From EduTechWiki - Reading time: 41 min

The Felix Pro 1 is a 3D printer made by FELIXprinters and that started shipping in December 2015. It features auto-calibration of the print bed, a dual head, etc. and strong, reliable steel extruders. This article is both a (fairly) subjective review and a tutorial on some aspects, i.e. I write down stuff I learned from trying out certain prints and certain materials and I notice things I found pleasant or less pleasant. This piece is evolving and may be split up in the future. There is information you can trust and other you should not since it takes time to somewhat master a printer.
We got a Felix Pro in Dec 2015. I believe it to be a very good buy (better than the heavy backbreaking US models that are popular in trade mags). I cannot offer a precise opinion with respect to print quality. That being said, I am now sure that this printer is (a) reliable and (b) easier to use than any other printer I have seen and/or used so far. - Daniel K. Schneider 17 Dec 2015 - 29 Jan 2016.
Update: Jan 2019. I upgraded the Pro 1 to a Pro 2. Print quality seems to be better. I did manage to rip off the extruders while printing large DEM models with lots of peaks and the machine went on printing for hours since it was an overnight print. After that I had a Z-sensor problem that is due to distorted geometries. Instead of repairing, I upgraded...
See also:
I takes about 5 minutes to unpack and assemble the printer.
It is crucial to:
For configuration, use manager.exe, available in the control panel. Direct access is:
C:\Program Files (x86)\Materialise\BuildProcessorSystem\Manager.exe
Then, update:
Configure Printer -> Edit Profiles -> Update (button)
Adding programs to the task bar
I suggest adding at least these the three major programs to the task bar if you print often. That are Manager.exe (Job Control), SubmitJob.exe (g-code submission) and Magics.exe (Felix Builder)
Calibration is done through software. Either by running calibration g-code or by including the calibration g-code in the startup code for each print.
There is no manual printer calibration to be done, except making sure that the correct Felix Builder software is installed. Alternatively (and better), you also can modify the startup code of another control/slicer software, e.g. Simplify3D, or just the run the calibration g-code. But it does need to be done once in a while and definitely the first time you use the machine.
At least in OEM version 10.0, special startup gcode will probe the print bed in three (or more locations), i.e. the hot-end is pressed down until it touches the bed and a sensor will capture this event. This can cause two little motors underneath the print bed to level (left-right and back/forth). The procedure also will tell the printer its Z position and adjust it.
If you do not run this calibration routine, it is very likely that the hotend is too low and it could scratch the print bed. There may be other strategies, i.e. you could adjust the bed through the LCD or through a control program. However, you still have to make sure that the generated gcode from Felix Builder does not defeat this. Frankly, I didn't have time to look into this.
Below, the gcode that was used in Felix Builder by 12/2016. Note that this gcode seems to trigger special firmware, e.g. G28 Z will turn the heater on to about 150 degs, G32 will trigger the leveling routine.
; Preparations
; ======================================================
M117 Preheating
{IF_BED} M140 S%%TemperatureBed%% ; Heatup Bed and and continue
{IF_NOZZLE1} M104 T0 S%%TemperatureNozzle1%% ; Heatup hot-end and continue
{IF_NOZZLE2} M104 T1 S%%TemperatureNozzle2%% ; Heatup hot-end and continue
{IF_NOZZLE2} T1
{IF_NOZZLE1} T0
; ======================================================
G91 ; Relative positioning
G1 Z5 F5000 ; Move platform 5mm away from nozzle
G90 ; Absolute positioning
G28 X ; Home X and Y first
G28 Y ; Home X and Y first
G1 X140 Y230 ; Move to optimal z-homing position
G28 Z ; Home z (Firmware will turn heater on up to approx 150 degC)
G1 Z5 F5000 ; Move table down 5mm
G32 ; Do automatic leveling routine
G1 X140 Y235 ; Move to home position again
G28 Z ; Home z
; Purge Nozzles
; ======================================================
{IF_BED} M190 S%%TemperatureBed%% ; Heatup Bed and and wait
{IF_NOZZLE1} ; Purge left extruder by drawing 2 lines
{IF_NOZZLE1} T0 ; Make sure first extruder is selected
{IF_NOZZLE1} M109 S%%TemperatureNozzle1%% ; Heatup hot-end and wait
{IF_NOZZLE1} M117 Purge left extruder
{IF_NOZZLE1} G92 E0 ; reset extruder
{IF_NOZZLE1} G1 Z1.0 F3000 ; move z down little to prevent scratching of surface
{IF_NOZZLE1} G1 X20.0 Y244.90 Z0.3 F3000.0 ; move to start-line position
{IF_NOZZLE1} G1 X200.0 Y244.90 Z0.3 F1500.0 E15 ; draw 1st line
{IF_NOZZLE1} G1 X200.0 Y244.6 Z0.3 F3000.0 ; move to side a little
{IF_NOZZLE1} G1 X20.0 Y244.6 Z0.3 F1500.0 E30 ; draw 2nd line
{IF_NOZZLE1} G1 E28.5 F3000 ; retract filament 1.5mm
{IF_NOZZLE1} G92 E0 ; reset extruder
{IF_NOZZLE1} ; done purging left extruder
{IF_NOZZLE2} ; Purge extruder 1 by drawing 2 lines
{IF_NOZZLE2} T1
{IF_NOZZLE2} M109 S%%TemperatureNozzle2%% ; Heatup hot-end and wait
{IF_NOZZLE2} M117 Purge right extruder
{IF_NOZZLE2} G92 E0 ; reset extruder
{IF_NOZZLE2} G1 X200.0 Y244.3 Z0.3 F1500.0 E15 ; draw 1st line
{IF_NOZZLE2} G1 X200.0 Y244 Z0.3 F3000.0 ; move to side a little
{IF_NOZZLE2} G1 X20.0 Y244 Z0.3 F1500.0 E30 ; draw 2nd line
{IF_NOZZLE2} G1 E28.5 F3000 ; retract filament 1.5mm
{IF_NOZZLE2} G92 E0 ; reset extruder
{IF_NOZZLE2} ; done purging right extruder
{IF_NOZZLE1} ; M104 T0 S0 ; only turn off when nozzle 1 is active.
{IF_NOZZLE2} ;M104 T1 S0 ; only turn off when nozzle 2 is active.
{IF_NOZZLE2} T0 ; make sure startup ends with first nozzle if the first nozzle is used.
M117 FELIXprinting...
This code can be changed in the machine settings (first item in the "Edit profiles" Window.

