Finally, after months of researching hardware choices, entering analysis paralysis, developing and testing own DIY linear bushings, I can present first results!
Hope this is the right place to post them.
µGen T/B
T/B stands for testbed
My goal was to have a tool in order to research and try out relevant hardware and software for the RepRap community; easily modifiable, moderately portable, yet fully functional as a high-quality printer.
Let me get this straight, first: I failed in some aspects. The Z axis is still too wobbly and the printer is not really even moderately portable. Still, I wanted to show this printer off because some aspects are already quite to my liking and also because others might learn from my mistakes.
On to the results:
The problems encountered and their solutions:
Wobble, wobble everywhere!
The Z axis is bolted to the sides of the sheet metal I used for the Y axis. The problem is that this is not really stable and will allow the portal to swing left and right quite a bit when even a small force is applied to it.
This needs a complete redesign as the sheet metal is arguably unsuitable for this application. Fortunately, the same hardware store also sells square aluminium extrusions with the same hole pattern (which I found to be very practical in order to build a frame quickly). So, first job for the finished printer: print parts for a second, better version which I plan to release. This one here has just too many flaws and I fear that some inexperienced builder might like the look (hey, it does look rather neat, I think) and waste time and money by building a sub-par printer.
Z binding
The POM nuts are fun. Quiet and smooth even without lubrication. The one big trouble is that I did not have good tools available when making them so that they are slightly crooked. The nut in the right X end is quite slanted, causing binding problems especially towards the Z home position.
Since I won't have access to suitable tools any time soon enough, I will substitute these nuts with a printed adapter and brass nuts as brass on steel should be better than steel on steel friction and wear wise (just look at ACME and TR nuts / metal bushings to know what I mean). I have already acquired some brass M8 nuts from the hardware store and will test that out on Monday.
In the long run, I hope that Taulman's 618 Nylon filament is durable enough to serve both as linear bushing material as well as Z screw nut (apparently, you can tap 618), thus further eliminating vitamins and closing in on the goal of a mostly-printed RepRap.
Portability
As mentioned above, I wanted a printer that I can take with me. I don't need to carry it every day, but it would be nice if I could take it home at weekends. So since I already have to upgrade the frame, I will incorporate a folding mechanism that can be actuated after loosening some (4?) nuts. It will not be as clever as the one in the Fold-a-Hux, but I am more aiming at long-time stability with the added benefit of having a space-saving transport mode, so I can compromise on the folding mechanism.
Hope this was interesting, sparked some ideas or was in any other way informative and entertaining.
If you have questions, please feel free to ask away.
Edited 2 time(s). Last edit at 03/16/2013 07:34PM by uGen.
