Part 1. Extrusion unit of blown film extrusion plastic machine
1. Screw of blown film extrusion plastic machine
1.1. Blown film extrusion plastic machine screw and barrel over view
Production of all kinds of plastic machine screw and barrel, strict selection of high quality alloy steel as raw material, using the latest technology and elaborate processing and testing equipment, to ensure the production of precision and quality, and has long service life and good abrasion resistance, corrosion resistance.The barrel is equipped with water cooling system.
1.2. Blown film extrusion plastic machine screw and barrel main feature
1.2. 1.The screw and barrel material: 38CrMoAl Nitride / 42CrMo intermediate frequency quenching + electroplating
1.2. 2.42CrMo bimetallic PTA + electroplating.
1.2. 3.Surface roughness:Ra0.4 um
1.2. 4.Nitriding hardness: HV ≥900 , alloy layer thickness≥ 2 mm
1.2. 5.Hardness: HRC58, Nitriding depth: 0.5-0.8 mm
1.2. 6.Nitride brittleness≤2 level, Chrome plating layer thickness: 0.03-0.05 mm
2. Gear reducer of blown film extrusion plastic machine
2.1. Blown film extrusion plastic machine gear reducer over view
Blown film extrusion plastic machine extruder gearbox series is designed for screw extrusion equipment of high precision, hard tooth face with thrust transmission device.Product design USES various technical specifications provided by JB/T9050.1-1999.
2.2. Blown film extrusion plastic machine gear reducer main feature
2.2. 1. The gear reducer for high strength steel alloy & carburizing steel, gear grinding after carburizing and quenching heat treatment processing, 6 levels of precision, high precision gear, gear hardness HRC54-62, low transmission noise.
2.2. 2. It is equipped with high bearing capacity of thrust, reliable performance and can bear big axial thrust.
2.2. 3 In addition to the individual small specifications products, all configuration has forced lubrication and water cooling system.
2.2. 4.Series gear box body are processed in the six sides.
2.2. 5. The gearbox transmission efficiency, low noise, can run for a long time.
2.2. 6.Bearing adopt chinese famous Wafangdian brand almost 100 years brand.
3. Hopper of blown film extrusion plastic machine
Blown film extrusion plastic machine automatic loader material vacuum device is automatic material feeder loader, which mix HDPE, LLDPE, Pigment well and auto load.
4. Main motor of blown film extrusion plastic machine
4.1. Blown film extrusion plastic machine main motor feature
If your motor overheat phenomenon occur, I think that it might be caused by 2 reasons:
1. The motor is overload, power is not enough.
2. The motor fan wiring is wrong, the fan motor correct wiring is separated from the main motor wiring, whenever the main motor speed is low or high, the fan power is strong power enough, otherwise, if the fan motor wiring is from the same connection of power supply, fan motor speed and main motor speed work synchronously, the main motor certainly overheat.
All of our fan motor wiring is separated from the main motor.
4.2. Blown film extrusion plastic machineain motor inverter feature
4.2. 1. Inverter can smooth speed regulation in a certain range, by adjusting the rotational speed of main motor, traction motor to produce different film products;
4.2. 2. Smooth start and stop, because the plastic extruder is the constant torque load, smooth start and stop is to avoid too much of a mechanical shock, on the other hand also can reduce the start-up process of unqualified products;
4.2. 3. Run a single direction of motor;
4.2. 4. Stable performance, reliable work.
5. Electrical components of blown film extrusion plastic machine
5.1. Blown film extrusion plastic machine heater
5.1.1. Blown film extrusion plastic machine cast aluminum heater
5.1. 1.1.Conditions: the environment temperature 20 ºC ~ + 60 ºC; relative humidity< 80%
5.1. 1. 2. Electric strength: passed by 1500V50HZ sinusoidal AC voltage withstand voltage test, when the pressure reach to 1M1N, no breakdown phenomenon.
5.1. 1.3.Leakage current: < 0.5 MA
5.1. 1.4.Insulation resistance: 2MΩ
5.1. 1.5.Grounding resistance: < 0.1 Ω
5.1. 1.6.Power deviation: + 5% ~ -10%
5.1. 1.7.Heat resistance: installed on the machine surface temperature almost up to 400 ºC.
5.1.2. Blown film extrusion plastic machine stainless steel heater feature
5.1.2. 1. Cr20Ni80 mica heater or thermal system is the heating element, adopt natural mica powder or synthetic mica plate for insulation, outer metal is stainless steel.
5.1.2. 2. It is portable mica heater but warming faster.
5.1.2. 3. Mica heater shell is made of 0.3 ~ 0.5 mm stainless steel plate, and the middle core the is made of high insulation resistance and anti-high-temperature mica plate, in which evenly around a variety of standard specifications of nickel-chromium alloy resistance wire as a heating element, be processed into various shape by the molding machine.
