Years ago, selecting a roll cover was made easy by the choices that existed rubber or rubber.
Today, roll cover decisions are much more complex. Modern paper machines run at high speeds, higher nip loads and higher sheet temperatures. The papermaking process also involves a larger variety of chemicals that can attack roll covers.
As a result, the industry has developed new roll cover materials to meet these challenges. Today, papermakers can select from a variety of roll cover types that include:
However, with these advances in technology, the stakes for selecting the proper roll cover have risen. A new roll cover for a high-speed machine may cost $50,000 to more than $100,000. In fact, a polyurethane cover can cost twice as much as a rubber cover, while a ceramic cover can exceed them all but for good reasons. Polyurethane and ceramic covers can provide significantly greater running time between grinds, and are typically more chemically resistant. Given the complex environment surrounding the selection of these sophisticated large capital items, mills face increased pressure to make all the right decisions in order to maximize their roll cover investment.
Making the most out of your roll cover dollars begins with a five step selection process, in the areas of application, mechanical, nip analysis, alignment and regrinding.
Examine each application because no two are exactly alike. Review previous operating records, including run times, to determine what is successful and what is not.
Note special operating conditions, such as high sheet temperature or steam boxes. What are the roll loading and operating speeds? Are there any chemical concerns? What is the pH in which the roll runs?
Roll histories offer insight into the past, but more importantly, the future of a rolls performance. A thorough roll history will include information detailing maintenance, breakdowns and failures. For example, are roll changes made on scheduled intervals or are they due to mechanical failures?
Has the performance of nipped rolls been monitored with nip impressions? Are rolls changed out in pairs? It is a good practice to take nip impressions on all newly installed nipped rolls. This is one of the best methods available to determine the crown/pli relationhip of the press.
Misalignment can cause premature cover wear and roll cover failure. A program that includes routine checks and alignment is recommended.
P&J and outcrown reading should be taken on rolls removed from the machine and from new, freshly ground roll covers. Comparing past and present P&J readings may indicate the presence of a chemical attack, whereas out-crown measurements may reveal uneven wear and chemical attack.
Dont gamble while making a roll cover decision. Following this five-step selection process provides the necessary information for making a sound roll cover decision. Also, including an OEM specialist in the decision-making process assures that each roll is suited specifically for the mills needs.
The functions of roll covers are to carry, drive and lead the paper web and fabrics, protect roll shells from corrosion, improve and optimize water removal and runnability, improve roll release and cleanliness, and enable film transfer and paper finishing. In addition, roll covers must be replaceable in the case of failure, wear or aging.
Lead roll covers have a relatively long lifetime today, being highly resistant against wear, moisture and chemicals. In addition, they can be customized for controlled friction, release, self cleaning and doctoring properties, according to the application. The covers adhesion to the shell must be excellent, so as to protect the shell against corrosion.
Resistance against heat, moisture and wear, and good dynamic properties, are the basic requirements for suction roll covers. Suction press roll covers must withstand high linear loads, temperatures and speeds, and the bonding layer must be reliable in all operating conditions.
Grooved press roll covers need good resistance against temperature, chemicals and wear, and must generate negligible heat in high speed/load applications. Grooved covers are typically applied to deflection-compensated rolls. The operating temperature of the cover is dictated by the roll cooling efficiency, together with the process environment and nip dynamics.
There are many requirements for press roll covers that are in direct contact with the paper. The cover must facilitate easy sheet release (giving a low and stable draw) and easy tail threading, have a low tendency for deposit collecting (stable surface properties) and no fiber picking. It must ensure a good doctoring result, minimize blade and cover wear, and be resistant against chemical and mechanical loads. It must be repairable and, of course, competitive in price.
Dryer section roll covers help to keep rolls and cylinders clean and protect surfaces from wear and corrosion in hot and humid environments. Choosing the right roll cover ensures good dryer runnability and allows savings in dryer fabric usage and doctoring. Especially in the case of dryer cylinders, non-stick surface features combined with good doctorability provide uniquely desirable features for cylinders, allowing users to enjoy clean surfaces and problem-free operation. Cylinder coatings can be manufactured during shutdowns inside paper machines. Thermal spraying is used for drying/cooling cylinder applications requiring excellent corrosion and wear resistance.
