Geeetech i3 pro B issues and questions

Greetings,

I recently purchased a Geeetech i3 and am experiencing some difficulties. The first is the extruder stepper not turning. Every thing was working properly until I calibrated my E steps. I was experiencing what appeared to be over extrusion so I did some research and followed the instructions for calibration. To my surprise I was 3mm short on the 100 mm test. After calculating the new E step parameter I flashed the eprom from the configurations tab on Repitier Host. When I closed the program and later restarted it the extruder would no longer feed. I went to the configuration tab and hit restore to factory default and all worked well again. I decided to adjust the calibration in the slicer settings under extruder multiplier. This again worked fine until I shut down the program and restarted it? Now every time I print I have to hit the restore to factory default settings in the configuration tab to get the extruder stepper to work?

I went to the (dread of dreads) Geeetech support forum to research the problem and found a sticky at the top of the extruder section. The post is from the tech department stating that this is a Marlin firmware problem and to download the attached file and re-flash the firmware. My problem is I have know Idea how to do that. There were some other references in another section about firmware that stated you should download Arduino 1.0.1. I have also looked at the wiki and the instructions are for configuration from scratch. The file that was on the form is a folder labeled Marlin filled with a lot of files with no instructions on how to load this preconfigured file to the Arduino compiler. I am at a loss here as to what to do. The board is a gt2560 with ramps 1.4.

My second issue is over extrusion. Every thing I have read about calibration has no information about the nozzle itself. I was under the impression that I was supplied a .3 mm nozzle end but am now wondering if I received a larger one by mistake. When I manually extrude some plastic and measure it with my micrometer it is .0157 which is .4 mm? There are no markings on the nozzle and I am reluctant to heat the hot end, remove the nozzle and burn out the plastic. I do not have gage pins small enough to measure the diameter of the hole. I suppose I could try the reticle magnifier with the .001s scale?

As a machinist and having built a few cnc machines I have some reservations about the Z axis design of the I3 variant along with some other mechanical issues that I feel should be addressed. I suppose I should post those in the mechanical section along with some of the modifications I have already made.

I have two other minor questions. The first is about Home offsets: If you are familiar with a cnc the machines home position is at the x and y limits ( or end stops as they are referred to on printers?). From the machines home you would then set a work home offset at maybe 10mm from x and y for example. Is there a place to do this in Repitier Host, Slicer or Marlin with out having to edit the g-code for every file? The end stops are too far from the corner of the platter and I thought that changing the mechanical layout for the stops seemed like a patchwork fix that could be better solved by software?

Lastly, imagine if you will you are printing a box with no top. You design the box with a solid 3 layer bottom and top and a min of 3 layers for the perimeter. When I draw the box I have tried to make the thickness of the sides to be exactly 6 layers or less dimensionally. When I print the box it will do three inside and 3 outside layers and always followed by an infill layer in the center. Consequently there is no room for the center infill and the extruder will occasionally stall from too much back pressure. My question here is this a result of over extrusion on the outside layers and how can I prevent slicer from infilling between?

If you made it this far through my long post ....Thanks! If you have any input I would greatly appreciate the help. This started as a father son project in hopes of sparking some greater interest in drawing and programing for my son. He is 14 and has been excepted into an engineering academy for high school. I am hopping to give him a jump start and help to make the math more interesting through real world problems. He has ideas of things he would like to make and he will suffer through the means to get to the end (I hope). I told him that tenacity and perseverance start here!

Thanks Again,

Jeff K.

You need to change the value of the extruder stepper in marlin using Arduino 1.0.1. It is the line that states the stepper values for X, Y, Z and E. Be sure your board is selected in Arduino. Open up the Marlin pde file. Click on the configuration.H at the top. Make your changes. Make sure your are connected to the board with correct baud rate through usb and then send. It will compile and if no errors will flash your board.

Tom's Guides are good. Here is one for firmware [www.youtube.com]

Don't do anything else until you fix that as extrusion steps are a key to getting consistent material deposition. As a rule don't measure the raw material extruded. Instead print a calibration piece with known dims and use that as a basis to guage how accurate your machine might be. The Wiki here and other places have cal parts and methods. You have an entry level tool and there is a big variance in what is possible from the tool. Think of this as a Harbor Freight mill, rather than a Tormach. It's certainly not a Mazak.

Offsets aren't widely used in 3D printing, the endstops are at the mechanical positions for the machine. There should be an area in your slicer to add codes at the beginning and/or end of every file you slice.

When using arduino ide to flash to your board, eg ramps 1.4 and mega, the board you would pick is arduino mega 2560. one of the main reason recommended to use v1.0.x because other boards can be added without any issues.

I suggest you to try flashing the preconfigured marlin firmware found/requested from geeetech forum or you could use this config.h. Bear in mind that this one is marlin 1.0.1 (I think. I don't know what version actually) and see if there's any differences especially in accel, steps and some other thing

for home offsets, I also suggest you to enable eeprom support, enabled from firmware config.h too, enable both chit chat and eeprom feature, then you use m206 command. I've been playing lots with z axis home offsets due to the initial layer height varies in time. Currently I'm waiting for some other parts to enable me using auto bed leveling (But I need to know the procedure first before converting into auto bed leveling)

When everything is homed, the head/nozzle will sit outside of the print area/glass/bed and this is good (in my opinion)

To measure nozzle diameter, extrude the plastic at very slow rate at about 1mm/s. Also ensure that you already used the correct extruder step value. Once you're done extruding, measure it with caliper

The cube, you don't have to manually model it as hollow, I use cura, so I just make a cube, make infill 0% and untick the top fill. But basically you have mechanical misalignment. Measuring the cube when you're having misalignment would give you more unnecessary adjustment and works. The wall is the parameter you should be fiddling with like a multiplication of your nozzle size would be good

Edited 1 time(s). Last edit at 07/26/2015 02:22AM by sarf2k4.

