Guangming Group will talk about the precision elements that affect powder metallurgy gears today

1、 Raw materials and mixing stage

Powder characteristics

Powder particle size and uneven particle size distribution → density fluctuation, inconsistent shrinkage

Poor loose density and flowability of powder → uneven compaction density

Impurities and high oxygen content → sintering deformation, unstable size

Formula and Mixing

Fluctuations in lubricant and alloy element ratios → Changes in sintering shrinkage rate

Uneven mixing → Local density/hardness differences, tooth profile deviation

2、 Compression forming stage (with the greatest impact on accuracy)

Mold accuracy

Mold processing accuracy: tooth profile, tooth orientation, and indexing errors are directly inherited into the product

Mold wear, uneven chamfering → tooth distortion, unilateral deviation

Poor mold clearance and guiding accuracy → Product eccentricity and coaxiality exceeding tolerance

Pressing process

Insufficient or uneven pressure suppression → low density, large shrinkage, and instability

Difference between bidirectional compression and unidirectional compression → large density gradient, deformation after sintering

Improper holding time and demolding speed → Cracks in the billet and deformation due to elastic effects

Raw state

Insufficient strength of green body → deformation during transportation and furnace loading process

Green body density fluctuation → large size variation within the same batch

3、 Sintering process (determining final size and deformation)

Sintering temperature and holding time

High temperature → excessive shrinkage, coarse grains, and tooth deformation

Low temperature → insufficient shrinkage, oversized size, insufficient strength

Atmosphere and pressure inside the furnace

Unstable carbon potential control → carburizing/decarburization, abnormal size and deformation

Impure atmosphere → oxidation, unstable expansion and contraction

Furnace installation and cooling

Improper stacking method and support → high temperature self weight deformation

Uneven cooling rate → warping, elliptical deformation

Contraction rate fluctuation

Material batch and process fluctuations → systematic deviation of modulus, tooth thickness, and common normal length

4、 Finishing and subsequent processing

Precision/Plastic Surgery

Unreasonable finishing allowance → Tooth surface strain, tooth orientation distortion

Precision mold wear → rapid decrease in accuracy

Heat treatment (carburizing, quenching, tempering)

Quenching deformation → gear ellipse, end face warping, skewed tooth orientation

Uneven hardness → changes in grinding allowance, affecting final accuracy

Machining (such as inner holes, end faces, and gear grinding)

Inaccurate positioning reference → radial runout, coaxiality exceeding tolerance

Rigidity of tooling and tool wear → Accumulated errors in tooth profile and pitch

5、 Detection and environmental factors

Temperature and humidity changes → thermal expansion and contraction of measuring tools and workpieces, affecting measurement results

Improper selection of detection methods and benchmarks → Misjudgment of accuracy

Batch stability and process control capability (CPK) directly affect accuracy consistency

Powder metallurgy, metal injection molding, powder metallurgy gears

Guangming Group focuses on the research and development of metal forming technology and wear-resistant materials. Its main products include metal compression molding and injection molding powder metallurgy products.

The company has a team of high-quality talents, with the founding team originating from the Guangzhou Nonferrous Metals Research Institute, a directly affiliated national and ministerial level scientific research institution. It has rich industry experience and research and development capabilities, providing a continuous source of innovation power for the company's development. The company has successively obtained 5 invention patents and more than 30 utility model patents. It has passed the IATF16949 quality management system, ISO9001-2015 quality management system, ISO14001 environmental management system, intellectual property management system, and obtained international trademark certification. It is an innovative enterprise in Guangdong Province, a small giant enterprise in science and technology in Guangzhou, a member of the Guangdong Powder Metallurgy Industry Technology Innovation Alliance, and an initiator of the Guangzhou Advanced Powder Metallurgy Cluster Promotion Center.