In sum, watch out for two things: Print bed must be positioned right, calibration routine should be run either separately or in the start code.
It is crucial that the platform is snapped in right. Usually I do that right, but it did happen. If the full calibration routine is run, then there isn't much harm if one peg is not properly inserted. If not then you may hear scratching noises ...
Depending on the FelixBuilder version, the start code doesn't do a full calibration, for example the OEM version 11.0 (early Feb 2016) does not. It just checks and adjust the z-height. A badly positioned platform, e.g. tilting to the left will have the nozzle come too close or far in some places.
Therefore I suggest, after checking if the platform is well inserted, to run the calibration code if it is not in the startup g-code.
Upgrading the firmware (on Feb 9 2016 and again on April 2016) went well. I just followed the instructions. They involved:
After that, I ran the calibration files again.
Important:
G90 ; Absolute positioning
; Compatibility for firmwares before version 0.92.8
; % ---------------------
G28 X ; Home x and y
G28 Y ; Home x and y
G1 X130 Y240 ; Move to optimal home position for z-homing
; % ---------------------
G28 Z ; this homes x and y also
For printing small objects with small 0.15 layers, the z-distance after probing may be a little bit too high and the filament may not stick. This happened to small Lego-compatible pieces. If you have the impression that the platform should be a little closer to the nozzles for all building styles, then you could edit the start code.
Other alternatives to fix non-adherence (also in combination).
Try moving the print bed from the controlling software, then figure out the right amount of distance to move. 1/10 or 1/20 of a mm should be about right.
In the manual control window of FelixBuilder, you can send g-code (from other control/slicer software too btw.). Try the following, it will not hurt if you do it in the right order.
G91 G1 Z10 F5000 G1 Z-5 F5000 G1 Z-5 F5000 G1 Z-.1 F3000
G-code explanation (there is more on the web).
Edit profiles -> Machine Settings -> Custom Code -> Start code
G1 Z-.05 F3000
If this is not enough, try:
G1 Z-.1 F3000
This will move up the platform by 0.1mm (which is quite a lot). Do not blame me if your print bed will get scratched, I am not an expert. Also, remember that you did change the start code !
configuration button in the Slicer TABWithin Cura:
Add at the end:
G1 Z-.05 F3000
When printing 0.2mm layers there shouldn't be any problems (except for filament that will warp or others that need glue to stick). However, after (ab)using the plaform for a while there will be irregularities, e.g. scratches or bubbles in the PVC. The aluminum below also many not be completely even. To compensate for this, Venkel, in a Felix Printer Forum post, suggests the following settings for 0.15mm layers:
His rationale is the following: “With the first layer you need to compensate for small errors in the print bed and in the calibration height. I measured the bed to have up to 0,04mm waves. Let's presume the calibration adds another 0,01mm error. If you would print a 0,15mm layer, the error is 33% of the layer thickness ((0,04+0,01)/0,15). At 0,225mm the error is 22% ((0,04+0,01)/0,225). Then, if you compensate flow to 120%, there is enough pressure on the first layer for good adhesion over the entire bed surface.”
I suggest:
Instead of using the 0.35mm nozzle you also can buy a 0.5mm one. The latter has two advantages:
When you change the nozzle make sure to grab the heater and only the heater, Place the open Wrench 12 around the body of the hot-end to be able to hold it firmly. Use a closed Wrench 7 to remove the tip of the hot-end. Do not hold the the hot-end above. After not reading the manual I managed to kill a hot-end, i.e. instead of removing the nozzle I twisted the tube and it broke off.
A few tips:
Overall: Worth the investment (I would buy it again as of 15:39, 3 February 2016 (CET))
If the correct gcode prequel is installed in your slicer program (Felix Builder by default), then printing has become much easier than before. Auto-calibration of the print bed before each print is a real blessing. That means that this printer can be used by real beginners without any help (provided that they are capable of installing the right drivers) and selecting printable objects.
It's the first of my printers that can print large flat surfaces without any problem. It's also the first one that doesn't require pre-heating and prior filament extraction. The removable print bed is a really nice feature. One now can force prints off the print bed without being afraid to damage the geometry.
As far as I can tell, the two nozzle system is well designed and I didn't have the usual "other nozzle rips off the part problem" yet.


