NO.1  About the K Show in Germany

K as the world’s leading trade fair, started in 1952 and is the world’s largest event of rubber and plastics industry. It is held every three years, and 21 sessions have been successfully held so far, and it will usher in the 22nd event in 2022.

NO.2  About DEKUMA

DEKUMA has always been focusing on the R & D, production and sales of pipe extruder production line, rubber injection moulding machine and hydraulic press. Our products are widely used in auto parts, building materials, energy transmission, telecommunications and other fields.

（1）、DKM-EII75x36 parallel twin-screw extruder

Equipped with the screw and barrel with high L/D ratio optimized by the DEKUMA engineering team, it is often used to produce high-quality UPVC and CPVC pipes, ensuring good plasticizing effect and increasing output.

The DKM-EII75x36 twin-screw extruder to be exhibited at K Show is a new model launched by DEKUMA, suitable for the production of small and medium size PVC pipes. It’s energy-saving, efficient, stable and reliable!

Please scan the QR code to access the official website of K Show 2022 for buying the tickets.

Traditional punching machine has no acceleration and deceleration functions.Instead, it produces by the collision and extrusion of the upper and lower dies. It will make noise when colliding.

But the servo press can slow it down before the collision.Then try to reduce the noise of the collision as much as possible.

Our steel backing hydraulic press can be almost silent when in standby.The impact force during operation can also be much lower than that of traditional punching machine.Reducing the working noise from a maximum of 120dB to 75-78dB,workers don’t need to wear earplugs when using DEKUMA steel backing hydraulic press.

If you feel better, your work will definitely be easier.The product qualification ratio will also increase.And the problems such as difficulty in recruiting workers or limited working hours due to loud noise will be easily solved.

Recently, DEKUMA’s upgraded and optimized new RC480 automated rubber track production machine has been commissioned, and successfully exported to South Korea and arrived at the customer’s factory.

This customer is one of the largest auto parts manufacturers in South Korea, with production bases in many countries and regions, such as China, Europe, Southeast Asia and South Korea headquarters where DEKUMA’s rubber track machines are widely used.

DEKUMA has been cooperating with this customer for more than 10 years, and continuously improves equipment during the cooperation, and creating greater value to the customer.

Today, let’s see how DEKUMA’s rubber track production machines meet customer needs and keep improving.

Excellent performance of DEKUMA’s rubber track production machine

High degree of automation, reducing labor intensity and manpower requirements

In the past, the traditional production of rubber track required manual feeding, demolding and product retrieval. Generally, the production of a rubber track of several hundred kilograms required 3~4 people to work together.

Abstract: This paper analyzes the production process of PTFE compression molding, and summarizes the causes why conventional pressing pressure and pressing process are easy to cause product defects and scraps.

To solve the problems of surface patterns, cracks, discoloration, hidden cracks, etc., the hydraulic press team of Dekuma has developed a precision servo hydraulic press for blank pressing of PTFE powder product, and solves the problem for customers from the root.

01 Introduction to PTFE Properties

PTFE, known as the “king of plastics”, features many excellent properties including colorless, non-toxic, wide temperature resistance, chemical inertness and low coefficient of friction.

It serves as one of the important materials that are indispensable to all industrial sectors, e.g. automobile, national defense, machinery, chemical industry, electronics and other industries. It can also be made into PTFE pipes, rods, belts, plates, etc.

02 Commonly Used Methods of PTFE

The most common method is compression molding when processing products with PTEE.

The process of compression molding goes roughly as follows: raw material inspection → mashing and sieving → measuring → molding → semi-finished product inspection → sintering → cooling → finished product inspection → packaging.

After investigation on the common problems encountered during production of PTFE compression molding, it can be found that the improper operation of pressing pressure and pressing process may easily cause product defects and scraps, and the unstable pressure output serves as the main reason for cracks.

On the basis of understanding the customer’s process, the hydraulic press team of Dekuma has developed a precision servo hydraulic press for blank pressing of PTFE powder product, and solves the problem for customers from the root.

03 Advantages of PTFE Powder Blank Precision Molding Machine

（1） Slow Pressure Rising and Controllable Time

For powder compression, the time will significantly affect the effect of product molding. In case that the speed is too fast, exhaust will be insufficient, which may easily cause problems such as surface patterns, cracks, and large differences in density between both ends and the middle.

For the time control of pressurization, the hydraulic press adopts servo motor oil pump hydraulic system to solve the problem. Under the cooperation of hydraulic pressure and electricity, it has developed a controllable function of slow pressurization based on the set pressurization time, and the pressurization time is controllable from several seconds to dozens of minutes.

（2）Almost no pressure impact and fluctuation in pressurization stage

At the critical point of signaling pressure, most common hydraulic presses will experience the process of overshoot – fallback – stabilization due to inconsistent pressure repeatability each time.