5.1.2. 4.According to the connection mode of user demand, voltage from 110 v, 180 v, 220 v, 380 v, the highest power load reach to 3.5 W per square cent meter.
5.1.2. 5. The sintering infrared radiating surface save electricity 35%. Mica stainless steel heater Is ring type.
5.1.2. 6. It is simple, reliable and easy to use, feature fast temperature rise, high thermal efficiency, small power consumption and long service life etc.
5.1.3. Cooling fan in first and second zone of heater
The screw and barrel are equipped with cooling fans.
5.2. Blown film extrusion plastic machine K type thermocouple
K type thermocouple refer to nickel chrome - nickel silicon thermocouple, which is a type of inexpensive thermocouple to measure high temperature.Because of this alloy has good high temperature oxidation resistance, can be applied to oxidizing or neutral medium.It can measure the high temperature of 1000 degrees for a long time, short-term measurable to 1200 degrees.
It cannot be used for reducing property medium, otherwise, it will be corroded soon, in this case can only be used under 500 degree measurement.
It is much cheaper than other thermocouple, its repeatability is very good, the thermoelectric potential is large, thus the sensitivity is high, and it has a good linear property. Although the measuring accuracy is slightly low, but can satisfy completely the requirements of industrial temperature measurement, so it is the most commonly used on industrial thermocouple.
5.3. Blown film extrusion plastic machine solid state relay (SSR)
5.3.1. Overview of SSR
Our switch adopts Chint and Delixi etc famous brand in china.
Solid state relay (SSR)with isolation function that is non-contact electronic switch, no mechanical contact parts in the process of switch, so solid state relay is also compatible with logic circuit besides has the same function as electromagnetic relay, resistance to vibration and mechanical shock, install location is unrestricted, has the good performance of moisture-proof, mildew corrosion resistance, the performance in terms of explosion-proof and prevent ozone pollution is also good, small input power, high sensitivity, small control power, good electromagnetic compatibility, low noise and high working frequency etc.
5.3.2. Advantages of solid state relay
5.3.2.1. Solid state relay feature high life and high reliability. There are not mechanical parts or mobile parts in solid-state relay contact, so they can work stably in high shock, vibration environment, due to the inherent characteristics of composition of the solid state relay components, determines that they are long life and high reliability of the solid state relay.
5.3.2.2. The solid state relay feature high sensitivity, small control power and good electromagnetic compatibility. Since solid state relay has featured wide input voltage range, low driving power, solid state relay can be compatible with most of the logic integrated circuit which does not need to add buffer or drive.
5.3.2.3. Rapid transformation: solid state relay switching speed can be from a few milliseconds to a few microseconds because of using solid state relay.
5.3.2.4. The electromagnetic interference is small.
5.4. DC motor regulator and DC motor
DC motor regulator and DC motor. We can offer the high quality DC motor and DC motor regular.
Part 2. Rotating die head of blown film extrusion plastic machine
2.1. Blown film extrusion plastic machine rotating die head
2.1. Blown film extrusion plastic machine rotating die head feature
2.1.1.Temperature control sensor: 2 points
2.1.2. Material: it is made of medium carbon steel S45
2.1.3. Adopt strict and tempering heat treatment process and the CNC lathe precision machining, to ensure that each part of die head processing precision is high.
2.1.4. Electroplating: the whole die head with environmentally friendly alloy electroplating, plating is more uniform, ensure that the die no dead Angle, die flow easier to clean up, die head is more durable, and the production of thin film surface brighter and higher quality (or according to customer requirements, the hard chromium electroplating).
2.2. Blown film extrusion plastic machine rotating die head maching process
Blown film die head is made up of die bodies (die core, die barrel and die ring) and heater (heating coil).
2.2.1. select right material, it is to choose the corresponding materials, for example middle carbon steel S45 .
2.2.2. forging, forging the ingredients into a mold of coarse embryos, as part of the more compact the molecular structure of the forging parts of the embryo.
2.2.3. The lathe processing, according to the die design drawings of the die head, a lathe processing, as far as possible with high precision lathe, and master skilled lathe technicians.
2.2.4. polished the flow way part of the mould after machining by lathe, the better smooth of surface of flow way, the better blown film quality, and the less the defect lines of film.
2.2.5. hard chrome electroplating in flow way after polishing, which increase the wear resistance and corrosion resistance, and make the mould is not easy to damage and not easily get stranded.
2.2.6. finally, install the die head, combined with heating coil parts.
Blown film co-extruder die head contrast test many times to choose optimal shapes, feature large inner pressure, uniform extrusion stability, better performance of strength of film, no slot with extruder etc. And changes of the proportion of mixture and the recycle material, blown film extruder do not need to replace the die head.
2.3. Blown film extrusion plastic machine die head regulating tips
2.3.1. If the die head is covered from top to bottom, loose or release the screw on the thick edge, and tight the screw on the thin side.
