Molded Fiber 101

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).

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.