Openrail Reprap

Hey, new to the forums but I wanted to share pictures of the new openrail concept reprap that I built. I originally put together a prussa I2 and decided it was time to go bigger so I designed this. I borrowed the foot design from Akhlut's prism 1.5 and then designed everything else myself. I'm using a budaschnozzle 1.2 for my hotend with a wade's reloaded extruder. The heated bed measures 13.5x12" and is made of aluminum with a flexible silicone-rubber heat sheet glued underneath. I'm going to put it through it's paces this weekend and see how fast I can take it.









Edited 1 time(s). Last edit at 03/28/2013 10:12AM by tkole.

Nice, looks good

Hard to see much detail from the smallish pictures, but what I can see looks good

Check out my T-Slot build if you get time
[forums.reprap.org]

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My projects are listed here - [www.el34world.com]

Are your parts printed out of PLA or ABS? The only thing I'd be concerned about is the Z-motor mounts. They look a little thin. If they're printed out of ABS they may flex (found this out the hard way). If they do you may want to beef them up.

Other than that the machine looks great! Very similar to something I had in mind a while ago. I'm liking the openrail. Using that for an upcoming CNC project.

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- akhlut

Just remember - Iterate, Iterate, Iterate!

[myhomelessmind.blogspot.com]

I've now found a source for MakerBeam/T-slot in the EU, but already there is a new thing called V-slot which looks even more interesting [www.kickstarter.com]

It's made by the same guys as openrail. It should be out in July I think. It will definitely be the way to go once it comes out.

Thanks Akhlut! The mounts are made of ABS and I have actually already made some improvements to beef things up since those pictures were taken. Besides upgrading to v-rail when it is released, the only other thing I'm thinking about is trapezoidal screws for the z-axis. I just don't know if it's going to add much to a z-axis that is already on linear rails. I guess there would be more consistency with the layer height but z-wobble is not really an issue with this design.

Hi Tkole!

Congratulations for the design. I am considering building one myself with openrails and I have a few questions.

1. How stable to vibrations are these rails?
2. I noticed that the Z rails are horizontal (also other designs online do it that way), but to increase the width printed area they could be rotated 90 degrees and connect the X carriage perpendicular to the Z sliders. Is there any advantage/disadvantage to do it that way?
3. How good is the printing quality?
4. How fast does it go?
5. Could you share the diagrams or stls of the printed parts?
6. Are those 80/20 20x20 and 20x40 aluminum extrusions?

Sorry for the number of questions, but I’d like to make sure what I am buying is good enough for the results I am looking for.
Thanks and keep up the good work!

alex_mp

1. Very stable thus far. I had some problems with a particular print on a certain section, but when I took apart the gcode I saw a small section oscillating at 60 Hz. I have since enabled the frequency limit in slic3r to 50 Hz and everything is good.
2. In theory you could, but I wanted to have enough separation between the z-axis roller bearings to limit wobbling so I am height limited by that anyway. I figured that I would try to reduce the torque on the z-axis my minimizing the length of the lever arm, in this case the distance between the front of the extruder mount and z-mounts.
3. Better than my prusa i2 thus far
4. I haven't been successful at printing over 80mm/sec for any sustained length of time at this point due to filament jams in my hotend. I'm working on that part though.
5. I will gladly post them once I've finalized everything.
6. It's mostly 20x20 with a couple of 20x40 pieces for the y and x axes. I would probably hold off at this point building anything until v-rail is released unless you are desperate to start a build. According to the website, it should be shipping in July. I'm definitely going to upgrade my axes once it comes out.

Tom

Hi Tom,

Thank you for the reply. You are right, the best thing to do right now is to wait for the V-slot rail to come out and try it in my new build. Regarding the jam you mentioned, is that a Lulzbot hot end? Because I have a Budaschnozzle 1.2 and it started to work great at more than 80mm/s after:

1. I put Teflon tape around the nozzle and around the PEEK insulator. (It had a small leak)
2. Put a small fan pointing above the heating block. (It is only required when using PLA)
3. Changed the internal PTFE insulator for a home made to the exact internal diameter of the filament I use. This works as a seal to prevent the reflow of soft filament from coming back up and jamming the hot end.

I hope some of my 2 cents help you.

Alex

I think I have solved my extruder/hotend issues. I was using my budaschnozzle 1.2 with 1.75mm filament and the lulzbot 1.75mm replacement PTFE tube. The problem is that even though you replace the PTFE tube, the threaded extension is still bored for 3mm filament. So as soon as the filament heats up a bit in the threaded extension, it bends because there is extra space. This has been causing my jams at higher speeds. I finally bit the bullet and ordered 3mm filament. It came today and I immediately ramped up to 150mm/s. It's currently in the 3rd hour of a big print running smooth as butter.

Hey tkole,

How is this printer going? Any major design issues etc. that you picked up while building this?

I've ordered parts and will build a similar design but using v-slot extrusion when it arrives.

Thanks.
Glenn

No issues at all. Over the last couple of months I did upgrade my z-axis screws to trapezoidal lead screws and beefed up the y-axis rail with 2 pieces of 80x20 v-slot. It's rock solid now. I'll post some updated pics later.

Thats great tkole. Yeah if you could put some pictures up that would be great. I was thinking of using just one centered length of 20x80 V-Slot for the Y axis. Do you think this will be adaquate?

Glenn

Glenn, one piece of 80x20 should be fine but it depends on the dimensions of your bed plate. I had 1m of the stuff sitting around and only needed 450mm so I figured, might as well use two pieces and make it that much stiffer. Sorry for not posting pics, I got side tracked. I will make a reminder to do this when I get home tonight.

Here are those pics:





Edited 1 time(s). Last edit at 09/12/2013 10:25PM by tkole.

Thanks for the pics, looks great!

Ill probably end up using two lengths as well, as ill have enough. When it finally turns up!