Limitations of the powder metallurgy process, Other Engineering

Q. What are the limitations of the powder metallurgy process ? How are some of these overcome ?

Ans. Limitations : 1. Dies and equipment costs are high. So, the process is economically feasible only for mass production. Minimum production run of 10,000 parts is needed to offset the tooling costs. Dies are made for long production runs, of the order of 1,50,000 to 2,00,000 parts.

        2. The material cost in powder form is high. However, high powder material costs are usually offset by an almost total absence of scrap. Part costs are also reduced by eliminating machining. Labour costs are also comparatively low.

        3. Metal powders are sometimes difficult to store without some deterioration.

        4. There is little flow of metal during compaction, so intricate designs in the products are difficult to attain.

        5. A completely dense product is not possible by this process. Also, a uniformly high-density product is very difficult to produce.

        6. Part size and weight are restricted. These are regulated by the capacity of available press and compressibility characteristics of the various powder combinations. P/M is principally restricted to the manufacture of comparatively small parts. Part weight can be under 5 Newtons. However, parts weighting upto 900 Newtons have been successfully mass produced by P/M. Typical part 

sizes :

                  100 mm Φ x 150 mm long on 900 kN capacity press

                  250 mm Φ x 200 mm long on 900 to 2700 kN capacity press.

        7. Some metal powders in a finely divided state, for example, of Al, Mg, Zr and Ti, present explosion and fire hazards.

        8. Product Design limitations, which will be discussed ahead.

        9. The residual porosity, makes sintered compacts rougher than the compacting die.

      10. Low mechanical properties compared to other methods for similar parts. Low impact and fatigue properties.

      11. Some thermal difficulties are experienced during sintering operation. This is particularly true for low melting point metals such as Sn, Pb, Zn and Cd. During the sintering operations, the atmosphere in the furnace should be reducing to avoid the formation of oxides which will have adverse affects on sintering process and result in an inferior product. The oxides of the above mentioned metals can not be reduced at temperatures below the melting point of the metal, whereas the sintering temperature is always less than the melting point of the metal.

Posted Date: 8/3/2012 4:48:46 AM | Location : United States







Related Discussions:- Limitations of the powder metallurgy process, Assignment Help, Ask Question on Limitations of the powder metallurgy process, Get Answer, Expert's Help, Limitations of the powder metallurgy process Discussions

Write discussion on Limitations of the powder metallurgy process
Your posts are moderated
Related Questions
i am building the above mentioned system and i intend using an arduino board together with the gsm shield. my problem is i don''t know if there is a way i can control a camera by p


A charitable organization wants to design a special ATM machine to be used by needy people. The association supplies the needy person with a pin number to be able to use the ATM

USE OF MULTICYLINDER ENGINE If, in a multi cylinder engine, power strokes are staggered, the limitation of flywheel can be overcome to a large extent. Torque diagram for 2 cyli

Interference fringes are produced by fresnel''s biprism in the focal plane of an eyepiece 200 cm away from the slit.Two images of the slit that formed each of the two positions of

Double acting propellers: This type of propeller is normally fitted to larger engine and, because of engine requirements, is more complicated than the propellers fitted to smal

Your objective in this lab is to convince the assessor that you understand the basic concepts of how shock absorbers affect the ride and handling of a vehicle.  This will involve d

Common faults - Fire safety management: Common faults found are: Combustible items left in protected routes Locked exits Fire doors wedged open Exits obstru

Drop-weight impact towers are frequently used to generate low velocity impact damage. Typically, the falling mass will be instrumented, containing a load-cell for measuring the lo

The centre of pressure (CP) is defined as the point about which the resultant moment is zero; the net effect of the flow in terms of forces and moments would be the same as if the