5th Gen - Review and Head to Head with Rep 2

[American 3D Printing]

As I mentioned above, the bed looked crooked, so I figured I should check on that first. But before that I decided to load some filament into the extruder. It took a good 10-15 minutes of fiddling to get the extruder connected to the X carriage. From the front panel, I selected Load Filament and waited for it to heat. It takes about twice as long to heat the filament as the Rep 2. Loading it is essentially the same procedure as the Rep 2. The front panel user interface takes some getting used to, as there are two buttons on each right corner of the display, in addition to the scrollwheel, and the scrollwheel button. At first it is not intuitive that the scrollwheel even has a button, but some of the commands are invoked by pressing the scrollwheel button, and others with the buttons on the right corners of the display. The Rep 2 has far more intuitive UI.

My normal procedure for leveling the bed on the Rep 2 (and all the rest of our different printers) is to make sure the extruder is hot so any ooze is soft and doesn't affect the slide-the-paper-under-the-extruder friction. But the 5th gen wanted me to unload the filament (!?!) before leveling the bed. So I had to unload the filament. When it finished that, it cooled the extruder and allowed me to proceed with the leveling procedure.

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There are two wheels to turn to level the bed, unlike the 3 on the Rep 2. One is in the front, and the other is on the side. I should also mention here that the bed is glass. We've purchased aftermarket glass for our Rep 2s that we use for PLA, and we use the original acrylic bed covered in PVA glue for our nylon and PET builds.

When you invoke the bed leveling procedure, it raises the bed with the extruder in the middle until the extruder just touches, then it goes down a couple mm and then just sits there. At first I thought it was hung or something, but every few seconds you could hear that familiar "thunk" that the Rep 2 does when it's lowering to the next layer, in this case it's raising the bed.

Ever.


So.


Slowly.


Go get a cup of coffee, because it really takes a long time to finally decide that it's happy. I think it's like 10 minutes or so. Then the extruder comes to the front of the bed and an animated graphic on the display tells you to turn the front knob in the direction shown until the LED on the extruder illuminates. It was telling me to turn the knob CCW, so I did.

Until the knob fell off.

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Huh? I looked underneath and saw that there is a threaded stud sticking down, and the knob has threaded female threads. Okay, so I put the knob back on and turn it CW, until it is completely finger tight. The last couple of turns. I could observe the front of the bed lowering, opposite from what the firmware is telling me it wants (and it's also visible that it is the wrong way, but hey, I got the knob back on!).

So I started turning the knob CCW like the firmware wanted and I could see the front of the bed raising up as we wished it would, but then you could feel the resistance of turning the knob go to nothing, the bed stops raising and the light never came on. I kept going until the knob fell off again.

I repeated the procedure above AGAIN, but this time, just before the knob got all loose again, I pressed upward on the bed with my fingers and got the LED to come on. The display said it was "calibrating", then it moved the extruder over to the right side of the bed, middle of the Y axis, and again wanted me to turn the knob, but I aborted, because I knew that I had cheated to get it past that checkpoint in the procedure and it just wasn't right.

I figured I was just not doing something right so I call Makerbot tech support.

[American 3D Printing]

Hold time was only about 15 minutes before I got a tech. I explained the situation, he asked me some questions and I performed a few diagnostics and things for him. He somehow concluded that the smart extruder was faulty and got my shipping info for a new extruder (I have one customer who's on his 3rd extruder on his 5th gen, and I have another 3D buddy who returned his entire machine after the 2nd extruder quit working). I figure that the drones in tech support are just programmed to send out a new extruder instead of using real logic to troubleshoot stuff, but that's probably what they're taught. I know the company has been growing like crazy and they're probably having trouble finding good help. I get that. But i don't see how a new extruder is going to fix a bed that won't mechanically level. Who knows, maybe it will?

But, while on the phone I did learn a few useful tidbits.

The business part of the extruder moves up and down on the Z axis, about a mm or so. It can sense when it touches the bed, and it can also go up and down. That's pretty cool. Teaser - when you build, when most printers raise the extruder or lower the bed to do a Z-lift, the 5th gen raises the extruder - it's cool to watch.

I asked him how the machine senses Z limit, as I didn't see any limit switches like all our other printer, including the Rep 2. He said that it was a laser. Later in the conversation he said it was a hall effect sensor. I don't know exactly what it is, but there certainly aren't any mechanical switches visible anywhere on the machine, not just for the Z axis, but for the X and the Y as well.