The main requirements of roll covers used in surface sizing, pigmenting and film transfer coating are mechanical wear resistance, elasticity and chemical resistance. Coating color is normally applied at relatively high temperatures, and the size press can have high overall temperatures due to its location between the pre- and after-drying sections. The applicator roll may have only limited internal cooling, which accelerates the aging of the covers. Abrasives in the paper and coating color wear and scratch the cover in the nip and under the blade or rod applicator. Paper wads in the nip and under the applicator units tend to burn the cover during uncontrolled web breaks. Chemicals in the coating color may attack the cover, and cleaning agents can increase the chemical load. The size press is a challenging environment for the cover material.
The main criteria ranking the roll covers used for size presses are the regrinding interval and the film quality, which has a direct effect on moisture and coatweight profiles. The roll cover must be uniformly hard to gain good film quality in the blade, grooved or smooth rod application.
The calendering process has a considerable effect on paper quality. The high loads and temperatures in the short nips improve the surface properties of the paper, but can easily destroy bulk and other properties.
Chilled cast iron rolls have been used in machine, soft and multinip calenders in heated thermo roll positions. But their wear resistance has become a limiting factor, especially in on-line calenders, leading to too short regrinding intervals.
Roll cover selection and optimizing roll performance no longer have to be the sole responsibility of the mill. OEM roll repair specialists are a viable resource to aid mills in reaching these specific objectives. Consulting OEM roll specialists such as Valmet roll experts ensures the wisest roll selection and optimization because we understand each rolls strengths and limits, and can provide complete "in mill" technical support.
Valmet roll service centers have roll covering capabilities, along with roll maintenance and other expert services. The one-stop service provided by the service centers ensures long and reliable roll operation and optimized service intervals.
For more information on maximizing your roll cover investments, contact your Valmet representative.
TRANSCRIPT
Welcome to Package This your guide to packaging machinery and materials, produced by the Emerging Brands Alliance in conjunction with Packaging World and PMMI, the Association for Packaging and Processing Technologies.
In todays episode, well cover the family of machines known as Wrapping Equipment. While there are many types of wrappers covering a broad range of applications, they all have one thing in common: they take a flexible packaging material such as film, foil, or paper and envelop it around a product.
One of the most widely used types of wrapping equipment is flow wrappers. They wrap individual packages or products by forming a continuous stream of material into a tube shape around the item that is later sealed and cut. Flow-wrapped products can be found all over the grocery store individually wrapped candy bars and granola bars are just two examples. This technology can also be used in many other applications, from medical devices to non-food items.
Syntegons Pack 301 LS solution is an example of a horizontal flow wrapping machine. As trays of biscuits are fed into the machine, film from an overhead roll wraps around the product. Crimper jaws then immediately cut and seal the ends, forming a package that preserves freshness. While this video shows the machine in a biscuit packaging application, Syntegon designed the Pack 301 LS for flexibility and fast format changes, so it handles a wide range of products. Because flow wrappers are often used during long production runs in food packaging, they need to be reliable under continuous operation and require a high-level of sanitation. Syntegon built this machine to be robust, using production-proven technology and high-quality parts. It also features a clean, stainless steel construction for easy accessibility and cleaning.
Shrink wrappers are another type of wrapper that uses heat-shrinkable film. These machines run all sizes of products, including items with irregular shapes or sharp edges. Shrink Wrapping Machines come in a wide range of formats from manual to automatic models.
In this video, we see an operator demonstrating a shrink wrapper with a manual L-Bar type sealer from Eastey. First, the operator feeds the item through an adjustable product tray that easily separates the film and accommodates a variety of product sizes. The operator then lowers the L-Bar to create the initial seal. Next, the sealed product is fed into a heat tunnel, which applies heat to shrink the thermoplastic film tightly, forming a protective, clean, and tamper-proof seal. Many shrink wrappers typically handle more than one type of film. For example, this Eastey model can shrink most polyolefin, polyethylene and PVC films. Eastey also equips this unit with a takeaway conveyor that can be raised or lowered to center the seal on the product.
