FDM 2.0 is our philosophy to make FDM a true industrial grade and affordable B2B partner in small scale production, mass customisation and rapid tooling / prototyping applications requiring on-demand, high quality and certifiable parts in a wide range of (recycled) materials.
Let us introduce you to the core of our philosophy.
Excited? Let’s get in touch to discover more and what this can mean for your project.
The basis of good FDM extrusion is having full control of your feedstock material from feeder to nozzle. Current available technologies have sufficient control to be able to printed parts but in order to print excellent parts and high speeds, full material control is essential.
Where traditional friction based pinch wheel mechanisms have been the standard for years, they do feature the inherent problem of slipping through the filament as a function of back pressure. This slippage will lead to under extrusion and thus weaker parts as layer bonding decreases with less material output than required as illustrated in these cross sections. Under extrusion becomes increasingly pronounced with higher printing speeds as the hot-end will reach its melting capacity starts to cause more and more back-pressure. Evident from the graph is that the VXS-150, our first product in the FDM 2.0 product line is able overcome this issue and retain extrusion volume along the entire range of volumetric flow speeds leading to consistently strong parts up to 90% of theoretical injection moulding strength.
Filament driven FDM systems have the benefit of doing retractions of the feedstock material to temporarily stop extrusion during non-printing moves. These retraction are absolutely essential in creating an aesthetically pleasing end-product finish without having to post process. Not being able to temporarily stop the extrusion process leads to material dripping from the nozzle (oozing) and deposits on the printed object. These deposits are usually present in the form of fine strings in the open areas of a print but they can also accumulate leading to serious deformations that can possibly block the movement of the extrusion head.
A typical problem with conventional extrusion systems is that they are limited in both speed and quantity due to their design. Performing a fast retraction on a friction based system again causes slip (in the other direction) meaning too little material is retracted. When the extruder feeds back to restart printing, this will cause a spike in back pressure and will damage the filament. Performing this action repetitively causes so much damages to the feedstock in a particular point that the feeder starts ‘grinding through’ leading to a complete stop of extrusion. In FDM 2.0, it doesn’t matter what movement of feedstock is needed, it must be done at any time without limitations our failures.
The viscosity of a polymer is a function of both temperature as well as pressure. By increasing pressure in the hot-end, less temperature is required to create the same viscosity. Introducing a pressure element in the 3D printing process allows the user to optimize the printing temperature based on the speed or quality required. This is beneficial as a lower temperatures causes lower rates of thermal degradation of thermoplastics by depolymerisation, scission and oxidation. Like in injection moulding, pressure is an elemental component of extrusion in FDM 2.0.
Thermoplastics intrinsically act as insulators meaning that when introducing heat from the outside in, penetrating and melting the core of the feedstock material can be a challenge. Especially when printing faster the time in contact with the heating elements is reduced making this even harder. Typical solutions available on the market either focus on getting more energy into the feedstock material by more heating power, induction or longer melt zones. However, both of these have a downside. Introducing more power does not remove the thermal insulating properties of the polymer and will lead to a big temperature differential from the outside in. When the inside is finally molten the outside can become hotter than optimal leading to thermal degradation and potentially burning the feedstock material. Longer melt-zones can be a solution allowing for the feedstock material to be exposed to the heating element for a longer time to provide a more consistently molten polymer. The big downside is that retractions become way less effective with a longer melting zone thus reducing the advantage of filament based FDM over pellet passed FDM. [comparison of melt zone lengths] An essential part of FDM 2.0 is fully melting the feedstock material without overheating or losing control of the molten mass.
Being able to introduce pressure into the extrusion equation is something that needs to be neatly managed and monitored for the most efficient result. An essential element is that the pressure is measured and direct feedback is provided to the feeder to compensate for unwanted deviations. Monitoring can even be used to detect possible extrusion errors in advance and warn the user to take action when automatic resolving fails.
The most interesting element of pressure monitoring in combination with temperature logging can create a report of theoretical engineering dimensional and strength specifications that can be used in certification of end-products. This is currently done by printing dogbones next the printed object which are later strength tested in the lab. If it fails, all prints of that batch a rejected. Also, this method is inaccurate as a dogbone will be printed in a different manner than any other object allowing conditions to be optimized for the dogbone to print fantastic while these same parameters compromise the integrity of the end-product printed next to it.
[photo of dogbone next to object]
Additive manufacturing is already redefining the manufacturing landscape being able to efficiently use resources to create highly complex parts. In addition, its on-demand one-off production character has the potential to shorten supply chains and bring production closes to the customer reducing our carbon footprint. We truly believe FDM doesn’t stop there and also has great potential to create circular products as well thus being even more efficient with the resources we use.
The baseline of FDM 2.0 is to fully close the product life cycle and create a fully circular and wasteless system. It needs a system that is able to handle recycled materials and is even capable of instantly recycling failed or old printed parts.
[illustration of circular printing, add old products an outside stream]
3D printers are generally ‘ stupid’ machines that execute a program based on user input like CNC machines have done for ages. When something unexpected occurs during printing, it requires user monitoring and response to save a print or possibly prevent damage to the machine. In FDM 2.0 the 3D printer is a smart machine that has a fully closed feedback loop and is capable of adjusting the printing process when unexpected events occur salvaging valuable prints and materials and greatly increasing printer utilization.
[illustration to be decided]