Tagged: comparison with prusa mendel
July 27, 2013 at 16:20 #741
Hello everyone (especially Mr Harley :)),
I wanted to have your feedback on a question I am asking myself at the moment. I have finally decided to start building my own printer, but I hesitate on which model to choose, between Morgan and Prusa Mendel.
I’d like to try the Reprap Morgan, because I like the design and the fact it’s “new on the market”, but I think that maybe this is not the simplest path, and that maybe a Prusa Mendel will be slightly more easy to build precisely/tune correctly after having built it, will it not ?
Regarding the cost, (I’m still a student 🙂 ), I think for the moment both design have about the same final cost, but the Morgan seems a bit more handmade, so maybe I can get a final cost lower with it.
What do you think ? Is there some relevant issues which may not have occured to me ?
For the moment I will buy components that are on both printers, and then I will decide.
Thanks for those who would be so kind as to try to answer my questions !
July 27, 2013 at 23:06 #742
The reason why Morgan works out a bit cheaper than a Prusa is the lower vitamin count. Compare the number of bearings required, the number of precision smooth rod etc. in order to build a reliable machine.
Additionally the original Prusa, like the Sells Mendel before it is inherently a bit unstable. It also requires an extra stepper motor on the Z axis. You also need to measure every bolt placement twice before tightening. I used an Ecksbot to print Morgan (a remixed prusa mendel) and while not a bad machine at all it inherited many of the drawbacks from the original Mendel, part and parcel.
Cartesian bots are definitely more straightforward to understand, and calibrate. That is common sense, but I have spent a lot of time to devise firmware routines that will make calibrating Morgan even quicker and more straightforward. I will make a video this weekend on the calibration routines since some of the builders out there have reached that point now.
That said, there is a printer out there for everyone, and if Morgan is for you, you will build it. If not, you will find the one that works for you!
July 28, 2013 at 01:24 #745
Thanks a lot ! I think that’ll help me take my decision. 🙂
July 28, 2013 at 01:56 #746
Small question : is there something special I should know if I want to print the parts by myself for the Morgan ? Do you got an idea of how long it would take ?
July 28, 2013 at 06:56 #749
Nothing special. Print the longer and larger parts out of PLA to prevent warping, and make sure the toolhead is printed from ABS (heat reasons). The rest could be printed in either.
I generally use 0.4 layer heights, 15% hex infill, but I like to do the threaded parts (21-Morgan_toolhead, cap_2, 23-extruder_bowden_adaptor) using ABS at 0.2 layer height to make the threads better defined.
July 29, 2013 at 02:38 #769CriocaParticipant
Are there any actual disadvantages of building / using a Morgan over a Prusa Mendel?
July 29, 2013 at 06:09 #771
Perhaps you are asking the wrong person…
These could be construed as disadvantages:
The microprocessor needs to process the Cartesian gcode into SCARA inverse kinematics. This happens 200 times a second, like on Rosstock deltas. This means that for printing move speeds of 200mm/s there will be a SCARA arclet every 1mm. This will cause a very slight ripple effect on straight lines at higher print speeds.
If you use high print speed for “Draft” prints, this is not a problem. This is true for all DIY printers, since higher print speeds cause issues like overshot corners, ringing etc. anyway.
We are waiting for reliable and lower cost ARM based electronics and firmware to become available to solve that issue. More calculations = smoother prints at very high speeds.
Other disadvantages are compensated for in the firmware, for instance the toolhead tracking of the build plate by carefully moving Z up and down to ensure a level build.
Hope this helps.
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