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SoliForum - 3D Printing Community → 3D Printer Discussion → trying to get my printer calibration closer
I have a Makerbot replicator 2x with over 3000 hours run time.
The stuff I have been printing have not been that critical
but now I need it on target but rite now I am .0762mm out of round.
I have checked belt tightness and alignment on X,Y and gantry all are ok.
Does anyone have any suggestions as to what to try next
Thanks
Dale
To be honest that is about the best you going to get. These are not CNC machines cutting metal. They are oozing molten plastic which is not exact. The plastic also shrinks as it cools as well. I never use a printer if my tolerance needs to be less than 05.
Thanks Carl
I was going to try and get it closer because parts are not fitting together.
If you really want to tune it do a series of circle and determine if the error grows . If the error does not grow then you have a backlash issue. if the error is doubled on a double size circle then you can tune your steps. also it is easier if the error is aligned with one axis . if the error is at an angle you may to play with some trig.
Thanks Carl
I was going to try and get it closer because parts are not fitting together.
As long as all the parts that fit are printed they should fit. The issue of tolerance comes into play when you are trying to fit printed parts to machined parts. Like in my case I am trying to fit
machined rifle barrels to printed parts and they are sometimes tricky. Don't ask......
Makerbot does not use pots to tune stepper motors it is done at factory in the software.
Thanks
Dale
If you really want to tune it do a series of circle and determine if the error grows . If the error does not grow then you have a backlash issue. if the error is doubled on a double size circle then you can tune your steps. also it is easier if the error is aligned with one axis . if the error is at an angle you may to play with some trig.
Makerbots do not run firmware like Marlin or Repetier. There is no open source to the firmware you can edit and upload. The closest thing is Sailfish and even it has limited editing. My CTC is a clone of the Makerbot and their firmware limitations was one of the reasons I swapped out my logic for the Azteeg X3 I use now. In fact I still have the original board and display.
As Carl has said - 0.0762mm out is about as good as you are going to get. getting any printer under the 0.1mm tolerance difference is pretty much the best one can hope for. Different materials will have different tolerances as well
printed part to printed part should not be an issue - printed part to machined part, yeah, it can be problematic.
The best way I can suggest to cope with the minor issue is to compensate in the modeling stage.. If you know it is going to be K.K mms off in
B direction, then you adjust your model that amount in the correct direction to offset the tolerance difference.
I usually lightly sand the parts if they don't fit, you can start with fine sand paper if difference is only 0.0762mm.
In my experience, such small difference can be fine tuned by adjust your flow rate, by reduce extrusion slightly, your part will become slightly smaller (thinner) after cool down,
OK, not sure if your makerbot still in stock mainboard, I start play with my CTC Dual printer today, I think it is clone of Makerbot replicator dual. and they are really over extruding and noisy. And yes the step motor driver don't have pots on it.
I think I know how to fix the over extrusion issue. So I go to C:\Program Files (x86)\MakerBot\MakerWare\default_configs and find replicatordual.json, you may need to open replicator2x.json for your Makerbot Replicator 2X. And I open the file with notepad++, you can use any text editor to open it. and I changed steps_per_mm for A and B from -96.275 to -88, which greatly reduced the over extrusion problem. I can then fine tune the extrusion by adjust the filament diameter.
I try to search where I can adjust step motor driver current, with no success with any of the keyword I tried, so I went through all code, and find "G130 X20 Y20 A20 B20 (Lower stepper Vrefs while heating)" interesting. It seems like makerbot use G130 to control step motor driver current. So I search all G130 in the document, and found "G130 X127 Y127 A127 B127 (Set Stepper motor Vref to defaults)" under end_start_sequence, so I change it to "G130 X100 Y100 A100 B100 (Set Stepper motor Vref to defaults)", OMG, the noise is so much better, I probably can lower the number further but this already make huge difference.
Keep in mind after you edit this file, you need to restart makerware and redo the slicing, so use a simple model to do the test, otherwise it is going to take long time. I'm not sure 100 is the best value for motor Vref, I need to run more test, but I imagine the best value will be machine specific, so it is best you do your own test.
You can also adjust acceleration (max_speed_change_mm_per_s) and jerk (rate_mm_per_s_sq). I also changed "max_inner_shell_speed": 90, to 40 so that it is same speed as "max_outer_shell_speed". There are also many other setting can be changed, and I'm quite happy with the printers performance after preliminary adjustment.
SoliForum - 3D Printing Community → 3D Printer Discussion → trying to get my printer calibration closer
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