Quote
sarf2k4


To measure nozzle diameter, extrude the plastic at very slow rate at about 1mm/s. Also ensure that you already used the correct extruder step value. Once you're done extruding, measure it with caliper

Good post.

With the variance in plastics composition and how they each cool and measuring tools it's going to be a challenge to get an accurate reading with a .1 mm window of tolerance. It's possible though is appears this particular machines has more pressing issues than that much nozzle variance.

I saw this info posted way back in time I think around 2014, posted by someone who made his own 3d printer model, probably the creator of mendel90 (I forgot). He said to extrude using this method. I did and got a good measurement. Of course, calibrate your extruder steps first

Thank you all for the input.

I would like to clear up a few points to be sure I understand the direction to take. Putzer, I am using Repetier Host and slicer for the printer. In The host software it has a configuration tab that allows you to adjust xyz and e steps. After you adjust it allows you to flash the board from there. Once I flash the board it works just fine. When I reboot the software the settings are still there as I left them but the extruder motor will not feed. I then hit the button to " return to factory defaults" and the extruder motor worked. When I again reboot the software the factory settings show up as they were left but the extruder motor again dose not work. I have to hit the factory default setting every time I boot the software to make it work? According to Geeetech this is a marlin firmware problem. I downloaded a preconfigured file from them to replace the original preconfigured file. The file, once unzipped is a folder named Marlin filled with 60 or so H and CCP file types? I have not a clue how to, or witch file to load. I realized after reading a wiki that I needed to down load Arduino 1.0.1 but again there are no instructions on how to update from another preconfigured file? The only instructions I can find is to configure each field from scratch. Sounds like a disaster waiting to happen.

Sarf2k4, When I open Arduino I selected the appropriate board but should I already be connected to the board first? Then once connected how do I select the correct files from the Marlin folder that I downloaded? Am I to assume once the configuration is compiled it just overwrites what is currently on there? If this is correct I don't want to go off half cocked and screw everything up. I have visions of a small problem turning into a huge one!

As for the diameter of the extruded plastic, is the conscious here to correct the e steps and then adjust the nozzle size in slicer to reflect the diameter of the extruded plastic? I assume it would then be prudent to do a printed cube as suggested.

Lastly, if I am understanding correctly, there is a section in slicer that has "special g-code" at the beginning and end of the program. I should insert some code there to set the x y 0 to be offset from the off the glass park position at the start of the job.?

Thanks again,

Jeff K

You need all the files in one dir. Then open marlin.pde file using Arduino. At the top you will see the list of files. Click on the configuration.h file Then you can edit it. #define DEFAULT_AXIS_STEPS_PER_UNIT line is what you want. There are four values separated by a comma. X,Y,Z and E. E is the value you want to change for stepping in the extruder. Printers vary so much I don't know the value of yours. There are sites that will show you how to calculate the value when you calibrate. I use pronterface to calibrate, There is a Button to extrude a certain amount of filament. You mark 100mm on the filament and see how much is fed through the extruder. Not what comes out but what goes in.

You could use the configuration.h file I posted before, it is the same throughout most geeetech printers that I know of, their prusa lineage because they've been using mk8 extruder (some model are not), so I assume the motor gear has same diameter thus you can use the steps/mm, accel and some other bits you can find in the configuration.h file.

It doesn't matter whether the board is connected or not when selecting the board type, but the com port does need the board connected first before selecting com port. What I mean selecting correct board in marlin configuration.h also was to open the configuration.h file and read (most of them) there, you will find some series number there like this

#ifndef MOTHERBOARD
#define MOTHERBOARD 62
#endif

There's a list of boards on top of them, just change the number. Mine is sanguino, pick the correct board for yours. Also don't forget your steps/mm values,

The above code however are different compared to the latest marlin. I believe in the latest marlin, you don't have to specify your board type instead the marlin will pick the correct one for you

The nozzle diameter is crucial for slicer to correctly position your printer head at the correct position. And yes, measure the extruded plastic that came out of the nozzle like the method I instructed you to before with caliper (I did before too and it does work).

Setting offsets in start/end of gcode in my personal opinion, are not recommended. I would recommend you to use the eeprom home offset. Here is my setting for stock hot end; x0 y-20. with my e3d v6 and my e3d mount is x-1 y-20. I didn't supply you z axis home offset because yours can be different. Why I didn't recommend you to use start/end gcode because marlin didn't let you to travel each axis over the max position. Also you have to include the offset setting on every slicer software that you will be using/test in the future

For example when y axis are homed, it can travel up to about 200mm max, but when homed your nozzle will sit outside of the print bed.
So by using eeprom, you don't have to worry much, it will move to proper position when all axis are instructed to go 0 position (after homed)

Hope this info helps