Upgrading the Flashforge Finder

These are some musing on upgrading the Finder - not a step-by-step guide. It is impossible to know what your printer will be like and what supplies you will be able to source so this is to be considered and 'inspiration' with a few hopefully useful bits of info along the way!

The Finder (Version 1 - with the internal power supply) was my first 3D printer. I picked this up as an open box deal on eBay and it was my 'access drug' to the world of 3D printing.

I many ways it was a great choice - simple. No heated bed. Just printed PLA and printed out of the box with the Flashprint slicer. Great.

Some of the features such as WiFi connectivity were missed opportunities especially as this thing has a 32bit ARM based controller. The WiFi allowed you to send a file and know what % completed and that was about it. Oh, and you have to connect to its own peer to peer network to do it so no browsing the web while you wait!

Friends with more open hardware raved about OctoPrint (https://octoprint.org) and rightly so. A wonderful way to control and monitor your printer running on simple hardware and open source. Having experimented with a Pi in a box I decided to integrate that and some (I hope helpful) tips follow.

The next step was to add a heated bed. No spare pins for this on the control board and closed firmware meant I needed another solution (that didn't involve stripping the brains out and replacing them!). I added a 220 x 220 bed for an ANET A8 which was cheap and some borosilicate glass controlled by a modified STC-1000 and switched by Octoprint. Manual adjustment of the temperature but since this little printer just stays loaded with PLA anyway that is just fine.

My first thought was to print an adapter to connect the new bed to the existing Z axis - I set that going for 15 hours on my CR-10 in lovely black Prusament ASA only to come back to find that it had warped and removed the top few microns of my print bed - GBP40 fail! So I ordered a 3mm sheet of aluminium and used the old bed as a template - drilled 3 holes then used the new bed as a template - drilled 4 holes and a bunch of M3 nuts and bolts later - all done and the bed levelling works just like before.

I run Octoprint (https://octoprint.org) on a Raspberry Pi Model 3 B+ (https://www.raspberrypi.org). Plenty of space inside the back case of the finder to mount it - I printed the base of a case from Thingiverse and then glued that in to hold it.

The finder (v1) has a computer style power supply so I tapped the 5v and Gnd lines and fed power directly to the GPIO pins. You can see the slot that I Dremeled (is that a verb?) to pass the ribbon cable though the the Pi Cam at the front. The case is a mash up of the laser cut thing it came with and a little bracket that I printed.

Octoprint set up...

Here is a list of plugins that I find helpful with a note about each:

FlashForge Plugin (0.2.6) - Sets up the connection parameters for you and gets you connected!!

Cura Thumbnails - assuming you are slicing with Ultimaker Cura (more on that later) you might enjoy having the little thumbnail images too.

Exclude Region - for when one of the models detatches from the bed and you want to finish the rest and stop printing just that one.

Floating Navbar - aesthetics onlly

OctoPod Notifications - get your phone to receive notifications of print status

PSU ControlPrint - used to control the heated bed

TimeGenius Plugin - accurated ETAs

Simple Emergency Stop - because I also run a CNC mill and know the value of of a whoops button!

Themeify - aesthetics

Touchtest Plugin - help setting bed level

Octoprint Gcode Scripts - These took some time to perfect and need to be reviewed in the context of the CURA start and end code!!!

Before print job starts

M146 r255 g0 b0       ;Set the LED to red<br>M907 X100 Y100 Z100   ;Set stepper current to 100pc
M80                   ;Turn on heated bed PSU
G4 S180               ;Wait for bed to heat
M146 r255 g255 b255   ;Set the LED to white

After print job completes

M148 S1           ;  Play a little tune<br>M146 r0 g255 b0   ;  Make the LED green
M81               ;  Turn off heated bed PSU

After print job is cancelled

G1 Z140 X0 Y0 F400    ; Move build plate fully down<br>M104 S0 T0            ;  Set hotend tempt to 0
M81                   ;  Turn off heated bed PSU   

After print job is paused

{% if pause_position.x is not none %}<br>; relative XYZE
G91

; retract filament of 0.8 mm up, move Z slightly upwards and 
G1 Z+20 E-0.8 F4500

; absolute XYZE
;M82
G90

; move to a safe rest position, adjust as necessary
G1 X0 Y0
{% endif %}

Before print job is resumed

{% if pause_position.x is not none %}

; absolute XYZ
G90

; reset E
G92 E{{ pause_position.e }}

; move back to pause position XYZ
G1 X{{ pause_position.x }} Y{{ pause_position.y }} Z{{ pause_position.z }} F4500

{% endif %}

NB these settings assume the Octoprint Gcode scripts in the previous step!!

Use Marlin flavour GCode. Honestly, this took me some trial and error.

Start Gcode

G28  
M132 X Y Z A B
G1 Z50.000 F420
G161 X Y F3300
M6 T0
M651
M907 X100 Y100 Z40 A100 B20

End Gcode

M104 S0 T0   ;  Set hotend tempt to 0
M132 X Y A B
M652<br>

I struggled to get the extruder offset setting to stick using the Flashforge Finder's LCD menu so I have been using the Z offset setting plugin (by fieldOfView) for Cura to set my nozzle height.

You will need an auxiliary power supply as the common 12v 220x220 PCB heaters draw around 10A or 120W.

Meanwell make reputable units for about GBP20 and this one (Meanwell LRS-150-12, 150W DC12V) fits neatly under the bottom panel next the original supply (which also cools both). I ran a second mains lead via a strain relief out of the back of the printer. I made some little stand offs which cemented nicely to the base to hold the PSU.

A 3.3V relay module with an on-board optocoupler (see AliExpress, ebay etc) is handy to control the secondary PSU via OctoPi (see the plugins section).

Temperature control was interesting. The heated bed has an integrated 100K thermister (NTC) but all the cheapo temperature controllers seem to have 10K NTCs. These STC-1000 units are ubiquitous but NOT STANDARD and it is pot luck as to what electronics you are actually getting. An NTC is usually set up as a potential divider across the supply with a similarly sized resistor. I decided (rather than having to cement the new thermister to the PCB) to replace the 10K resistor in the divider with a 100k one. Now this IS a hack - pure and simple - and I know that the temp-resistance curve of my 100k NTC is not the same as the 10k one but it is very close and since my bed is operating in a narrow range of temps I was able to adjust the offset on the controller a few degrees and perhaps by dumb luck it runs bang on.