Fixed the bed levelling - fault in the grid code.

Had it printing but filament not sticking to bed - didn't seem hot enough.  Should be 100°C but it wasn't that hot to the touch so the thermistor calibration must be out.

Increased the bed temperature and it's sticking fine now.  First layer speed of 40mm/s subsequent layers at 120mm/s.  It is NOT quiet!!  But it's working

Had to reduce speeds a bit to 30mm/s and 100mm/s.  Also, increased temperatures.  Seems to be printing alright now after 8 attempts

This printer has a number of minor faults though seems to print well enough.  The print bed is not really well supported - it still wobbles a bit.  It could do with having the same arrangement as my Mini printer with a rectangular framework with wheels running on the four uprights.  It also could do with the pulleys replacing with better ones as I think they are the main cause of the noise.  I may consider rebuilding it after I've finished the Giant printer.  I have a number of pieces of 500mm long V-Slot extrusion which I can use.  I might also change to CoreXY for simpler construction.

Latest upgrade was to change from 12v to 24v operation with the Duet WiFi control board.  This has produced a remarkable improvement - greatly reduced noise and much increased Z speed.  There is still some noise from the pulleys and vibration of the print bed so a major rebuild is planned.  In view of this I think I shall call the new build "GinaRep Titan Mk2".  This will not only have a completely new frame instead of the acrylic and wood box construction (together with new Z drive and CoreXY) but also a new X carriage with interchangeable hotends.

Some parts of the original Titan will be re-used - the X and Y rails which are the right length for the new version and the acrylic sheets will provide a fume cabinet.  I shall probably need to re-design and print new side and top parts to hold the acrylic sheets.  The Y carriages can probably be reused but it would be no problem to design new ones if necessary.  I shall use all the motors and the "E3D Titan Extruder" (the name is pure coincidence - I named my printer before E3D sold their extruder). 

The rebuild will also be an appropriate time to change the print bed heater to the mains version with over twice the power.  The 24V 300W bed heater takes 4-5 minutes to heat the bed to ABS/ASA/PETG temperature and the new heater should reduce this to below 2m.  The 24v 60W hotend heater takes only around a minute to heat the hotend so the bed heating is looking dreadfully slow.

Here is the new power wiring diagram for the Mk2.  The ATX PSU is used to control main power and uses the +5v Stand-By to power the Duet WiFi control board in standby mode.  The Duet switches the main power via the PS-ON control line of the ATX PSU.  The standard +5v line from the ATX PSU operates a Solid State Relay to switch on the main 24v PSU for the Duet board and thereby all the stepper motors and the hotend heater and various fans.  A second (higher current) SSR is used to switch the mains to the 240v bed heater and is controlled by the bed heater output from the Duet.  Advantage is taken of the ATX PSU having a 12v output to power the fume extraction fan which is 12v.

It may seem odd to use a relatively high power PSU for the 5v standby supply but I have lots of these ATX supplies recovered from old PCs and it has a built in control of the main power lines.  The main +5v line provides control voltage for the SSRs.

Wire frame diagram below shows location of rails required for the MK2.

1. Rails required = 19.  Mainly but not exclusively 20x20x500mm.
2. Rails on current printer = 3.
3. Spare 20x20x500mm rails in stock = 6.  Also have 20x40x500mm and 20x20x550mm rails.

Overall, nearly half the number required I have already and may be able to use the other two.  But before ordering new rails I need to work out exactly how everything will fit together - some rails may be a little shorter and want cutting to exact length.

This diagram shows the Z carriage and how it runs on the corner uprights of the frame.  Only the slots used for the Z carriage wheels are shown in the corner uprights.

To be the same size :-

1. Corner uprights will be 600mm.  4 off.
2. Bottom and top horizontal rails will be 500mm.  8 off  6 available.
3. The Z carriage will consist of 2 500mm rails with threaded holes and 2 460mm rails. 
4. Y rails are 500mm.  From original.
5. X rail is a little shorter than 500mm.  From original.

For the order :-

1. Corner uprights will be 600mm.   4 required.
2. Bottom and top horizontal rails will be 500mm.  8 of 6 available.  2 required.
3. The Z carriage will consist of 2 500mm rails with threaded holes and 2 460mm rails.  All required.

The parts for the frame and Z carriage have arrived so now it's a matter of connecting it all together.  The corner joining pieces came a few days ago.

The Mk2 will use the standard timing belts and pulleys for the CoreXY drive system and also the common trapezoidal screwed rods for the Z axis.  These will be driven by a timing belt and pulleys from a single Z drive stepper motor.  I now have all the parts for this.

Wanted the 24v 15A PSU that was powering the 24v bed heater for my Giant printer so I've swapped the bed heater for a mains voltage one controlled by SSR and have connected that instead.  Titan is now using the mains voltage bed heater and printing fine.  Bed heating is now much quicker.  About a minute instead of four minutes.

This shows another problem with the print bed mounting.  But in spite of this the correction still works.

Been looking at how I could arrange dual extruders and hotends.  Having tried Bowden feed a couple of times and always found it unworkable I shall be going for both extruders mounted on the X carriage.  The E3D Titan extruders have smaller and lighter Nema 17 stepper motors available with them which should help with the weight/mass.  The extruders themselves are very light and efficient.

I want to get the nozzles as close as possible and this is what is causing the main difficulty.  Firstly I thought of putting the extruders face to face on the front which certainly gives nice close spacing but it would then not be possible to take the covers off for clearing filament blockages.  E3D provide a mirror image extruder for this very purpose but that still leaves problems.  I see E3D have a forum and I have applied for membership so I can see how others have solved this problem.

Now a member of the E3D forum and had a good look through the "E3D Titan Extruder" posts but found nothing about dual extruders so I'll probably post a query.

I got my pre-publication copy of my 3D printing book today.

Do you recognise this in figure 1.11?

Looks a bit familiar

This printer has been superseded and now dismantled with parts used in replacement printer called "GinaRep Concorde".