My first 3D printer

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Trnquill
Posts: 66
Joined: Fri Oct 05, 2012 10:01 am

My first 3D printer

Post by Trnquill »

Hello, newbie here! :) I have been tinkering with all sorts of things quite some time, mainly milling carbon fiber parts with my small CNC router. However, my latest creation needed some more complex parts so I decided to jump into 3D printing world! After browsing different makes and models for quite some time I ended up ordering Felix 1.0 early this month. Due to slight delay I received the printer kit yesterday. I thought someone might find it interesting if I wrote down my observations, so here goes. :) This is not a build review, just some random notes, so don't make too serious assumptions based on my some what random blabber...

UPS guy dropped the kit to my work and after arriving at home I carefully ripped it open. I was amazed how well the thing was packaged in the cardboard box. The foam pillow filling really kept the components in place. After unpacking all the parts from the box I was unable to put just the filling back in and close the box... :) I was also happy to find the "bag of extras" containing all sorts of goodies: full roll of kapton tape, huge tube of heat resistan glue (?), thermal paste, bag of zip ties, cable management spiral, tweezers, ... Nice!

What concerned me a bit was the big bag of electronics. A huge bag containing (almost) all the electronics, including sensitive things like the RAMPS board and optical endstop PCBs but also the bulky and heavy power supply with sharp edges... RAMPS was wrapped in bubble wrap but the endstops were floating around the bag. One of the optical gates had took a hit and was sitting crooked on the PCB. Few of the components on the RAMPS board were also a bit off. No biggie, I guess nothing had broken.

Another observation about packaging was how the build platform was packaged. It was just tucked in between the parts bags. Not quite like I would like to have a part packed, of which the absolute straightness is crucial. I eyeballed the plate from different angles and it looks quite straight, but time will tell.

One fine detail about the kit is the box of bolts & nuts. Nice to have all different sizes and types of bolts and such in different compartments. Nicely done!

Trnquill
Posts: 66
Joined: Fri Oct 05, 2012 10:01 am

Post by Trnquill »

I had some time last night to start the build. First I printed out the manual and I have to say the font is just too small. It's really hard to read without actually taking the printed sheet in hand. Would be nice to just keep it on the table and look it from some distance while building. I also find the "layout" of the manual quite difficult to follow. Having a picture of the ready built component in the beginning of each chapter sounds like a good idea but it all becomes really hard to follow when you can't know where a chapter starts! I also found the build instructions somewhat lacking in detail, especially when describing how to put together the extruder. The texts in the pictures have also too small a font and using red font color on top of pictures of red plastic parts is far from optimal. There's also some typos and/or missing words, like page 15, right column: "The curved washer is to compensate for an uneven surface of the m8 nut. If you mount it too the curved washer will not help anymore." Excuse me, what? :) If I mount the curved washer, too, it will not help anymore? :) But all in all, the manual is OK!

First step of the build was putting together the frame. The frame pieces are cut to length quite nicely and I was able to get the frame absolutely level and square just by making sure all the ends of the extrusions were aligning up properly. Drilled holes had some nasty burrs all around and some of the holes were filled with aluminum chips. Other than that the frame built up quite nicely and it feels really solid.

After putting together the Z-axis slider and the shelf for Y-axis I noticed how loose the Z-axis slider was. There's noticeable play in up/down and left/right directions. The up/down slop is nothing to worry about since the weight of the Y-axis mechanics will be pushing things down all the time. But what worries me is the left to right play. Pushing and pulling gently from the tip of the Y-axis support structure I can make the tip move 1-2 millimeters back and forth. I would presume there will be some movement in this direction when the build platform moves quickly back and forth. Time will tell... To me it would seem more solid to have round bars with linear bearings sitting on either side of the vertical frame bar for Y-support. This would make it absolutely solid in all directions. It would eliminate especially the horizontal play. If I find the play in Z-rail a problem, linear rails will be the first upgrade/modification I will try.

Rolling the Z-axis threaded shaft carefully on flat table revealed it to be slightly bent. I did my best to make it straight but could not reach perfection. We'll see if that matters or not. Dreaming of a ball screw solution... :)

In the instructions (for Felix 1.5, the version I have) it shows a slot for Z-axis threaded rod nut in the Y carriage. My plastic part does not have such a hole/slot. The nut is just inserted from below and nothing holds it in place. In other words the Y carriage can be lifter up away from the nut along the Z-axis threaded rod at any time. In normal operation this should not be a problem but during transportation there's nothing holding the Y-axis in place along the Z-axis. No biggie, I'm not transporting my printer.

Almost all of the plastic parts fit together just fine. I had to drill out few holes and remove some loose strings of filament from some gaps but other than that the quality of the plastic parts is good.

Kjetilei
Posts: 334
Joined: Fri Mar 16, 2012 8:26 pm
Location: Stavanger, Norway

Post by Kjetilei »

Hi Trnquill.

