Flexible Vacuum Furnaces

ALD-Holcroft Vacuum Technologies is the partner of choice for vacuum furnace systems and vacuum processes.  In 2008, our owner ALD Vacuum Technologies, during the normal course of continued product development and improvement, restructured the single batch vacuum furnaces within their heat treatment equipment sector.

The brand name “MonoTherm” comprises a “kit” from which a customer specific vacuum furnace system may be derived.  The system is designed according to the specific needs of a customer by allowing the selection of various standard system options.

Depending on process requirements, the MonoTherm can be configured with graphite heating elements and graphite insulation as well as all metallic heating elements with metallic radiation shield type insulation.

Hot Zone Designs

MonoTherm provides your choice of two hot zone configurations.  The most common design is cylindrically oriented with longitudinally arranged heating elements and a 360° cooling nozzle pattern.  This design is especially recommended for solid, large surface tools due to low distortion cooling provided by the 360° cooling.

Our second hot zone configuration is arranged as a square and includes cooling gas flow patterns from top to bottom and from left to right, each with reverse flow capabilities.  A four direction cooling gas flow capability is also available for applications requiring more versatility. 

Quench pressure and gases

MonoTherm is offered with quenching pressures that range from 1.4 bar (gentle cooling) to 20 bar quenching (rapid transformation needs).  Other specific pressures within these parameters are also available.

All conventional neutral gases can be used for cooling including:

• Nitrogen
• Argon
• Helium

A recovery system for the quench gas can be supplied if helium or argon are used.

Further Options

The MonoTherm “kit” offers further options from which to select depending on process requirements:

• Convection heating for faster, uniform heat-up to 800°C
• Quench fan speed control via a Variable Frequency Drive for low-distortion quenching and “dynamic quench” events.
• Subzero cooling system to transform residual austenite
• Partial pressure control to prevent sublimation of alloying materials.
• NADCAP Compliant Controls 

Additionally, individually controlled heating elements on the front door and rear wall are also available for temperature uniformity needs of +/-3°C.

Applications

Generally, the MonoTherm is best employed for the following applications:

• Vacuum Annealing between 150°C and 1250°C
• Vacuum hardening and vacuum tempering
• Vacuum Carburizing (also known as Low Pressure Carburizing or LPC) with high pressure gas quenching
• Vacuum Brazing (Diffusion pumping available for deep vacuum)
• Vacuum sintering

The system permits process combinations such as vacuum brazing followed by hardening events.  Additional processes are possible as well as special applications and special load sizes.