So far, most our objects came out fine, but as we wrote elsewhere in this page, we didn't print any benchmark pieces so far. As an exception, the Lego compatible pieces to the right have a flaw. They show some missing filament at the level of the first roof in one of the corners. This happened in all six pieces printed of a same batch. I suspect that after printing the roof, there is not enough filament in the tube of the nozzle and I wonder how the result would look with different slicer settings (including different in-fill policies (wall first), temperature, speed, etc.). I didn't have time to explore this...
Since there is only one officially available slicer, it is difficult to evaluate if certain print flaws are related to the printer, its debatable filament spooler, the slicing quality, or the slicer settings. I suspect some interaction between the spooling, the slicing algorithm and the slicer settings.
I also had one print abort during a night. Impossible to find out why, maybe there was a filament problem and the printer just aborted the print after a while or maybe some electricity problem ?. It would be nice to receive some sort of trace (both in the console interface and the controlling software if a computer is connected)
So far, I didn't have time to try out all the various polymers, except for the ones below, i.e. PLA, a low cost limp TPE, a high-end TPE, Nylon and T-glase. Clearly, the printer is optimized for PLA printing but it prints well a number of others. Printing composites (wood, stone), TPEs and T-glase is better done with a larger 0.5mm Nozzle that one can order from Felix Printers.
It also prints ABS (smaller pieces) but that needs some glue (So far we only tried one little piece).
For more information about filaments for 3D printing, including general tips, read 3D printer filament
Different types of PLA print very well (but that was expected). I printed from 180 to 215 degrees C and at various speed and resolution.
The following was printed with medium settings (sorry of the bad picture quality)

When printing objects with a small footprint, consider:
I do have difficulties printing with 0.1 layers. Maybe the print beds are not level enough. Printing a really fat first layer does help though.
Tip:

NinjaFlex is as of Feb 2016 the best known Thermoplastic Elastomer (TPE). It is fairly easy to use, but also fairly expensive. So far, I didn't manage to print nice smooth surfaces, although bigger layers (up to 0.3mm) higher extrusion rates and lower speed produce acceptable results as in the owls to the right. Both were printed with 0.3mm layers and slowly. One has 5% infill and the other 40%. One was printed with and the other without support.
Properties of Ninja Flex
This filament should be fairly safe in terms of toxic fumes (less than ABS). It is not bio-degradable.

