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.
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.
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.
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.
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.
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.
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.
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.
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:
I granuli di carbone attivo sono utilizzati per diversi processi, tra cui la purificazione dell'aria e dell'acqua, la decaffeinizzazione, l'estrazione di oro e metalli e il trattamento delle acque reflue.
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
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.
For sintering, it is imperative to remove the binder for several reasons:
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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.
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.
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.
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.