"GinaRep Giant" 3D Printer - 2021

[Gina]

This is a home built 3D printer designed for printing very large objects.  Things like a micro sized observatory, garden ornaments, chandelier with steam-punk theme.

 

The outside measurements of the "box" are 740mm x 660mm x 1m high.  I was using ABS when I first designed it so the box consists of an extruded aluminium frame with clear acrylic panels for use as a fume cabinet.  Now I use only PLA and fume control is no longer an issue.  The bed is a 500mm x 500mm x 5mm aluminium plate with a mains powered 1200W heater pad stuck to the underside.  I expect printing volume to be 290mm x 290mm x 700mm high.

 

I'm planning to have the bed moving up and down for the Z axis.  In one of my earlier versions I had a moving XY carriage and fixed bed but that proved impractical.  The Z drive will consist of three trapezoidal threaded rods with 1mm pitch driven in unison by one stepper motor, 3 timing pulleys and timing belt.  Adjusters will be provided on the nuts for rough bed levelling and fine bed levelling will be automatic using the software in the Duet 2 WiFi control electronics.

[Gina]

With the very long timing belt needed to connect the 3 Z rods and stepper motor plus the problem of where it would run, I've decided to go for 3 separate motors.

Edited November 17, 2021 by Gina

[Gina]

Z probing both for normal operation and automatic bed level compensation will make use of a piezoelectric probe attached to the nozzle.  This works be allowing the nozzle to move minutely with respect to the X carriage.  The bed is moved slowly up to the nozzle and a signal generated when bed and nozzle touch.  I'm talking about a minute fraction of a millimetre.

 

See this link :- https://www.precisionpiezo.co.uk/

[Gina]

Taking a cue from my Creality Ender printers I have reconsidered Bowden feed for the filament.  The only disadvantage I can see with Bowden feed is with soft/flexible filament.  I've used this in the past but see no need for it in my Giant printer.  Indeed I expect to keep to PLA.  Also, I shall be using 2.85mm filament as I have a significant stock of that size.  Mainly PLA but also a lesser amount of PETG and some ABS though whether I actually use the ABS is doubtful.

 

Using Bowden feed reduces the mass of the X carriage considerably and also reduces the cables.  Additionally, it moves the extruder to a more  convenient location. 

 

As a result I ordered an E3D Volcano hotend with Bowden coupling as I didn't have a Bowden type nor one for 2.85mm filament.  Otherwise I have my own hotend build designed for large nozzles and super-fast printing.  My current needs for the Giant printer don't go this far and suit a smaller nozzle.

[Gina]

The hotend for Bowden coupling has a longer top part as compared with direct feed.  This has meant the "groovemount" top won't fit the PrecisionPiezo body.

 

 

Won't fit!!

 

Answer to this was to design and print my own piezo body.

 

This has the two webs (top and bottom) that hold the moving part.  The latter has been made higher to take the taller "groovemount" and the fixed outer casing to match.

Edited November 17, 2021 by Gina

[Gina]

Standard direct feed piezo sensor.  The " groovemount" at the top fits in the extruder.

 

This is the sensor board :-

 

The probe consists of the two body halves bolted together to hold the top of the heatsink (called "groovemount") then the sensor and finally the top which clamps the sensor onto the body.

[Gina]

Piezo body altered to allow screwing to the X carriage including a third screw.

 

Heatsink and Volcano hotend added.

 

Attached to front plate of X carriage.  Several changes of X carriage have occurred in getting to this design.

 

Parts cooler airduct added.

 

Angle view of CAD assembly.