Under the cooperation of server and plc program, the hydraulic press can control the critical point of signaling pressure well under the high sampling frequency and high-speed scanning cycle.

Thanks to the research results of hydraulic team of Dekuma for years, the set target value can be achieved under cooperated control of the server and the plc program. In the pressure holding stage, the pressure fluctuation is controlled within 1 bar, which can also maintain long-time operating of oil pump without damage.

Due to the specific characteristics of PTFE powder, after the initial pressurization to the set pressure and entering the holding pressure stage, the volume can still be compressed continuously. Once the volume is compressed, the pressure shall be reduced and the press will supplement pressure. Therefore, the pressure holding stage of PTFE product serves as a process of hydraulic system continuous pressure dropping and supplementing.

The stability of hydraulic press is realized based on years of application experience. Under the perfect coordination of high response of servo hydraulic PID and discharge flow of hydraulic oil circuit, the pressure fluctuation reaches almost zero.

For accurate pressure output, the hydraulic press engineers continuously optimize the hydraulic system and program. In application of servo system, sometimes a single PDI parameter is often not sufficient for the pressure range of the whole area. With the PID parameters set with low pressure, it will be still not applicable when reaching medium and high pressures.

After finding this situation in practical application, the hydraulic press combines with years of application experience, adopts multiple sets of PID parameters, corresponding to the multi-stage signaling pressure of the hydraulic press, and avoids the inapplicability of a single PID parameter to different pressure stages.

（3）After completion of pressing, the pressure relief time is controllable

For pressing of PTFE powder blank products, sometimes the pressure holding time takes dozens of minutes, with the purpose of obtaining a blank product with uniform density after reaching a certain compression ratio. However, after reaching the pressure holding time, in case of pressure relief instantaneously for some products, it is easy to cause the quality problem of hidden cracks inside the product.

To solve the problem of pressure relief, the hydraulic engineers have developed the function of slow pressure relief process and controllable time, and the pressure relief time can be controlled from several seconds to dozens of minutes.

For this, the pressure relief process can be considered as an inverse process of pressurization. During pressure relief, the pressure is output according to the time ratio for the purpose of reducing pressure until the final pressure relief in place. Conventional hydraulic presses have no such function.

（4）Convenient setting of process parameters

Adopt PLC + touch screen + servo drive control, for intuitive and efficient setting of technological process and parameters.

Most PTFE blank molding methods require two-sided pressurization + product demolding, and one product forming requires pressing twice + demolding once. However, the pressing parameters of the three times are not the same, and common hydraulic presses require repeated manual filling of different parameters three times.

Based on the special process of PTFE, the hydraulic press has compiled the parameter setting method for this process, allowing the customers to input parameters that conform to the product for one time, and the pressing can be completed with only operation controller. The operation is simple and fast, which reduce the probability of errors, improves reliability, and significantly reduces the technical threshold of operators.

For products that require to maintain pressure and exhaust for a certain period of time under different pressures to ensure transmission of pressure to all parts of the resin, it provides a free parameter setting function. (As shown in figure below)

For commonly used product parameters, after completion of debugging and passing inspection, it can be saved as a recipe, which supports one-key save and recall. (As shown in figure below)

（5）Energy saving and environmental protection

Common hydraulic presses produce large noises when working, which can easily pollute the production environment and affect the health of operators. The Datong hydraulic press adopts a servo motor as the power source, whose noise level is only about 70 decibels when working, and is almost silent under standby state. When operating, the torque is output according to the size of immediate load. The power loss is small, which can save 30%-50% of electric energy compared with common hydraulic presses, with significant energy saving effect.

Note that the pressing and holding time of PTFE powder blank products is long. For high precision, the user shall basically maintain the pump on and holding pressure. In this process, the servo motor system of the press only needs a dozen or so percent of output to conform to the pressure holding requirements. The hydraulic system produces less heat, reduces the cooling cost, and extends the service life of oil pump.

Common hydraulic presses require full speed output when the pump is on and pressure is holding. The actual utilization rate is only about 10%, and the machine is doing useless heating work for the rest time. The power loss is large, the energy utilization rate is low, and the oil pump service life of each hydraulic component is reduced.

04 Conclusion

For PTFE powder molding, accurate and stable pressure serve as the key factor to molding; for investment income, machines with energy-saving, energy conservation and environmental protection and high-utilization features are the key to cost recovery and realization of benefits; for operators, simple and efficient operation mode is the key point; the hydraulic press meets all the above key points, which can meet customer needs, and help customers solve problems from the root.

Abstract: With the continuous improvement of productivity of extrusion production line main unit, the capacity of its downstream equipment shall also be continuously improved to fulfill the requirements. This section introduces the method that Dekuma solves the problems of difficult adjustment of the cutting machine feed mechanism and difficult control of the feed speed with TRIZ innovative theory.