Welcome and thanks for a great write up of your experiences so far!

I like the camera mount with integrated FPV camera transmitter :) Do you only use it with a RC helicopter or also with multicopter? I have an older FatShark rig that I have mounted on a 3D printed Tricopter (similar to the RC-explorer style).

It would be interesting if you later on share with us your experiences from combining 3D printed parts with CNCed carbon and metal parts.

Trnquill
Posts: 66
Joined: Fri Oct 05, 2012 10:01 am

Post by Trnquill »

To Kjetilei: I use the camera gimbal only mounted to a multicopter. I have different kind of gimbal (just two axis) for my helicopter. Because the helicopter carries the gimbal in the front, having third (pan) axis is not that useful. You can pan only little over 180 degrees before getting the helicopter in the view. On multicopter the gimbal hangs under the body and thus has a clear pan view all around.

Ok, on with the build! Yesterday I had time to complete the mechanical build of the printer. I try to remember to write all the notions of my joyful evening here.

Next up in the manual was putting together the extruder. There were some parts of the process that were not too clearly laid out in the manual and I struggled a bit to find all the correct nuts and bolts and fit the parts together properly. I had extra hard time removing the hot end bolt. The part in which the nut sits in was screwed on extremely tight. But after long struggle with heavy pliers and a wrench I managed to screw the bugger open and removed the nut. The bronze extruder wheel was extremely tight fit. I tried drilling it out with a 5mm drill bit but in avail. It didn't fit. Finally after half an hour of careful filing and sanding of the wheel I managed to push it on the motor shaft. Phfeef!

My next WTF was accommodating the hot end in the extruder body without interfering with filament tensioner bearing. No matter how well I positioned the hot end or how much I wiggled it around I didn't manage to fit it in without it touching the bearing. When closing the "door" (the bracket with fan) the hot end pushed so tight against the bearing it was blocking movement of the bearing completely. Not too good a thing for free filament flow I thought. After loooong think and fiddling and scratching my head I finally got it: When filament gets squeezed between the motor shaft/wheel and the bearing the bearing will be pushed away from the motor and away from the hot end "cold nozzle"! I think this will be enough for the bearing to clear the hot end and rotate freely again. I'll have to pay close attention to this point when doing my first print.

Mounting the X-rail to printer frame and extruder to the rail carriage was a no-brainer. I tried to mount the rail as straight as possible using a calibre. There was enough play to mount it way off. I first used wrong bolts (M3x8) when mounting the extruder to the rail carriage but after the first try I searched and found the correct bolts in another bag (not in the box of bolts).

I have to say the belt mounting and tensioning system is superb! Simple, yet effective. The manual has some errors regarding the tensioners (you first mount them when assembling the part and then the manual says to mount them again when putting the belt on) but that's not a big problem.

Mounting the build platform support arm to Y-axis rail was a bit confusing. Simple process but the only "slide in rail nut" I could find had a M4 threaded hole in it! A bit loose for a M3 bolt. I almost started to grind end cap of a M4 bolt smaller to fit in the Y-rail recess but then I noticed a M4 bolt would not fit through the hole in the rail... But at that very moment, by accident, I noticed two more "slide in rail nuts" in another parts bag! Lo and behold, they had M3 threaded holes and I was able to mount the support arm just fine.

Nothing really to say about building the build platform. Except the amount of heat resistant glue supplied with the kit is... ehm... generous! :D 75ml tube for mounting tiny thermistor should be more than enough. After mounting the build platform to printer I quickly confirmed my earlier fear: the platform aluminum plate is not dead straight. It has a slight bend to it and is sagging in the middle. I can tune the table very precisely near the corners but distance from printer head to table is greater in the middle of the plate. We'll have to see if this is a problem or not.

After mounting the build platform and trying to level the table I faced my first major problem. Y-axis motor shaft was hitting the bottom corner of X-axis motor body well before the extruder nozzle was even near the build platform. I measured 5mm distance from the build platform surface to nozzle when the motor shaft was in contact with the other motors body. Not too nice. I verified many times I had all the parts in correct orientation but could not find any errors. One of the motors should be just 1-2mm further away from the other (horizontally) for the shaft to clear the corner of the body but there's no way to move the motors even that much. Finally I decided to cut the Y-axis motor shaft clean off right where it exits the belt pulley body. This was enough to clear the X-axis motor body and finally I was able to rise the build platform up to touch the nozzle. Minor design fail here, perhaps?

Closing to the end I found the manual "skipping steps" more and more. Not all the bolts were specified anymore (for example you just "mount" the fan to electronics box, no mention about what bolt to use) and some of the bolt specifications were just wrong (you mount the Y-axis rail end pieces "with m4x16 bolts and the m3 self locking nuts", might be a tight fit!). I had no problem following the instructions or putting the printer together, though, so no biggie there. Just a minor quality detail to point out.

