Monday, 24 October 2011

Firming Up

In getting where I have with my printer, I have had to spend some time experimenting with and tweaking the various firmware and software settings to improve the overall quality of my prints. I have made good progress, but I am not finished yet, by any means! (For the record, I am using Sprinter firmware, Pronterface software with Skeinforge, with RAMPS 1.4 electronics.)

Here are my main firmware settings (software settings will be in a following post), which are producing reasonable prints on my machine (your mileage may vary!):

Firmware Settings – Sprinter:


The settings I have had to adjust are in the “Configuration.h” file.

Line 15: Set the Motherboard ID value to match your electronics hardware; I am running a  RAMPS 1.4 so it’s:

#define MOTHERBOARD 33

Line 25 / 26: Define your temperature sensors; I have a 100k thermistor on my Hot End, and no Heated Bed as yet:

#define THERMISTORHEATER 1

#define THERMISTORBED 1

Line 30: Calibrating the steppers; after a bit of trial and error, printing and measuring calibration blocks, etc, I am using:

float axis_steps_per_unit[] = {80.*40./51., 80.*40./51., 3200./1.25, 700.};

(This was originally {80, 80, 3200/1.25, 700} by default for a metric Prusa Mendel with a Wade’s Extruder.)

Line 45: Set the comms baud rate:

#define BAUDRATE 115200

Lines 81 – 83: Setting the build volume; as reported in an earlier post http://julianh72.blogspot.com/2011/08/assembling-y-is-there-always-something.html  , my print range is somewhat restricted, so I am using:

const int X_MAX_LENGTH = 175; // (was 200)

const int Y_MAX_LENGTH = 175; // (was 200)

const int Z_MAX_LENGTH = 110; // (was 100)

I think pretty well everything else has been left as per the defaults. Save the whole Sprinter Sketchbook project in Arduino, upload to the Arduino Mega, and we’re ready to start tweaking the software …

2 comments:

  1. I was measuring travel with a caliper util I discovered that my kit did not come with a T5 belt, but instead came with a 0.2" belt. I used those figures instead, no calibration necessary (well, except for the extruder)

    Backlash is another story.

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  2. pnit,

    Since I haven't been able to see what quality others are able to achieve on their machines first-hand (other than photos etc that they paste on their blogs and the RepRap wiki and forums), it is difficult for me to know how my quality stacks up. However, suffice to say that I am very happy so far, but I can also see there is still room for improvement.

    For controlling backlash - the main thing as far as I can tell is to get your belts tightened really taut - as Triffid Hunter said in a comment to an earlier post http://julianh72.blogspot.com/2011/10/cheers.html :
    "They should make a tone of 100hz or more when plucked like a guitar string. That's a low G sharp for the musically inclined"

    I found a really effective way of tightening the belts was using plastic cable ties - see
    http://julianh72.blogspot.com/2011/10/youve-got-to-admit-its-getting-better.html - I'm not sure if my backlash is "as good as it gets", but it is a whole lot better than I was able to achieve before!

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