COEX-80-2 Double-stage Ceramic Extruder

A. Features of our ceramic extruders

In 2017, our company digested and absorbed the alumina ceramic membrane extruder VAHRS120B with double-stage vacuum exhaust spiral ceramic extruder technology introduced from EAC-Elektro, Germany, In order to better adapt to the needs of the molding and extrusion users of different kinds of ceramic materials, we first used better cost-effective, more targeted and longer service life materials to manufacture the core components of the extruder that deal with the extreme friction wear and corrosion wear conditions of ceramic materials, At the same time, we further optimize the related technology of ceramic extruder, for example, we further optimized the design of the screw combination module structure, Improve the heat exchange performance of the screw, And facilitate the replacement of the screw module; For example, we have further optimized the structural design of the vacuum exhaust chamber, added the flow channel design, eliminate the risk of possible material deformation resulting in pressure leakage in the future. Over the years, our company's ceramic extruder with its more acceptable price and superior performance has been the majority of users at home and abroad welcome.

By December 2021, our company optimized the double-stage vacuum exhaust ceramic extruder with its excellent design and performance, in addition to exporting Poland and other European and American users, but also successfully won the Pakistan national water treatment project bidding, making contributions to the development of another industrial field in the "One Belt and One Road".

So far, our various ceramic extruders have been accepted by ceramic product manufacturers in more fields. In addition to aluminum oxide flat film (pipe) extrusion, they are also widely used inthesilicon carbide extrusion, the activated carbon extrusion, the molybdenum dioxide MoSi2 molding extrusion, the raw material with cement and silica sand wallboard extrusion andthethermal insulation/decoration integrated wallboard extrusion, etc., these extrudershave been widely praised by users at home and abroad in various industrial fields.


B. Structure diagram of COEX-80/80Double-stage ceramic extruder


              Structure diagram of COEX-80/80 Double-stage ceramic extruder

The picture above does not include supporting devices, such as achiller,acontrol cabinet, etc


C. Main structure of COEX-80-2Double-stege ceramic extruder:


     Main structure of COEX-80-2Double-stege ceramic extruder


D. Structure and configuration features ofCOEX-80-2 Double-stage ceramic extruder 

1. The L/D ration and motor power of the double-stage ceramic extruder of the model COEX-80-2: 

Upper-stage L/D7.8, matching motor power7.5kW;

Lower-stage L/D9.8, matching motor power11 kW;

2. COEX-80-2 double-stage ceramic extruder specifically designed for the characteristics of high water content of ceramic raw materials, adopta vacuum exhaust system design with high strength to eliminate moisture, that is, the material is extruded from the upperstage into a "vacuum chamber" inan internal negative pressure state, adjust the negative pressure in the vacuum chamber under visible and quantifiable conditions, so as to realize the quantitative moisture elimination function, as shown in the figure on the right.

Material entering the negative pressure vacuum chamber between the upperstage and lower stage, the user can decide whether to open or how much vacuum negative pressure is required to eliminate the required water quantity according to the field production requirements, such as the water content of the product. When the vacuum negative pressure is in a state of disappearance, the vacuum chamberonlyprovides a channel for the mixing material from the upper machine to enter the lower machine smoothly under a  condition of no water loss, so as to realize further fine mixing and pressurization function.

The extruder vacuum chamber is made of transparent acrylic materials to facilitate the field operators to intuitively and accurately control the material vacuum situation;

COEX-80-2 double-stage ceramic extruder

3. On two feeding sections of the upper and lower extruder of the double-stage machine is equipped with a counter-rotating double screw feeding system designed for the characteristics of ceramic clay material. Unlike polymerrawmaterialsin the extrusion, ceramic mud generally doping have high proportion, as an adhesive of organic cellulose, mud performance high water content and mutual adhesion "ball", fluidity is very poor, leading to the difficulty of extruder feed, sothe  double stage feeding system forceramic extruder is very special direction inward "double wrist" structure design, as shown in the right, in order to realize the mandatory feeding of ceramic mud function;

two feeding sections of the upper and lower extruder of the double-stage machine

4. Ceramic materials inside the extruder barrels, there is a very significant, completely different characteristic from other operating materials, that is, hard solid phase ceramic materials“contact and rub” the barrel bore wall and the screw edge surface, which will produce serious "shear force". The shear force will produce a high "shear heat". However, there are certain components of organic cellulose as adhesives in the ceramic material. Once these organic cellulose decompose after bearing high shear heat, its function as adhesives will be greatly reduced or even disappeared.