Configuration for my first print, a little Duck:
This configuration was based on 03_FLEX FELIXprinters (PolyUrethane)
The result is not so good. Many holes. The flow of plastic is not regular enough, but difficult to know why. Probably a speed problem. The rubber-like plastic may offer too much resistance to the small 0.35mm nozzle. Therefore, we can try going slower and also push some more filament through.

Second print, the same little duck (constant flow settings)
Changes made with respect to the first print:
Settings for the 2nd print gave slightly better results. The contour is now more even.

Third print, a holder
This third print produced a piece that turned out to be too flexible. The larger walls turn out to be OK, the small parts are not, i.e. they got some "holes". These parts are still strong enough to be functional, but the result is just too ugly. Probably these parts should have been printed with even lower speed. One also can notice a lot of strings. This is normal, since we used little retraction. A correct amount of retraction probably would lead to even bigger holes (to try out)


Since the third print didn't go too well I decided to print something that is more difficult in principle. Two low-poly cats reduced to 3cm length. The result was OK, but the contours still could be a bit more smooth.
Recommended settings for a 0.35mm nozzle
Although Ninja Flex is not very precise, it will stick to the print bed and therefore tiny objects can be printed easily. The challenge is to find a good compromise between print speed, temperature, extrusion rate and fill.

Recommended settings for a 0.5mm nozzle
Results with a 0.5mm nozzle are better than with a 0.35 mm nozzle. I.e. you can more easily see the layers but the the result is nevertheless much smoother. Make sure that your slicer will adapt to the 0.5 nozzles, e.g. adjusts extrusion width.
Other tips
The Duckator below was printed as suggested by the model's STL position. The backs of its head and tail (i.e. where the support connected) were really ugly and I used a blow torch to even out.
Alternatives
Low cost TPE (http://www.3dprima.com/en/filaments-for-3d-printers/flexible-175mm/ 3-Prima]) - less than half price of Ninja Flex - prints also well. The stringing you can see in the picture below is due to my slicer settings. Since the filament is very weak, retraction probably leads to congestion, so I turned it off.

Settings:
To do:
Tips:

This pretty co-polymer filament is made by Taulman from PET(G). It is somewhat translucid, has a rather good surface finish, and it shimmers. Prettier than translucid PLA. It seems to have low shrinkage and little warping or splitting while printing. It sticks to acrylic, glass, and Kapton. T-glase (aka "Tought Glass") can be used as replacement for ABS and it's stronger but more brittle. Unlike ABS, bonding between layers is very good (i.e. makes cups watertight). Finally, it does not produce fumes when printing. This article by Mike Adams (March 11, 2015,) makes a good case for t-glase: It's solid, safe for (cold) food, watertight, both rigid and flexible, etc.

On the negative side, it bends at 78 degrees C. T-glase seems to be fairly strong. However, if forced it will break (rather than bend). Now the story:
First prints
My very first print failed. I.e. the feet of a little cat did not stick. My second print finished well, but it was printed too fast and without fan (for most of it). The 3rd print worked much better, but the result wasn't great. I made a copy of the ABS profile, then altered the settings to lower speed (about 25 ms for contours), temperature at 240C, bed temperature at 45 C, fan was on, raft and resolution was 0.15. The result was really ugly.


I read that on should increase layer thickness to a minimum of 70% but preferably 80-90% of the nozzle setting, according to a post at Taulman. Also read this. I read in several places that one should use at least a 0.5mm nozzle. Not true, since I managed to print.
4th attempt: Printing Lego bricks
I compared the same brick with very different settings.
The second one came out much better. Too much filament on the roof (you can see the nozzle "digging in", but otherwise, rather good quality. I still believe that 120% extra extrusion is fine, but I should reduce upskin/downskin extrusion factor a bit (I believe it was at a 100% of the 120% global settings).
Recommended settings (for now, this can change)
Slow speed seems to be the most critical success factor.
To do:
Reliability
We tried a long, but easy overnight print, megaphone for smartphone w/ flat bottom using our recommended settings or similar. The object was there in the next morning and pretty well done.
Conclusion (as of Feb 19 2016): Overnight prints (> 12h) can be trusted to succeed for simple objects with our recommended range of settings (fat layers, some extra extrusion, slow speed). It's probably good to use a resistance-free spooler underneath the filament cleaner intake (as shown below in the "laybrick" section).
We also printed the same object 33% wider (so it could fit a Galaxy S6) with 0.3mm layers, only 20% of infill, an slightly higher speed (changed in the Build style, in particular for the fill). I worked nicely, although the slicer could optimize the esthetic quality of walls by putting the joins in different places. Maybe I also should use a negative value for contour overlap.