2.3.2. If the die head open under bigly, and put the die head in above, loose the screw on the thin side, and tight the screw on the thick edge.
2.3.3. Die head with four or six adjustment bolt which generally is hex socket, adjust on the edge of upper part of the die head.
2.4. Blown film extrusion plastic machine die head cleaning tips
Step No. 1. Paint the die head with available paraffin or methyl silicone oil.
Step No. 2. Wipe the paste waste material gently with 1000 mesh sand paper until clean.
Step No. 3. According to the material property, adjust temperature while changing different material because of heating temperature difference of virgin and recycle material, increasing extrusion amount to extrude paste material after replacement of the filtering screen.
Step No. 4. The key is to add methyl silicone oil into the hopper in the process of production within a week, which lubricates the screw, barrel and die head, also clear die head meanwhile.
2.5. Blown film extrusion plastic machine rotating die head with dual lip air ring
Rotating die head with dual lip air ring, wind pressure is very strong, the wind ring is cooling fast, so you can speed up the main motor and increase production, also has benefit of thickness deviation.
3.1.Blown film extrusion plastic machine air rings overview
Air rings do more than just blow cooling air on your film. Their complex aerodynamic effects also help form and stabilize the bubble. Yet operators often misuse air rings because they don't understand how the stabilizing function works. Here's a practical guide to making an air ring be your trusty helper instead of an unruly troublemaker.
The air ring is not only the cooling film,it also contributes to the formation of stable bubbles to the complex aerodynamic effect. However, operators often abuse air ring, because they do not know how to stabilize the air ring. In fact, the wind ring is your trusted helper, rather than a wayward troublemaker.
How to solve the problem of uncontrolled air ring? Even an experienced operator can see that the air ring is unstable or mysterious. Yesterday, efforts to adjust the control well, it seems to have no effect to today. So, about the air ring in the end is how the work of the problem, the basic is to guess, rather than ready-made knowledge. Even if it is an experienced operator, the answer they give is usually, it should be a very uniform cooling of the film bubble. The complete answer is to control the stability of film bubble
The secret of the air ring is to stabilize the bubble's function. This is partly through the training of the operator's method to reduce the fault. Teach them how to regulate the air ring is mainly to control the bubble on the frozen line. Increasing the supply of cool air from the air ring loop, down the frost line; decreases the cooling air supply of the air ring allows the frost line to rise.
3.2.Blown film extrusion plastic machine air rings effect
On a hot afternoon, the frost line can rise because of warm ambient air (that is, if you're using tower-cooled air rather than chilled air). When the frost line rises too high, operators typically increase air delivery to the ring to increase cooling on the bubble. But turning up the air has other more subtle effects on bubble stability.
On a hot afternoon, due to warm ambient air (although the use of cooling tower air is not the common cool air), the frost line will rise. When the frost line rises too high, the operator will usually increase the amount of air to air ring, so as to increase the cooling bubbles. However, increasing the air capacity will bring about other more subtle effects and reduce film bubble stability.
3.3.Blown film extrusion plastic machine air rings working principle
The stability is not entirely controlled by the adjustable ring or the wooden fence, the roller, the board, or the other guide roller assembly. The stability of air bubbles is controlled by using the principle of Venturi effect, which is the bubble caused by a local vacuum air flow. Therefore, the increase or decrease of air supply also increases or decreases the effect of this vacuum suction on the air bubbles.
To increase the air supply, the thin film air bubbles will drag to the wall near the wind ring. In the area of the most thin, it can drag the bubble until it contacts the wind ring wall. Slight contact, the walls of the film will leave a pattern of stripes. Heavy contact, even the bubble may collapse.
Unless the increase in air volume is quite large, the above effect usually does not appear immediately. This process is usually gradually drifting from the balance. The air bubble may occur for several minutes or longer before the apparent problem occurs, when the operator may have left the immediate area. So it is recommended that the operator to adjust the air ring and air flow should be observed after 10-15 minutes, after adjusting the air ring it is not to break the balance of it.
3.4.Blown film extrusion plastic machine air rings lips
The change of the height of the air ring is also likely to have a delay effect on the stability of the bubble. Height adjustment has no effect on the air volume, but the speed of the airflow. Reducing the height of the air ring lip is equal to increasing the air flow rate and increasing the Venturi effect. On the contrary, increasing the height of the lip of the air ring is equal to the reduction of the Venturi effect, and the air flow is reduced. This is similar to the hose used to wash the car, when you use the thumb to clamp the narrow hose openings, increase the flow rate and volume unchanged. Once the film production line is in production, the adjustment of the height of the air ring lip is very important. Adjustment may actually lead to production line shutdown and production scrap waste.
