High Performance Compounding

Smart Feeding & Application Example Conveying Solutions High Performance Compounding

Introduction The production of plastic consists a continuous, uniform infeed with Electronics, Furniture, Health & allows formulations with reduced of many important process steps, very tight short-term accuracy and Hygiene, Leisure & Sport, Packag- wax content or no wax at all. This which are needed to generate a ho- repeatability. ing, Pipes, Textiles, etc. means that high performance mogeneous application specific compounding technology not only plastic compound from a number Typical Production Output Masterbatch benefits productivity and quality of different raw materials. Twin screw compounders are With high performance com- but also contributes to reduced equipped with different screw pounding technology, the time- raw material costs. Process diameters from 25 up to 150 mm consuming step of fine grinding The compounding process is a in various steps depending on the of pellets and premixing in batch Engineering Plastics continuous process. The main manufacturer of the compounder. quantities can be eliminated. Compounding and pelletizing of steps in the compounding process The typical line rates range from Pigments are fed directly into engineering plastics (i.e. filling, are: 50kg/h up to 6’000 kg/h. the melt by means of gravimetric reinforcing, alloying, colouring  conveying feeders. Pigment concentrations and degassing of PA, PP, PET, ABS, End-Product Industries up to 70 percent are possible. PUR, PC or POM) are the specialty  plasticizing/melting Automotive, Building & Construc- Compared with the old premix of high performance compound-  mixing tion, Appliances & Housewares, feeding method, the new process ers.  homogenizing Fillers  blending Polymer A, polymer B Chopped glass Typical layout for filling, and additives fibers  dispersing as a premix reinforcing, alloying  devolatizing and colouring  reacting Loss-in-weight  Loss-in-weight Loss-in-weight screw feeder heating/cooling belt feeder vibratory  visc-breaking feeder

 cooking Twin screw side feeder  pressurizing Devolatizing High Performance Strand Compounder Main Ingredients die head Air knife Pelletizer Water bath The main ingredients which must be continuously and very accu- rately fed are base polymers such To bagging station as PP and PE.

Typical Additives Polymer Additives Pigment  Stabilizers, lubricants, plas Masterbatch production using tifiers, colour pigments, fillers, new split feed technology flame retardant, cross linking agents, foam agents, etc.  Glass or carbon fibers for rein- for-cement, base polymer pellets Loss-in-weight for alloying to new compounds screw feeders Twin screw  Recycled material side feeder Devolatizing The additives can be in the form of High Performance Strand Compounder powders or masterbatch pellets. die head Air knife Pelletizer Water bath Key Requirements One of the key requirements in high To bagging station speed compounding is to ensure

1 Higher Accuracy with Advanced Feeding Technology

Feeding Process Typical Scope of Supply For sticky additives, such as via Modbus (Modicon) RTU, Allen Irganox, Tinuvin, or CaCO , etc. Bradley DF1 or Siemens (3964R). The main polymer and additive The main polymers are normally 3 masterbatch are fed very accu- pellets or powders fed with a single K-Tron Premier P-Series receivers Alternatively, a K-Tron Smart Com- rately with a single screw feeder, screw feeder type K4G or K2-ML- are the ideal solution. mander could be used for up to 30 e.g. K4G, into the main inlet of the S60/S100. Alternatively a K-ML- feeders and 8 lines. Control System compounder. KV2/3 vibratory feeder can be used. The loss-in-weight feeders dose Environmental Conditions Refill is conducted via a Premier  The typical feed range for screw the ingredients in a preset ratio, set Plastic compounding systems are Pneumatics vacuum loader sys- feeders is 0.2 - 15’000 dm3/h in the operator interface or down- typically classified as IP55/NEMA tem from an octabin station and  The typical feed range for vibra- loaded from the host computer 12. In some processes N blanket- large storage silos. 3 2 tory feeders is 2 - 5’000 dm /h via K-Vision Line controller to the ing is required. This means that the A K2-ML-T35 feeds the stabilizer in  The additives are feed by Loss- locally mounted KCM. LWF’s are equipped with a well- the form of powder into the main in-weight screw feeders such as All the process relevant param- proven pressure compensation extruder inlet. K2-ML-T20/T35 at rates of 0.2 eters for each feeder are stored in system at the inlets and outlets. The chopped fiberglass is fed via – 200 kg/h, depending on the the appropriate recipe. Depending on the process, gas K-ML-KV2F into the side feeder of recipe. The on-machine KCM combines explosion protection may be re- the second inlet of the extruder. the function of motor drive and quired, i.e. Zone 1, Temperature The ratio control is handled via the Refill feeder control in a compact pack- class T3 for Europe and Zone 1, K-Vision operator interface which For free flowing products K-Tron age. Division 2 for USA. In this case in turn controls the feeders via KCM Premier vacuum loaders or receiv- standards K-Tron XP executions In this example the K-Vision pro- (K-Tron Control Module), mounted ers can be used to keep the feed- must be applied. locally at each feeder. ers well supplied. Thanks to the vides a single user interface for up to 16 feeders. The integrated All the recipe handling and line patented dual cyclone technology, K-Link feature allows for commu- monitoring is done via the factory most materials can be fed without nication with the host DCS system DCS-System. needing a filter.

