MIM process
Sintered parts process
01
Powder selection
The metal powders are selected according to the properties required of the component.
02
Feedstock preparation
03
Injection molding
04
Cooling and ejection
05
Debinding
06
Sintering
07
Secondary finishing
08
Quality control
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THE BENEFITS OF POWDER METALS
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MATERIALS AND TECHNICAL CAPABILITIES
VALVES & PUMPS
Are MIM and sintered parts the same process?
MIM belongs to powder metallurgy and includes a sintering step. On this page, however, “sintered parts” refers to the conventional pressing and sintering process. In MIM, fine powders and binder form a mixture that is injected into a mold; after forming, the binder is removed and the part is sintered. In the conventional process, the powders are compacted in a die and then consolidated thermally. Geometric freedom, tooling and achievable density differ. EDR assesses the route based on the function of the part, avoiding treating the two processes as equivalent.
Which geometries suit the two technologies?
MIM is mainly suited to relatively small, intricate components, provided geometry, wall thickness and ejection from the mold are compatible with the cycle. In conventional pressing, compaction directions and part ejection from the die matter: transverse holes and some undercuts may require secondary machining. Maximum dimensions depend on material, shape and equipment. For both routes, shrinkage or dimensional changes during sintering and the functional surfaces to be completed must be evaluated.
When do molds and dies pay off?
Dedicated tooling makes these processes particularly attractive for repetitive production. The break-even threshold varies with complexity, material, number of cavities and the machining avoided compared with a part machined from solid. EDR compares initial quantities and recurring demand to assess mold or die, sampling and series cost. There is no minimum batch valid for all components: quantities, tooling properties and maintenance conditions must be defined in the supply proposal.
Which materials can be considered?
Materials used include stainless and alloy steels, iron-based powders and copper alloys. The usable families differ between MIM and pressing. EDR verifies the required grade and the availability of the cycle at the selected manufacturer.
Is density enough to guarantee the strength of the component?
Density affects properties, but is not enough to define the strength of the component. Alloy, pore distribution, sintering and treatments also matter. The required performance must be verified with tests and criteria agreed in advance.
How are precise fits achieved in sintered parts?
Dimensions depend on the mold or die, geometry and changes during the thermal cycle. Sizing or secondary machining can complete the fits. Tolerances and roughness must be defined on the functional surfaces of the part.
How are porosity and conformity checked?
The plan may include dimensional measurements, density, hardness and mechanical tests. Porosity can be functional, for example in self-lubricating bushings, or needs to be limited. For sealing applications, specific requirements and tests on the component are needed.
Are subsequent finishes and treatments possible?
Depending on material and process, heat treatments, coatings, sizing and CNC machining can be considered. Porosity can affect surface treatment, so the cycle must be defined before the series.
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