There are many complex air rings in blown film production line which are equipped with double air ring lips. Some with a conical adjustable air ring lips, some do not. Any outer air ring lip adjustment will also affect the Venturi effect, even in the air cone height has been adjusted. If the air ring lip does not set a specific height, change the original balance of the air ring outer lip easily upset, because it is from the two separate air ring lip together to play the Venturi effect.
If the inner air ring lip is not fixed, the outer air ring of the venturi effect cover the height problem of the inner air ring. The operator may not be aware of the problem, or try to correct it by adjusting the outer of air ring lip. The operator may find, as long as a slight adjustment will make the air bubbles suddenly become very unstable. If the operator tries to return to the previous set of stable bubbles, but unable to return to since the root of the problem in the inner air ring lip, rather than the outside air ring lip. In addition, the overall air ring lip adjustment becomes more closely, even minor changes in the air ring can easily make the production line shutdown
Inner air ring lip and outer air ring lip will be loose over a long time. Fastening screw threads used to keep these parts moving may not be maintained regularly. If this is the case, the air pressure or vibration will move the air ring lip. If the operator has been aware of this, outer air ring lip may be sealed with tape. But the inner air ring lip gradually moving is difficult to be found. This problem is uncertain until the air ring components are removed and cleaned. Return to the original position of inner air ring lip, will broaden the operating window.
The operator is familiar with the height of the inner air ring and the air pressure. If the outer air ring position is correct, habitual regulating is okay. If the inner air ring position is not correct, usually the regulation will not work, but also the adjusting range will be smaller. Any change in the air flow and more likely to cause problems.
In addition, the problems of air-ring movement also tend to work gradually to reduce the window of stable operation, so that the operator can not determine the real reason for instability
The air ring adjustment is very hard to learn, because the extrusion of blown film machine is easily affected by the environment. The original draft may cause local cooling or likely to pull the air bubble out from air ring concentricity. As a result the uneven film thickness and the influence of the uniformity of film coil.
The observant operator will recognize the difference in different environmental conditions change in the film blowing operation. The same machine, the same resin and the same product, will be very different in the hot afternoon and the cool morning and evening. Operators that do not follow the subtle indicators will not be able to adjust the production process, resulting in a shutdown of the production line.
3.5.Blown film extrusion plastic machine air rings over-adjust problem
Operators should be trained to find the lip-height and air-pressure settings that initially give the widest window of control. When it's necessary to change frost-line height, rather than adjust air delivery, it's better for operators to look first at process conditions and then for changes in the ambient environment. The right adjustment may well be to lower the melt temperature, not raise the air delivery. Conversely, melt temperature may have to be raised again as ambient temperature drops later in the day.
If you want more consistent operation, leave air-ring settings pretty much alone once a line is in production, and work with melt temperature to control frost-line height. This approach maintains the bubble control that has been established by the venturi in a much tighter window than will occur if you use air delivery as your primary means of adjusting frost-line height.
Part 3.Collapsing air bubble frame of blown film extrusion plastic machine
3.1. Blown film extrusion plastic machine nip rolls
3.1. 1. Blown film extrusion plastic machine nip rolls summary
As the film continues to cool, it is pulled out through several sets of nip rolls and flatten the tubular film lay-flat, and then be spooled on the reel or slice.
Some rollers are made of nitrile rubber. The traction device adopts an electromagnetic sliding mechanism, double rollers are driven by a gear part, or a winding roller is driven at the same time. Flat plate or nip roller is fixed on the collapsing frame, according to the film thickness can be adjusted freely tilt angle of plate.
Thin film production presents some unique challenges for the extruder operator, including the following 10 common considerations.
There are three basic ways to eliminate the adverse effects on the deflection of roll. Among them, the most versatile is roll skewing. It uses a cross-axis positioning of the roll, the roll deflection is wrapped about the mating roll, creating a uniform gap over a wide operating range.
A horizontal configuration of the roll holder eliminates the adverse effects of sag and droop, allowing the introduction of accurate melt volume and direct entry into the main roll nipping location.
Controlling the position of the melt is essential to avoid rapid cooling and melt pre-skinning. Experienced operators will adjust the height of the roller frame relative to the die lip outlet, allowing the melt to run along the middle roller. It also eliminates the adverse effects of the sag and droop of the sheet.
3.1. 2. Blown film extrusion plastic machine nip rolls encountered considerations
Thin-gauge sheet production presents some unique challenges to the extrusion operator, including the following set of 10 commonly encountered considerations:
3.1. 2. 1. Raw-material affects
A proper configuration of the extrusion system can achieve a stable working state. This ensures that the melt is uniformly delivered to the die head. Different raw materials in form of new materials and blends of recycled form can prove to be challenging to try the process to achieve a stable state and avoid undesirable surging pressure oscillation. The head of fluctuating pressure in the uniformity of melt between two main rollers. In ± 50 psig (about ±3bar) pressure oscillation standard is acceptable, but the higher value is challenging the process conditions.
