The P/M Process

What powder metal can do for you

Powdered metal (P/M) technology excels at producing complex parts to high standards of quality, in a variety of metals, at a cost which compares favourably with other manufacturing techniques.

As a general rule, manufacturing costs can be cut 30 to 70% when P/M replaces machining, casting, stamping and similar processes.

In addition, P/M is well-suited to the production of complex shapes which may not be readily achievable by any other processes.

P/M is ideally suited for quantity production of small parts.  Because each part is formed in a precision mold, close dimensional control is possible and production rates of over one thousand parts per hour can be achieved.  P/M can be cost-effective in lower volume production, provided that care is taken to hold tool making and set-up costs to the minimum.

Many P/M parts are ready for use as they leave the sintering furnace.  Close dimensional tolerances can be achieved without secondary machining.

When necessary, secondary machining and processing can be carried out on the parts.  Options include operations unique to sintered materials, such as impregnation of the metal with lubricants or resins; standard metal-treatment processes such as carburizing or annealing; and machining.  Machining may be necessary to drill crosswise holes, cut channels and tap threads which cannot be formed in the die.  These operations can be offered in the green or in the finished state.

P/M is a low-cost method of producing simple and complex parts to exacting standards, in a wide variety of ferrous and non-ferrous metals.  It is cost-effective because it reduces waste and eliminates many traditional operations.

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The P/M Process

Stages in the development of a sintered metal part.

Powder metal is deposited into a precision die cavity.  Tool members, operating at typically greater than 35 tons per square inch, are brought together to compress the powder into a solid form, known as the “green” part.

The form is placed in a controlled atmosphere furnace, where the sintering operation takes place.  Sintering takes place at an elevated temperature, typically 1100C to 1300C, where powerful metallurgical bonds form between the particles.

Many sintered parts are ready for use as they leave the furnace.  The part shown here requires secondary machining.

1. The raw material: iron in powder form.

2. The green part, as it leaves the press. The slug is copper, which will be absorbed into the part in the sintering furnace.

3. The sintered part, as it leaves the furnace. The iron body has been infiltrated with copper, for greater strength. Secondary machining: the part has been bored and sized, accurate to .0008" on the diameter.

4. Finally, an internal thread is cut.

5. Secondary operations may be needed.