Next up will be doing the electronics! Can't wait!

dognotdog
Posts: 181
Joined: Tue Sep 04, 2012 9:22 pm

Post by dognotdog »

Strange, the Y-axis shaft does not interfere with the X-axis motor in my setup. There is about 0.5mm clearance, even with a spacer behind the X-axis motor to keep it straight (on both X and Z axis, I find it quite annoying that the motors don't stay squared up to the supports with the supplied mounts). However, I positioned the Z-axis rail slightly to the right, as I used the left side to align it parallel to the extrusion.

Trnquill
Posts: 66
Joined: Fri Oct 05, 2012 10:01 am

Post by Trnquill »

dognotdog wrote:However, I positioned the Z-axis rail slightly to the right, as I used the left side to align it parallel to the extrusion.
Ah, that explains it! How could I have not realized that!? :) I have the Z-rail centered and that's why the shaft was hitting the motor body. I know there is some play in the fitting of the rail so I could have just moved it tiny bit to the left. Oh well, live and learn... :) (and maybe add a note in the manual?)

One thing I forgot to mention in my last post about the mechanical build: I am no very impressed with the rigidity or mechanical stability of the printer. Coming from "CNC world" I find the printer to have slop and give in almost any direction. I can for example shake the table back and forth (in Y-direction) by poking the Y-axis support cradle. The table can be moved up & down, too, just by putting some pressure on it. Not much, but certainly enough to mess up the calibration. I know the printer is not a CNC machine where everything has to be absolutely rigid but it still amazes my how loose things are. I wonder how accurate prints can the machine produce when there's this kind of mechanical slop all around. But once again, I'll have to wait and see what happens when I start printing! And I have to adjust my expectations to better fit a 3D printer rather than a CNC machine, on which you can basically stand and wiggle around without disturbing the calibration or tool position noticeably.

danielkschneider
Posts: 49
Joined: Thu Apr 12, 2012 3:29 pm
Location: Geneva
Contact:

Post by danielkschneider »

Trnquill wrote:
One thing I forgot to mention in my last post about the mechanical build: I am no very impressed with the rigidity or mechanical stability of the printer. Coming from "CNC world" I find the printer to have slop and give in almost any direction. I can for example shake the table back and forth (in Y-direction) by poking the Y-axis support cradle. The table can be moved up & down, too, just by putting some pressure on it. Not much, but certainly enough to mess up the calibration. .
IMHO, Z-give-in is needed. Most designs will have bumps (as a result of filament deposition physics) and the nozzle ought to be able to push the table down :). Pushing in x/y may be better than ripping the object off the platform. Not sure about this.

Trnquill
Posts: 66
Joined: Fri Oct 05, 2012 10:01 am

Post by Trnquill »

danielkschneider wrote:IMHO, Z-give-in is needed. Most designs will have bumps (as a result of filament deposition physics) and the nozzle ought to be able to push the table down :). Pushing in x/y may be better than ripping the object off the platform. Not sure about this.
Yes, of course! That's not what I meant. :) What I meant was if I apply some force to table, it will not return to it's former height. This actually applies to the while Z-axis mechanics: Some pushing or pulling at any point of the structure and the table will be at slightly different height. And by "slightly" I really mean fractions of millimeters. But according to what I've read fractions of millimeters actually count in 3D printing. Especialy in Z direction and for the first layers. I woudn't care calibrating the table before every single print to ensure proper starting height... But as said, we'll see how she prints as soon as I get all the wireing in place!

I have now soldered and zip-tied all the wires except hotend loom & the fans. So, enough of writing and back to soldering! :)

danielkschneider
Posts: 49
Joined: Thu Apr 12, 2012 3:29 pm
Location: Geneva
Contact:

Post by danielkschneider »

Oops sorry for the misunderstanding. I admit that I only care for reliable printing (unsupervised night prints, no warping, etc.) and yes for perfect prints, fractions of mms do count IMHO.

But some guys here do seem to be able to get near perfect prints done using half layers or less for perimeters. You'll see ! Good luck with the wiring !

dognotdog
Posts: 181
Joined: Tue Sep 04, 2012 9:22 pm

Post by dognotdog »

Rigidity as in a Mill isn't required, as ideally no force is exerted by the print head onto the bed.

However, I do find the Z axis movement annoying, especially the Z axis slider. I cannot really tighten the bolts connecting the printed parts and the slider, as then it just binds up. I would very much like a proper ACME threaded rod on there. Replacing the Igus slider with a double MGN slider like the new X and Y axes, though, is an expensive proposition, as you'd need probably need a total of four carriages.

I am trying the next best thing, ordered some flexible couplings for the Z axis, to see if that gets rid of the annoying wobbling. And it's true that calibrating the Z axis height is a bit hit and miss. I just scraped half the kapton tape off the bed, as I must've bumped the endstop piece while fiddling with the printer. Not fun.

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