Post-extrusion procedures produce various amounts of scrap or regrind that should be recovered. As an example, thermoforming can generate high levels of regrind. This depends partly on the tooling component density each of surface area within the tooling platen. Some devices can produce scrap levels as high as 70 % or more. As a result, it is essential to have the ability to process high levels of regrind on one occasion as well as lower levels on another, depending on the quantities of regrind being created and recuperated back with the sheet procedure. In terms of bulk density, the measured variation is likely to be a span of 2:1 or more as a result of this thin-gauge, high regrind material when compared to blends of virgin and greater concentrations of heavier-gauge regrind.
Along with a great total feed screw layout, the extrusion system needs to control stable pressure, keep regular temperature established points, and also thermally homogenize the melt flow prior to the sheet die. A backpressure valve located upstream of the gear-pump inlet could allow the buildup of head stress to ensure that the feed screw metering flights are effectively filled up when processing higher levels of regrind. This additionally allows adjusting the valve when the content of low-bulk-density regrind decreases. On the whole, the crucial objectives is achieving a consistent melt pressure and melt homogeneity to the sheet die to precisely regulate as well as lessen the melt bank in between the main nipping rollers.
3.1. 2. 2. Process conditions and set points
The procedure operating window is lower in thin-gauge manufacturing than in heavy-gauge sheet extrusion. This can be easily clarified by analyzing exactly how the melt resides in the nipping location as it gets in the roll stand. The melt bank tends to freeze quicker, offered the lowered volume within the main nip point. This fast freeze minimizes the nip-point flow that is needed to achieve uniform "dispersing" of the polymer within the nipping point so that great sheet polish is accomplished. It likewise creates high roll loads in the gap at the primary nipping point. The absence of melt-bank harmony will trigger formation of local areas of shiny as well as plain areas on the surface area of the sheet because it is not being appropriately polished throughout the face size of the roll. To manage these procedure requirements, a tighter array of controls becomes necessary. This also causes repeatability throughout the production work week or month.
An overall tighter level of control for a thin-gauge extrusion system is paramount (from the extruder barrel through the die) while keeping the chrome-roll temperature setups high enough to stop quick cold on the center roll. Regular melt temperature levels needed for numerous polymers.
3.1. 2. 3. Die-lip exit to roll-nip
Preferably, it is constantly preferable to operate with minimal die-lip exit distance to the entrance where the key nipping rolls meet. Minimizing this distance subsequently lessens the adverse results of pre-skinning (fast freezing) of the molten polymer as well as excessive neck-down of the melt "curtain" that will ultimately form right into the rolling melt bank. At the very same time, this permits greater general control and also development of melt-bank harmony.
There are restraints that need to be taken care of to reduce this physical range. The blunt cross-sectional appearance of the sheet die is one restricting factor. Externally protruding sheet-die deckles and/or appendages are other factors, in addition to the physical size (diameter) of the chrome rolls.
The sheet die could be profiled by using a contoured body so it fits closely into the mating chrome rolls. Interior and/or " squeeze " shim deckles may be utilized to manage the curtain width getting in the nipping area while avoiding protrusions from the die surface area, so as not to compel the distance to widen. Squeeze shim deckles stay between and also inside of the lips as well as are typically constructed from light weight aluminum shim stock to appropriately fill up the die-lip spaces. An additional method is to lower the roll diameter so that the gap is decreased.
As a basic rule of thumb, this range needs to vary from 100 to 200 mm (4 to 8 in.) relying on the size of the parts being utilized.
3.1. 2. 4. Targeted width & die deckling
Several accepted methods are used for restricting the overall width of the molten polymer curtain that exits the sheet die as well as forms the rolling melt bank in between the nipping rolls. Interior and also squeeze shim deckles are discussed above as effective deckle techniques. External deckles are likewise commonly utilized, yet they stick out from the face of the sheet die, which raises the die-exit to roll-nip gap distance. On top of that, increasing this distance while raising the total line rate, the roll stand will lower the width of molten curtain as a result of the sensation of "drawdown."
By drawing the sheet width down, the thickness of the melt curtain will boost along with the edge bead that consequently forms. This is not a preferable outcome for thin-gauge sheet processing since it creates much more troubles compared to it fixes. Difficulties consist of excessive sheet orientation, which could bring about dimensional stability problems, and also heavy sheet-edge gauge bands that make it hard to maintain a consistent melt bank and correctly polish the sheet across its entire size.