I tried Wood from Felix printers, using a 0.5mm nozzle. This plastic has tendency to warp and we recommend glue (or another means) to make it stick better
Provisional settings:
To try out:
With these settings, one can see layers like in the good old days. I don't mind since printing takes less time.
Do not forget to change the machine settings to 0.5mm (and then change it back if you switch the hotend). I use the second nozzle for 0.5 mm printing, but so far did not manage to configure repetier-host (at some point switches back to nozzle 1). I therefore use FelixBuilder.
I also add a z-correction for the first layer in the start-up g-code (see above).
The Felix Pro 1 can print laybrick, but I don't have any opinion yet on the best way to print. A lot depends also on the kind of object. Sculptures, landscapes, and simple (!) buildings probably should do well but need different settings.

Since extrusion can be a bit erratic, the first layer may not stick too very well to the print bed, i.e. on my first print, the cooling tower got ripped away. It's probably a good idea to run the printbed calibration routine first if it's not included in the start code and also to start with a warmer temperature and a reinforced first layer. Also, since laybrick produces fairly brittle objects, it's not a good idea to print something with small walls (e.g. Lego bricks) that you then will use to play with.
Laybrick filament does not come spooled on a roll which is hassle since you cannot let a print unsupervised. I found an old horizontal spooler from the Felix 1.0 days that can help a bit. Re-spooling the filament, e.g. on an empty PLA roll, does not seem to work since the filament can and did break when I tried that. It probably could be done, if one does it a very gentle way without applying any sort of torsion.
Print settings 0.35mm
In FelixBuilder, I made copy of the default PLA settings
Other tips:
My first prints:


Second series:
After the first prints, I decided to print a sculpture. This time I had trouble getting the filament stick to the platform. It probably was due to too low speed for the first layer. The result are two Einsteins. The one to the left was printed with 190 C, 0.2mm layers, 40mm/s base speed and "normal build settings", e.g. contours at 50% and first layer at 22%. The left one also suffers from filament getting stuck. The right one was printed with the same settings, but at 200 C.
In sum, I believe that the key for being able to print this material is
To do:
Bridge nylon is produced by Taulman. It is not as strong as his other variants, but easier to print and cheaper. This Nylon sticks very well to the PVC (Kapton) print bed.


Printer settings for the first print based on official instructions. I modified the default ABS style and use the Single Head Normal Detail print strategy.
The result is OK for a first print. There is stringing, maybe 3.5mm retraction is really needed. Some spots look "burned". IMHO some PLA residues left inside the tube or around the nozzle. It's probably a good idea to clean the outside of the nozzle once in a while. For a second print of the little duck I used 255 C and retraction of 3mm and the result was better.
Recommended settings for small objects with small towers:

Printing useful objects
The point of using Nylon (and even Bridge) is to create pieces that are sturdy, like this iphone tripod. A first version was done in PLA, but one of the feet broke. So, a third print with Bridge Nylon was printed with the three sticks flat on the print bed with a little bit of support.