Keywords: TRIZ extrusion line Cutting Machine

01  The main problems of commonly-used feed mechanism in the industry

The feed mechanism of the cutting machine commonly used in the industry meets the processing requirements of the feeding and retracting with a group of hydraulic pump, supply hydraulic oil to hydraulic cylinder to control the swing movement of tool arm.

To cut pipes with different diameters and different wall thicknesses, firstly, it needs to adjust the initial feeding position, and meanwhile, it also needs to effectively control the feed amount of the tool arm; on the other hand, the feeding length is generally controlled by the cylinder stroke, and the initial position of the feed is controlled by adjusting screw of hydraulic cylinder support assembly.

In addition, for different cutting methods, the feeding speed shall also be controlled. The feeding speed is realized by adding the flow control valve in hydraulic circuit. If the speed is too fast, it will easily damage the cutting blade or saw blade.

02  Solve problems with TRIZ theory

The TRIZ theory was first proposed and summarized by the Soviet scientist Genrich S. Altshuler. TRIZ theory contains many systematic, scientific and operational creative thinking methods and analytical methods for finding problems. After years of development, TRIZ theory has become a mature classical theoretical system for solving practical problems in product development.

The general method of TRIZ theory to solve problems is that, first, abstract the special problem to be solved into a standard problem; then obtain a general solution based on the methods and tools provided by TRIZ theory; finally, obtain the final solution based on the user’s experience.

Heavy Duty Chipless Cutting Machine DKM-PO450

（1）Find and analyze problems – abstract into standard problems

Based on the analysis of the actions of feed mechanism, Dekuma’s engineering team conclude that in the approaching stroke, the feeding speed is expected to be faster, to reduce the feeding time and improve efficiency; while in the working stroke, the feeding speed is expected to slow down. On the one hand, it is aiming to reduce the load resistance of hydraulic cylinder; On the other hand, it is to reduce the rigidity requirement of the whole mechanism, and to improve the service life of the blade. From this analysis, the feeding speed shall be combined fast and slow, forming a pair of physical contradictions.

（2）Conduct resource analysis to find out contradictions

Four separation principles are summarized with TRIZ theory according to space, time, condition and system level, which are space separation, time separation, condition separation, and whole-part separation.

Among them, the principle of time separation is to separate the conflicting parties in different time periods, aiming to solve the problem or reduce the difficulty of problem. Based on analysis, Dekuma’s engineering team solve the problem of different speeds required by feeding speed at different times with this principle.

Comparing the corresponding 12 innovative principles in the principle of time separation, the “fast principle” that completes harmful operations at the fastest speed serves as the most effective one of the 12 innovative principles. For the feed mechanism, slow approaching travel can be considered as a harmful operation, which is very harmful to the improvement of efficiency.

（3）Problem solving

To quickly complete the harmful operation, the “fast principle” is adopted to solve the problem of approaching stroke. Dekuma introduces a deceleration cylinder, which quickly feeds and oil return to complete the action during approaching stroke. When it comes to the working stroke, the oil return of cylinder reduces the speed of working stroke by decelerating to meet the process requirements.

03  Main advantages of the new segment-controlled feed mechanism

To solve the problems encountered by commonly used feed mechanism in the industry, achieve the convenient operation of the extrusion production line, and reduce the cycle time required to replace different pipe specifications, Dekuma’s engineering team has developed a new segment-controlled feed mechanism, with the main advantages and principles as follows:

（1）Fast adjustment of tool arm initial position

The position of tool arm can be adjusted quickly by way of clamp-type tool arm assembly. The operation method goes as follows. Loosen the fixing screws of the clamping block, and swing the tool arm quickly to the marking scale line of the required specification according to the scale displayed on the sign, and then tighten the fixing screws of the clamping block. The initial operation of tool arm position adjustment is thus completed.

（2）Control the oil via deceleration cylinder

Therefore, two stages of fast and slow feed speeds can be achieved. Fast feed is adopted during the approaching stroke, and slow feed is adopted during the working stroke, which can effectively reduce the feeding cycle of tool arm. Taking the 40mm feed stroke as an example, 20mm is the approaching stroke, the time required for fast feed in the approaching stroke is 1s, and the time required for slow feed in the working stroke is 30s, and it takes total 31s to complete the whole stroke, which can save approx. half time of the original mechanism.

（3）Springs configured by deceleration cylinder and feed cylinder

The hydraulic cylinder can be reset actively, allowing the action of tool retracting to be completed faster, which further reduces the time of the whole process and improves the stability of actions.

05  Conclusion

By applying the invention principle of TRIZ theory, Dekuma has proposed the idea of solving the problem of feed segmented control, which improves the action performance of feed mechanism cylinder and the time of each process.

The new segmented-control feed mechanism developed by Dekuma doubled the feeding speed, and ensured the stability and reliability of the retracting action. The cutting machine, as part of the extrusion production line, can better match the productivity of the entire production line!