New electronics: RAMPS-FD and DRV8825 drivers

I got some new electronics a couple of months ago! I was hoping it would help me solve some issues I was having with the RAMPS 1.4 board which runs on an 8bit Arduino Mega.

The biggest issue I was facing was momentary stalling/ pausing when printing curves and circles, this was causing quality issue because whenever the print head would stall plastic would still ooze out.

I never had this problem when I was using the Megatronics board which uses the same ATMega 2560 chip, My bad for blowing up the ftdi chip I guess. :(

Anyway! Something that has interested me for a while is 32bit 3D printer controllers, there are a few options out there, the Duet http://reprap.org/wiki/Duet which at first seems a bit pricey however after a little bit of research is actually quite good value, it has all the stepper drivers built in with the capability of 1/32 microstepping  and the possibility to expand, it's a tidy all in one board with ethernet and SD card reader built in too and the firmware is in constant development. The downside for me was if anything happened to the drivers I'd be a bit stuck and would have to either solder new components on or get a whole new Duet board if it couldn't be repaired (highly likely with my lack of soldering skills). That's when it would start getting quite expensive.

So then I started looking at the RAMPS-FD board (RAMPS For Due)
http://reprap.org/wiki/RAMPS-FD
This board really appealed to me as my ultimate goal is to create an all in one system using a Udoo.
http://www.udoo.org/

If the name doesn't give it away, it's been designed to work on the Arduino Due, a 32bit Arduino that uses the AT91SAM3X8E micro controller. I think it's still under development, it's currently on V2.A but I bought V1.A from Geeetech a couple of months back, sooooo I'm not sure what changes have been made since. So far there haven't been any fires though. It's compatible with most 3D printer stepper drivers on the market today and they can easily be replaced.
From looking through the forums and various other posts people had made regarding the quality of the board from Geeetech I wasn't expecting much for my £18 but I have to say the soldering quality was actually quite good and there weren't any bent pins either. The only things I did change were the fuses for my own peace of mind really.

The first big challenge I had was finding firmware that would work with the Due, the first one I tried was the one on the Geeetech wiki.
http://www.geeetech.com/wiki/index.php/Ramps-FD#FILES
It's a modified version of RepRapfirmware for the Duet and is uploaded via the Arduino IDE.
I didn't change anything with this just uploaded and made a note of the baudrate but once uploaded I couldn't connect to the board through Repetier-host, Cura or Simplify3d...very weird!
The same happened with the Repetier for due firmware, I spent a while searching online but couldn't find the reason so scrapped those two (If anyone can shed any light on this then please do).


I then decided to try aprinter, this has been rewritten from the ground up in C++ and is compiled and uploaded in linux using the supplied script. All configurations are made in one main config file, it's very easy to use and once your build environment is setup It's very easy to modify and upload to the Arduino Due. I had a few minor noob issues but Ambroz was really helpful and responsive.


Useful info
A few things I have noticed with this firmware are:

• It doesn't like the default start gcode in Cura, anywhere in the code where it says {travel_speed} it needs to be changed to an actual value otherwise the printer returns an error and won't print.

• When you start a print and the printer prepares the hotend and heat bed, the temperature read outs in the communication console stop until the print actually starts so you never really know when the print is going to start.

Both minor issues really but worth mentioning.
Check out the Git for more info, (link below) Ambrop has done a really good job with this, I can't wait to see more features to be added.
https://github.com/ambrop72/aprinter


Once the firmware was all setup and my laptop was talking to it and I could control the stepper motors using my current blueice stepstick drivers, I installed my shiny new DRV8825 stepper drivers, They are capable of 1/32 microstepping, are a direct replacement for A4988 or A4982 drivers, support up to 2.5amps and along with my new control board make the printer run very smoothly and a little more quietly.

Check out this video on youtube to get an idea of the noise difference.

https://www.youtube.com/watch?v=tGd2ulVkDTM


I will be putting some on Ebay soon so stay tuned.


Here's a link to the printer in action, It's a corkscrew glass printed in T-glase.

https://www.youtube.com/watch?v=CXgFLbCsfT8


I've added some pictures of prints since the upgrade.

The cup from the video

Open RC truggy tyre printed in flex filament. you can check it out here:

http://www.thingiverse.com/make:87781#comment-496059

 This was a test with ABS, historically I've been unable to overcome warping but this went well.

I put the heat bed up to 130 degrees and extruder was at 240.

  

Printed with old electronics

Same print with RAMPS-FD

(Check out the difference in the curved corners)

Dual extrusion test...very tricky print.

Mine and Mark's printer build

Our Prusa Mendel I3 machining and building process

I’m not going to go through the entire build process but here are some photos and notes on various parts of the build.

All machining was done Mark's mill and lathe.

Here is a test print bed bracket made out of wood, it has mounting points to bolt straight onto four 8mm pillow blocks.

Once the jig for the mill was tested and proven to work we made it out of aluminium.

These are the mounting blocks/ corners for the y axis frame.

They have 10mm holes for M10 stainless threaded bars and 8mm holes for the 8mm stainless round rails.

Y axis assembled

Brass trap nut being turned down on the lathe to fit an SK16 rail shaft guide as it was originally 20mm...I think.

One side of the Z and X assembly

8x1.5mm trap screws and brass nuts much less play and friction than standard threaded bars and nuts.

 

Test rig for Z axis

X axis brackets

Printhead assembly

 In the end the main body of this was made out of three separate bits.

Print bed

This has been changed since but that's something for another day.

And as you already know here is the finished product...ish.

Hi All!
This is my first blog post...EVER!
I've been 3d printing for nearly a year now, I got my first printer in April 2013 as a birthday present to myself, It was the SUMPOD basic... there were a few problems and limitations with it, I made my own modifications and it was a good start and I made some pretty cool things. :)

 Tablet stand

 Experimental RC car wheel...never used

 connected an LED strip to the printer

geared extruder added

After a month or so I showed a good friend and engineer how it worked and what it was capable of, at this point we decided we could do better :) and decided to start designing our own, we chose the Prusa Mendel i3 as a starting point and went from there.

The entire design and build process took about 3 month, we used as many standard CNC parts as possible and came up with this.

Really messy I know, but this was still work in progress. It's very sturdy and all mechanical components were as good as we could justify, things like the trap screw nuts being made of brass, all the belts and pulleys being high quality anti backlash, all parts that would normally be 3d printed were machined in aluminium, including the extruder assembly. We also decided to buy E3D V5 hotends, (In my opinion one of the best hotends available).

This is the basic setup I've been using since September now, I'm constantly tweaking and modifying things but it's basically the same. Since this photo was taken I've added a water cooled dual extruder (still only using one at the moment though), added my own geared bowden extruder that uses bevel gears (available to download here: http://www.thingiverse.com/thing:239085). 

Replaced the heated bed for a 240V silicone mat and anodised aluminium sheet and made a base to enclose all the electronics and water reservoir.

These are all upgrades I plan on blogging.

Here are some pictures of projects I've worked or am working on.

 Displaying values from a thermocouple board my mate made

 I just thought this was cute

 using a raspberry pi and 7" touchscreen to control my printer

 printing my bevel gear extruder

 some fails

Print head design my new compact print (still in design process)