Overwrappers are machines that are typically designed to package flat, straight-edged products such as cartons or flat boxes. Overwrapping equipment is often used to provide an additional layer of protection to a primary package, such as wrapping clear plastic film over a small carton containing a perfume bottle or personal care item. The overwrapping process starts by pushing the product through heat-sealable film that is cut from a larger roll. The film is then tucked and folded around the product before heated plates seal the film with a tight crease, giving the package an appearance that is reminiscent of gift wrapping.
Last but not least is a specialty type of wrapping machine: twist wrappers. Also known as bunch wrappers, these machines are widely used in the confectionery industry to package small, individual units such as hard candies, bonbons or caramel rolls. In a typical twist wrapping application, the product is fed and staged in line for wrapping. At the same time, the machine unwinds the film rollstock to get the precise amount of film needed to wrap the product, cuts the film to size, and pushes the piece to be wrapped into place around the film. Then the rotary grippers grab the two ends to quickly fold and twist film around the product, forming the double twist wrap.
As we have seen, wrapping machines can be used to package a wide range of goods, from small round items to rectangular cartons, horizontal trays, and large flat products. We hope you enjoyed this video and learned a little bit about some of the most common types of wrapping equipment.
For more videos on packaging machinery and materials, please subscribe to our full Package This 201 series on YouTube. Looking for a searchable directory with 1,000 packaging and processing suppliers? Visit ProSource.org to search suppliers by package type, material, or features. Thanks for watching!
Shrink wrapping is one of todays most common secondary packaging techniques. It is widely used all around the world for packaging needs including maximizing shelf appeal, protection from external factors, bundling and multi-packaging to ease transport and storage, and last but not least tamper-proofing. This wide array of functionality makes it an excellent option for almost all industries from food to cosmetics or even boats and construction materials.
Even though the shrink wrapping process is pretty straightforward, many considerations go into choosing the right shrink packaging solution that best meets your need. So how do you identify the ideal shrink wrapping machine for your product and production needs? Here are the 6 important questions & tips that will give you a headstart:
1- What is your product and what is the desired outcome you expect from shrink-wrapping?
2- What are the dimensions of your product and the orientation you want it to be packaged?
3- What is the production speed/capacity your operation requires?
4- Do you need an inline solution or a hand-feed operation?
5- What type of shrink film will you use?
6- Do you need any peripheral equipment such as extra applications or control points in the packaging line such as labeler, checkweigher, discard arm, etc.
What is your product? Is it a frozen pizza, a wheel rim, a cosmetic product, or a book? Do you want it to be shrink-wrapped for display or logistic purposes?
Here are a few common desired results you can expect from shrink wrapping:
Display
The shiny outer packaging is to be noticed among other products while protecting the primary package. The use of printed film also adds the advantage of branding.
Protection
Fully closed shrink wrap protects the product against scratching during transport, water, dust, or any other unwanted external factors.
Tamper-Resistance
For some products, Packaging serves as proof of the first usage by the end-user. An unopened shrink wrap gives end-users the confidence to buy the product.
Grouping or Bundling of Products
Do you want to group multiple products to display or logistics purposes? Is your product heavy and do you need openings on the sides of the package to easily carry by hand? Or you have a promotion and you want to put together two products that will be sold together in the supermarket?
Logistics/Storage
To create an easy-to-carry package for heavy items.
The minimum and maximum dimensions of the products you will shrink wrap is the second most important question to determine in terms of identifying the right shrink wrapping machine. All packages have three dimensions, the product width, length, and height. Also, the orientation that the product will be packaged is another important data needed.
Shrink wrapping machines have limitations in terms of the maximum dimensions they can package. In the L-Sealer manual or semi-automatic machine models, this limit is decided by the size of the L bar.
In fully automatic machines, there is no limit to the product length however the product height and the width do have some mechanical limitations.
Selecting the right-sized shrink wrapper optimizes the packaging cost and production capacity. Keep in mind that the size of the shrink wrapper and heat tunnel should be able to accommodate your largest product.
The number of products you need to package daily is another critical piece of information in choosing the right shrink wrapping solution.
The capacity of shrink wrapping machines varies from Low Capacity to High Capacity and is typically measured as packages per minute and varies according to the length and the height of the product.
Low Capacity
If you are looking for more details, kindly visit Eopac Machinery.
