Print 3D

Edit:23 févr. 2021, Cre:21 juil. 2015

Fisher delta

The Fisher Delta was a compact, low cost, delta printer kit issued by RepRapPro (still sold by RepRap Ltd -this is another company).
I bought the Beta version in May 2015, the V1 version was issued in October 2015.

Presentation

This printer benefitted from the Delta geometry and Delta Calibration software implemented by David Crocker (DC42) for the Duet Board.
The Duet board does include a web server done by Christian Hammacher (Chrishamm) which makes this board really an ‘all in one’, as no external computer is needed for Internet Web server. The only drawback compared to Octoprint it is less easy to install a camera.
If your router/switch is configured to use DHCP, the connexion to the printer web server is entirely automatic.

The ultimate usable area specified is 150mm in diameter and 180mm height (at the middle only). In practice, it is lower than that for miscellaneous geometrical reasons - see my note on lengthening the arms.
It is built with printed part and acrylic panels and parts (acrylic was also used for effector and extruder, now this is abandoned).

There was no Heatbed, neither native nor in option (a heated bed was later proposed as an option). The bed surface is done with BuildTak ™.

Resources

I made a technical analysis of the Fisher design.

Modifications

The version I have is the first beta version and while it work well, there are some points which, in my view, were needing improvement, or were not working:

Hardware modifications:

  • Added a switched plug to start/stop the machine (imperative for safety: there is no on/off switch on the Fisher)
  • Reinforced the structure with wood lath and done modifications to the idlers
  • Made an aluminium bed as the original acrylic bed was really warped, which drives to many problems
  • Set the spool support on top while modifying the filament route for a very direct path, which also allowed bowden length reduction
  • Replaced the weak extruder by a geared extruder of own design
  • Insulated with polyimide tape the hotend heating block, as the part cooling very efficiently cool this block
  • Printed new arms after having broken one and lengthened them
  • Replaced the SD card by a faster one to double the transfer speed
  • Added rubber feet
  • Glued the fan on its support, as vibrations were separating it from support

Ultimately the Fisher was dismembered and its components were used to build an enclosed printer of own design the Lily, which also have a larger usable volume.

Software modifications

  • Modified the configuration file
  • Modified the web interface file for better viewing
  • Modified miscellaneous calibration macros according David Crocker recommendations.

What I would like to had, but was not doable then:

  • Having a pause/resume button on the printer (firmware evolved and it is possible now and I did that on the D-Box)
  • Aborting a print shall not shut down the heating - could be solved in a macro now

Fisher Delta is still sold by RepRap Ltd

I discovered recently (February 2021) that the Fisher is still on sale by RepRap Ltd, which gives me mixed feelings. Nearly six years later, the Fisher is definitely not a good printer by today standards and a lot of Chinese printers do better.
The Duet Board which was a major asset in 2015 is still the best board you can get and have improved continuisly. Firware of the original Duet board was updated till early 2020, wow! There were small evolutions, the extruder is geared till the V1 and a heated bed is now available as an option. The effector is no longer in acrylic but 3D printed. The stepper drivers are the ‘silent’ ones on the now supplied Duet Maestro. And it seems that the power of the heating cartridge was reduced, as it was fairly excessive and difficult to control.
But what about the remaining problems?
The very brittle arms, the too flexible panels, the single(and noisy) fan, the thin PLA parts which develop cracks, the non flanged idler which make the belt rubbing on parts. The acrylic warped bed. There is still no power switch which is dangerous. The power connection plug is fragile (Mine created a short-circuit, but the power brick have a safety which preserved it from damage).
Laser cut acrylic was a BAD thing then, it still is real bad (developing cracks due to the laser cut process). Most of the critics I issued then are still valid as the printer evolved marginally.
PLA is not a good material for printers. With time, it develop cracks and on the Fisher the structural parts are tiny. When I dismantled the Fisher to build the Lily with its components, some parts had already developed cracks and were on the way to fail. The alternative (as now adopted by Prusa since years) PETG is much more durable but a lot more flexible, which needs entire redesign of a printer and probably more material. Also, PETG may be a bit longer to print than PLA.
The good news is that you can still built my Lily with the components of a Fisher, which is a much better and durable printer (with twice the really usable volume). You can tell that I am biased toward a printer I designed, for sure but this printer is now running since 5 years, see the dedicated page. No Fisher could have done that without very serious upgrades.

A note about the board. Fisher is now supposed to be sold with Duet Maestro but this boards seems no longer built due to manufacturing difficulties. It is replaced by the Duet 3 Mini 5+, a nicer but more costly board (by 20%). Depending their stock, the manufacturer may have to change again the board. There is a thing badly needed since years on the Duet Mini, now a 12V converter is on board and you can more easily use 12V fans, easier to find than 24V fans or the very exotic Fisher 19V fans (used instead 24V because 18–19V power brick are somewhat standard).

(c) Pierre ROUZEAU
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Page mise à jour le 23/02/2021 13:47