According to insiders, it seems that BigRep is secretly developing a potentially revolutionary new 3D printer extruder.
The Berlin-based company produces very large scale 3D printers for use by industry that have proven quite popular.
They’ve explored the large scale 3D printing problem in some detail over the past few years, and have identified and resolved many issues. The nature of their solutions have been mechanical, material chemistry, thermal, software and more.
But now it appears they’re working on something new that we haven’t heard of previously.
BigRep’s equipment uses the well-known filament extrusion method of 3D printing, in which a friction or geared wheel grabs a thermoplastic filament and pushes it into a heated nozzle. The nozzle moves about in 3D space, layer by layer, to produce solid objects.
They informally describe this traditional approach as “drool and draw”, and that’s actually not far from the truth. Filament extruders invariably must be tuned for each type of thermoplastic to avoid the unpredictable fluid nature of the material in the nozzle.
For example, in a dual nozzle 3D printer, the idle - but still heated - nozzle often drips out material. And why shouldn’t it? The material is heated to a soft state as required, and there is very little to control it within the hot nozzle.
3D printing parameters account for such effects with things like “retraction distance”, where the filament is swiftly pulled back out of the hot zone while waiting to print again. But these practices are really trying to bypass the actual problem: you can’t control what’s in the nozzle.
We understand that BigRep’s project is to develop an extruder that is quite different, and does actually control the material all the way to deposition. It’s a kind of “metered extruder” that will know very precisely what amount of material has been deposited.
We don’t know exactly how they intend to do this, but it does sound quite interesting.
If such an extruder were developed it would make 3D printing quite a bit more reliable and increase print quality because there would be extremely consistent extrusions.
The vagaries of input filament diameters, motor speeds, feed slippage and other troublesome occurrences would be isolated from the deposition by this new extruder. It might mean you could be able to use filament of lesser quality and still obtain quality results.
Today that’s almost always not the case: if you put crappy filament into your 3D printer you will no doubt obtain crappy print results. This shows you how susceptible the filament extrusion process is to materials and other effects. It can be a questionable process, and that is another reason why some many 3D printer operators spend lots of time tuning 3D print parameters, and iterating through trial and error tests.
Some of these issues would evaporate in the face of a metered extruder.
But I have not seen this mystical device, and BigRep isn’t showing us anything, at least not yet. Perhaps we’ll see one of these extruders later in the year.