Molded Fiber 101
Molded fiber, also known as moulded pulp or molded pulp, is a collective term descriptive of the process for producing, strong and environmentally friendly protective material. Typically made from recycled paperboard and/or newsprint it is widely used for packaging solutions. Our industry has seen a growing use of waste non-wood products such as wheat and bagasse for pulp production.
Manufactured with wastepaper or other natural fibers (which are essentially cellulose), molded fiber products are recyclable along with other wastepaper and are biodegradable and compostable where facilities are available. They can also be incinerated without damaging incinerators. Both fiber & water are recycled and reused in manufacturing, resulting in almost zero waste. There are no toxic or hazardous waste materials expelled into the environment.
Inherently flexible molded fiber offers substantial benefits to manufacturers of Food related, Horticultural, Industrial and Medical products:
- Clam shell and carryout food containers
- Cups, bowls, plates and serving trays
- Planter pots and seedling trays
- Egg, fruit, berry and mushroom containers and trays
- Vehicle Parts; gears, panels, headlights, wheels, etc.
- Household items; toasters, coffee makers, furniture, etc.
- Electronics, cell phones, TV, modems, DVD, etc.
- Single use medical bowls, kidney dishes, bedpans, etc.
Molded fiber is a renewable and recyclable resource that sustains the environment and is capable of providing the following benefits:
- Recycled pulp fiber
- Recycled material
- Biodegradable
- Compostable
- Safe for Incineration
Molded fiber’s innovative makeup delivers extensive packaging solutions including:
- Transportation cost efficiencies (up to 10x more than polystyrene) from superior nesting capabilities
- Completely usable with no assembly in comparison to cut and fold paper board products
- Exempt to packaging penalties as with polystyrene in many countries.
- Zero or negligible disposable costs, unlike it’s alternative non compostable products.
Frequently Asked Questions
Tooling
A: Labelling and printing of MF have been in existence for decades on egg packaging and Thermoformed products are even more conducive to print due to the amazing surface smoothness. The application of these and other processes to Type 3 (Thermoformed product) is widely being used. Take a look at IMFA’s webinar series on Type 1 , 2 , 3 & 4 and in the Type 4 episode you can see high speed labeling and printing of egg cartons, and this can easily be applied to Thermoformed product.
There are many smaller bits of equipment for smaller scale applications. Cheaper inkjet printing and self-adhesive labelling which is way more versatile and will suite small volumes compared to egg carton volumes.
A: There are certain additives that can be used with multiple benefits including assisting in releasing product from the mold. The sticking issues are most typical on the press tools and not in the molding/forming tools. Release agents sprayed onto the tooling (either manually or built in as part of your machine system), can be very helpful in releasing problematic products. One should always try and understand what is causing the issues with releasing to better address the problem. Whilst not limited to the following, it could be poor tooling alignment, poor tooling design with problem angles or depth, tool temperature, unfavorable raw material being more prone to producing “stickies”, dirty or poor tool cleaning and many more.
A: Typically, your tool will need to land up facing up so that the transfer tool can pick it up off the forming tool and then deposit it down onto a bottom press tool, so much depends on the geometry of the tool/product and whether you have deep “wells/ dams”. Some forming systems allow for a tooling platen holding the tools to rotate through 180 degrees allowing for a “tool facing down” before submersion and rotating again (“tool facing up”) before transfer. These machines can also then be submerged “tool up and returned without rotating to transfer “tool up”. The issues with forming on Thermoform are unlikely to be different, in principle, to conventional forming.
A: Temperature is the last resort for drying a thermoformed product. One should first off spend every effort in reducing the moisture content of your wet product before placing it on the heated press tools. Pressure is vital and particularly controlling the pressure/time curve on closing. Most simple TF machines will not allow you to manipulate in milliseconds, the closing pressure. Heat, whilst the most impactful in reducing cycle times, comes with a host of consequences. Most TF press tools are aluminum and heat softens them chronically and leads to damage and high wear. Extreme temperatures also aggravate the “burning” of “stickies/ residue” onto the press tools which in turn cause fiber off the next product to stick and further aggravate the situation. So, try ensuring you have every other moisture reducing trick covered before heading for the increase temp button.
Molding
A: In a very generic answer which ignores many product specific requirements; cleanliness (no plastic, sand, metal, wet strength contaminants) and freeness of your fibre are very important. Conventional is way more forgiving on cleanliness but only to a point. Since TF has very high cost, soft aluminum pressing tools, which do not like raw material with abrasives of metals, nor plastics even in micro form which will stick to your heated press tools and quickly stop the Thermoformer. A conventional machine will also accommodate a lower freeness fibre than TF will.
