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Debinding Furnaces heat treatment for binder removal by melting or thermal degradation

Carbolite Gero offers a variety of different debinding furnaces to suit your application needs. Debinding causes a polymer binder to thermally decompose. The use of binders ensures cohesion between the powder particles and allows the component to keep its shape. This process is often used before sintering of metal or ceramic parts.

Thermal debinding can efficiently be performed in an ashing furnace. Both processes, debinding and ashing, involve the removal of materials. During debinding binder is removed from the furnace chamber.

Hornos de calcinación AAF 3 & 7
Hornos de calcinación AAF 3 & 7

  • Temp. máx.: 1100°C
  • volúmenes de cámara: 3 to 7 litres
  • Cumplen con ISO 1171:2010, ASTM D3174-04:2010 y ASTM D4422
  • información del producto

Hornos de calcinación AAF 18 & 32
Hornos de calcinación AAF 18 & 32

  • Temp. máx.: 1100 - 1200°C
  • volúmenes de cámara: 18 & 32 litros
  • Cantidad doble de muestra gracias al rack para dos platos de Inconel


  •
  • información del producto

Hornos de calcinación AAF-BAL
Hornos de calcinación AAF-BAL

NUEVO

Annealing Furnace GLO
Annealing Furnace GLO

  • Temp. máx.: 900 - 1100 °C
  • volúmenes de cámara: 10 to 1300 litres
  • Para procesos en los que una atmósfera específica necesita ser mantenida de manera fiable
  • información del producto

Industrial Furnace HB
Industrial Furnace HB

Laboratory Furnace HTF
Laboratory Furnace HTF

NUEVO

Serie TF de hornos tubulares
Serie TF de hornos tubulares

  • Temp. máx.: 1100 - 1600 °C
  • Longitudes de calentamiento: 150 - 1200 mm
  • Horno Ø: 32 - 125 mm
  • Posición: horizontal / vertical
  • información del producto
NUEVO

Serie TS de hornos tubulares articulados
Serie TS de hornos tubulares articulados

  • Temp. máx.: 1200 °C
  • Longitudes de calentamiento: 150 - 1200 mm
  • Horno Ø: 60 - 200 mm
  • Posición: horizontal / vertical
  • información del producto

Debinding under a protective gas atmosphere is vital for the effective removal of binder, to prevent oxidation of parts and for maintaining a safe and controlled environment within the debinding furnace. During the furnace cycle, gas constantly flows through to remove the binder. Carbolite Gero offers HTK and HTBL furnace options for rest debinding. While for tube furnaces, it is important to note that a low binder content (< 1 gram) is acceptable for R&D.

NUEVO

Annealing Furnace GLO
Annealing Furnace GLO

  • Temp. máx.: 900 - 1100 °C
  • volúmenes de cámara: 10 to 1300 litres
  • Para procesos en los que una atmósfera específica necesita ser mantenida de manera fiable
  • información del producto
NUEVO

Serie TF de hornos tubulares
Serie TF de hornos tubulares

  • Temp. máx.: 1100 - 1600 °C
  • Longitudes de calentamiento: 150 - 1200 mm
  • Horno Ø: 32 - 125 mm
  • Posición: horizontal / vertical


  • información del producto

Catalytic debinding has strict requirements for debinding components containing Polyoxymethylene (POM). The EBO debinding oven is an ideal solution for ensuring efficient binder removal from green parts.

Hornos para eliminación de aglutinante EBO
Hornos para eliminación de aglutinante EBO

Safety options for debinding furnaces

The debinding process produces volatiles that can prove to be harmful. Precautions should be taken to reduce any risks. Carbolite Gero debinding furnaces are available with a range of options to optimise the production process.

Afterburner

An afterburner (left) is used to oxidize volatiles from the removal process into NOx, CO2, and H2O. This ensures all volatiles are transformed into safer molecules and released into the environment. It burns all volatiles, including those with a boiling point below 20°C, e.g. hydrogen, ammonia, and ethane. 
 

Condensate trap

A condensate trap (right) is used to condensate all compounds over 20 °C. All volatiles with the boiling point lower than 20 °C are let through.

 

Catalytic Converter

A catalytic converter (left) is a heated ceramic component that is doped with noble metals. The oxidiser contains a high surface area which supports the oxidation of organic components or gasses like CO and NO. In comparison to the afterburner, the catalytic converter runs at much lower temperature. The catalytic converter is compatible with models AAF 3 & 7 as well as AAF 18 & 32.
 

Heated gas outlet with a heating band

A heated gas outlet (right) is used to prevent condensates from forming in the outlet.

If required due to the process or recommended by the customer, the afterburner and condensate trap can be combined. As experts in high-temperature technology we have multiple solutions in our portfolio to guide you to the right debinding furnace and safety equipment. Please contact us for any enquiries on a suitable solution for your application needs.

Debinding Furnaces Reporte de aplicación

Thermal Debinding

A thermally induced decomposition and evaporation of the binder occurs due to gas flow through the debinding furnace. The gas flow guides vapours to leave through surface-connected pores within the sample.

