Environmentally Conscious Design & Manufacturing (ME592) Date: April 24, 2000 Slide:1 Environmentally Conscious Design & Manufacturing Class 20: Remanufacturing.

Environmentally Conscious Design & Manufacturing (ME592)

Date: April 24, 2000 Slide:1

Environmentally Conscious Design & Manufacturing

Class 20: Remanufacturing

Prof. S. M. Pandit



Why Remanufacture?

Co

st

New

Remanufactured

Reused

(40% less)

Po

ten

tial

Per

form

ance

&

reli

abil

ity

loss



Why Remanufacture ?

• E.g. - Cartridge remanufacturing saves 38,000 tons of metal & plastics annually

• 18 million gallons of oil needed annually to make cartridges

• Encourages local small business• 1000 years needed for plastics to decompose



Bearing Remanufacture - 1




• WEAR LIFE vs. FATIGUE LIFE

- The estimated service life of ball and roller bearings is based upon metal fatigue.

- Few bearings reach full life expectancy but are retired early because of wear, not fatigue.

- One recent investigation of 50,000bearings removed from service revealed that less than 10% were scrapped because of fatigue failure.



• Rated average fatigue life = 80,000 hours.• By the time they had averaged 22,000 hours in

service, the internal clearance had increased an average of 0.10" and the bearings could no longer perform smoothly.




• YOU SAVE ABOUT 40-50%

- Worn bearings are restored to original prime

condition-with performance guaranteed-for

about 50% to 60% of the cost of new bearings

of the same size and rating.




Remanufacturing Processes

Multi - stage remanufacturing process for engines



Example - 1

• Step 1 - Engines are stripped bare. - The block is baked for eight hours in a

thermal oven at 700 degrees. - Naturally cooled, then steel shot for ten

minutes. - The block is then magnafluxed and carefully

inspected for flaws.



Example - 2

• Step 2 » The block is align honed

– to insure the crankshaft main journals are on the same centerline;

– this reduces bearing wear and improves oil pressure and performance.

» Cylinders are then bored to specification and honed.



Example - 3

- The block deck surfaces are checked in reference to the crankshaft centerline.

- The block then goes through a high pressure wash to clean all galley holes followed by the application of several coats of rust protectant after deburring and tapping.

- New plugs and a set of cam bearings are installed.



Example - 4• Step 3

- The crankshaft is precision ground, and oil holes are chamfered, micro polished, and rebalanced.

- Shafts that won't grind to size arc discarded. - Connecting rods are resized and balanced,

pistons are precision fitted to connecting rods, and assemblies are weighed and checked for balance.



Example - 5

• Step 4- The block receives three coats of high

temperature engine paint. - All bolts are heat treated, stress relieved,

deburred, and hand inspected. - All external parts are inspected, painted,

and brought to the clean room for final check out and final assembly.



Example - 6• Step 5

- Cylinder head castings are remanufactured to exact specifications.

- All heads receive hard seats for unleaded or regular fuel.

- Valve seats are triple angle cut, and valve guides are replaced or resized.

- Valves are refaced or replaced as required.



Example - 7

- The head surface is milled to ensure a perfect mating surface.

- All valve heights are measured and adjusted. - Each spring is pressure tested and each

combustion chamber is vacuum tested.- Every bolt hole is tapped. Cylinder heads

receive three coats of high temperature paint.



Example - 8

• Step 6 (Blue print and final assembly)

- Each bore is checked with a precision dial bore gauge.

- Lifter bores are checked for size and correct clearance.

- Each lifter bore is polished with flap wheels – to assure smooth lifter rotation.



Example - 9- Each piston ring is checked in bore for proper

end gap. - Crank and main bearings are installed in block

and bearing clearances are checked. - Camshaft is installed in block and checked for

proper clearance. - Timing chain and sprockets are installed, and

camshaft degree is checked. Pistons and rod assemblies are installed in bores.



Example - 10

- Each rod is checked for correct clearances. Crankshaft thrust end play is checked and centered.

- Cylinder heads are installed and torqued to block.

- Lifters are installed and clearance checked.

- New pushrods are installed.



Example - 11

- All valves are adjusted perfectly to obtain optimum lifter preload.

- All cylinders are vacuum tested. - Complete oiling system is pressure tested

to ensure all internal clearances are perfect.



Example - 12

• Step 7 - Dyna testing. Every engine is installed in a

dyna testing machine. Engine is tested for – Internal oil pressure– The ability to hold pressure without leaking

out internally;– Oil pressure and volume running at 1000 RPM.



Example - 13

- Each cylinder is checked for instant compression and leak down.

- Engine is load tested to ensure there are no tight spots.

- Engine is visually inspected for any external oil

leaks and smoothness of operation.





Quick Facts - 1

• 53 billion dollar industry • There are over 73,000 firms in the U.S. • Automotive remanufacturing is a 36.5 billion

dollar industry • 46% of the parts on today’s automobile are

available as remanufactured units



Quick Facts - 2

• Automotive remanufacturing recycles 80% of the energy and 85% of the materials.

• Automotive remanufacturing reduces emissions



References

http://www.laser-service.com http://www.cardone.com/products/articles.htm

Environmentally Conscious Design & Manufacturing (ME592) Date: April 24, 2000 Slide:1 Environmentally Conscious Design & Manufacturing Class 20: Remanufacturing.

Documents

pandit slide

fatigue life

wear life

metal fatigue

life expectancy

fatigue failure

estimated service life

roller bearings