Recommended settings for larger and solid objects:
Bridge Nylon sticks very well to PVC. However it does have a tendency to warp (less than ABS), so it is critical to print the first layer well: Clean printbed, slow temperatures, a cooling tower, etc. Otherwise, if only a small edge is a bit detached, it will warp. I had to abort printing the upper larger piece of the Felix 2.o extruder because of warping.
Other ideas / stuff to try out:
Problems, Questions, Tips
Bits that stick out (probably deposited after a longer jump) turn brownish when touched again by the hotend. To reduce this: make sure to reduce stringing, augment fill, add an auxiliary structure (cooling tower), Avoid long jumps that go over parts, or increase hopping (Z-retraction)
Nylon will quickly absorb water, i.e. in 18 hours it already is full of it. Therefore, it is suggested that you dry the Nylon before each print. Read this. Bridge Nylon is probably a bit less sensitive. I could hear some "sputtering" even with the newly acquired roll. Nylon with water inside creates uglier prints and may not bond well between layers. Some people put the Nylon in the oven for a few hours at about 80 C. Try first with a smaller piece ! You also can print larger layers and use a higher extrusion rate to increase adherence if there is a problem, but I found nylon to be solid and it doesn't seem to delaminate like ABS.
Taulman Bridge can warp for larger parts. To reduce warping, use the usual tricks that also work for ABS.
If the object sticks to the platform (that is decided after the 1st layers and then again after 10 or 20 layers in larger objects) then it may be difficult to remove it from the platform without damaging the PVC, i.e creating air bubbles. I believe that heat could help and next time I will use a heat gun.
Bridge Nylon can and does warp, it the first layer isn't perfect. The object also can warp after removing of the print bed. I don't know how this could be prevented. Again, maybe heating it up with a hot air gun ?
Printing objects that need support is fairly difficult I find. The problem is that support structures can create "bits" that stick our here and there. These will prevent filament to flow regularly, sometimes the nylon will be burnt and one can wind up win an object that has ugly and damaged walls. This happens in particular for slopes, roofs print more or less OK. Adding some extra distance between support structures and the walls maybe could help. Also decrease density a bit.
So far, I didn't have time to print any sort of benchmarks or play with high-resolution settings. Therefore, prints I produced are good. However, I really don't like the filament spooler. In addition to creating too much resistance, wider (13cm) rolls don't fit, and there is no space to have two "higher", e.g. 25cm rolls.
Stability of the printer seems to be good. So far, I did not try to open the top and bottom parts to see what is inside. I didn't check either whether everything looks really tight. Even if a printer is well designed, it might have been badly assembled. Probably there are "Monday models", but I don't think that I got one of these.
If found it amazing that printing large surfaces has become hassle free. On the Felix 2.0 I did encounter lateral warping of the first layer and had to turn of the fan in order to get first critical 3 layers printed. I also had to make sure that the bed was well calibrated. This is no more the case. The only problem I encountered (with a different print of a large 3D molecule) was that Felix Builder put the object too much to the right and I had to fix that. Also, make sure to attempt prints like this with a print bed that isn't damaged from forceful removing of prints (bubbles, scratches, etc.)
The following picture shows the first layers and the final result of a 3D Rorschach picture. As you can see in the first picture, large flat surfaces really print well (with PLA that is). The whole print, flat bottom and 3D landscape on top, took about 8 hours.



During the first month, I only had two print aborts (not counting the ones due to mismanipulation or computer failures) despite the debatable quality of the filament spooler. One of the two could be easily explained. I scheduled a 2-day print for a large molecule. As some point during the first night, the print head got blocked by an "atom" that detached itself and folded upwards. This caused the next layer to be displaced and I had to abort the print myself in the morning. The other, a 3D landscape with 2 colors, could not.
All 8-10 hour prints went fine. For example, below is a smaller molecule (envelope) with support in progress.

The following lamp shade was printed in 21 hours, using "normal" settings (medium speed and 0.2mm layers). Such an object is fairly easy to print. However, due to the bad ("flat") overhangs at the bottom, things could go wrong in the first few hours of printing. According to Felix Builder and netfabb Pro, the model has 468512 triangles and a volume of 86609 mm3. The area volume is 1400cm3, i.e. more than a liter.
Printing a second one with a different type of PLA and somewhat different settings also went fine. I launched it on Friday and collected it the next Monday and it took about day, but I forgot to check.

Finally, I also had the problem that small pieces detached (got ripped away). One solution (as with any other printer) is to used a raft (called "extra adhesion" in Felix Builder's support strategy). A second one is to make it stick better. For example: lower the nozzle, rise the temperature of the first layer and of the print bed, slow down, and finally print a larger first layer.
The following pictures shows a Raspberry PI case. Print settings were "medium". Sorry, I forgot, but probably 0.2 layers and medium speed. Maybe 0.15 layers. As you can see the difficult petal didn't print very nicely. The small lettering has some extra stuff inside that could be removed. The walls include some holes, probably due to not so good plastic flow using the default not good spooler (soon to be replaced ...). I also noted (not juste on this printer) that PLA with lots of pigments doesn't print as nicely as more traditional PLA with less pigments.
Overall, the result is good and should better with slower speed and smaller layers. The PI did fit inside. One also could use support (but spaced out).