In order to avoid the "thermal decomposition", in addition to the screw structure design as far as possible to reduce the "shear heat", all the barrels in upper and lower stage of the ceramic extruder are designed with a forced water cooling circulation system inside. With the coordination of circulating water input from an external high-power chiller and set to the temperature required for ceramic material operation, accurate temperature limiting control is achieved for the material temperature inside the extruder.

The water circulation system inside all the double-stage barrels of the designed ceramic extruder is shown in the right figure.

The manufacturing materialfor the double stage machine barrels is 304 stainless steel to prevent corrosion, especially in summer, from condensation water. The barrelinner liners are equipped with a segmented, quenched and hardened 1.4112 (corresponding to the Chinese brand 9Cr18MoV) martensitic stainless steel to resist the extremely severe friction wear and acid-base corrosion wear conditions of ceramic materials mixed with organic cellulose.

COEX-80-2 Double-stage Ceramic Extruder

5. The modular threaded components are connected to the shaft through splines andget the power torque transmitted by the shaft. Inside the inner of the shaft is installed with a stainless steel pipe, and circulating constant temperature water is sprayed out of the steel pipe and flows back along the inner wall of the shaft, take away the shear hot received by the material, as shown in the following figure: 

modular threaded components 

6. In view of the extreme serious friction and wear characteristics of solid phase high shear of ceramic "mud material", and the acid and alkaline corrosion characteristics of high water content of mud material, all the core components of ceramic extruder adopt the modular design for convenient replacement. Once the user encounters the extrusion output decline, the extrusion product is unstable and needs to replace the parts, only need to replace the local seriously worn parts to reduce the operating cost of the extruder and quickly restore the production.

The schematic diagram shows rightis the screw design structure and modular thread element code of COEX-80-2 ceramic extruder.

The manufacturing materials of the above modular screw parts are made of martic corrosion resistant stainless steel of 1.4112, and the ultimate quenching hardness can reach HRC 62 or above;

schematic diagram

7. In order to meet the user's demand for various products of ceramic extruder molding, including the high size precision requirements of extrusion sheet and tube products, the control system of ceramic extruder configuration needs to achieve the most stringent feedback and closed-loop control on the pressure fluctuation range of operating materials. In order to achieve this goal, the ceramic extruder adopts a PLC programmable logic controller host to accurately control two screw speedby precise PID tuning and closed-loop control of the two main motors of the COEX-80-2 extruder from the upper to lower stages. All of these controls can be easily and intuitively operated through a 10 inc touch screen installed on site. 

To this end, for the lower stage machine which directly for the molding, in front of the molding template configuration with a high-end DYNISCO brand pressure / temperature double sensor, to accurately feedback the pressure and temperature of the nose, makes the closed loop control system can be more accurate and timely monitor material dynamic online condition, as shown in the right.

COEX-80-2 extruder

8. In order to ensure the high reliability and stability of the machine operation, while the pursuit of the lowest running energy consumption, all the main motors on upper and lower stage extruder COEX-80-2 to be set up with high-end Shanghai HaoGuan FCA brand motors, together with two sets of domesic famous Jiale frequency conversion governor, using accurate and reliable frequency conversion speed control mode, so can more strictly control the screw speed to achieve the purpose of accurate control product size, at the same time can achieve the purpose of energy saving, reduce consumption.

E. Main technical parameters of COEX-80-2 Double-stage ceramic extruder:


Upper Stage Extruder

Bottom Stage Extruder

Raw material

Silicon carbide, cordierite, ceramics, alumina, and so on

Feeding system

304 stainless steel hopper, twin screw forced feedingin

counter-rotating way

Vacuum and twin screw forced feedingin counter-rotating way

Main motor and power

High reliability variable frequency gear motor, 7.5 kw

High reliability variable frequency gear motor, 11 kw

Screw Diameter (mm) and Manufacturing Material

¢79,Martensitic stainless steelafterquenching

¢79,Martensitic stainless steel and some is PM-HIP

ScrewL/D ratio



Screw Speed (rpm)



Screw maximum thrust



Screw bearing torqueunder a maximum speed (Nm)



Vacuum exhaust system

Germany Busch brand, model R5-Single stage oil rotary vacuum pump. Motor power 0.75kw,final vacuum 0.1hPa (mbar),

maximum speed 1800rpm, maximum vacuumpumpingrate: 25m3/hr.

