M200 Plus hotend and extruder exploring


#1

An opportunity to have a peek inside the extruder and hot-end of the M200 Plus presented itself yesterday,  since it had started skipping now and then, when loading filament and while printing the first raft layer.

My printer has so far only ever printed Z-ULTRAT and Z-ABS. Z-SEMIFLEX has arrived but not yet been used.
 
I'm not familiar with the M200 hot-end, but the M200 Plus seems to have a white teflon? tube located above the heater block, i.e. above the top face of the heater block. So it looks like the teflon is not in contact with the hottest parts.
Inside the heater block, it looks like the filament runs throug a thin metal pipe, which is pressed against the nozzle when screwing it in.
I found molten plastic well above the nozzle contact plane, but under the teflon, and removed it with acetone and a small brush. However i think this was not the cause of the skipping.
 
Also unscrewed the extruder motor for cleaning there. Luckily it is possible to displace the motor enough for cleaning the cog and the filamant channel, without removing or even unplugging any connectors. You only have to unscrew the motor and the metal bracket which holds the top parts including the connectors. (Alternatively i think you can leave even the bracket in place if you only disconnect the motor connector.)
I put a piece of cardboard in the printer resting on the side belts to create a small "workbench" where the extruder motor can sit on, without straining all the wires.
From what i've seen in the M200 extruder maintenance guide, the extruder mechanism in the M200 Plus is similar, but with an extra internal (removable) profile plate that restricts the filament below the cog to only go straight down. It would be hard for filament to buckle or wrap around the cog wheel.
 
With the motor shifted aside and the hotend removed, it is possible to see through the whole filament channel and clean it, e.g. with a "3 mm interdental" brush.
Mine surely contained plastic string junk, presumably originating from some unload operation(s). I wonder if it is really good practice to unload filament after each print, especially if you use the same filament the next day.
 
 
Roel
 

#2

Thank you for this clarification on the hotend of the M200 PLUS.

 

Zortrax never gave information on the differences between the two extruders.

But it is unfortunate that Zortrax has not further modified its extruder because it is not very effective for filaments too hard or not having a regular diameter.

Many other extruders from other manufacturers have an adjustable spring mechanism that continuously drives the filament and drives it much more efficiently.


#3

I don't want to sound like an apologist for things Zortrax gets criticism for, but consider the following:

 
Suppose the ideal force for pinching the filament is that force which indents it by .35 mm.
Now, if you are a printer manufacturer who does not want to manufacure with better tolerances than say +/- .2 mm or cannot apply a stiff basis, then you NEED something like an adjustable spring-loaded counter bearing:
 
1- to let the user adjust for the variation in "dentability" of the various filament types, 
2- to absorb your machine construction tolerances or to counter bending of the mounting frame
 
If, on the other hand, the relevant parts are stiff and precisely manufactured, then you can omit the spring by just designing the ideal filament indenting of .35 mm. You also relieve the user from worrying about yet another tuning, and gain simplicity.
 
There are of course weaknesses and assumptions in the above, but still..
 
 
Roel

#4

An opportunity to have a peek inside the extruder and hot-end of the M200 Plus presented itself yesterday,  since it had started skipping now and then, when loading filament and while printing the first raft layer.

My printer has so far only ever printed Z-ULTRAT and Z-ABS. Z-SEMIFLEX has arrived but not yet been used.

I had same concerns a few years ago with my M200 but overall Zortrax engineers know what they do, If you increase force of the motor then it will not skip any steps but extruder gear will scratch filament if you have distance inconsistency between platform and nozzle and in real life if you want to build machine which has perfectly flat axes and platform then I don't know if 20k USD is enough only for this parts. Because Zortrax printing with the raft then first 2-3 layers do not need to be smooth and beauty they are only for filling the gaps to prepare even surface for next layers.

Overall skipping is not an engineering/production mistake but a feature which in case if a pressure in the nozzle is too high then it will skip few times and recover at the moment when pressure back to normal. Thanks to this you don't need to disassemble extruder to clean scratched material by the extruder gear which is very common failure in other printers on the market.


#5

Yes agree, and thanks for the reassuring. I was looking for an excuse to open the printer anyway :) . Still i must admit that i don't like this skipping even when it is harmless.

The material in the filament path was not grains from scratching, but rather long pieces of thin strings. The kind you get when pulling molten plastic apart.
But i take it you only really need to remove it when there is too much accumulated.
 
 
Roel

#6

3 examples to show that the Zortrax extruder is not very efficient :

I recently tried 3 nylon filaments (NYLON ULTRA of VOLUMIC, NYLON TECHLINE of TAG3D and STYX-12 of FORM FUTURA) : impossible to load them in the Zortrax : the pinion of the extruder skated and the filament was not pushed into the nozzle.

The 3 filaments work very well in a Witbox printer equipped with the DDG extruder (see photo below) and a heated bed !

 

We find this kind of extruder in many printers now.

 

Why Zortrax can not build an efficient extruder ?


#7

3 examples to show that the Zortrax extruder is not very efficient :

I recently tried 3 nylon filaments (NYLON ULTRA of VOLUMIC, NYLON TECHLINE of TAG3D and STYX-12 of FORM FUTURA) : impossible to load them in the Zortrax : the pinion of the extruder skated and the filament was not pushed into the nozzle.

The 3 filaments work very well in a Witbox printer equipped with the DDG extruder (see photo below) and a heated bed !

 

We find this kind of extruder in many printers now.

 

Why Zortrax can not build an efficient extruder ?

But you writing about M200 extruder and not M200 Plus about which is topic here. Zortrax already built efficient extruder which is used in M200 Plus. It is right what you wrote but only valid for M200, not Plus version


#8

"But you writing about M200 extruder and not M200 Plus about which is topic here. Zortrax already built efficient extruder which is used in M200 Plus. It is right what you wrote but only valid for M200, not Plus version"

Exactly: That's why I'm trying to get a lot of information on this new extruder, to try to understand if it can be effective with more filaments !