No miracles there. As before, these must be printed in a special way, e.g.:
Otherwise, there is a chance that the printhead will displace one of these. Actually in the picture to the right, you can see that the middle one doesn't look right on top. There is a tradeoff for over night prints. Warm means that you guarantee flow, but at some point some extra filament that comes out may just be enough for the nozzle to touch a bit and make the stick fall.
Printer settings:
You also can see see some stringing. I usually print at night in my office and in order to make sure that prints finish, I don't want too much retraction and I printer at warmer temperatures, e.g. at 195-200 for PLA. This PLA has a lot of pigments and doesn't print a nicely as "old-style" semi-transparent one. On the Felix 2, I printed most PLA at 215, but then I don't know if the temperature sensor gave correct results.
I really wish that someone could write a program that adds some smart support for the sticks. E.g. some like
/|\ /_|_\
If the objects build up (e.g. like the sticks above) then printing is not reliable. I.e. I do not suggest using over night prints. Otherwise, if the objects "join" into something bigger and more solid (e.g. Lego pieces or animals with feet), then you can expect a finished print sometimes later.
I any case, the first layer remains mission critical. It really must be "complete", it must stick and it also should be precise (see printing tips for PLA, e.g., print hot, thick and slowly). If you cannot achieve this, then do not print delicate objects.
After a year of using the printer I experienced Z sensor triggered messages. These are annoying because the printer will not home correctly. Firstly you should just head before calibrating. If the message is still there after removing and re-inserting the hotends then you have to act.
Things to do:


Apparently the Felix Pro 2 has less sensitive sensors.

We did not test that a lot so far. Printing one layer on top of an other worked fine with a simple object, a 4x4 Lego with a hamburger on top.
If we understood right, in order to print an object with two different colors, one has to load and re-position two or more different parts. So far, we use the following method:

It would be nice if in Felix Builder, one could "tag" regions of a same part with different colors and then pass this information to the slicer.
The above print used two layers of colors which is a fairly easy task.
We also printed two colors that sit "aside", e.g. one part of the object in green and three parts in red. That type of print takes extra time since the printer will let the other extruder cool down to 140 degrees (to prevent clogging). The Felix Pro has a superior design with respect to other printers I have seen. The nozzle on the right is a tiny bit lower (as it should be) but will retract (turning its tip backwards) when not in use.
We also recommend printing the auxiliary structure, i.e. the little square. Before printing a layer the nozzle will do turns on this one get rid of extra filament or also make sure that fialement coms out. (Edit profiles-> Build strategy. Select a strategy, then open Auxiliary Structure and tick)

Slicing quality
I cannot tell yet, but I have the impression that the slicer could do a better job optimizing somewhat messy constructs, in particular ones that have several overlapping parts. The picture below shows a bad layer where 3 parts overlap with the one below. In principle, the slicer should optimize this and not print two (or more parts) in the same place. At least it should give a warning and advise the user to redesign the object. Best would be both, i.e. a warning and an option to slice either one of the overlapping areas and ignore the other.