A: This could be answered from so many different perspectives, but I will answer it from a MF manufacturing point of view. Conventional machines with high volume outputs are more able to compete with Polystyrene products on price but not necessarily on aesthetics unless after pressed. There are big issues with after pressing which typically require high volume and infrequent product design changes. Egg packaging is typical of a MF product which has easily displaced polystyrene and outperformed it on many levels.
So many of the polystyrene products we currently identify with are in the foodservice industry (food clams etc) and whilst Moulded Fibre and particularly Thermoformed MF, easily competes aesthetically, the same cannot be said for pricing. Our industry’s biggest challenge here is the ratio between capital cost vs output. We are seeing a plethora of equipment manufacturers in plastic thermoforming or injection moulders now converting to Molded Fibre. The issue is that “typically” the pulp version of the machine making the displacement product but only in pulp, costs the same to buy as it’s plastic producing counterpart but puts out only around 10 to 20 percent of its plastic/ polystyrene counterpart. Again, this is a very broad comment easily identifying with food service products and could be different for many other products. So, getting our pulp Thermoformed cycle times down is the single biggest influence we can have in reducing costs and being more competitive in our bid to displace polystyrene. (And yes, legislation, after all of these decades, is coming to our aid along with better informed consumers).
TF machines produce amazingly smooth product with exceptional dimensional stability with no further after pressing required.
TF products are typically much lower caliper, and this added to the exceptional finish and dimensional stability, ensure that they stack very well resulting in much higher shipping. efficiencies. Also, much enhanced denesting capabilities for ultra-high speed denesting.
Conventional product right out of the drier ( like egg trays -not egg cartons), do not require after pressing but are subject to dimensional instability related to raw material shrinkage and drying variations. The denesting of these unpressed products , whilst possible, are not kind to ultra-high speed applications.
Conventional product requiring smoother finishes or improved dimensional stability will need to be after pressed. After presses require tooling and are typically not that versatile in terms of dealing with multiple different product designs.
TF product is always going to have better aesthetics than Conventional and better dimensional stability, it is whether the pro
A: Temperature is the last resort for drying a thermoformed product. One should first off spend every effort in reducing the moisture content of your wet product before placing it on the heated press tools. Pressure is vital and particularly controlling the pressure/time curve on closing. Most simple TF machines will not allow you to manipulate in milliseconds, the closing pressure. Heat, whilst the most impactful in reducing cycle times, comes with a host of consequences. Most TF press tools are aluminum and heat softens them chronically and leads to damage and high wear. Extreme temperatures also aggravate the “burning” of “stickies/ residue” onto the press tools which in turn cause fiber off the next product to stick and further aggravate the situation. So, try ensuring you have every other moisture reducing trick covered before heading for the increase temp button.
- A: Capital cost per output is the single biggest differentiator between the two. A typical comparison would be (and this is very broad) , buying a Thermoformer or a Conventional machine from the same company and spending the same capital, the conventional (excluding after pressing and printing) would produce about 7 x more per given time frame than a Thermoformer.
- A: Tooling cost per ton of output per day on TF could be about $100k vs a conventional putting out 7 ton per day costing the same $100k for all of its tooling. A small 2 ton per day conventional could tooling as low as $25k
- A: TF machine whilst able to run on thermo oil (many manufacturers will not venture into this due to the ongoing oil leak issues) typically runs on electrical energy whilst conventional machines can run their driers on many different options such as gas, steam, biomass etc.
- A: There are many more considerations between the two but too vast to answer in this forum.
A: The items that influence solids content off the moulder include but are not limited to the following: Fibre freeness, pulp/water temperature, cycle time (obvious and least attractive), drainage aids, efficiency and capacity of your vacuum system, tool design (back-end drainage) and screen wire selection. Understanding all of the aforementioned elements influencing solids will lead you to determining which of them you have scope to improve on and which will give you the best return on your cost and efforts.
A: The diversity of water treatment systems is such that this cannot be answered on this forum. Typical water usage in a system that does filter and recover/reuse all of its systems’ water will be limited to that which is flashed off in the drying process, this being pressing in Thermoforming or the drier in a conventional system. Assuming you were running an underwhelming solids content of 25% off your moulder (TF or Conventional), in drying you would flash off around 3L of water for every Kg of product produced. (This is not a science lesson on splitting hairs between incoming raw material moisture content and outgoing 6 to 8% product moisture, it’s a simple arithmetic take on it). There are many efforts taking place which strive to recover, through condensation, evacuated moisture during the drying process, this will obviously result in lowering the amount of water lost to atmosphere and hence a lowering of the typical 3L/Kg.