These are manual shrink wrapping machines that hold the capacity to produce 5 to 10 packages per minute. These machines are run by an operator whose experience level has a considerable effect on the total packaged products per minute.
Medium Capacity
Semi-Automatic L sealers fall into this category. In semi-automatic shrink wrappers, the sealing arm is automatic. This automatic motion gives the operator time to prepare the product in line for sealing. The average output expectation for semi-automatic shrink wrapping machines is anywhere from 10 to 25 packages per minute.
High Capacity
High capacity shrink wrapping machines are Fully Automatic Shrink Wrappers. These systems can integrate into your production line if wanted. Equipped with conveyors and multiple sensors they dont require an operator which in return maximizes the output and saves cost. The capacity of automatic shrink wrappers is 25 to 80 packages per minute.
Its important to take into consideration your production volume growth projections at least for the following year.
Do you want to integrate the shrink wrapping station into your production line is another defining question you need to answer when choosing the right shrink wrapping machine. If the answer is yes, then you would require a fully automatic shrink wrapper. In an inline system, the alignment, rotation, separation, collation, upending, dividing, or even bonding of the products must be well projected initially.
If the answer is no, then a stand-alone shrink wrapping system that will be hand-fed is what you are looking into. In this case, an operator manually feeds the products to the conveyor.
This takes us to this question What is the desired result you are aiming for with shrink wrapping? To achieve the right outcome the shrink film you choose the film with proper specifications for your product and shrink wrapper.
You can be directed to the right film by the shrink wrapper manufacturer or your film supplier. But before doing that the following information will allow you to get familiar with shrink films.
There are different types and thicknesses of shrink film and which one you need to use depends on what you want to achieve by shrink wrapping your product. If you want to package a box of chocolate to be displayed on a market shelf then preference should be a film that gives your package an extra shine making it stand out among other products. In the case, you have multiple and/or heavy products such as a pack of soft drinks or a steel spare part then you will need a film that is strong and durable.
In choosing the right shrink film the products shape, shrink wrapping machine being used, and temperature restrictions all play a role. It is best to get a professional opinion for your unique product before purchasing a shrink film.
Polyolefin (POF) Shrink Film
Polyolefin aka POF film is preferred almost in all industries due to its versatile and environment-friendly nature. It is also safe to use for edible and non-edible products. The film is highly clear making the content of the package visible to the end-user and has a glossy appearance that makes the product presentable and attractive on the market shelf. Especially cross-linked POF film provides extra clarity and is stronger than the regular POF film. It is widely applied to products including food, toys, cosmetics, books, and stationary just being a few.
Polyethylene (PE) Shrink Film
The clarity of Polyethylene shrink film is lower than POF film. It is mostly used for heavy products mostly for industrial products. It is a highly durable and strong film making it ideal for protection and transit purposes. It is also the most cost-effective Packaging material. It is widely used for packaging products such as spare parts, doors, and window frames, bundling of cans or glass jars to name a few.
PVC Shrink Film
PVC film is a lightweight and inexpensive film option. However, the hazardous fumes, it releases when heated making it the least ideal choice of film. However, it still finds use for industrial products.
Gauge (Thickness) of The Shrink Film
Using the right thickness of shrink film will support you in a good-looking and functioning packaging. Also, the right shrink film will help you save money as the price of the film is defined by its width and thickness.
Labeling Unit
A labeling unit can be integrated into the shrink wrapper to add labels to the product or the package. Used to apply barcodes, product labels, etc.
Checkweigher
Checkweighers serve as a control point to ensure the correct weight of the product being packaged. If the product is lighter or heavier than indicated it will be pushed off the line with a discarded arm.
Feeders
Feeders can be used to place items on the product before it is packaged such as a sheet of paper.
Discard arm
Products that are found unfit by the sensors or the checkweigher are pushed off the packaging line via a discard arm for future inspection.
You are now ready to start looking for a shrink wrapper. You can get in touch with our Project Engineers to find the ideal shrink wrapping machine for your products.
Shrink wraps have remarkably changed how the packaging industry operates. Also, more and more organizations are shifting from manual shrink wrapping to machine wrap, owing to its benefits.
There are many questions though, regarding its usage, and specifically how to operate shrink wrap machine. But for those who dont know, lets start by explaining what shrink wrap really is.