3.1. 2. 5. Roll design and quality
Appropriate roll design as well as construction are necessary when running at greater roll loads. Thin-gauge sheet manufacturing calls for high-quality rolls and also a system with the ability of running at high roll loads with accuracy. Specifically crucial are the roll journal and bearings. C1 spherical tapered roller bearings offer the most effective operating accuracy, producing an overall indicated run-out (TIR) of 0.0005 in. or less. Roll shafts as well as bearing journals should be made appropriately. The general roll shell construction and design have to accommodate exact running while under extreme loads. Required roll loads as high as about 1000 PLI (lb/linear in.) are not uncommon in producing thin-gauge sheet. High-quality roll surfaces are likewise important to lower the variability found in coarser roll-finish treatments. Usually, an extremely polished chrome super finish of 0.5 Ra is recommended.
3.1. 2. 6. Roll closing forces and nipping loads
To create suitable operating roll loads so that the rolls stay closed, an improved pneumatic or hydraulic roll-actuation method is advised. Inadequate loads generation will prevent the rolls from holding the preferred gap and a bad end outcome will result.
3.1. 2. 7. Minimizing roll deflection influence
The general design and high quality of steel chrome rolls will determine the degree of deflection realized when put under load. Higher loads will certainly lead to higher deflections. The level of deflection could be considerable when compared with the target gauge preferred and also could lead to a failure to create high-quality sheet. A deflecting roll will certainly cause a relatively high gauge band to form in the center of the sheet, coinciding with the deflection pattern that is being generated. For instance, if the sheet gauge target is 10 mils as well as the resultant roll deflection is 3 mils, the net variation is an unacceptable 30% over the target gauge. An reasonable gauge performance would certainly be ± 3% of target throughout the range of thinner sheet gauges.
There are three basic methods for counteracting the adverse effects of roll deflection.
1). A crowned roll includes a pre-ground camber to the roll. While this technique works, it is limited to a narrow variety of products since that the geometry of the camber is fixed and limits the operational deflection conformity to a reduced processing window.
2). Counter-bending rolls have designs that attempt to flex the roll in an opposite direction to the load such that it conforms to the mating roll as well as thus reduces the effects of the deflection pattern. This strategy likewise limits the general efficiency throughout a wide operating range. Roll loads much less than 800 PLI are needed as a result of the spring constant and mechanical limitations of the operating window for this kind of roll layout.
3). Lastly, roll skewing utilizes a cross-axis positioning of the roll such that the roll deflection is covered about the mating roll, hence producing a consistent gap over a wide operating range. Thinking about the universal operating range for processing thin-gauge materials, the roll skewing technique is highly versatile and also consequently suggested. The adjustability function runs over a wide range of deflection patterns and also succeeding sheet gauge targets.
3.1. 2. 8. Counteracting the sag & droop influence
The attitude of the sheet die relative to the roll stack will influence the direction where the molten curtain exits the die because of gravitational results. There are a number of varieties of roll-stand configurations, as well as each has its advantages (merits) and limitations. The vertical roll stand is widely utilized and has the greatest level of versatility throughout a wide operating window of sheet procedures. Yet it is not the very best configuration when attempting the thinnest sheet gauges, as the gravitational effects are extreme, causing sag and droop as well as bring about rapid freezing as well as pre-skinning of the melt bank on the center roll.
Stack roll stand to ensure that the die attitude method goes to a 45 ° angle. This method allows a reduction of gravitational effects as well as offers a better center-roll cover due to the unique web path that result. Nonetheless, there is a propensity for the melt curtain to sag onto the lower roll in this up-stack setup, where the web path traverses goes across up throughout the roll stand.
A third configuration is a horizontal roll stand. While this arrangement is recommended for superior thin-gauge outcomes, it likewise has operational limitations and also restrictions as a result of its geometry when processing heavier gauges.
The horizontal roll stands gets rid of the unfavorable impacts of sag and droop and also permits introducing the melt bank precisely and also directly right into the primary roll nipping area. This allows the operator a greater range of processing when trying the challenges of thin-gauge sheet manufacturing, particularly when processing tenacious products that otherwise can offer challenges with various other roll-stand arrangements.
3.1. 2. 9. Melt-bank position
No matter which roll-stand arrangement is utilized, controlling the melt-bank position is vital to stay clear of the negative impacts of quick freeze-off and also pre-skinning of the melt bank. Usually a knowledgeable operator will certainly adjust the height of the roll stand relative to the die-lip exit to permit running the melt bank against the middle roll. This decreases the adverse effects of fast freeze-off and also pre-skinning while also negating the unfavorable effects of sheet sag and also droop.
An external air bar provides an excellent tool for precisely positioning the melt bank by flipping it from one roll to the other. The melt bank will certainly look for the flowing air, hence putting it against the middle roll. When it comes to a vertical roll stand, the air bar would be underneath the sheet die, blowing upward versus the middle roll towards the melt pool of the melt bank at the nipping place.
3.1. 2. 10. Precise speed coordination
Precise speed regulation and coordination are essential in creating premium thin-gauge products of all resin kinds. With a great digital drive control platform, roll-to-roll rotating speed coordination should be on the order of ± 0.01% of setpoint. This comes to be an important aspect, because the processling window is narrower on these products and therefore calls for a higher total level of coordination and also control accuracy.