A poor temperature distribution and an inhomogeneous binder removal can lead to the formation of cracks and other defects within the sample. Hence, it is necessary to regulate and control the heating rate and speed of the removal.

Temperature for debinding ranges from:

  • Low Temperature Removal: room temperature – 200°C - for solvent removal.
  • High Temperature Removal: 200°C - 600°C - for volatiles with higher boiling point.
  • Backbone Binder Removal: ≥ 600°C.
Employing a multi-step debinding process, where the sample is set to dwell at various boiling points, ensures the complete removal of compounds. Heating too quickly can lead to an increase in expansion rates, potentially damaging the sample and the afterburner. This, in turn, can hinder the conversion of organic compounds into NOx, CO2, and H2O. It is important to avoid trapped gasses and an incomplete removal process, as these lead to defects and an undesirable microstructure.

El gráfico muestra los resultados del análisis termogravimétrico.

Análisis termogravimétrico (TGA)

To track and optimise the progress of thermal degradation, thermogravimetric analysis (TGA) technique is recommended.

A decrease in reactant mass is often seen with an increase of the output product. This change can be recorded by monitoring the real-time mass loss during the thermal cycle.

TGA up to 5g: Thermal Analyzers for thermo-analytic processes - ELTRA
TGA up to 2kg: Ashing Furnace AAF-BAL with integral balance - Carbolite Gero

ELTRA: TGA Thermostep
Carbolite Gero: AAF-BAL

Catalytic Debinding

During this process, the main binder is directly attacked by an acid vapour. The material, when reacted with acid acting as a catalyst, transforms into smaller molecules that can subsequently be removed. Catalytic debinding eliminates binder faster than during a purely thermal process. This method is particularly useful in situations where there are large components or high throughput, as it takes a considerable amount of time to dissipate the gaseous products. Low temperature catalytic debinding ensures the removal of gasses which may create pressure within the pores and prevents the breakage of the component.

Nitric acid is vaporized at around 120°C and introduced into a furnace along with a nitrogen carrier gas. The recirculation fan helps the acid circulate around the green part, facilitating the interaction between nitric acid and the main binder, Polyoxymethylene (POM). This polymeric binder is composed of a continuous chain of oxygen and carbon atoms. The oxygen atoms in this macromolecule are susceptible to acid attacks, leading to the conversion of the POM polymer into formaldehyde. Given its low molecular weight, formaldehyde can be quickly removed from the binder matrix in the form of a vapor. The gas flow within the debinding furnace guides the formaldehyde towards the gas outlet, where it is safely combusted using an active torch afterburner.

Importance of Debinding

For sintering, it is imperative to remove the binder for several reasons:

  • The presence of binder during sintering causes a higher defect density within the structure. As the furnace temperature rises, binders can burn off and create gasses. These gases get trapped within the structure leading to a highly porous structure.
  • Unburnt binder doesn’t allow parts to achieve their full density. This is due to, particles not being able to come closer together and fully fuse, which is necessary to achieve a full density component.
  • If binder is not removed before sintering, it can cause the mechanical properties of the part to deteriorate. This is because sintering causes to improve the microstructure of the part, but the presence of unburnt binder can hinder the process.
  • If the binder remains after debinding and sintering, it will react with the other elements of the part and lead to a drop in the part’s melting point and other general properties.

 

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Póngase en contacto con nosotros para una consulta gratuita y hable con un especialista en productos para encontrar la solución más adecuada a los requisitos de su aplicación.
 

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Debinding Furnaces - FAQ

What is debinding?

Debinding is a critical step in powder metallurgy and additive manufacturing as it helps parts keep their shape before further processing steps. The binder removal process involves the thermal degradation of binding agents or additives from a moulded component. Debinding allows for the consolidation of powders and ensures minimal porosity or voids within the structure.

What is the difference between debinding and pyrolysis?

While both debinding and pyrolysis involve heat, the two processes serve a different purpose during the manufacturing processes. Debinding involves the removal of binder via degradation or evaporation. The debinding process is necessary before sintering to produce a fully dense component. Pyrolysis, in contrast, is a thermally induced chemical decomposition that occurs in the absence of oxygen. Organic precursors are decomposed at an elevated temperature and an inert environment to produce non-carbon volatiles.

What industries benefit from the debinding process?

Debinding is used by several industries as it prepares components for sintering. Industries that benefit from debinding are additive manufacturing, metal injection moulding (MIM), ceramic injection moulding (CIM), production of technical ceramics, automotive, aerospace, defence and MedTech. Products produced from this process range from consumer products to industrial hardware.

What solutions do we offer for debinding?

Carbolite Gero offers three different solutions to debinding which include thermal debinding in air, thermal debinding under protective atmosphere and catalytic debinding. A range of furnaces or an oven option can be offered depending on your application needs. It is necessary to know the size of your component and the amount of binder content it contains before making your choice.