Temperature control system

Constant temperature and soft water circulationinside both barrel and screw

Barrel and screw

temperature control method

Constant temperature and soft water circulation outsidebarrel

Constant temperature and soft water circulation outsidebarrel andinside thescrew core

Barrel and screw

temperature control range



Temperature control

section on barrel

2 Sections

3 Sections

Backpressure on material



Center height (mm)




The different material formula, the different process and the different product, then the different maximum capacity.

Installed capacity (kw)


Normal production power



Exterior dimensions (mm)

Length2100 × Width960 × Height1700

Full weight (kg)


F. Main configuration of COEX-80-2 Double-stage ceramic extruder:

Power system

Motor/ reducer combination

For the upper and lower stage extruder, all adopt domestic high-end & high-torque Shanghai HaoGuan FCA brand frequency conversion speed regulating gear motor, combined with domestic Jiale brand frequency conversion speed regulator, with the characteristics of compact design and space saving, large motor bearing torque, stable and reliable, and long service life


sion system


tion box

The radial bearings of the torque distribution system are NSK bearings, gears are high-speed heavy load hard gear surface, gear shaft material 20CrNi2MOA, HRC 58-62

Extrusion system


304 Stainless steel hopper,double screw in opposite inward rotation, made from amartensite stainless steel 1.4112(Chinese brand is 9Cr18MoV), with aforced-feeding structure

Double-stage barrel

Combined barrel structure, constant temperature water circulation temperature control, barrel cylinder made of 304 stainless steel, inside cylinder there is replaceable liner made of martensitic stainless steel 1.4112 (Chinese brand is 9Cr18MoV) and to be hardened

Double-stage screw

The modular thread components of the extruder screw are all made of martensitic stainless steel 1.4112, after quenching, its hardness is more than HRC 58

Exhaust system

Vacuum exhaust

From an upper stage machine into a lower stage machine, material through a vacuum chamber to achieve controllable and visual exhaust function, with the world's leading German Busch brand vacuum pump, its innovative oil-free vacuum pump technology can ensure strong, economic, reliable and silent operation state, with efficient, oil-free, contact-free operation and maintenance-free performance


ture control system

Accurate tempera-ture control

One air-cooled dual-systemchiller with 10HP is mainly equipped with compressors imported from Europe, America and Japan, Danish Danfoss and American Eco throttle parts, and high efficiency evaporators and condensers. The normal temperature water is cooled to the set temperature through the compression mechanism of the chiller to control the operating temperature of each barrel and screw section of the extruder.

Electronic control system

Vertical control cabinet and its

touch screen control

Using human-machine interface HMI system of domestic high-end Xinjie brand, window type 10-inch touch screen, with Xinjie brandPLC programmed logic controller host, implement precise control of the system, realize the PID setting linkage control of two main motors of doublestage extruder.The operation control functions and the main configuration of double-stage machine control system are as follows:

1. Set the screw speed of the upper stage machine as the set value from the touch screen, to control the 7.5KW Jiale frequency converter drive motor, to realize the precise control of the power of the upper stage machine;

2. Set the screw speed of the lower stage machine from the touch screen as the given value, control the 11KW Jiale frequency converter drive motor, to achieve the accurate control of the power of the lower stage machine;

3. The PLC mentioned above can perform PID control of the extruder through analog communication for data acquisition and processing. For example, according to the back pressure change of the feedback by the pressure sensor installed on the nose, the power system of the extruder host can be accurately controlled, so as to realize the accurate matching of the speed of the upper and lower stage screws, so as to control the material back pressure and melt flow, realize the closed loop control, and realize the automatic operation and control purpose of the extruder. These functions of the PLC control system, compared with the ordinary extruder only using the manual control mode of the instrument display, its automation advantages are incomparable;

4. Display the second order motor parameters from the touch screen, could manually adjust the speed of the second stage screw, and display the detection value of the vacuum (negative pressure) sensor, and start / stop the vacuum pump, see the following example control interface:

5.  Using a human-machine interface HMI system of domestic high-end Xinjie brand, window type 10-inch touch screen, with Xinjie brandPLC programmed logic controller host, implement precise control of the system, realize the PID setting linkage control of two main motors of doublestage extruder.The operation control functions and the main configuration of double-stage machine control system are as follows:

operation control functions 

6. The temperature and pressure values detected by the lower stage pressure / temperature double sensor on the touch screen are shown in the above design figure, and the system is designed with extruder pressure protection and early warning function;

7. Electrical parts of control cabinet, including contactor, air switch and solid state relay, are mainly using French SchneiderSchneiderBrand, in pursuit of high stability and high control system reliability.


Chief Engineer's Office / Shanghai Omega Machinery Co., Ltd