Guilemin/DSP Couplings

Guilemin/DSP couplings are suitable for heavy machinery and precision equipment. How does its production process balance high strength and precision?

1. Material selection: the underlying foundation of high strength and processing precision

Guilemin/DSP couplings use a composite system of "high-strength alloy substrate + functional coating" in material selection. This strategy is similar to the rigorous logic of Jun'an Fire Technology in the selection of fire hose materials. To ensure the stability of the hose under extreme conditions such as high temperature and high pressure, Jun'an Fire Protection strictly screens raw material suppliers and requires them to provide certification reports. Guilemin/DSP prefers the following material systems for the high load requirements of heavy machinery and the tolerance sensitivity of precision equipment:
Base material selection: High-strength nickel-chromium-molybdenum alloy (such as 42CrMo) or titanium alloy (such as TC4) is used. The yield strength of such materials can reach more than 850MPa and can withstand the alternating load during the operation of heavy machinery. At the same time, it has good cutting performance and can achieve IT6-IT7 level accuracy (equivalent to a tolerance band of 0.01-0.02mm) through precision machining to avoid machining deformation due to excessive material hardness.
Coating technology: The surface is covered with an anti-corrosion protective coating (such as nano-ceramic coating or PVD coating), and the coating thickness is controlled at 5-10μm, which not only enhances the ability to resist environmental erosion (meet the requirements of outdoor operations of heavy machinery), but also avoids affecting the accuracy of the mating surface due to excessively thick coating (the installation error of precision equipment must be ≤0.05mm).

2. Forming process: dual control from macro strength to micro precision

Forging process optimization
For the high strength required by heavy machinery, Guilemin/DSP adopts hot die forging process, which refines the grains of the alloy substrate through high temperature forging above 1000℃, improves the grain boundary bonding force by more than 30%, and eliminates casting defects (such as pores and shrinkage). At the same time, in order to take into account the installation accuracy of precision equipment, isothermal annealing treatment is required after forging to control the internal stress of the material below 50MPa to avoid deformation caused by stress release during subsequent processing. For example, the forged blank of the coupling flange will reserve 0.5-1mm machining allowance, which not only ensures the density of the forging (≥7.8g/cm³), but also provides a benchmark for precision machining.
Application of precision casting technology
For coupling parts with complex structures (such as elastomer connectors), investment casting (lost wax method) is used, and the mold accuracy can reach ±0.03mm, and the surface roughness Ra≤1.6μm. During the casting process, the casting temperature (such as titanium alloy is controlled at 1650-1700℃) and the cooling rate (10-15℃/s) are controlled to make the internal structure of the casting uniform, the tensile strength reaches more than 900MPa, and the surface roughness problem of traditional sand casting is avoided (the surface roughness of sand casting is usually Ra≥12.5μm).

3. Precision machining: multi-dimensional precision control technology

CNC machining and error compensation
Using a five-axis linkage CNC machining center, through tool path optimization (such as spiral interpolation instead of linear cutting), the coaxiality of the coupling shaft hole is controlled within 0.01mm, and the keyway symmetry is ≤0.02mm. For the mating surfaces required by precision equipment (such as flange stop), the mirror grinding process is adopted, the grinding wheel linear speed reaches 60m/s, and the surface roughness Ra≤0.4μm, to ensure the sealing and coaxiality during installation (precision equipment requires assembly clearance ≤0.03mm).
Special processing technology
For the processing of small apertures of high-strength materials (such as positioning holes with a diameter of ≤2mm), electrospark machining (EDM) is used, and the electrode loss ratio is controlled below 1%, and the aperture tolerance is ±0.01mm. For example, the locking hole in the anti-drop structure of the coupling needs to be processed on an alloy substrate with a hardness of HRC45-50. EDM can avoid the tool wear and hole wall burr problems of traditional drilling, and ensure the clearance accuracy (≤0.01mm) after the locking pin is installed, thereby improving the reliability of anti-drop.

4. Surface treatment: a balanced process of functionality and precision

Coating deposition technology
The protective coating adopts physical vapor deposition (PVD) or chemical vapor deposition (CVD), such as TiN coating deposition temperature ≤500℃, to avoid the influence of high temperature on the mechanical properties of the substrate (tempering of 42CrMo alloy above 500℃ will cause strength reduction). During coating deposition, magnetron sputtering technology is used to control the uniformity of the film layer, with a thickness deviation of ≤±0.5μm, ensuring that the dimensional accuracy of the mating surface (such as the inner hole of the coupling) is not affected (the inner hole tolerance of precision equipment is usually H7, i.e. ±0.015mm).
Surface strengthening treatment
For high wear-resistant parts required for heavy machinery (such as the gear teeth of the gear coupling), laser surface quenching is used, with a quenching layer depth of 0.3-0.5mm and a hardness increased to HRC55-60. At the same time, the quenching deformation is controlled by laser scanning path to ≤0.02mm. Compared with traditional carburizing and quenching, this technology can reduce heat treatment deformation (carburizing and quenching deformation is usually ≥0.05mm), meeting the strict requirements of precision equipment for part deformation.

5. Structural design: Coordinated optimization of mechanical properties and assembly accuracy

Topological optimization design
The coupling structure is topologically optimized through finite element analysis (FEA), such as adding a 15° chamfer at the transition fillet of the flange to reduce the stress concentration factor by more than 30% (the peak stress under the impact load during the operation of heavy machinery can be reduced from 300MPa to 210MPa); at the same time, the positioning stop required by the precision equipment is designed as a stepped structure, and the coaxiality during assembly is improved (≤0.015mm) through multi-reference surface matching (flatness ≤0.01mm).
Elastomer integration technology
For occasions that require vibration resistance (such as heavy machinery engine connection), the coupling has built-in damping elastomers, using injection molding + vulcanization process. The bonding strength between the elastomer and the metal substrate is ≥15MPa, which can absorb vibration (amplitude attenuation rate ≥80%), and through mold precision control (mold tolerance ±0.02mm), the elastomer size consistency is guaranteed to avoid assembly errors caused by elastomer deformation (precision equipment requires elastomer thickness tolerance ≤0.1mm).

6. Quality inspection: full process strength and precision verification

Mechanical performance inspection
Tensile test: The tensile strength of the substrate must be ≥950MPa, and the elongation must be ≥12% to ensure that heavy machinery does not break under high load;
Fatigue test: Under an alternating load of 1000 times/minute (load range 0-80% yield strength), there is no crack after 10⁶ cycles, which meets the long-term operation requirements of heavy machinery.
Precision detection
Coordinate measurement (CMM): Full-size detection of key dimensions (such as shaft hole diameter and flange parallelism) with a measurement accuracy of ±0.005mm, meeting the micron-level tolerance requirements of precision equipment;
Dynamic balancing test: Dynamic balancing correction of high-speed rotating couplings, residual unbalance ≤1g・mm/kg, ensuring that the vibration amplitude of precision equipment during operation is ≤0.01mm (the maximum amplitude allowed for precision equipment is 0.05mm).
Environmental adaptability test
Simulating the outdoor working conditions of heavy machinery, salt spray test (5% NaCl solution, 96 hours) and high temperature aging (120℃, 500 hours) were carried out, and the coating did not fall off and the substrate was not corroded; at the same time, the precision re-measurement was carried out in the constant temperature environment (20±2℃) required by the precision equipment, and the dimensional change was ≤0.003mm to ensure that environmental fluctuations do not affect the accuracy of use.