A: Any bottle shaped MF product that is a single piece product is made in a split forming mould, it is the only way to remove such a shape from a forming or pressing mould. The mould literally opens in two to remove the product. You are likely to find an example of a medical urine bottle being made on the internet and this clearly shows the split mould process.
A: Egg tray design is critical for many reasons, some of which I will list below.
- Firstly, are what size eggs you will put in the trays as eggs are graded into size categories by specified weight. Jumbo eggs will not fit in a tray designed for small or medium eggs and likewise, you would not want to waste the shipping space of having a Jumbo tray carrying only smaller eggs.
- Many egg grading (weighing and packing) machines are highly sophisticated and high speed and require all packaging passing through to comply to a recognized set of standards related mainly to dimensions. This is due to “pre-sets” on the machines that apply to sizes of packaging. Even the most basic farm collection and packing machines will require a compliant tray.
- Material shrinkage is a major factor in MF drying and very specific shrinkage dates needs to be factored into your tool design to compensate for this shrinkage.
Tray with or without “holes” refers to holes at the top of the posts on an egg tray (or a high post egg carton for that matter or anything with high posts in the geometry).
- If you don’t already know you would quickly learn that any geometry on a conventional Type 1 or Type 2 product will battle to dry the “pointy bits.” This is because of the poor air flow to this area during drying. Designing a hole at the tip of this geometry allows air to flow through there and brings that area more in line with air impingement of the rest of the product.
Drying
A: In my 30 years in this industry and with many personal investigations into this in various countries, I have not been able to get the economics to stack up using electricity in big conventional driers. This is not to say that technology will not change this situation.
A: This is a topic that would best be dealt with in some future collaborative workshop rather than in a Q&A for the website. My best practice is to run frequent (manual) moisture profiling in the different zones in the drier. This needs to be done on all products in order to optimize drier settings for energy consumption and in order to manage shrinkage of the product.
A: Not any easy one and not able to address it on this forum. There are many steam fed driers that are being powered by biomass from annual agricultural crops which are clearly renewable.
Miscellaneous
A: Unfortunately, not. This industry has played its cards close to its chest for its entire relatively short history. Snag a rare, retired fella 😊. Join IMFA and work flat out at building your network.
A: The East has long been producing and selling top quality non wood fibre for use in the Thermoforming industry. This has been mainly aligned with Thermoformed products being made in big volumes in the East. With developments in non-wood pulp production outside of Asia in recent years, along with current significant investments in the likes of USA, Australia and elsewhere, I see the global supply of pre-processed fibres actually being less of an issue than the ability of the industry to turn on viable, quality Thermoformed machine capacity. There are also significant developments with Thermoformers using virgin wood fibres which will further feed into the TF raw material needs.
A:
Dry moulding of Type 3 MF products.
Environmentally friendly barriers and laminates including PFAS replacements.
Machine developments leading to higher operational efficiencies, particularly in Type 1 and Type 3 equipment.
Robotics being used in main forming lines and in secondary quality control and packing.
The ability to now disrupt high volume high application where previously only plastic could perform
A: The single biggest thing related to our industry would have been to be able to expose the plastic catastrophe for what it is and to have had people understand that 25 years ago.
A: Many of our members, through deep involvement on committees, feed info into IMFA that IMFA can then use to further many issues on many fronts.
A: Reference, reference, and more reference from someone who has used them in the past.
Any machine builder worth their salt should be able to get you into a facility somewhere in the world where you can see a machine running and talk to operational staff.
Buying a machine off plan without multiple references and seeing one running would be considered extraordinary.
A: Following are some considerations when deciding to scale up stock prep to feed multiple machines vs stock prep per machine.
Pros of large stock prep feeding multiple machine.
- Economies of scale always favour this option on capital spend.
- Typically, a smaller footprint and less operating staff.
- Often more options of supply when getting bigger equipment.
Cons of large vs individual per line.
- If one piece of equipment goes down for maintenance or breakdown it effects many machines.
- Individual stock prep can run bespoke recipes for one machine.
- Colour runs on a single large stock prep system can be challenging depending on how close to the forming machine you can separate the supply stream.
