Tuesday, 30 April 2013

The up!: The truth

The up! 3d printer,

while it's true you can pull it out the box install the software and it will print pretty much whatever you can fit on the build table, it doesn't come without it's caveats, and things you simply aren't told before you buy one and really discover yourself the hardway

for a lot of people this printer seems to be fairly reliable, for us ... not even close to the kind of reliability we get on our prusa derivative which is built from nuts and bolts and printed parts,

in it's original form:

Software: aside from the occasional slicing bug where you have to rotate a part on the z axis to get it to print and crashing requiring a PC restart or loosing the usb connection to the printer, there are some serious safety and logic errors that haven't been fixed and even have been added:

- temperature in later versions have been changed to display as percentages
- temperature can only be seen in the maintenance window
- confusing nozzle height setup where it actually prints 1mm higher than the nozzle height you set it to
- no actual infil percentage is shown just pictures which you have to make a guess from
- you cannot turn off support material
- infill patterns are limited to 1

Firmware: I'm not sure i can have much confidence here, we experienced randoms freezes, stepper motors just stopping, random shutdowns, what i call the "death music" ( it plays a tune then requires being initialised again to get it to do anything) , and the long beep of death (needed power removed)

Hardware: for the price it's not a bad platform especially if you are going to do what i'm about to, however physically there are issue some of which in my opinion and many other have been designed into it,-

- the y axis has a cable which is clearly not built for flexing in the way that it is asked to, the cable itself is one of those all in one pieces where you have a plug on one end with the heater cartridge and thermistor on the other end, to replace it when it breaks is about $45 , the type of wire that has been used has this really thin insulation on it which the internal wiring goes straight through on failure and potentially do some serious damage if the wrong ones failed at the same time, possibly requiring you to replace a the main board which won't be cheap if the printer is out of warranty

- the z axis is belt driven although not a bad thing until a power cut happens or unless you get a random shutdown then it will slam itself into the bottom which i don't imagine is good for the stepper drivers,

- the x axis in more recent versions of this printer now have a rigid mount piece for the extruder to sit one, however this still uses only 1 screw previous versions like our old up! has a flimsey mounting tab which lets the extruder flop around a bit, i strinly recommend you purchase this piece or make one yourself

- the extruder is probably about the worst part of the whole thing,

1 - it ships with this fixed distance while nylon piece that contains a bearing and just clips on the front of the stepper motor, leaving you wondering what holds it on other than being against the heatsink,

2 - the wiring to the hotend is terrible and is more of the same type of wire that you find inside the y axis, not designed for any flexing and will not last very long at all especially if you have to frequently dismantle it, bottom line be very careful with this piece because it's $110 to replace it if it breaks, and you have to replace the whole hotend not just the cable with the heater and thermistor, apparently the heaters cartridges won't come out ... in reality it's held in with a grub-screw

3 - the way the hotend is mounted is a little weird, depending on how well each particular piece is machined this can leave you hotend to progressively be pushed out over a few prints and can cause damage to wiring if it comes out in the middle of a long print and you aren't there to stop it,

4 - the hotend has an internal hole in it of only 1.8mm (+/- 0.02mm) now when you consider that the advertised tollerance on even the oem filament is 1.75 +/-0.1mm and that this means the filament could be up to 1.84mm or down to 1.64mm and still be within tollerance, but according to my distributor it is all ok since the filament they sell doesn't go that big! to me this is false and misleading advertising plain and simple,

*the 1.8mm figure i mention above has been verified by my distributor,  it is not a fictional number i plucked out of thin air

5 - the drive gear and idler are a set distance thing, any variance in the filament diameter lower than 1.73mm  and it just becomes easier for the filament to be stripped,  the evidence suggests this whole extruder has been built to only extrude a very specific filament diameter which is the oem filament which by the way doesn't even measure 1.75mm instead a very consistent 1.73mm

While i could probably just get a new board and hotend and y axis cable from my distributor its only going to fix a few problems in the short term and probably leave me with them again in a few months of printing anyway ( if i get that far) and i don't believe that pp3dp or my distributor have any plans on making this platform any better or have set any priority towards fixing some of these issues, some of which wouldn't even be tolerated in the open-source community , this opinion is shared by a few ex-resellers of the up! and some current ones, 

the current state of the printer is that it is a statue, it cannot run long enough to print a bar clamp without something catastrophic happening, so i now have alternative plans to replace the board with a Smoothie-Board which so far hasn't produced a single problem in tests on my prusa derivative, and it's still in beta