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OSC flex 1

by OpenSourceClassroom May 24, 2016
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I have started printing bits so I can build one :)
As mentioned, there are the new aluminium brackets. I need to make as many things as possible myself, so I assume that I can just go ahead and use the original FlexMendel plastic brackets as a starting point?
And the Slic3r config supplied gives an infill of 5%. Is this correct?


Major differences with the OSC Flex 1 are the additional custom aluminum parts, larger build volume (220x220x220) and the lead screw upgrade on the Z axis which creates almost perfect walls on your prints. The aluminum part files were created using software provided by eMachineShop. That is also the company where I order them from. You will need to go to their website to download their software to be able to open the part files and see dimensions there. Sorry about that. Also, the lead screw upgrade doesn't have a complete 3D printed part version, so make sure you completely decide what you are doing first. You could use original flexMendel 3D printed parts as a starting point, but what kept happening was any time plastic parts are exposed to continuous stress or force (like the parts we replaced with aluminum parts) the plastic starts to "creep" and you will have to continuously be checking and tightening your X and Y belts. With the aluminum parts, you are able to use continuous belts and essentially will only require belt re-calibrations maybe once a year depending on use.

And yes, the Slic3r config provided has an infill of 5%. That does not mean to print the parts for the 3D printer at 5%, I print all parts for 3D printers with 100% infill. What is important about the config file is not the 3D print settings but rather the filament and 3D printer settings that accompany the OSC Flex 1 upgrades.

Frame's built, and I've almost got everything ready for assembly, but one thing I can't figure out on your version, the Flex or the original Aluminium.....

Where/how are you mounting the heating element? Under the aluminium, between the aluminium and glass? I only have an Acrylic Prusa as a referance point and can't see the heating elements in any of pics lol.


Upgrades look awesome and the machine is built very well. I did have some questions regarding some of the updates made to this from the flexmendel version. Do you have anything available going over the updates/upgrades done to this from the flexmendel? One of the main things I see is (outside of brackets being changed to aluminum from plastic) the addition of a lead screw nut instead of a regular nut captured between two pieces. Is there any info on this? And is the shaft still 8mm threaded shaft or did this change to something else? I'll compile my questions into a more complete set since I'm still looking through the files.

On the firmware, the OSC Flex Firmware is called "flexMendel_firmware_8mmLeadScrews_20tooth"
The gearbox housing on the original is "Gearbox4" and on this version it's labelled as "Gearbox6" so there is the possibility that they have changed the pinion on the gearbox from 16 to 20.
I'm assuming that the spacing on the gearbox will then change to accomodate that?

I kept reading through this comment trying to figure out what you meant about the pinion and gearbox until it clicked to be that it was part of the extruder. I'm actually not using the extruder they built for this printer, instead I've modified the extruder mount I had on my older printer, 3DPrintMi, to mount on to the xCarriage parts so I could then use my own extruder. Once I put the printer back together I'll be testing the E3D Titan Extruder, hopefully it works. Before taking this apart to rebuild I was using the Bulldog XL extruder, I prefer having a somewhat universal mount to use the extruder of my choice instead of having to machine parts to build this one.

Sorry for the ambiguity lol.


So far I've discovered the following.....

  1. Lead screws, not threaded rods. So the top of the z-axis is quite different. No thrust bearings but looks like a single radial bearing? It looks like this is held in place by "Z Bearing Housing"
  2. This impacts the "XRodSupportV5" and "XRodSupportV5Motor" files which now use aluminium to wrap around the frame instead of the single printed piece on the original. The DXF files for these Aluminium pieces are in a folder "AluminiumPartFiles.zip" and this includes the top mounts for the Z rods and what appears to be the tray to hold electronics beneath the bed. I'm not sure how to work out where the bends go on the X-rod support pieces?
    It appears that the file "SmoothRod lock" holds the printed "XRodSupport" pieces onto the bent aluminium parts.
  3. the "Y Slide RetainerV2" has a hex shape sunk into it which is pretty cool as you can tighten the bolts from the top of the Y carriage and not have the bolt heads underneath like the original PDF suggests.
  4. Led lights look like an awesome addition.

Hope that helps others out a bit.


I agree with a lot of the info you posted.
I've actually spent more time than I am willing to admit taking a look at this and the flexmendel. I actually built a flexmendel so I'm trying to rebuild with many of the upgrades.
Here's a few points:

  1. The lead screws look to be 8mm, I'm assuming T8x2 lead screws. The lead screw nut does look like something slightly custom as I haven't found something to match but I have modified "XRodSupportV5" and "XRodSupportV5Motor" to bolt on generic lead screw nuts for T8x2 that can be readily purchased through ebay or china or any seller.

  2. The "Z Bearing Housing" seems to be the precise match for 608 bearings, assuming it's for 608ZZ since those are commonly used in 3D printers.

  3. The "SmoothRod lock" piece is only used on the motor side ("XRodSupportV5Motor), the idler side aluminum piece wraps around so it becomes a barrier for the smooth rod. The aluminum pieces bolt on using two screws/nuts on to the rod support parts. The bends are called out within the eMachineShop software, the aluminum parts folder has files that will open in the software.

I've printed most, if not all, of the parts I need to upgrade the printer and will be putting it together within the next few days.
I did go through and turn all of the aluminum parts into plastic pieces (except for the electronics tray) and have the STLs available for them. I can't vouch for them withstanding the forces on the printer but I guess I'll find out.

Thanks for the info.
My brain is scrambled from jumping between the original Flex Mendel and this version trying to figure out what the changes are:)

I would REALLY appreciate the STL files of the aluminium parts. Then I can stick to this version :) I'm new on here..... how do I get them from you?
Private message?

I just sent you a message about this, let me know if you get it. Although OSC has done a great job at the printers they have posted, they are doing a horrible job at supporting the files and documentation. "Open Source Classroom" seems to be very closed source, on their website they list that you'll receive "Supportive files and documentation for the flexMendel: Autodesk Inventor part files, Custom aluminum part files, Arduino Firmware file, Complete BOM with hotlinks to components." as well as "Open Source 3D Printer Manual: Assembly, Operation, Maintenance, and Safety" but of course you have to pay for the workshop, on here they only put the minimum they can to get by.