Typical Process Layout Host communication Control network

Fiberglass Powder additive

Main polymer Masterbatch Host computer K-Vision DCS / PLC Operator Interface Bag dump Octobin station discharging station K-Tron Premier receivers

Loss-in-weight vibratory feeder K4G screw feeders Loss-in-weight screw feeder

Degasing Side feeder Main inlet

Pelletizing Drying High Performace Coating Compounder

Conveying to storage

2 Advantages of K-Tron’s Smart In order to even be able to speak Proven Performance with K-Tron Smart Technology Weighing Technology of adhering to recipes with chang- kg/h The goal of a compounding plant ing operating data, one condition new setpoint is economical production! Among must be fulfilled: the mass flow other things, this means as little must adapt to the setpoint as Feeder 1 waste as possible and minimum quickly as possible. This is only reconfiguration time. The K-Tron possible with advanced gravimetric control and the high sampling feeding system makes this pos- Feeder 2 new setpoint achieved sible. An important factor is the rate and resolution offered by adherence to the recipe during K-Tron’s Smart Force Transducer t t1 t2 t3 ramping up of the extruder and weighing technology. naturally also during large setpoint Conventional feeder control t1+ t2 ModernK-Tron SmartConnex feeder control t1 changes. The short-term accuracy of a high performance extruder is Massflow during setpoint change a key factor for quality of the end This image shows the requirements of an extruder manufacturer with product. regard to the desired behaviour during a setpoint change in the line. It is nice to show that this challenge could be met in the test lab well beyond any expectations. Instead of overriding the new values first and then working them in, the desired value could be obtained almost directly. This is extremely advantageous for high speed extruder feeding.

Feeding test with free flowing material 1.8 Modern K-Tron SmartConnex Control System

) 1.6 1.547 Conventional Control System ( %

s 1.4 1.2 m ple

s a 1 c . 0.93 0.925 S e

0.8 5 , 0.6 m a g

S i 0.4 0.506 2 0.2 0.343 0 0 100 200 300 400 500 600 700 800 900 1000 1100 Feed rate (kg/h)

Feeding test with poor flowing material Modern K-Tron SmartConnex Control System 2.5 Conventional Control System ) % (

s 2 1.999 e l

p 1.921 m

a 1.727 s 1.5 . . c e S 1.139 5

, , 1 1.186

a 1.135 m g i S

2 0.5

0 0 500 1000 1500 2000 2500 3000 3500 4000 4500 Feed rate (kg/h)

The graphs above show a comparison of feeding accuracy, which was obtained with different gravimetric control systems. To obtain these results, the following conditions must be given: a high sampling rate (here 112/sec.), efficient digital filtering and a fast control algorithm. In other words: the sampling rate must be higher than the controlled K-Tron feeding station with refill system elements can react.

3 Smart Solutions

Advantages of K-Tron Modular Future Potential Feeders with Powersphere The plastic compounding market + practically no wear parts is steady growing approximately + smooth surfaces avoid contami- 3% annually. The auto industry nation is replacing more and more steel parts with highly reliable plastic + weighing technology with inte- parts. New plastic composites will grated digital filter for dynamic be developed which will lead to weighing even in difficult envi- the building of new compounding ronments lines. + feeder does not cause weight Retrofitting and debottlenecking fluctuations of existing compounding lines also Competing Technology offers the opportunity for process improvement.  Feeders with flexible walls - PU sheath must be replaced Typical Applications regularly There are a number of well known - PU sheath can become con- users of high performance com- taminated (pigments, etc.) pounding lines in the following - conventional weighing systems industries/processes: - paddles cause vibrations  Technopolymers compounding  Heavy Duty Screw Feeder  Engineering plastics - generally older technology  Thermoplastic - lower grade stainless steel with  Masterbatch Producers pickled finish is not smooth  Special areas in BOPP-Film - ratiometric weigh sensor with lines  Adhesives and Sealants lever system K-Tron feeders with refill system on a compounder - large, heavy equipment generally cause more vibrations. Testing Facilities Services References K-Tron has well-equipped testing Additional services are also avail- Several thousand customers facilties to test high rates of PE able, such as: worldwide are successfully using powder and additives. We can - System Engineering handle up to 20 t/hr of PE powder K-Tron Modular Feeders in their - Installation Start-up compounding processes. Our for accuracy testing. Long term - Operator and Maintenance Sales department will be glad to testing is also available since ma- Training provide you with a reference list. terial can be recirculated. We will be glad to provide contact information or to help arrange visits to reference sites.

Manufacturing plants: K-Tron America Inc. Premier Pneumatics Inc. K-Tron (Switzerland) Ltd Routes 55 & 553 606 North Front St. / P.O. Box 17 Lenzhardweg 43/45 Pitman, NJ 08071 USA Salina, KS 67402-0017 USA CH-5702 Niederlenz Tel: (856) 589-0500 Tel: (785) 825-1611 Tel: +41 62 885 71 71 Fax: (856) 589-8113 Fax: (785) 825-8759 Fax: +41 62 885 71 80 e-mail: [email protected] e-mail: [email protected] e-mail: [email protected] www.ktron.com