Base materials
Alloy grades, section thickness, surface condition and any material pairing that can drive contamination or distortion risk.
VTHB Series · Batch High-Vacuum Furnace
High-temperature vacuum brazing furnace
Configure a clean, repeatable brazing process for stainless steel, nickel-base alloys, titanium alloys, copper assemblies, cemented carbide and other high-value components. The furnace architecture is selected around your base material, filler metal, joint geometry, load size and acceptance standard.
1300°CMaximum operating temperature across the VTHB range
±5°CTemperature uniformity across the effective work zone
Graphite / MoHot-zone options matched to material and process cleanliness
≤6×10−4 PaHigh-vacuum capability for demanding brazing programs
Start with process fit
Choose this furnace when cleanliness and joint control matter more than simple heating
The VTHB is a batch vacuum brazing platform. It is designed around controlled pump-down, staged heating, uniform soak, optional partial pressure and managed cooling—not a universal furnace for every brazing route.
Strong fit
High-temperature batch brazing
- Stainless steel and nickel-base alloy heat exchangers, manifolds and precision assemblies
- Titanium-alloy parts where hot-zone cleanliness and vacuum architecture are selected accordingly
- Cemented carbide, diamond-tool and copper-to-steel joining with a qualified filler system
- Mixed production requiring programmable recipes, records and repeatable load handling
Use a dedicated route
Different intent, different equipment
- For aluminum heat exchangers and cold plates, use the High-Vacuum Aluminum Brazing Furnace.
- For takt-driven line production, use the Continuous Vacuum Brazing Furnace.
- For pressure-assisted solid-state joining, use the Diffusion Bonding & Brazing Furnace.
Selection rule: a reliable VTHB specification aligns temperature, vacuum level, hot-zone material, fixture design and cooling rate with the filler, joint clearance and load condition.
Engineering selection path
Five decisions define the furnace you actually need
Send these inputs first. They determine whether the solution should use a graphite or all-metal hot zone, which pumping train is required, and how the work zone and cooling system should be sized.
Filler & clearance
Filler designation, liquidus range, joint gap, placement method, stop-off and fixture concept.
Thermal window
Ramp limits, equalization holds, brazing temperature, soak time and part-specific cooling constraints.
Work zone & mass
Maximum envelope, gross load, fixture mass, orientation, loading frequency and annual throughput.
Quality evidence
Leak test, metallography, dimensional limits, temperature survey, process records and customer standards.
Have a material, filler and joint drawing?
Send the core process inputs and receive a focused hot-zone and vacuum-system recommendation.
Application evidence
Designed for dense loads, precision joints and production repeatability
Typical programs include stainless heat exchangers, nickel-alloy assemblies, carbide tooling, sensors, waveguides and complex metal structures. Cycle development incorporates the work fixture, load density and total thermal mass.
Stainless heat-exchanger loads
Fixture stiffness, contact pressure, load spacing and equalization holds affect flow, distortion and leak-test results.
Carbide and dissimilar-metal joints
Filler choice, joint geometry and controlled heating help manage differential expansion and residual stress.
Hot-zone decision
Graphite and molybdenum are process choices—not cosmetic options
Both hot-zone types can be engineered for high-temperature vacuum brazing. The correct choice depends on material sensitivity, required cleanliness, vacuum target, maintenance strategy and total operating cost.
Flexible and maintainable for broad industrial work
Graphite heating and insulation can provide efficient high-temperature operation with practical serviceability.
- Good fit for many stainless, copper, carbide and general industrial brazing programs
- Lower hot-zone replacement cost and robust thermal design
- Pump sizing and dry-out practice must account for gas load and moisture pickup
Selected when process cleanliness is the priority
Metal heating elements and shield insulation support cleaner high-vacuum processing for sensitive loads.
- Preferred route for titanium-bearing materials and demanding nickel-alloy or aerospace programs
- Lower risk of carbon-related process interaction
- Requires careful handling, shield maintenance and a vacuum system matched to the cleanliness target
Specify the load, not only the peak temperature
Heater material, insulation, hearth design, thermocouple placement and usable work-zone definition work as one thermal system. Temperature uniformity is verified across the effective work zone under the selected operating condition.
Match the hot zone to your material system
SYNHTE evaluates cleanliness, vacuum level, thermal mass and maintenance priorities as one selection.
Furnace architecture
Vacuum, heating and cooling are sized as one production system
The high-vacuum system can reach an ultimate vacuum of ≤6×10−4 Pa with a pressure-rise target of ≤0.5 Pa/h. Pumping capacity, pump-down time and gas handling are matched to the chamber volume, hot zone and production load.
Vacuum package
Mechanical and Roots pumping for industrial vacuum duty; diffusion or molecular pumping can be added for demanding high-vacuum and cleanliness requirements.
Heating & control
Multi-zone control, programmable ramps and holds, over-temperature protection, recipe management and cycle data recording.
Cooling & partial pressure
Natural or inert-gas assisted cooling, with optional partial-pressure control when the process requires vapor management or surface protection.
