Re: PTFE coupler - Theory and practical details
Posted: October 20th, 2016, 3:03 pm
Hi Anders,Anders Olsson wrote:Well, the E3D design certainly has it issues, technically it works but I much rather change nozzle on my own heater block than on the E3D.Iltacitoduca wrote: I never bought a hotend from E3D for the simple reason that I never thought that an interchangeable nozzle as proposed by E3D could work without leaks...besides the fact that achieve the precise connections between the steel part and the aluminum side and the nozzle side of so reduced size, it would result in a high precision mechanical processing. and from the proposed price I highly doubt that this is the case
For the same reason I never purchased an Olsson block, no offense, but I really don't like your solution, which more than anything else is a compromise to have an interchangeable nozzle
I not even take into account the ruby nozzle ... in the printing of thermoplastics I do not see the use of nozzles Sapphire / Ruby, and certainly not for the cost since the synthetic rubies cost nothing (more than anything else could be costly one initial investment to get a custom made ruby) nor for the dimension or anything else ...
So all I see behind the use of the nozzle with ruby is unconvincingly ...
Instead, it would be helpful to draw experience from what already exists in the field of injection molding... don't you guys?
The E3D hotend appears mainly to be designed to be cheap to manufacture on simple machines with cheap labor, that is my opinion.
My "Olsson block" on the other hand is a rather complex product, as I had no budget to change the printer or to manufacture my own nozzles and as I never thought we would make more than 200 pieces in total
When I only had the prototypes Ultimaker were not interested. When we had sold a few hundred we had done all the R&D, testing and lots of marketing and it was for that reason suddenly hugely interesting for Ultimaker and they did not want to change a thing on it as it was working good enough. And luckily this rather complex block can still be manufactured relatively cheaply using complex machines and well paid labor.
It is often like this in product development, things are rarely optimized but there are often various unpredictable chain events, sourcing issues, assembly considerations and random things that ends up forming a product that is good enough for a particular task.
The ruby is mainly a project for my boron carbide filament, which requires something of that magnitude to be printable at all.
It has advantages for more common filaments too though and I am hoping that solving the wear issue once and for all will have other effects. For example filament manufacturers might start selling more interesting composite filaments if they know there is a nozzle that surely can handle it.
The PBI that gudu used is a typical example of injection molding materials, but you can not always compare injection molding with 3D-printing.
You for example get a much more challenging wear issue on the tip of a 3D-printer nozzle than inside an injection molding machine.
WHAT?? sorry but I not agreed with your statement about the complexity of your "Olsson block"... seriously there is nothing complex about it...
nor in the design, nor in the manufacturing process.
And what at UM choose for their 3D printer is under the eyes of all ... They saw a market opportunity and have ridden the wave... opinable but it's the law of market, nothing more nothing less
Printing B4C with a material of a lower hardness, will be tricky... especially dispersed in a fluid medium... even the inner wall before the nozzle tip will wear out rapidly...
Advantage over other materials, perhaps...
Yes absolutely sure that you can not always compare the two procedures/processes and I never wrote that are comparable I wrote that from similar processes we can take advices.
Instead, about the "much more challenging wear issue on the tip" I have many doubt ... first because the tip operates at pressures which are at least 10 or 20 times lower than that in an injection molding process
and second because the material that came out (unless it is not B4C) may, at most, have a polishing effect... (but I doubt about it, due to the fact that it's brushing without pressure over the nozzle tip)
Kindly regards
Claudio