Custom Powder Metal Services

Advantages of the PM process | Materials | Tolerances | Industries served | Design considerations

Advantages of the PM process:

Ridgway Powdered Metals, Inc. is a true pioneer in this industry having aggressively invested in the technology and equipment which allows it to take full advantage of its many benefits.

Among PM's advantages are:

Eliminates or minimizes machining by producing parts at - or close to - net shape
Eliminates or minimizes scrap losses by typically using more than 97% of the starting raw material in the finished part
Permits a wide variety of alloy systems – some brand-new, others RPM proprietary grades – for customers' items.
Produces good surface finish – 32 RMS or better
Provides heat-treatable materials for increased strength, wear resistance and durability
Provides controlled porosity for self-lubrication or filtration
Facilitates manufacture of complex or unique shapes which would be impractical or impossible with other metalworking processes
Is suited to moderate to high volume component production requirements
Offers long-term performance reliability in critical applications
Is a "GREEN" and SUSTAINABLE industry
Is cost-effective - minimal average cost advantage is 30% (others more than 100%) over other metal working technologies

Our modern facilities list includes:

30 presses whose compacting forces range from 4 through 550 tons, and whose large presses include 5 level capabilities
Sintering furnaces – both conventional and high-temperature units – with large volume production capacities and precise controls for each application
Ancillary deburring, impregnation and other secondary apparatus are on hand and available for customers' critical applications.
RPM manufactures parts measuring from 0.06"to 4.0" long with diameters from 0.25" to 6.0" and weights from a few grams up to 8 lbs.
RPM consistently achieves net shape tolerances as low as ± .0003" on horizontal surfaces
Production rates are rapid at RPM, and dimensional integrity is maintained from part to part, order to order.
Applications are almost limitless, and prices are very reasonable.

Materials:

RPM builds parts in all of the standard Metal Powder Industries Federation (MPIF) grades as well as RPM proprietary grades. (Information by request)
(See "Materials Standards for PM STRUCTURAL PARTS", and "Materials Standards for SELF-LUBRICATING BEARINGS" MPIF Standard 35)

Listed below are some of the more common grades and their possible applications:
(It is recommended that you discuss material selection with RPM Engineering prior to specifying one for your application.)

Material: MPIF CODE; Characteristics

Iron: F-0000; Electro-Magnets

Iron/Carbon: F-0003/F-0008; Moderate Strength, Heat treatable

Iron/Copper/Carbon: FC-0200 to FC-0208; Good strength and wear resistance, Heat treatable

Iron/Nickel/Carbon: FN-0200 to FN-0408; Good impact strength and wear properties, Heat treatable

Alloy Steels: FLN2C-4005 to FLDN4C2-4905; A wide variety of materials with specific properties to match the critical requirements of the application – all are Heat treatable

Copper Infiltrated Steel: FX-1005 to FX-2008; Good strength, improved machinability, gas tight Heat treatable

Stainless Steel: SS-303, SS-304, SS-316, SS-409,
SS-410, SS-430, SS-434, 17-4PH; Select the stainless grade that will satisfy your requirements for corrosion resistance, ductility, machinability, etc.

Copper: C-0000; Electrical applications

Bronze: CT-1000; Self-Lubricating Bearings

Brass: CZ-1000, CZ-2000; Mechanical components and Hardware

Tolerances

Below are shown the typical tolerances for PM parts having uniform cross-sections.

Characteristic

As Sintered

Decimal: Metric

As Sized or Coined

Decimal: Metric

Length Inside Diameter Outside Diameter Concentricity Flatness Parallelism Perpendicularity

± 0.005" ± 0.002" ± 0.002" 0.003 0.002 0.002 0.002: ±0.126
±0.051
±0.051
0.076
0.051
0.051
0.051

± 0.002" ± 0.0003" ± 0.001" 0.003 0.002 0.002 0.002: ±0.051
±0.008
±0.0025
0.076
0.051
0.051
0.051

Some dimensional and feature tolerances may be reduced with secondary machining and grinding operations.

Discuss those possibilities with RPM Engineering.

Industries served

Automotive: The largest market for PM parts

Home Appliances: Virtually every appliance in use today contains some PM parts

Power Tools: PM parts have helped to make them available and inexpensive

Fluid Power: High-density and copper infiltration produce pressure retaining components

Lawn & Garden: That lawn mower, hedge clipper and others are full of PM parts

Agriculture: See that big green or yellow or orange machine in the grain fields - they are all using many PM parts

Construction: Even the mighty bull-dozer must rely on certain PM parts

Motors: Self-lubricating bearings and PM magnets (electro and permanent) keep the motors running

Off-Road: Both for utility and sport

Recreation: Fishing reels and skate boards, outboard motors and bicycles, guns and golf clubs, and many more use PM parts

Hardware: Fasteners, washers, bushings, connectors, spacers, and all sorts of necessary products

Business: Computers, shredders, printers, recorders, fax machines happily find PM parts just what they need

Vending: Multiple applications

Conveyors: Rollers, cams, sprockets, gears

Materials handling: Connectors, latches, fingers, catches, pushers and many more

Miscellaneous: Exercise apparatus, cutter blades, gas filters, weapons, munitions, etc., etc., etc.

Design considerations

Many features that are found on parts made with other metal working techniques are there due to how they were built. PM usually can eliminate them.

PM parts can be produced with great geometric complexities. There are feature considerations, somewhat unique with PM, that should be avoided. Some are listed below.

No feature that would resist ejecting parts from tools: reverse tapers, holes other than in the direction of pressing, threads, undercuts, diamond knurls (all of these can be included using secondary machining)
Thin walls, narrow splines, fine pitch gears (finer than 48 pitch) and sharp corners should be avoided
Features that require very delicate tools to compact – due to the very high compressive forces needed to compact metal powders.
Vertical lengths not to exceed ratios of 4 to 1 of their horizontal ones on heavy-walled objects; 2 to 1 on thin-walled ones
Knife or feather edges should be designed out of parts
Small projections on top faces of parts need to be large enough to allow for tool safety, ease of ejection, and be located inboard from outside edges of parts.

It is always good practice to discuss your parts – those having questionable features – with RPM Engineering.

Virtually any feature that would create problems or be impossible to compact with hard compacting tooling can be added using machining operations.

Whenever a part can be modified to eliminate the additional secondary operations its price will obviously be more advantageous.