Chamber furnace, metal insulation HTK

The metallic furnaces are constructed using tungsten (HTK W) or molybdenum (HTK MO), resulting in the highest possible purity of the inert atmosphere and final vacuum level. Upon request, a high vacuum upgrade is available. The most commonly used gases include Nitrogen, Argon, Hydrogen, and its mixtures.

The HTK series features heating elements and insulation made of either tungsten (HTK W) or molybdenum (HTK MO). A retort can be utilized to guide the gas flow, particularly for debinding applications or to enhance temperature uniformity. The maximum temperature for the HTK W is 2200 °C, while for the HTK MO, it is 1600 °C.

APPLICATION EXAMPLES

carbon free atmosphere, metal injection moulding (MIM), metallization, sintering, thermal debinding, pyrolysis, synthesis, annealing, tempering

OVERVIEW

Furnace Type	Usable Volume	Max temp	Number of heated zones	Debinding Option
HTK 8 MO/W	8	1600 °C / 2200 °C	1	Torch/ condensate trap
HTK 25 MO/W	25	1600 °C / 2200 °C	1	Torch/ condensate trap
HTK 80 MO	80	1600 °C	4	Torch/ condensate trap
HTK 120 MO	120	1450 °C	4	Torch/ condensate trap

STANDARD FEATURES AND OPTIONS

• Metallic furnaces provide a precisely defined atmosphere with the highest possible purity
• Metallic furnaces offer the best possible vacuum
• Hydrogen partial pressure operation is optional available
• Data recording for quality management: CC-TP1200 smart, CC-TP1900 or CC-IPC1900
• Option for debinding processes
• Option for clean high vacuum processes

Required infrastructure

• Gases: hydrogen, argon, nitrogen
• Electric power supply
• Fail safe cooling water
• Exhaust

	HTK 8	HTK 25	HTK 80	HTK 120
Usable space in the retort H x W x D [mm]	160 x 180 x 180	240 x 240 x 400	380 x 410 x 500	380 x 400 x 770
Number of plates*	3	3	40	60
Plate dimensions [cm²] *	225	860	930	930
Picture of sample rack

* The displayed values refer to a typical retort layout. The specific arrangement can be customized to meet the requirements of the customer.

EXPLANATION OF THE DEBINDING AND SINTERING PROCESS STEPS OF THE HTK-MIM-3 FURNACE

The HTK-MIM-3 furnace program enables debinding and sintering of MIM components in two stages. The program's progress is displayed in a diagram, and important parameters such as pressure, gas flow, and gas type are recorded. The debinding stage utilizes partial pressure and high nitrogen gas flow, while the sintering stage focuses on temperature uniformity, resulting in a consistent density of the MIM parts.

INSIDE THE FURNACE

HTK 8 – 80 furnaces consist of:

1. Heaters
2. Retort
3. Radiation Shields
4. Thermocouple
5. Gas Inlet
6. Gas Outlet
7. Vacuum Gauge
8. Water-cooled vacuum vessel

Exemplary cross section of a HTK 8 molybdenum

 

 

 

HTK 120 furnaces consist of:

1. Heaters
2. Radiation Shields
3. Gas inlet
4. Gas Outlet

 

Heating cassette of the HTK 120, CAD drawing. Designed for highest lifetime and easy maintenance.

 

 

BINDER HANDLING OPTIONS HTK8 - 80

AFTERBURNER ASSEMBLY:

1. Retort
2. Gas outlet
3. Trace heating
4. Torch
5. Position controlled ball valve

The torch of the afterburner ensures controlled conversion of remaining flammable or toxic volatiles into non-flammable gases.

The condensate trap may be installed for binder handling. During the process the trap is cooled to condense the binder. After the process the trap can be heated to release the binder safely which has been liquified.

Afterburner

Condensate trap

SOME HTK120 OPTIONS

AFTERBURNER ASSEMBLY:

1. Gas outlet
2. Trace heating
3. Torch
4. Position controlled ball valve
5. Fresh oil pump
6. Oil condenser

The stand alone safety purge tank ensures full safety for hydrogen applications. The furnace can only be started, if the tank is completely filled. Therefore the furnace is flood with nitrogen gas in case of major errors, such as power failure etc. The size is adjusted according to the furnace volume.

Heated gas outlet and vacuum line of the HTK 120

Stand alone safety purge tank

LEAKAGE RATE RESULTS

With the high vacuum upgrade the leakage rate results in values below 10-3 mbar*l/s. The leakage rate is determined by evacuating the furnace, closing all valves and meassuring the pressure increase over time. The desorption of water molecules from the metal surface takes approximately 20 h, and leads to a faster increase in pressure, represented by the blue line.

HIGH VACUUM APPLICATIONS

Cross section of HTK 8 with high vacuum upgrade. The turbo pump is at least connected via an DN100 flange.

1. Turbo pump
2. Vacuum valve
3. DN 100 flange

High vacuum upgrade

Schematic of a turbomolecular pump for high vacuum applications.

CONTROLLER OPTIONS

The furnace is operated via a 12" or 19" touch panel controller. It provides an overview of the furnace and its behaviors and allows the user to preform any possible adjustments to the furnace.

• User friendly 12” touch panel, provides a detailed overview of the furnace status.
• Configuration of an automatic programm
• The smart software is mainly used for simple processes
• The full automatic function ensures full flexibility
• The pre-program ensures that the furnace is evacuated prior to heat treatment to ensure safety in case of any occuring errors
• The system is based on an industrial standard Siemens PLC ensuring full safety.

Size of Panel	12
Number of programs	12
Export data	csv
Remote access	Yes
Keyboard	No
Remote maintenance	No
Online changes	No
MFC	Yes
Rotameter	No
Heated gas outlet	Yes
Turbopump	Yes
Hydrogen	No
Partial pressure	No
Sliding TC	Yes

• Full visualization of the furnace with 19’’ touch panel, mainly for fully configured units or for the use of hydrogen (>5%)
• Configuration of an automatic program
• The automatic software is used for more complicated and hydrogen processes
• The CC-IPC1900 version additionally includes an industrial PC with standard windows software
• The system is based on an industrial standard Siemens F-PLC ensuring full safety even for hydrogen applications
• The pre-program ensures a fully automated leakage test which takes place in overpressure and vacuum

Size of Panel	19
Number of programs	20
Export data	csv
Remote access	With Siemens software
Keyboard	Optional
Remote maintenance	Optional
Online changes	No
MFC	No
Rotameter	No
Heated gas outlet	Yes
Turbopump	Yes
Hydrogen	Yes
Partial pressure	Yes
Sliding TC	Yes