Top 5 Technical Ceramic Forming Methods You Should Know

Ceramic forming aims to produce green bodies with a uniform internal structure and high density. It is a crucial step in the ceramic fabrication process. The forming technique largely determines the uniformity of the green body and the ability to prepare components with complex shapes, and it directly affects the material’s reliability and the final cost of ceramic parts. There are several ceramic forming methods, and the five most commonly used ones can be summarized as follows.

 

If you work in the industrial ceramics industry, whether upstream or downstream, as a supplier, technician, or salesperson, it is helpful to be familiar with the most commonly used ceramic forming methods.

 

1. Dry Pressing

 

 

 

Dry pressing, also called uniaxial pressing, is a common forming method, especially for making flat or thin parts. In this process, granulated ceramic powder with good flow is placed into a steel mold. Pressure is then applied from above and below to compact the powder into a dense shape.

Advantages:

* Simple process, Easy to handle, short cycle, high efficiency — suitable for automation.

* Produces high-density parts with precise dimensions and minimal shrinkage; High mechanical strength and excellent electrical properties .

Limitations:

* It is difficult to produce large green bodies; the mold wears easily, with complex machining and high cost.

* Because pressure is applied only from the top and bottom, the distribution of pressure, density, and shrinkage tends to be non-uniform, which may lead to cracking and delamination. However, with the development of modern forming techniques, this limitation has been largely overcome by isostatic pressing.

Applications:

Ideal for small, flat, and thin-walled ceramic components such as ceramic sealing rings, valve cores, and ceramic liners.

 

2. Cold Isostatic Pressing (CIP)

 

 

Cold Isostatic Pressing uses liquid pressure transmission (oil or water) to compress powder uniformly from all directions. This ensures a homogeneous density and high green strength.

Advantages:

* Uniform pressure and density throughout the part.

* The green body has high density with few defects, and the sintering shrinkage ratio is generally lower than that of dry pressing.

* Suitable for parts with concave shapes, slender profiles, and other complex geometries.

* Low mold cost and minimal friction loss.

Limitations:

* Low production speed, difficult automation.

* Difficult to control accurately. Dimensional control requires experience and precision.

Applications:

CIP is commonly used for large alumina ceramic insulators, zirconia plungers, alumina tubes, and high-performance structural ceramic parts that require high strength and uniformity. For example：

(1) Large, thin-walled, high-precision, and high-performance alumina ceramic radomes, as well as large, thick-walled, complex-shaped 97% alumina ceramic high-frequency terminal insulating sleeves with umbrella ribs, are manufactured using wet isostatic pressing technology.

(2) Alumina and zirconia ceramic plungers, and large-size zirconia ceramic cylinder liners for petroleum drilling are produced using isostatic pressing technology.

(3) Transparent alumina ceramic tubes for high-pressure sodium lamps and alumina ceramic spark plugs are commonly produced using dry-bag isostatic pressing technology.

 

3. Hot Slip Casting / Thermal Slip Casting

 

This process mixes ceramic powders with molten wax to form a flowable slurry. The slurry is injected into a metal mold, solidifies upon cooling, and the wax is later removed by controlled heating.

Advantages:

* Capable of forming complex and near-net-shape parts. 

* Low equipment cost and small mold wear.

* Easy to operate, with low labor intensity and high production efficiency;

* Highly adaptable to raw materials, suitable for oxides, non-oxides, composite materials, and various mineral raw materials.

Limitations:

* High wax content results in longer debinding times and lower density.

* Not suitable for large or thick-walled parts.

* High porosity, relatively more internal defects, and low density, resulting in poorer mechanical properties and lower performance stability;

* Requires a dewaxing step, which increases energy consumption and production time. Due to limitations of the dewaxing process, it is difficult to produce thick-walled components.

* Difficult to produce high-purity ceramic products, limiting the application of this process in high-end technical fields.

Applications:

Used for intricate ceramic components in engineering and industrial applications where shape precision is critical.

 

4. Ceramic Injection Molding (CIM)

 

CIM combines polymer injection molding with ceramic technology. Ceramic powder is mixed with a binder system, molded under high pressure, then debound and sintered to full density.

Advantages:

* Near-net-shape forming deal for mass production of small, precise, and complex ceramic parts，so that the sintered ceramic products require little or no machining, thereby reducing the high costs associated with ceramic processing

* High automation level, excellent surface finish, and uniform density.

* Minimizes or eliminates post-machining.

Applications:

This technique is most advantageous for the mass production of ceramic products with high dimensional accuracy and complex shapes. It has been widely used for zirconia, alumina, and silicon nitride precision parts in aerospace, automotive, medical, and electronic industries.

Mingrui Ceramic uses advanced CIM techniques for high-precision industrial components where tolerance and consistency matter.

 

5. Extrusion Forming

 

Extrusion, also known as extruded forming, involves mixing ceramic powders with clay or organic binders that provide plasticity, along with water, and repeatedly kneading the mixture. Through processes such as vacuum deairing and aging, the extrudable batch attains good plasticity and uniformity. The mixture is then forced through a die at the extruder nozzle under the action of a screw or plunger, producing products of the desired shape.

Advantages:

* High efficiency and suitable for continuous production.

* Perfect for tubular or rod-shaped ceramics. But the die structure is complex, and high machining precision is required.

Limitations:

* Higher shrinkage during drying and sintering due to the higher content of solvents and binders.

* Defects such as warping, cracking, or delamination may occur without proper control.

Applications

Extrusion molding is suitable for manufacturing ceramic products with a uniform cross-section, especially tubular or rod-shaped products with a high length-to-diameter ratio. It can be used to form various oxide ceramics as well as non-oxide ceramics such as carbides and nitrides. Currently, it is widely applied in the production of ceramic furnace tubes, electromagnetic insulators, catalyst carriers or supports, heat exchanger tubes, honeycomb ceramic carriers for automotive exhaust filtration, ceramic rods and bars, and other ceramic products. It can also be used for forming sheet-type capacitors, magnetic material substrates, and electronic substrates.

 

Mingrui Ceramic's Insight:

Some of our customers have specific requirements regarding the forming methods. However, some customers may not be very familiar with these processes and might have questions such as:

— Why is there a mold cost for this product?

— Why can't this ceramic tube be made by injection molding?

— Why does the part still need to be machined after demolding?

— Why is this product smaller in size but much more expensive?

……

Our cost is closely related to the manufacturing process, which in turn has a strong impact on product quality. For example, some customers have asked us why their previous products showed no issues in powder or material testing, yet the performance still failed to meet requirements. In such cases, the reason often lies in the forming and processing methods, as well as the control during manufacturing.

 

Choosing the right forming process is not a one-size-fits-all decision. At Mingrui Ceramic, we select forming methods based on:

* The ceramic material (Al₂O₃, ZrO₂, SiC, Si₃N₄)

* Component geometry and size

* Mechanical and thermal requirements

* Cost-effectiveness for scale production