Matching the roll speeds from roll to roll is important to make certain minimal orientation is being presented in between the rolls. It likewise stabilizes the roll-stand take-off speed, which will certainly decrease the damaging results of drawdown at the die leave. Proper tension control in between the primary chrome rolls and pull-roll device will likewise reduce formation of unwanted transverse-direction lines in the sheet in the form of faint chatter marks and will avoid introducing orientation from stretching the sheet. This tension must be kept in a range of 2 to 4 PLI throughout the width of the sheet.
3.2. Blown film extrusion plastic machine lay-flat tube
Nitrile rubber roller has deep lines so that it opens LDPE film during work. It is equipped with a few such rollers on my machine. If the film is very thin and it can not get together during work.
Two pairs of traction roller consists of rubber roller and alloy steel roller, can effectively prevent the air to escape and ensure the smooth progress of the coil winding. Traction frame adopts assembly structure, outfit is convenient to tear open, which is advantageous to the transportation loading and unloading. Take-up device adopts the center winding of the effective mechanism, and keeping the constant tension, friction piece is driven by sprocket, and the big gear is driven by friction piece, to drive the winding shaft, so as to ensure the re-winder works smoothly while the winding diameter changes from small to big, the friction force can be controlled by adjusting the spring-loaded of edge.
We adopt nitrile rubber roller, also you can choice the Polyurethane and Silicone rubber roller, but we recommend nitrile rubber, because it is of high quality and inexpensive.
The motors have separate cooling fans with 380V. These are more powerful motors of fans. They are of high quality.
Our fan motor wiring is separated from main motor.
3.3. Blown film extrusion plastic machine guide rolls
Air ventilation controller micro mobile parts is fixed on the bubble shelf which is equipped a lot of film shaping guide roller, air ventilation controller is connected with main motor of wind ring. Micro sensor is fixed on the top of the blown film. Micro mobile parts of air ventilation controller need to get a fixed pole.
Film air bubble size is related with internal inflatable pressure of tubular film, and has nothing to do with external cooling.
Cooling air volume is related with the position of blown film air bubble which located up and down. The bigger of cooling air volume, the blown film air bubble down the farther. The smaller of cooling air volume, the blown film air bubble up the farther.
3.4 Blown film extrusion plastic machine collapsing frame
In choosing the method of bubble collapsing, the specific processing methods of film manufacturers must solve the special characteristics of the substrate. In addition, film manufacturer must carefully assess of the special requirements of the end user.
The film production line to produce 100% LLDPE single layer of trash lining as an example, the use of complicated film bubble collapsing method has no any advantage. In this case, the simple wooden board system is sufficient and the cost is relatively low. In contrast to the use of a complex co extrusion structure and high speed laminating applications, it is necessary to pay attention to ensure sufficient pressure and wrinkle-free of the film. This application requires a more elaborate film bubble collapsing design. The key is to match the film requirements to the collapse of the shape of the surface.
Guide plate of collapsing frame of extruder is made up of towing, flap board or nip rolls, traction roller and traction motor, the unit of traction driven two pairs of drawing roller through gear parts, and the winding roller meanwhile. Clip board or nip bar is fixed on the shelf, the adjustment of inclined angle of clip board or nip bar can be adjusted freely according to the blown film thickness.
Provides a full range of top nips bubble collapsing frames and up to 2.5 meter wide optional gusseting assemblies.
Robust design, top nips design provides long term usage cycle.
The collapsing frame assembly can be applied to a variety of L/D ratios (screw diameter ratio) and film bubble collapsing surface, meet customer requirements.
Part 4. Winding parts of blown film extrusion plastic machine
4.1. Blown film extrusion plastic machine drive roll
Two pairs of drive roll adopt assembly structure, outfit is convenient to tear open, which is advantageous to the transportation loading and unloading. Drive roll device adopts the center winding of the effective mechanism, and keeping the constant tension, friction piece is driven by sprocket, and the big gear is driven by friction piece, to drive the winding shaft, so as to ensure the re-winder works smoothly while the winding diameter changes from small to big, the friction force can be controlled by adjusting the spring-loaded of edge.
4.2. Blown film extrusion plastic machine idler roll
Tractors of extruder is made up of towing, clip board or nip bar, traction roller and traction motor, the unit of traction adopts electromagnetic slip type mechanism, driven two pairs of drawing roller through gear parts, and the rewinding roller meanwhile. Clip board or nip bar is fixed on the shelf, the adjustment of inclined angle of clip board or nip bar can be adjusted freely according to the blown film thickness.
