically the process of joining materials to make objects from a three-dimensional model, usually adding layer upon layer to create the product, as opposed to the traditional subtractive manufacturing methodologies.

The term “3D printing” is generally associated today with hobbyists and consumer-oriented models that use fused deposition modeling, a special application of plastic extrusion. The term “additive manufacturing” comes into play when people are referring to industrial processes. The two processes are generally the same. Whether polymers or metals are the ingredients, the technologies share the common practice of sequential-layer material addition—a joining throughout a 3D work envelope under automated control.

The AM process can either result in a finished product so that it qualifies as direct production, or it can result in a mold or a product that requires heat, finishing or assembly, which means it’s considered indirect production.

In the valve industry, indirect AM production of valves is considered to be the first real innovation for the sand casting process to come about in 200 years. While it can be costly in comparison to conventional methods, many steps and much time are taken out of the process.

However, it is within the direct production process that the most exciting developments have been made, thanks in part to the work being done to develop models for the medical field.

Newer Technologies

Fused deposition modeling (FDM, a term trademarked by Stratasys) or fused filament fabrication (FFF, a more generic term) has been used since the 1980s. This process produces the model or part by extruding small flattened strings of molten material to form layers, and material hardens immediately after extrusion from the nozzle. While this is a good process, the technology is limited for use in the valve industry because the products cannot have fine details, it is basically limited to plastic materials, and the need to remove support material leaves open the possibility of damage to the finished product.

But a newer technology has been developed, based on polyjet technology, which is being used in a machine known as the Connex3. This technology is the first to be able to simultaneously use multiple colors and materials. Because it is capable of producing extremely smooth surfaces and fine details, it can be used for intricate parts, including duplication of an actual human heart.

It was in the process of using this newest technology and manufacturing working models of human hearts in partnership with Houston Methodist DeBakey Heart and Vascular Center in Houston, that Herman Fontenot of 3D Print Texas began to see how this work on human valves could be extrapolated to industrial valves—an industry that is so prevalent in Texas.

Cost and Weight Savings in 3D Printing

Fontenot learned the current construction of industrial valve cutaways used for demonstration purposes was generally quite expensive. He worked with one manufacturer who advised him that currently, their valve cutaways were manufactured with aluminum, and weighed 40 to 60 pounds. The company needed about 250 valves for demonstrations around the world, and every time a unit was sent to a sales representative, it could cost up to $150 just for the shipping.

Because this technology means the model of the valve can be built with transparent polymers, and in many colors, the actual function of the valve can be demonstrated in a complete, 3D model. Actual working models of complex products can be created in one process, even incorporating gaskets and seals, and using various material components, so that 3D printed models can be used to check flow (whether liquid, gas or oil) through the valve, which can also be actuated with a 3D printed actuator.

Additive Manufacturing in Action

While there are plenty of well-known consumer products created with 3D printing, there are more and more industrial products being produced around the world with this technology.

At the Kariwa Plant north of Tokyo, Japan, intricate metal valves are being 3D printed. The valves include arrays of tiny holes and flow channels, which had been difficult to make and had to be assembled from many parts. This project required the expertise of seasoned metal craftsmen to come up with the designs for 3D printing that eliminate not only the assembly, but also the need for burdensome and time-consuming post-processing, like removing burrs from the holes.

In May of 2016, the GE Oil & Gas plant in Talamona, Italy began operating a new additive manufacturing line that uses laser technology to 3D-print end burners for gas turbine combustion chambers.

And finally, this fall Emerson Process Management and Nanyang Technological University in Singapore are creating a new center for research and development on the methods of using 3D printing for the manufacture of industrial control valves. The joint lab program is set to start on Oct. 1, 2016 and continue for five years.

The research projects are aimed at developing methods to design and manufacture control valves for the process industries much more quickly, economically, and with better mechanical properties than were possible in the past. It is believed that much of the technology to be developed will also be applicable to other areas of manufacturing in multiple industries.

Summary

With innovation also inevitably comes the need for standards, and the America Makes & ANSI Additive Manufacturing Standardization Collaborative (AMSC) has been created to address this issue. The purpose of the AMSC will be to coordinate and accelerate the development of industry-wide additive manufacturing standards and specifications.

While additive manufacturing or 3D printing is not economically feasible for large-scale production of commodity or even more specialized valves, there is no doubt that the ongoing technological developments that are accelerating in this field will make innovation in the valve industry easier and faster as time goes by.

Kate Kunkel is senior editor of VALVE Magazine.