This print aborted in the middle of the night, probably due to some computer problem (its screen was locked in the morning) and I redesigned a better piece without overlapping parts that sliced and printed just fine.
This actually makes me remember an old gripe with control software (since my "Rapman days"). Why can't someone design a system that allows continuing a print where it stopped ? At least display the line of g-code and then provide a functionality to manually restart printing at this line using the g-code file that was generated and used for the aborted print. With the Felix Pro one could image an even much cooler feature. Using the "touch" sensor, it could detect where to restart.
(not tried so far)
Felix Builder is an officially supported slicer and control software. It allows importing, repairing and positioning objects, slicing, and managing a print queue, etc. Felix Builder is made in partnership with Materialise, i.e. it is a version of its Build processor, as explained here.
See below for the open source officially supported control and slicer software, i.e. RepetierHost + CuraEngine / Sli3r. If you copy the start code, most other open source control/slicer software also should do. I prefer using repetierHost. However the version I have doesn't handle printing with the second extruder only (or I didn't figure out how to ...
Since (sometimes in 2016) FelixPrinters also support Simplify3D, a slicer that has a very good reputation. If you can afford it, I recommend rather using Simply3D than FelixBuilder.
Since Felix Builder was new, we described it here in more details...
Menu items are a bit confusing and some software components cannot be found in the initial Felix Builder window without loading and submitting a part. I.e. to see all software components, you either have to load a part or else locate these other programs in your computer.
For configuration use manger.exe, available in the control panel. Direct access is:
For quick submitting a gcode file to the printer, use SubmitJob
Anyhow, once you understand the above and after 2-3 prints, the software is fairly easy to use. Again, do not forget to update. Auto-calibration does work through a routine that has the nozzle tap on the print platform in various places and then firmware will react to that.
I cannot judge the quality of the slicer yet. I found that it had fairly few configuration options, but maybe they are enough. There are four different types of settings that can be configured:
In case of trouble, util.exe, a command line utility may be useful. It allows to manage queues. E.g. below we can see something that went wrong, the queue includes a job that it cannot identify. After that the GUI refused to display the print queue (i.e. the
C:\Program Files (x86)\Materialise\BuildProcessorSystem>Util.exe status -verbose
Build Processor System Configuration Utility, Version 1.6.29.0, Copyright © Materialise N.V. 2010-2015
1. Queue "FELIX Pro 1.0" at "Office DKS" is None:
b8857040-90e4-473c-9713-71999699da78 | Unnamed Processed, Printed, Comple... ProcessLocally, KeepInQu..
.
dc5471cc-0bf3-4201-8a01-6c09614e9ec8 | My_FELIX Pro 1.0_Job_16_02_17_21_13... Processed, Print... KeepInQueue
You then can try something like:
C:\Program Files (x86)\Materialise\BuildProcessorSystem>Util.exe remove -job b8857040-90e4-473c-9713-71999699da78 -queue "FELIX Pro 1.0"
Build Processor System Configuration Utility, Version 1.6.29.0, Copyright © Materialise N.V. 2010-2015
The job was successfully removed.
C:\Program Files (x86)\Materialise\BuildProcessorSystem>
If you decide to reinstall the system for one or another reason, make sure to deinstall first. Use the installer program for that. But firstly, you can export your profiles and then reimport (I did not try so far). After deinstalling, make sure that all programs are gone. Then, if your removed the system because something is wrong like it won't find your printer or cannot remove hidden print jobs, remove all files in the System and Personal Appdata folders.
Of course one cannot define universally suitable styles.
Things I immediately changed:
Sometimes I use double 1st layer or make it fatter.
When printing over night, I usually lower the speed on the printer console. Better chance to see a printed project when I arrive in the office. The Felixprinter while much more reliable is still a filament printer. A bit of extra filament can "grow" and have something displaced.
When printing with 2 colors it is crucial to print the extra auxiliary structure (by default it is on, but it's a bit a waste of plastic and time).
Some of these issues may have been fixed...
The FelixBuilder software requires several improvements:
Usability
Interaction with the printer
In sum, I believe that the control software doesn't interact with the printer as it should. It doesn't seem to get/digest much feedback, i.e. the control software doesn't seem to know what the printer is doing (it is not showing it)
Calibration and styles
Interaction with the PC
Missing features
Open questions
Alternatives
Of course, one can use an other control software and slicer. Just make sure to include some of the start-up g-code shown above (i.e. Z-positioning). Print bed calibration is not necessary, i.e. it can be done once in while. I did not test this, since it probably would take time to do it. As of 2016, there is also Repetierhost configuration for this machine. It may be more suitable for most needs, however I cannot take the time to compare slicing quality to be sure.
The control software used for the Felix 1, 2 and series is also available for the Felix Pro since Feb 2016 (?).
I much prefer its interface and functionality over the one from Felix Builder (however, this does not include the slicing quality) and for four reasons:
This version only includes two slicers: Sli3r and Cura engine.

Default settings for both slicers should be tuned a bit IMHO, in particular
Negative:
Slic3R seems to include more parameters than CuraEngine, i.e. a bit more suitable for my needs.
Modifications I made so far for printing Lego-likes (PLA)
When printing single head with a raft and/or support
Problems: Slice3R does have deficiencies, e.g.
So far, this is the best slicer I have used with the Felix Pro. Felix Pro profiles are OK, except that temperatures for PLA are set too low for the first layer (185C) and speed for the first layer is much too high...