4.3. Blown film extrusion plastic machine bobbin
4.3.1. Blown film extrusion plastic machine overview
Film thickness is controlled by changing the proportion of the speed of the motor, inverter steady speed is precision, leading to speed stability, and uniform film thickness. Two clip roller and winding roller adopt tension control, the tension of different materials requirements is different, the tension of the rollers should be adjusted independently. Rewinding axis is leaning on the winding roller, relying on the winding roller's friction to drive the rewinding axis rotation, thus the material tension has nothing to do with the coil diameter
4.3.2. Blown film extrusion plastic machine merits
The tension is produced by differential speed and frequency converter work under the mode of open loop vector control speed, fast dynamic response, overcome the smaller torque motor speed tension and larger deceleration tension.
The motor constant torque output as speed control. While the linear velocity and tension is constant, the winding roller speed keep constant too, will not be changed by the changing of coil diameter and load line, so overcome faults of constantly adjusting the motor output torque from empty to full volume process, in order to maintain a constant tension.
System is easy to manipulate.
4.4. Blown film extrusion plastic machine rolled film
Nitrile rubber roller which will have deep lines so that it opens LDPE film during work. It is equipped with a few such rollers on my machine. If the film is very thin and it can not get together during work.
Two pairs of traction roller consists of rubber and alloy steel roller, can effectively prevent the air to escape and ensure the smooth progress of the coil rewinding. Traction frame adopts assembly structure, outfit is convenient to tear open, which is advantageous to the transportation loading and unloading. Take-up device adopts the center winding of the effective mechanism, and keeping the constant tension, friction piece is driven by sprocket, and the big gear is driven by friction piece, to drive the winding shaft, so as to ensure the re-winder works smoothly while the winding diameter changes from small to big, the friction force can be controlled by adjusting the spring-loaded of edge.
We adopt nitrile rubber roller, also you can choice the Polyurethane and Silicone rubber roller, but we recommend nitrile rubber, because it is of high quality and inexpensive.
The motors have separate cooling fans with 380V. These are more powerful motors of fans. They are of high quality.
Our fan motor wiring is separated from main motor.
4.5. Blown film extrusion plastic machine pre-treatment unit
4.6. Blown film extrusion plastic machine edge cutting
4.7. Blown film extrusion plastic machine ultrasonic sensor system
Part 5. Operator interface of blown film extrusion plastic machine
Blown film extrusion plastic machine main control pannel
The blown film extrusion plastic machine main control panel is a application, which starts all the other software components. Altough they are standalone, it is recommended to start them from control panel, to assure the propper initialisation.
We offer you well-developed and universally employable solutions for new plants and upgrading exercises of extruders. Our systems are used by reputable precision engineering firms and end-users. Our components are standard equipment at leading plastics processing machine manufacturers.
Configuraton list of blown film extrusion plastic machine:
|
Model |
SJ-45 |
SJ-50 |
SJ-55 |
SJ-60 |
SJ-65 |
SJ-80 |
SJ-100 |
|
Screw diameter |
45mm |
50mm |
55mm |
60mm |
65mm |
80mm |
100mm |
|
Screw ratio (L/D) |
28:1 |
28:1 |
28:1 |
28:1 |
28:1 |
28:1 |
28:1 |
|
Screw speed |
10-100r/min |
10-100r/min |
10-100r/min |
10-100r/min |
10-100r/min |
10-100r/min |
10-100r/min |
|
Main output |
20-30kg/h |
25-35 kg/h |
35-50 kg/h |
55-65 kg/h |
55-70 kg/h |
70-90 kg/h |
110-140 kg/h |
|
Power of main motor |
7.5kw |
7.5-11 kw |
11-15 kw |
15-18.5 kw |
18.5-22 kw |
30-37 kw |
45-45 kw |
|
Specification of die head |
φ40-80mm |
φ60-120mm |
φ100-170mm |
φ100-170mm |
φ120-220mm |
φ150-300mm |
φ500mm |
|
Rotational mode of machine head |
Continuous rotation |
Continuous rotation |
Continuous rotation |
Continuous rotation |
Continuous rotation |
Continuous rotation |
Continuous rotation |
|
Single-side thickness |
0.01-0.10mm |
0.01-0.10mm |
0.01-0.10mm |
0.01-0.10mm |
0.01-0.10mm |
0.01-0.10mm |
0.01-0.10mm |
|
Max.folding width |
600mm |
600mm |
800mm |
1000mm |
1100mm |
1500mm |
2000mm |
|
Total power |
19.5kw |
22kw |
26kw |
30kw |
42kw |
56kw |
88kw |
|
Weight of machine |
1900kg |
2000kg |
2300kg |
2000kg |
3800kg |
4600kg |
6000kg |
|
Overall dimensions (m) |
4.5*1.8*3.5 |
4.5*1.8*3.5 |
5.5*2*3.8 |
6*2.2*4.2 |
6*2.4*4.3 |
7*2.7*5.8 |
8*3.2*7.6 |
More machine details:
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Machine packing and delivery:
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