Shrinkwrapping is a process in which any product item is covered or wrapped around in a free sleeve of loose polyolefin shrink film. The desired product is wrapped around by such film on the application of heat and this results in a clean, crystal clear, tight, and safe wrap around the product. It is not only cost-effective but also gives the required protection to the product.
Having talked about shrink wrap machines, now lets deliberate on the main topic. So heres how you work on the shrink wrapping machine.
I-Bar Sealers
These are wrapping solutions for small business houses. They are simple and easy to use. All you have to do is seal one side and turn 90 degrees to seal again. After completing this process, you have to use a heat gun to shrink the film.
L-Bar Sealers
This sealer machine eliminates the need of having to turn the item being sealed 90 degrees by sealing two sides at the same time.
Shrink Tunnel
They are arguably the most efficient and easy to use. Not only just this, but shrink tunnel also offers consistency as no use of handheld heat gun is necessary. All the operator has to do is set the required temperature and speed on the machine and place the product on the conveyor belt.
After putting the product on the conveyor you have to leave it up on the machine to do its job. The product you place would come out fully wrapped.
Foot Sealers
These are apt for wrapping products and require foot pedals to do the job. Youll have to use this pedal to raise and lower the sealing bar. As these are hands-free and use the work of foot, youll be free to use your hands in doing some other work.
Chamber Sealers
A chamber sealer works differently than the shrink tunnel. Here, the product is put up with the shrink wrap through a compartment. Thereafter the compartment is heated so that shrink wrap is wrapped around the product. Once the heat is applied to the whole compartment, shrink wrap gets compressed, giving a tight, clean, and sophisticated finish.
There are several benefits or advantages of using this technique, and weve listed them in the below section.
Below are the 5 advantages of using this technique. This would enlighten you on the positive sides of shrink wrapping.
More Stronger than alternatives
As compared to alternatives like overwraps or stretch wraps, shrink wrapping is stronger. This ensures the packaging doesnt fall apart even when occasional bumps come in transit. As the film sticks pretty tightly to the product there are fewer chances of it getting torn or messed up.
Aesthetically pleasing
While we seldom look for aesthetics when it comes to packaging, theres no harm when such advantages come in the bundle of benefits. The shrink wrap confers a shiny look on the product which not only looks clean but also seems tight and professional. The products packaged through shrink wrap are also easy to clean as dust attached to the product could be cleaned with just the application of a damp cloth.
Cost-Effective
There are several types of sealing machines available on the planet. A business houses requirement would depend on its scale of operation. If you are just starting, then I-Bar sealers would be helpful. They come at a cost ranging from $100 to $550, for medium-sized enterprises, L-Bar sealers are a good option and if your factory needs to wrap 100s of products in a minute, the Shrink Tunnels would be helpful. Their cost range from $ to $.
At Pro-Pack Solutions, we deal in Shrinkwrap machines and services to organizations of every size. These solutions are a cost-effective and initial investment as well as long term investment for these machines would be quite low as compared to alternatives available.
Speed up the whole process
Speed and efficiency are two aspects that are indispensable in the present world. Corporates are spending money to save that extra second and provide quick service to customers. Shrinkwrap machines serve this purpose too and drastically reduces the time that is taken on the production line. As manual wrapping is eliminated, the automated machines work towards saving as much time as possible.
The convenience of using different types of films
Its important to know that you could use three types of film shrink wrapping: polyvinyl chloride, polyolefin, and polyethylene. As they come with distinct characteristics, upsides, and downsides, you can choose the one which serves your purpose. While Polyolefin is durable, versatile and FDA approved, PVC may seem a little brittle and unreliable under extreme temperatures.
On the other hand, polyethylene comes with its own benefits and downsides. We suggest reading more about their characteristics and settle for one which serves your needs.
As these machines are more like a one-time investment with a substantial upfront cost, you should rely on professionals when buying one. Having been in the market for more than 63 years, at Pro Pack Solutions, we deal in the best shrink wrap machines available on the internet. Browse our store to find more packaging equipment and products. Wed be happy to associate with you!
Are you interested in learning more about paper roll wrapping machine? Contact us today to secure an expert consultation!