- Options for refining or cleaning are reduced and sometimes not even available if dealing with say one small machine.
Fiber
A: Yes, many applications of wood and non-wood fibre being mixed.
A: The single biggest manufacturing challenge is the different shrinkage aspects of these various paper types. ONP may shrink as little as 2% and DLK as much as 7%, (I have used virgin waste stream kraft from a next-door paper mill and the shrinkage was as high as 11%). Your tooling (and assuming that if we are talking about OCC, DLK & ONP then we are talking conventional and not Thermoformed) is designed such that shrinkage through the drier is compensated for in the tool design. If you start introducing different fibres you will most certainly influence that to a point of serious consequence on dimension and denesting, also transfer out of your tooling.
A: Since refiners are typically expensive bit of equipment and the refiner plates are very expensive consumables, you cannot be feeding refiners things that could wear or damage the plates. There are many different levels and costs of cleaning equipment for pulp preparation, but the following would be typical of an upstream refiner in a moulded fibre manufacturing operation: Some type of screen (Johnson, Kadent, Poire, custom made) for removing larger non fibre elements. Centrifugal cleaners for removing smaller but heavy (sand, glass, etc.) elements and then a magnetic trap for catching as much metal as possible, like staples from OCC etc.
A:
Cost:
- The cost of refining is significant in terms of capital, and operational cost of electricity and refiner plates. Throughput and scale also have an influence on cost and availability of credible refining equipment.
Benefits can be:
- Better formation leading to stronger, lower weigh product and hence lower drying energy and lower transport ( improved volume).
- Improved fibre distribution and caliper control.
- Microfibrilated fibres enhancing barrier properties.
A: Yes, you can but they are very limited in angle and directly influenced by depth. There are many tooling specialists in our industry that can advise on specific draft angles for specific applications/designs.
A: Yes, you can. It is not common nor widely understood but it is happening at the pointy end of our industry.
A: A typical TF machine will produce around 1 metric ton per 24hr day. (Many at the 600kg- 800kg mark and some approaching 1500kg but not many).
It is easy to see that if you were competing in the commodity market against large scale, how one TF machine may be unviable. However, you may be in a situation where you have uniqueness in your product or location that may make this work.
Remember that there are support and infrastructure services that may be difficult to justify against one machine and would not necessarily increase if you had multiple machines.
A: This has been around since the turn of the century. There is no doubt that Asia led the way on this up to the early 2000’s but now the growth and development of Type 3 outside of Asia is prolific.
Colours have been used in MF egg packaging since the mid to late 90’s and some amazing pastel colors since the turn of the century, so not new. There is absolutely no difference in process or complexity to dyeing Type 1, 2, or 3 product.
There is some of the finest, smooth, brilliant colored Thermoformed product being made by one of IMFA’s members in the UK.
A: The simple answer is yes.
There are many credible machine builder that will offer a small sample type machine in either Type 2 or Type 3.
Small quantities of fibre, depending on how specialized it is, may be more challenging. Even in the case of specialized fibre it may well be possible to piggyback on someone for small volumes. If you were an IMFA member, we could certainly help in pointing you in a direction on this.
A: This is a question that could fill a book on its own. Below are a few comments that won’t scratch the surface of this topic.
MF machines have many things that influence output/profitability and none more than cycle time. Fibre length and quality have the single biggest influence on this cycle time. The fibre characteristics are dominated by amongst other things, freeness which is its ability to drain water.
The functional requirements of the product will determine “how much you can get away with” on fibre quality. Shorter fibre typically lends itself to poorer bonding strength and more fines.
There are many Type 1 and Type 2 products that will allow you to get away with a percentage of very short fibre, but you do hit a wall eventually. Type 3 product due to the already long cycle times is more negatively affected by running a “too short a fibre.”
The above does not mean to detract from the highly technical considerations on this and serves only to offer a “layman’s” view of fibre length.
Chemical Additives
A: This is such a broad question that cannot be answered in this forum. Discussing your product performance requirements with a consultant of paper chemical supplier would most certainly have you going in the right direction.
A: Retention aids are very common and assist in many aspects of manufacturing, some of which are keeping your back water cleaner for reuse, improved retention of dye/colorant, improved solids content, and higher fibre yield.
A: Many IMFA members have found competitively priced alternatives to PFAS. The biggest issue with the PFAS replacements is matching the PFAS performance not price. The food industry utilizing foodservice MF product have realized that “fit for purpose” is being realized with lower hold out specifications for hot grease than what PFAS was offering.