What is the difference between direct drive and bowden on a printer?? Its there and diference in print quality, or material usage scope? Anyother advantages or disadvantages??
It is often harder to print exotic flexible filaments in a bowden, but it is usually easier to get faster smoother prints with a bowden.
Bowden puts less moving mass on the carriage/effector, which helps with ringing. But the long Bowden tube has additional elasticity and backlash in the extrusion path, which makes it more difficult to tune out blobbing and stringing flaws. It’s really a trade-off.
My personal opinion is that Bowden is great for small, light printers (like a Mini Kossel or Bukito) where the tube is short and both extruder envelope and moving mass are critical. But the bigger of a build volume and stronger printer you build, the more you should switch to direct drive / direct extruder. Basically, with a big printer and quality motion hardware, the weight of the extruder motor isn’t as important, and a long Bowden tube starts to become a problem.
Another factor is acceleration vs speed. Higher extrusion speeds can be an issue with Bowden drives because high plastic flow rate means high extrusion force, so the extrusion path elasticity exacerbates pressure lag afterflow issues. But, the lower moving mass means higher acceleration is possible.
@Ryan_Carlyle my enquiry is because i am geting a Prometheus system in the mail( hopfully soon ) and i am going to install it on my printrbot simple metal, which is now a direct drive. So i was woundering if i should mount the motors on the y arm with very small bowden tubes or should i mount them to the base of the printer with long tubes
I would go shorter tube. Reasonable people can differ though.
All my printers are Bowden, I have used direct drive, but it was on cheap acrylic framed Chinese Prusa i3s, which ringing can become a big issue, for Y splitter systems, I would recommend a full Bowden system over trying to direct drive them, mainly due to the ease of fitting them and the Y splitter being designed to be a Bowden addon.
I run 3 CoreXYs and a Delta and really haven’t had issues with blobbing or anything of the sort and I run 700-800mm tubes. For me it’s pretty much set retraction settings and forget, ymmv, but 6-7mm at 40-80mm/s dependent on extruder setup works for pretty much all materials I use, including Nylon Bridge, which is really quite soft and flexible. As long as you run slow and have a good filament path, you should be able to print flexibles with a bowden, I will admit, it can be tricky to get right.
For me, the pros of a Bowden setup outweigh the cons and like the fact with the right setup (32bit electronics) I can fire out prints at 120mm/s base speed on the latest CoreXY and get pretty much perfect prints every time. It really does come down to what you want out of your printer.
Normally, I would advise for a Remote Direct Drive type extruder like the Nimble, where only the extruder head is mounted on the hot end and the stepper is mounted remotely on the frame, but for the Prometheus system I would suggest to use a bowden setup.