Products rarely fail in the lab under a single stress. In the real world, vibration and temperature & humidity act simultaneously: a circuit board in a car engine bay sees engine vibration and 85°C ambient at the same time; a satellite payload experiences launch vibration and vacuum; an outdoor telecom enclosure faces wind-driven vibration and 95% humidity. Running only a vibration test or only a climate test misses the failure modes that appear when these stresses are combined.

A vibration climatic test chamber — also called a combined environmental test chamber or a vibration-and-climate chamber — applies vibration, temperature, and humidity to a specimen in a single integrated test cycle. This approach is mandated by the most rigorous reliability standards: IEC 60068-2-64 for random vibration, MIL-STD-810 Method 514 for military vibration, and the automotive vibration series ISO 16750-3.

Model Range

Control & Data Acquisition

Phase 1 — Test Plan & Profile Definition

The test plan defines the vibration profile (sine sweep, random PSD, or shock), the temperature/humidity profile, and how they are combined. For automotive applications, the profile typically follows ISO 16750-3 with vibration on the test rig and climate inside the chamber. For military hardware, MIL-STD-810 Method 514.8 provides the canonical random vibration profile, and the chamber is configured to deliver the specified power spectral density (PSD) at the fixture interface.

Phase 2 — Fixture & Specimen Mounting

The fixture must be rigid enough to transmit vibration to the specimen without distortion but light enough not to load the shaker. Common patterns: aluminum or magnesium plates with M5/M6 threaded holes on a 50 mm grid, vibration-isolated standoffs, and slip tables for horizontal excitation. Thermal bridging must be considered when the fixture passes through the chamber wall.

Phase 3 — Test Execution

The chamber ramps to the setpoint temperature and humidity, holds, and the shaker applies the vibration profile. The three stresses overlap for the specified dwell time. Real-time monitoring captures accelerations on the fixture and at critical points on the specimen (PCB, connector, solder joint). Deviation triggers automatic abort if any safety threshold is exceeded.

Phase 4 — Post-Test Inspection & Report

After the cycle, the specimen is inspected visually, electrically, and functionally. The report includes pre/post test data, vibration PSD plots, temperature/humidity strip charts, and any observed defects (cracked solder, loose connector, delamination). The report forms the evidence package for certification and customer submission.

Primary Standards

Climate Companion Standards

Selection Parameters

1. Specimen mass and size — The chamber internal volume and the shaker force/payload rating must accommodate the specimen + fixture. Allow 20% headroom on volume and 30% on shaker force for future test growth.
2. Frequency range and acceleration — Aerospace and military often require 5–2000 Hz with 20–60 g random. Automotive typically 10–500 Hz with 5–30 g. Consumer electronics 5–500 Hz with 2–10 g.
3. Temperature range — If the application is automotive under-hood, plan for −40 to +125°C. Military ground vehicles: −46 to +71°C per MIL-STD-810. Outdoor telecom: −40 to +70°C. Cryogenic aerospace: down to −70°C.
4. Humidity range — Most programs require 20–98% RH. Confirm the chamber delivers the full range simultaneously with vibration, not just in standalone climate mode.
5. Test throughput — If you run qualification testing 24/7, plan for dual chambers or a faster chamber. The combined-stress test cycle is dominated by temperature ramp time, so look for ≥5°C/min average ramp rate.
6. Fixture & slip table interface — Confirm the chamber has a vibration-transparent window or a feedthrough that mates with your slip table. The horizontal/vertical orientation drives the chamber geometry.

Common Sizing Mistakes

• Undersizing the shaker — the fixture alone can be 30% of the rated force
• Overlooking the temperature gradient when the chamber is at extreme humidity — the wet-bulb/dew-point control is the hardest spec to maintain
• Forgetting about cable feedthroughs — power, signal, and sensor cables need vibration-rated hermetic feedthroughs

Mechanical Construction

The chamber shell is typically 304 or 316 stainless steel for the inner liner (corrosion resistance against humidity and salt mist) with a cold-rolled steel outer shell and a high-density polyurethane foam insulation layer (typically 100–150 mm). The observation window is multi-pane heated glass to prevent condensation. The door has a silicone gasket and a positive-pressure latch. Cable ports are vibration-rated, with KF/NW flanges for sensors and gas lines.

Refrigeration & Heating

Heating is by finned stainless steel heaters with PID control. Cooling is a cascade refrigeration system using R404A (high stage) and R23 (low stage) to reach −70°C. The system has a hot-gas bypass for temperature control near setpoint and an automatic defrost cycle for the low-stage evaporator.

Humidity System

Steam humidification is preferred over pan-evaporator humidification for combined-stress testing. A stainless steel steam generator feeds dry steam into the chamber plenum; the dry/wet-bulb sensors drive the humidity PID loop. Dehumidification is by refrigeration coil dehumidification, which is faster and more linear than desiccant-based systems.

Vibration System Integration

The chamber is mounted on a heavy granite or reinforced-concrete plinth. The vibration head is either built into the chamber floor (most common) or accessed via a horizontal slip table on the side. Pneumatic isolators decouple the shaker from the chamber during standby. Cooling water to the shaker armature is routed through the chamber wall via vibration-rated flexible couplings.

Safety Systems

Mandatory safety features: door interlock (cannot run vibration or heating with door open), over-temperature cutoff (independent of the main controller), over-humidity cutoff, vibration abort on accelerometer fault, emergency stop accessible from inside the chamber, and a leak detector for the refrigeration system. Optional: smoke detector, video monitoring, and remote alarm notification.