Track Link Manufacturing Solutions
Track links, pins and bushings form the core of crawler undercarriage systems. They operate in highly abrasive, impact‑loaded and contaminated environments where hardness–toughness balance, pitch accuracy and sealed lubrication are critical to service life and uptime.
Common Customer Challenges
- Hardness/toughness trade‑off on links and bushings: tip spalling vs. abrasive wear under impact
- Pitch tolerance, hole position and parallelism affecting chain runout, noise and sprocket engagement
- Bushing OD/ID and pin surface integrity after hardening; sealing and grease retention for SAL (sealed and lubricated) chains
- Press‑fit forces and alignment consistency across variants; crack control during assembly
- Coating/anti‑corrosion performance for storage and coastal logistics
- Mixed models, fast changeovers and high OEE with rigorous material/process traceability
Wing Structural Parts Manufacturing Solutions
Forged Track Links (Alloy Steel)
- Technical Points: Grain flow orientation, controlled Q+T, hole positional accuracy, track shoe interface flatness.
- Process Route: Forging → Heat treatment (Q+T) → Precision machining → Induction hardening (contact zones) → Coating → Inspection.
- Success Case: 20‑ton excavator link, pitch tolerance ±0.05 mm, hardness 38–45 HRC, field life +28%.
Cast Manganese/Alloy Track Links
- Technical Points: Chemistry and defect control, stress relief, machining of joint faces and bores, wear pad hardening.
- Process Route: Sand casting → Stress relief → Machining → Local hardening → Paint/mark.
- Success Case: Quarry application, casting scrap −35%, interchangeability Cpk≥1.33.
Pins And Bushings (SAL/SAB)
- Technical Points: Case depth/uniformity, OD/ID roundness, sealing groove precision, surface finish for grease retention.
- Process Route: Bar prep → Turning → Induction hardening → OD/ID grind/hone → Groove machining → Clean/pack.
- Success Case: SAL bushing Ra≤0.2 μm, case depth 1.2–1.6 mm, leak‑down rate within spec, chain life +32%.
Complete Track Chain Assembly
- Technical Points: Press‑fit force window, pitch build‑up control, sealing integrity, grease metering.
- Process Route: Press‑fit assembly → Grease fill → Seal install → Pitch check/runout → Endurance/NVH test.
- Success Case: Dozer chain, pitch build‑up ≤±0.15 mm over 10 links, runout reduced 25%, warranty claims −30%.
Track Link Manufacturing Process
Raw Materials And Incoming Materials Inspection
Process step description: Verify alloy chemistry, dimensions and surface quality; collect MTRs and sample hardness/microstructure. Equipment: Optical spectrometer, universal testing machine, CMM, ultrasonic thickness gauge, hardness tester, metallographic microscope.
Forging/Casting Preparation
- Process step description: Prepare billets/dies or sand molds/cores; control heating/pouring and gating/risers for target properties.
- Equipment: Induction heaters, forging hammers/presses, melting furnace, molding line, core shooters, temperature monitoring.
Knockout, Cleaning And Reference Machining
- Process step description: Shakeout, shot‑blast, remove flash/gates and establish datum faces/bores for precision operations.
- Equipment: Shakeout line, shot blaster, swing frame grinder, cut‑off saw, reference milling/boring setup.
Heat Treatment (Q+T / Stress Relief)
- Process step description: Apply solution treatment, aging or stress relief to achieve target mechanical properties and dimensional stability.
- Equipment: Heat treatment furnace, aging furnace, stress relief furnace, temperature monitoring system, atmosphere control.
Precision Machining And Finishing
- Process step description: Machine critical features, surfaces and assembly interfaces to specified dimensions and surface quality requirements.
- Equipment: 5-axis machining center, precision milling machine, turning center, grinding machine, CMM.
Induction Hardening (Links / Pins / Bushings)
- Process step description: Harden wear/contact zones and pin/bushing surfaces to specified case depth and hardness uniformity.
- Equipment: Induction hardening machines, quench systems, pyrometers, microhardness testers.
Grinding/Honing (Pins/Bushings)
- Process step description: Finish OD/ID to roundness and surface texture targets for press‑fit and sealing performance.
- Equipment: OD/ID grinders, centerless grinder, honing machine, roundness/roughness gauges.
Coating And Corrosion Protection
- Process step description: Blast to Sa standard, apply primer/epoxy/PU or zinc systems; verify DFT/adhesion.
- Equipment: Blasting booth, coating line, curing oven, DFT gauges, adhesion tester.
Press‑Fit Assembly And Sealing
- Process step description: Press‑fit pins/bushings into links within force window; install seals and meter grease for SAL chains.
- Equipment: Hydraulic presses with force monitoring, seal installation tools, grease metering systems, pitch gauges.
Functional And Endurance Testing
- Process step description: Check pitch build‑up/runout, sealed leak‑down, torque/drag and endurance under load/dust simulation.
- Equipment: Pitch/runout gauges, leak‑down rigs, drag torque benches, endurance test stands, data acquisition.
Final Inspection, Marking And Packaging
- Process step description: Dimensional/visual checks, laser/label marking, anti‑corrosion packing and crating.
- Equipment: Gauging stations, laser marker, barcode/RFID, VCI packaging, wooden crates.
Data Traceability And Quality Control
- Process step description: Maintain complete traceability of materials, processes and inspections for airworthiness compliance and quality control.
- Equipment: MES, data acquisition system, quality management system, barcode/RFID system, document management.
Track Link Production Line
Production Line Layout And Configuration
- Overall Layout: Linear/U‑shaped flow—forging/casting → cleaning → heat treat → machining → hardening → grinding/honing → coating → press‑fit assembly → testing → packing.
- Workstation Division: Foundry/forge bay; knockout/shot‑blast; heat treat; machining; induction hardening; grinding/honing; coating; assembly/testing; packing.
- Logistic Passage: Main aisle 4–5 m, auxiliary 2.5–3 m; overhead cranes 5–10 t; WIP buffers 3–6 h before heat treat and assembly.
Equipment Configuration And Automation
- Foundry/forge: Induction heaters, hammers/presses (1–3 kt), molding lines, MF furnaces; auto billet feed/temperature control.
- Heat treat: Furnaces with closed‑loop control, oil/polymer quench, tempering; recipe/curve logging to QMS.
- Machining: CNC mills, drill/boring centers, fixtures; in‑process probing, tool‑life monitoring.
- Induction: Multi‑station hardening with force‑position synchronization and quench control; microhardness mapping.
- Grinding/Honing: OD/ID and centerless grinding, honing with automatic gauging/feedback.
- Assembly/Test: Servo press with force–displacement trace, grease metering, pitch/runout and leak‑down rigs.
- Coating: Blasting booths, paint/curing lines; automatic DFT logging.
- Automation: Robot/gantry loaders between adjacent cells; fixture RFID for recipe recall; barcode traveler with inline SPC dashboards.
Production Flow And Material Handling
- Material Flow: Raw steel → forging/casting → knockout/clean → heat treat → machining → hardening → grinding/honing → coating → assembly/testing → packing.
- Handling: Overhead cranes, forklifts, AGVs optional; protected racking by link family/size; FIFO lanes to stabilize takt.
- Protection: Edge guards and non‑marring supports; corrosion‑preventive handling post‑coat and post‑assembly.
