Pros / Cons
As mentioned earlier,
sintering by itself is a necessary step in the powder metallurgy
process. This step can not be eliminated. Thus, we don't talk about
the advantages and disvantages of sintering as a step. Rather, we
talk about those of the process as a whole.
Advantages:
- The greatest advantage powder metallurgy methods have over other
processes is that it does not waste material. Almost all the material
that is not used to make the product is left in its powdered form
and can be recycled for use with the next product.
- Complex shapes are feasible and advantageous in many cases.
Disadvantages:
- There are some limitations on the shape of the parts. Undercuts,
cross holes, and screw threads are best provided with secondary
operations.
- In general, P/M parts have low resistance to shock loading and
lower physical properties than wrought metals.
Additional advantages
and limitations of the powder metal pressure sintering process over
other metal forming processes are summarized in the table below:
Competitive Features of P/M and Other Manufacturing Processes
| Process |
Advantages Over P/M |
Limitations Compared to P/M |
| Casting |
- Generally low mold and setup cost;
- Very wide range of part sizes and shapes
produced.
|
- Not feasible for some high-temperature
alloys;
- Waste of material in processing.
|
| Forging, hot |
- High production rate of a wide range
of sizes and shapes;
- High mechanical properties through control
of grain flow.
|
- Waste of material in processing;
- Die wear;
- Poor dimensional control
|
| Extrusion, hot |
- High production rate of long parts;
- Complex cross- sections.
|
- Constant cross-sectional shape;
- Die wear; poor dimensional control
|
| Machining |
- Wide range of sizes and shapes;
- All materials;
- Short lead time;
- Good dimensional control;
- Simple tooling
|
- Waste of material in processing;
- Low productivity;
- Possible adverse effects on surface
integrity.
|
Source: Kalpakjian, Manufacturing
Processes for Engineering Materials.
|