VTHB model range
Size the usable work zone around the complete load and fixture
The VTHB range covers compact precision loads through large production assemblies. Chamber dimensions, loading arrangements, vacuum packages and cooling capacity are engineered around the complete load and target cycle.
| Model | Usable work zone (W×H×L) | Loading capacity | Heating element | Max. temperature | Uniformity |
|---|---|---|---|---|---|
| VTHB-335 | 300×300×500 mm | 100 kg | Graphite / Mo | 1300°C | ±5°C |
| VTHB-446 | 400×400×600 mm | 150 kg | Graphite / Mo | 1300°C | ±5°C |
| VTHB-557 | 500×500×700 mm | 280 kg | Graphite / Mo | 1300°C | ±5°C |
| VTHB-669 | 600×600×900 mm | 450 kg | Graphite / Mo | 1300°C | ±5°C |
| VTHB-8812 | 800×800×1200 mm | 800 kg | Graphite / Mo | 1300°C | ±5°C |
| VTHB-9918 | 900×900×1800 mm | 1200 kg | Graphite / Mo | 1300°C | ±5°C |
Each model supports graphite or molybdenum heating, with the vacuum package, hearth structure, loading arrangement and cooling system matched to the material and production cycle. SYNHTE confirms the selected work zone and load rating in the furnace specification.
Need help selecting the work zone?
Share the largest part envelope, fixture layout and gross load to receive a model recommendation.
Process sequence
Build repeatability into the complete brazing cycle
Clean and assemble
Control oxide, oil, fingerprints, filler placement, joint clearance and stop-off before the load enters the chamber.
Load for uniform heating
Support parts without blocking radiation or filler flow; include fixture mass and nesting density in cycle development.
Pump down and dry out
Verify leak-rate condition, remove gas load and apply staged heating where binders, stop-off or complex geometry require it.
Ramp and hold
Use equalization holds so the full assembly reaches a controlled thermal state before crossing the filler liquidus range.
Control the process window
Hold only as long as required for wetting and flow while limiting erosion, grain growth, distortion and volatilization.
Protect the joint
Match natural or gas-assisted cooling to part geometry, alloy response and distortion limits before unloading.
FAT, SAT and records
Define how the furnace will be accepted before it is built
The acceptance plan connects equipment performance directly to brazed-part requirements and gives production teams clear release evidence from FAT through SAT.
Vacuum performanceUltimate vacuum, pump-down curve and pressure-rise/leak test under defined test conditions
Thermal performanceControl accuracy, temperature uniformity survey method and qualified work zone
Functional testingAutomatic cycle, alarms, interlocks, cooling, gas control, data recording and power-failure response
Process evidenceCustomer test load with joint inspection, leak testing, metallography or dimensional verification
Delivery packageManuals, electrical drawings, spare-parts list, maintenance plan, training and SAT protocol
Useful RFQ, faster engineering
Send one representative part and one target cycle
These inputs allow SYNHTE to define the hot zone, vacuum train, work-zone size, cooling route and acceptance tests, then recommend the appropriate VTHB model.
Include these inputs
- Base material grades
- Filler designation
- Joint drawing and clearance
- Part envelope and weight
- Fixture layout and mass
- Target brazing cycle
- Monthly batch volume
- Surface-cleanliness target
- Cooling and distortion limit
- Plant utilities and voltage
- Applicable standards
- FAT/SAT evidence required
Continue your evaluation
Technical resources for specification and qualification
Frequently asked questions
High-temperature vacuum brazing furnace FAQs
Should I choose a graphite or molybdenum hot zone?
Choose from the material and cleanliness requirement. Graphite is practical for many industrial stainless, copper and carbide programs. Molybdenum is preferred when titanium-bearing materials, carbon sensitivity or a very clean high-vacuum environment makes an all-metal hot zone the safer route.
Can this furnace braze aluminum heat exchangers?
Aluminum vacuum brazing has a different oxide-control, filler and furnace-contamination strategy. Use a dedicated high-vacuum aluminum brazing furnace rather than assigning aluminum production to this high-temperature page by default.
Is 1300°C required for every brazing cycle?
No. The operating setpoint follows the filler liquidus, base material, joint design and approved process window. The 1300°C figure is the maximum operating temperature of the VTHB range, not the default brazing temperature.
What determines the required ultimate vacuum?
Material reactivity, filler behavior, allowable oxidation, hot-zone cleanliness, gas load and customer standards determine the vacuum architecture. Pump-down time and pressure-rise performance should be specified together with ultimate vacuum.
Can the furnace support FAT and SAT qualification?
Yes. The test scope can include vacuum performance, temperature uniformity, controls, alarms, records and a customer test load. SYNHTE defines the methods and pass criteria in the acceptance plan before manufacture.
Configure from the joint outward
Turn your brazing requirement into a testable furnace specification
Share the material, filler, joint drawing, load envelope, target cycle and acceptance plan. SYNHTE will return a recommended VTHB configuration with matched options and acceptance scope.