Wallace lost his head

The very first prints on new 3d printers tend to be somewhat nearly perfect here. Which is strange because first prints on new printers should look ugly, messy, not proportional and overall malformed. What then after some time happens is even more strange. With tweaking and tuning they start to look ugly and all of the above stated.

So after a very nice 0.5mm thin wall print and the Groot bust I ran into alot of troubles with the Merlin Hotend and the Wallace printer itself.
After these first unmatched prints everything went downhill. I will list it in non-chronological order…

I Rack

As I started out with a 38 tooth rack instead of the original 40 tooth rack I had my printable area slightly reduced. Not a big problem as this could be fixed later by just printing a longer rack I eventually went that way and started to print the 40 tooth rack. I had to rotate it for 30° to fit the print bed on the Wallace and after aligning the infill angle I hit print.
The problem that occured is that the rack I previously printed on my TwoUp was not taaaaaaaaaaht precise and because of that outer straight walls were a bit wavy.

Wavy walls

II Layer shifting

From the pictures above you can see that besides the wavy walls there is some slight layer shift. This layer shift is on the X axis. Though the 3d object is tilted by 30° to the X axis for it to fit on the print bed, the shift is not as distinct as when the object would be placed in 0° on the X axis.

X shift

Printing a herringbone gear this comes more visible.

Eventually I replaced the Y-rack with a common drive belt to increase my printable area and to get rid of the wavy walls but then again I got shifts on the Y axis.Doh !

Wallace Y drive belt

Another word on one of the features of the Wallace++ M8 Edition: The sled on which the extruder is mounted vibrates a lot with quick direction changes. I think the horizontal alignment of the X carriage is to blame. So when replacing this X carriage with the original vertical design on the stock Wallace this might help alot to improve print quality.

III Merlin Hotend

Utilizing an airbrush nozzle the hotend promises really fine and nice prints. No ironing over layers. I achieved some really nice first layers after calibrating the extruding thickness.
From left to right I printed with different thickness’es.


a) Jamming

The prints from the hotend looked promising on the first look. Another advantage is that it can be run without cooling. Designed for passive cooling, they say. Well…not really. After the first prints went well, the hotend clogged, jammed. Call it waht every you want. Several times I had to disassemble the whole mess, clean it, drill it, assemble it again. After countless tries I finally got it working again. For one print. Then it decided to go on strike again.

jammed merlin hotend
jammed merlin hotend
jammed merlin hotend
jammed merlin hotend






b) Pull strings

I tried several solutions but none worked out. The hotend pulls strings like crazy. I adjusted the retract amount, the retract speed, “raise on layer change”… everything to no avail.

Herringbone gear printed with Merlin Hotend.
Herringbone gear printed with Merlin Hotend.


All in all this leaves me very frustrated. Frustrated with the Merlin Hotend which is going to fill another place in the Hall of the Shame, following by the downhilled prints the Wallace producdes. One word of comfort to the Wallace though. It is still an experimantal build. Even more expiramental as I mixed two design branches together. The next step is to fall back to the original Wallace which means replacing the X idlers from sponnets Wallace++ M8 Edition (this build clearly does NOT deserve the double plus behind it’s name!!!) with the stock parts from Whosawhatsis.


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