Powder MetalsChapters 3.12

http://www.alliedsinterings.com/

Sintered bronze begins as powdered metal which is packed into a die and pressed under heavy tonnage to finished blank - near net - sizes.

This material, now in a "green state”,is then sintered in a furnace to fuse the powdered particles into a solid form. This form remains approximately 20% porous.

Lubricant is absorbed and stored in countless thousands of tiny interconnected pores - between sintered groups of powder - by vacuum impregnation or hours long immersion in hot oil.

Capillary action holds the oil in the bearing and prevents it from dripping out.

http://www.lm-tarbell.com/machining_sintered_bronze.htm

Oil Impregnated sintered bronze bearings

Make Powder

http://asmcommunity.asminternational.org/static/Static%20Files/IP/Magazine/AMP/V163/I03/amp16303p036.pdf?authtoken=6822a0527194782b33d96e9d5b876b165673a344

Press and Sinter

http://asmcommunity.asminternational.org/static/Static%20Files/IP/Magazine/AMP/V166/I08/amp16608p054.pdf?authtoken=a394a51d5b522109a2ba7208a9e20cf210e67530

http://www.marquette.edu/engineering/pages/AllYouNeed/Mechanical/Labs/cjmaprojects.html

Case Study 10

Component: Automatic- Tramsmission Oil Pump

Process: PM Assembly

Weight: PM slide 245 g, PM rotor 178 g,              PM lid 545 g, PM body 495 g Alloy: Slide—FC-0205, other parts—FC-0208Tensile Strength: 50/60 ksiElongation: Less than 1%Apprent Hardness: Steam-Treated Surface—       HRB 85, Rotor Spline—HRA 70Secondary Operations: Double-Disc GrindingAlternative Process: Cast and Machine Annual Production: 1,000,000Description: This oil pump is supplied to General Motors as a complete stand-alone component, ready to install in their 4T40 front-wheel-drive automatic transmission. It is the world's first non-select-fit, high-volume transmission oil pump. Previous automatic pump designs employ cast-iron or aluminum housings and lids. The housing pump pocket would be machined to a typical tolerance of .050mm, necessitating the use of select-fit pump components to maintain the clearance required for good pump performance.The net-form capability of powder metallurgy, combined with grinding the length and parallelism of each component to tolerances of less than .010mm, provides a low-cost, efficient, and reliable oil pump that eliminates the requirement to select-fit during assembly.Eliminating the select-fit operation improves the overall efficiency of the pump, reduces the amount of inventory in the system, and reduces the cost of the assembly operation.Transmission pumps also typically require two powder metal pumping components. This design employs a total of 4 PM parts: rotor, slide, body, and lid. All parts are steam treated for improved wear resistance, and the rotor spline is induction hardened.

CLOSE

                                                                                                                                       

Component Name: Automatic Tramsmission Oil Pump

Weight:•  4 P/M parts: slide 245 g

          rotor 178 g                     lid 545 g

          body 495 g

Alloy: FC0205 - slide; FC 0208 rest

Tensile Strength:

50/60 ksi

Elongation: Less than 1%

Apparent Hardness:

Steam treated surface HRb (85) Rotor spline HRA 70

Secondary Operations:

Double disc grind

Alternate Process:

Cast and machine

Annual Production:

One Million

http://www.mpif.org/

http://www.mpif.org/

Kalpakjian

http://www.iti-abrasives.com/img%5Csolutions%5C2527_Air_Pump_Powder_Metallurgy_Parts.jpg

For the “crankshaft/counterweight, what is the purpose of the small “flat” at the edge of the part?

Powder Metal Air Compressor Parts

What is the advantage of making gears using powder metals?

What draft angle is needed on this connecting rod wall to facilitate removal from the die?