A look at the market for powder injection molding


Randall M. German, professor at Pennsylvania State University (University Park, PA) and Robert G. Cornwall of Innovative Material Solutions Inc. (IMS, State College, PA) have assembled a comprehensive overview report on the technologies, trends, markets, applications, properties, sales, and profits of the metal and ceramic powder injection molding (PIM) business. This detailed financial and technical market report, entitled "Powder Injection Molding-An Industry and Market Report" is 670 pages long, and includes 520 company profiles, more than 1000 literature citations, and 290 patents, as well as a description of vendors, suppliers, and technology variants. What follows is an edited synopsis of this report, which also may serve as a good introduction to PIM.

PIM is a newer manufacturing technology that has undergone considerable maturation and growth during the past five years. The field is aligned with the evolution of advanced materials, formed to net shapes, as used in many consumer products. Overall industry growth is strong and expanding rapidly, with currently about one new entry in the business every few weeks.

Worldwide, there are more than 245 companies, with direct employment in parts production exceeding 4000 people. In addition, many powder suppliers, equipment vendors, research institutes, consultants, and professional organizations are involved in promoting the technology.

These activities amount to another 100 major participants with an additional employment near 1000. The commercial value of the component fabrication portion of the industry has passed $400 million in sales per year, and is currently growing at 22 percent per year. The identified potential market for the year 2010 is $2.1 billion in present day dollars.

About half of all production is in captive or proprietary parts. These products include orthodontic brackets, firearm components, camera and business machine parts, casting refractories, cutting tools, microelectronic packages, wirebonding and other assembly tools. Wristwatch cases, jewelry, investment casting cores, thread guides, spray nozzles, wear components, oxygen sensors, biomedical implants, and automotive airbag components are other popular applications.

The portion of the industry that manufactures custom parts is equally large in total sales, but it consists of many smaller, specialized operations. In addition to the applications mentioned previously, custom molded components are also used for computer disk drives, locks, hand tools, automotive parts, radiation shields, sporting goods, cutters, clippers, thermocouples, connectors, turbochargers, and valves.

PIM Manufacturing

Almost all high-temperature materials are used in PIM, with stainless steel, alumina, silica, iron, and various steels dominating the market. Ceramic production by PIM is almost as large a commercial activity as is metallic production. Ceramic components, though generally larger, sell at a lower price per unit mass. However, some of the most profitable operations use PIM for shaping nonoxide ceramics, including silicon nitride. By comparison, use of cemented carbides is less prevalent. Most of the cemented carbides find applications in wear components, nozzles, and cutters, but they are unsuccessful in high-stress applications.

Current PIM component sizes range from less than 1g to 20 kg (.002 to 44 lb). The process is capable of wide size variations, with parts in production having final thicknesses as small as .1 mm (.004 inch) and as large as 1m (about 39 inches) for some refractory ceramics. Size variations in a single component are minimal, but several successes have been reported with combinations of thick and thin sections with up to a hundredfold variation.

Generally, final part tolerances depend on three factors: molding sophistication, binder composition, and the debinding approach. Essentially the industry can hold dimensional scatter to within .5 percent (one standard deviation), and today even .3 percent is common.

With today's more homogeneous feedstock production, and more widespread use of closed loop feedback control on the molding machine, it is possible to obtain uniform part weights. This gives excellent dimensional control, with a scatter of .1 percent possible on most parts, and .05 percent on both larger ceramic casting cores and smaller metallic parts.

Final properties of PIM materials rival those of most other forming processes. New sintering cycles and processing schemes have delivered sintered properties equaling forged steels, with strengths up to 3 Gpa (435 kpsi) and 3 percent elongation. Thermal, magnetic, electrical, optical, and other engineering properties generally are competitive with standard material forming technologies. Because of a high initial tool cost, it is necessary to seek out complex shapes with high performance requirements and high production volumes for PIM. A cost reduction of at least 30 percent seems to be the benchmark for considering PIM.

Most companies use wax-polymer or related binders (oil-polymer, oil-wax, or polymer-polymer). Low-pressure molding is common at ceramic operations and accounts for about 25 percent of industry sales. However, because of better consistency and improved dimensional precision, most growth is in high-pressure molding.

The dominance by wax-polymer binders leads to considerable use of thermal debinding, followed by solvent and catalytic debinding as the next most popular method. Catalytic debinding of polyacetal binders is the fastest growing segment of the industry. Wicking debinding is still widely employed, especially for ceramic components. Emerging from the research laboratories are binders customized for PIM. These new binders include an acrylic-based system, a polyethylene glycol binder system, a silicate precursor binder for ceramics, a water soluble wax, and a silicate-containing wax binder.

Thermosetting and other cross-linking binders have nearly disappeared from use. Vacuum debinding of wax-based systems has a modest share of the installed capacity. Several other binder systems also are achieving production status, including in situ polymerization and photo-optic depolymerization.

PIM Challenges

With respect to geographic breakdowns, North America is the largest producer of PIM components, accounting for nearly half of all sales. The balance of the world's production is nearly equally split between Asia and Europe. The breakdown of applications shows no major differences in metallic, ceramic, or cemented carbide production via geographic regions.

The top quarter of the industry controls about three-fourths of sales and the same proportion of employment. Total molding capacity exceeds 700 molding machines, 550 furnaces, and 300 mixers. Newer operations buy precompounded feedstock and avoid the capital expense of mixers. The development of continuous sintering furnaces with built-in debinding also is improving productivity.

Since PIM is a new technology, there is a severe shortage of experts. Consequently, many experienced industry leaders have frequently moved between operations, inadvertently bringing uniformity to the technology. A shortage of process engineers is limiting growth.

New binders, debinding processes, sintering furnaces, automation equipment, and molding ideas are constantly outdating the installed equipment facilities.

Customer complaints on PIM largely focus on the lack of standards and poor quality. On the other hand, PIM molders complain that their customers have a poor understanding of the process. A consistent probelm in the industry is long lead times in obtaining tooling. Many large-volume products have not been placed in the PIM industry because of problems like quality, capacity, and lack of multiple vendors.

New applications are just waiting for PIM in most consumer and industrial product markets. For metallic materials, these are usually based on replacing machined components or investment castings. For ceramic materials, conversion is based on elimination of machining steps. Major growth will come in automotive, medical, consumer, and electronic applications. Some impressive opportunities depend on the further fine tuning of such new materials as the amorphous metals for permanent magnets, titanium for consumer products, tool steels for high wear resistance, and ultrahigh-strength steels for high-stress applications.

New developments may overcome several of these barriers. For example, a new low-cost water atomization facility is delivering high tap density stainless steel powder that should be priced below carbonyl iron powder. The BASF process is emerging as an industry standard, especially when coupled with new continuous catalytic debinding and sintering equipment. And new rapid tooling technologies have reduced the time to first tooling to three days. PIM equipment also is evolving to a more desirable level of standardization, with several vendors now offering PIM grade molding machines, debinding devices (solvent, vacuum, thermal, and catalytic), and continuous sintering furnaces.

Plastic molding companies are beginning to recognize the value-added profit potential of metal and ceramic parts and are establishing capabilities in the technology. They are either setting up complete processes, from high-shear mixers to high-temperature furnaces, or they are purchasing premixed feedstocks and jobbing out thermal processing to furnace manufacturers.

The full report is available from IMS for $1800.

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