"No mode" thermoforming sheet production technology

The continuous introduction of new sheet production lines in China, the introduction of foreign and imported equipment, and the application of new raw and auxiliary materials have enabled the thermoforming industry to flourish. Thermoforming sheet processing technology also varies from device to device to material and application. The increasingly mature processing technology gradually breaks the old conventional theory. Now, even in the same production line, you can use different processes to produce qualified sheets of different uses, different specifications, and different materials. Sheets of the same specification and use can also be processed with different equipment and processes. "It brings great convenience to production.

The so-called "modeless" thermoforming sheet production technology means that thermoformed sheets can be produced in a variety of technological ways without a fixed pattern. It is to break the "conventional" thermoforming sheet production technology theory, is the continuous development of the times, broaden the horizon of thermoforming sheet production technology theory. This is the result of our theoretical analysis and practical proof of the fact that after ten years of our time, we have come to the forefront of production, through on-site inspections of production lines for the United Kingdom, the United States, Germany, Austria, and China (including Taiwan). The purpose is to broaden the field of vision for workers, technicians, and engineers who produce sheets, and to understand that there is more than one way to produce sheets for thermoforming. While high-end configurations are beneficial to production, low-end configurations may not necessarily produce high-end, practical, inexpensive, and qualified hot-forming sheets. I often see those who have advanced production lines but may not have advanced production technology, processes, and good results. Those who have middle and low-end equipment often have experienced staff. Their ideas are more open and often let us admire. Endlessly. Their sheets are inexpensive, practical and have a variety of production methods.

This article is an overview of the "patternless" thermoforming sheet production technology, mainly for the "extruder - head - three roll - traction - take-up" thermoforming sheet production process. For your reference only, we also hope to help improve the domestic thermoforming sheet tree production technology. Inappropriate, please correct me.

A variety of extruder configuration

(1) Speed ​​control configuration: Some use slip motor speed control device; some DC motor speed control device; some with three-phase asynchronous commutator motor speed control device; some with frequency, electromagnetic speed control motor.

(2) Screw configuration: no matter if it is a gradual change or abrupt change type; single-section or double-section; single screw groove, double screw groove; single screw, double screw; combination type, integral type; diameter from ¢45mm-¢200mm, Aspect ratios (L/D) have successfully applied examples from 20-48.

(3) Barrel configuration: exhaust type, non-exhaust type, combination type, integral type.

(4) Screen changer configuration: manual, automatic type; rotary type, linear type; single chamber type, double chamber type; single flow channel type, double flow type without network switching. Some of the melt transfer pumps and static mixers are equipped and some are not configured.

(5) Head configuration: hanger type, fishtail type; damped and non-damping strips; elastic lip and active lip; narrow adjustable width in the die mouth and no adjustable device inside; Board, width from 700mm - 2200mm; head horizontal installation, vertical installation down.

(6) Head structure: single flow channel, multiple flow channel; internal composite, external composite, etc.

(7) Feeding configuration: artificial ingredients, machine ingredients; automatic feeding, artificial feeding, automatic batching and feeding; there are magnetic racks and magnets in the feeding bucket; the feeding port has cooling water, no cooling Water; hopper with drying device, without drying device; with drying device, crystallization device, etc. have successfully applied examples.

(8) Barrel cooling method: wind cooling, water cooling: air-cooled water cooling combined; natural cooling and other methods, there are practical examples.

(9) The screw center is water-cooled and not cooled.

(10) Before and after screen changer pressure has closed-loop control and no control; there is pressure gauge display and no pressure gauge display; net pressure control from 10Mpa-40Mpa.

(11) Filters are available in standard mesh stacks; scissors-cut, punch-punched; also available in imported thick single- or double-layer 60-100 mesh filters, but also not required.

(12) Configuration of temperature control: resistance heating, electromagnetic induction heating, etc. The common methods of temperature control are "on/off", proportion, PID, etc.

(13) The number of extruder configurations: single, two, or multiple (common 3-5).

(14) Exhaust device of machine nose lip: Domestic machine is almost not equipped, and the imported machine is configured individually, but it is only used when there are many problems such as air bag, air bubble, and bad attachment.

Second, a variety of three roll, cooling rack configuration

(1) A variety of arrangements: horizontal, vertical, and tilt; two rollers and one air knife replace the upper (or lower) roller.

(2) Feeding mode: vertical upper roll feed, lower roll feed; horizontal upper feed.

(3) Transmission: Servo motor independent transmission, worm gear drive, gear transmission, chain transmission, rubber timing belt transmission and so on.

(4) The cooling water can be taken in and out in a variety of ways: on one side and one on the other, on the one hand, on the other side, on the other hand, three rollers in series and in parallel.

(5) Matching method for three-roller production: upper roll and lower roll are not moving; upper and lower rolls are pressed; upper and lower rolls are not pressed; air knife is additionally provided; upper and lower rolls are not pressed and air knife is not used; produce.

(6) Three-roller specification: From the width of 700mm to 2200mm, the diameter of 200mm-¢490mm, and the arrangement of three different roller diameters, and the arrangement of different diameter rollers.

(7) The lengths of the cooling racks vary: Air-cooled units are usually added to the shorter cooling racks, or an additional roll of cooling water is added.

(8) There are single station, double station, four stations in the unloading rack; automatic rotation, fixed; manual, mechanical; There is nothing wrong with it.

(9) roll lift mode: pneumatic, hydraulic, manual.

(10) Roll gap limit mode: manual, automatic.

(11) The relative movement of the three rollers and the machine head: using electric motors, cylinders, and hydraulic cylinders as power, and control methods such as rack and pinion and wire rope.

(12) The relative positions of the three rollers and the machine head: The machine head is 1-50mm higher than the middle roller, slightly lower than the middle roller, and parallel to the middle roller; there are successful examples of 50-250mm from the middle roller.

(13) Three-roller cooling medium: The heating medium includes steam, oil, and electric heating rods. Some of them are equipped with dedicated circulation thermostatic control systems, some directly tap water, and some use chilled water.

(14) Treatment of scraps: smashing after random coiling; bagging at random for smashing; scraping into the basket after smashing; or directly on a clean floor.

(15) Cutting knife selection: round, square, hooked and other shapes, made of iron, stainless steel, commonly used cutting blade, there are special cutting equipment and other form.

(16) Thickness detection method: The manual micrometer, high-grade automatic thickness measurement device, and various other thickness measurement instruments are widely used.

(17) Corona treatment configuration: Most of the manufacturers do not need to use except occasional thermoforming products for secondary processing.

(18) Adoption of coating process: Most of the products do not need to be used except that they are used for demoulding and transparency.