As for how it is actuated to move up and down, I'm not sure. I know that on the high speed pens plotters I used to design, we used a voice coil driven by a linear amplifier to moved the pen up and down.

[American 3D Printing]

Being somewhat impatient and curious as well, I went ahead and went through the whole bed leveling exercise using the cheat of holding the front of the bed up manually. I looked at the left and right levels and it still looked really crooked. So I adjusted the right knob until it was visually level, then went through the procedure again, and by the time it was done, it was crooked again. It occurred to me that the gantry itself might be cockeyed and it was compensating for that?

Bear in mind, that each of these bed leveling sessions take a good 15 minutes or so. Also bear in mind that there is a piece of solid PLA sticking out of the end of the extruder because it doesn't want to level the bed with a hot extruder like i am used to. Turns out it doesn't matter. It turns out that before EACH AND EVERY BUILD it "calibrates" Z-height. And this takes about 10 minutes or so with this incredibly S L O W business where it gradually eases its way to what on most printers is the "bounce" part of finding Z home. Add the 5 minutes or so to heat and you've got an automatic 15 minutes before EACH AND EVERY BUILD before it starts building. Let's just say we are not impressed and do not consider this an improvement over the Rep 2 (and all our other various printers).

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I shrugged my shoulders and decided to make something, the ubiquitous stretchlet that comes with all Rep 2s and 5th Gens. Turns out the one inside the 5th Gen's memory is on a raft.

How nice.

The raft itself is an identical slice to the one that good old Makerware 2.2 and 2.4 make:

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Drum roll:

It took ONE HOUR AND 8 MINUTES!!!! To make what the Rep 2 does in 16 minutes! WTF??

Bear in mind this is on top of that darn Z-height calibration and heating which total around 15 minutes per build.

Okay, calm down, maybe it's making .05mm layers at 15mm/sec or something? I can't see the slice because it is inside the machine. Maybe it is something in the firmware? The support tech wanted to know what version firmware I was on, and I have read that there have been a LOT of firmware updates on these things.

[American 3D Printing]

Sorry, been busy in the store. Still putting the 5th Gen through its paces and taking lots of pictures, just haven't squeezed the time in to post here. I see 250 views - feel free to comment or ask questions, we've had the thing for most of a week and are starting to get a better feel for it.

Picking up where I left off - I thought maybe the slow build was something to do with the slice settings - really high resolution, slow print speed, something like that. So we need to do it straight from makerware.

Turns out Makerware 2.2 and 2.4 (our in-house staples) aren't compatible with the 5th Gen, so we downloaded and installed the latest "Makerbot for Desktop" 3 point something. I think I remember this from previous versions, the drivers aren't properly signed or something and Windows keeps asking if I really want to continue installing at several points. It took a fairly long time to install and required babysitting to get past the prompts, but it worked just fine out of the gate, which is not something I can say about the Sunbeam Smoothieware drivers that make the Z-Morphs go.

So we load the stretchlet into the software and set it for 10% infill, 0.2mm layers, 90mm/s print speed, no raft and and slice it up. A new twist with this software is that it splits slicing and printing, unlike older versions which are a 0ne button affair. In addition, when you go to print, you don't see all the settings like in the older versions, there's a separate Settings screen that you have to save. Not too inconvenient or unintuitive, but more clicks nontheless.

Drum roll.....



One hour, no minutes and 33 seconds. Ahem. Okay, let's try some of our other standard objects...

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Oh and for the benefit of the doubt, maybe the build quality is better?



Please forgive the point and shoot image quality, the good Nikon's at home, but trust me, it is absolutely impossible to distinguish which one was made on the Rep 2 and which one was made on the 5th Gen. Remember, not only does the actual build take 4 times longer, but you have that 15 minute Z-height and warmup procedure before the timer starts ticking.

A couple other random observations that i hadn't mentioned before...

The 5th Gen is noticeably louder than the Rep 2. In fact it is now our 2nd loudest machine after the Z-Morph, which is in a class by itself. But then, the Z-Morph is about 5 times faster and every bit as good. The stepper motors are really musical though, second only to our plywood Type A machines Series 1.

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This rook from Thingiverse takes about 56 minutes to build on the Rep 2. One hour 44 minutes on the 5th Gen, not including that 15 minute pre-print overhead.



As with the stretchlet, the one from the Rep 2 is indistinguishable from the one from the 5th Gen that took twice as long to build.



Right around now the guy that owns the 5th Gen saunters into the store and I explain what I've found so far. He almost started crying. I showed him the stretchlets and the rooks and asked if he could tell them apart. The closest thing he could find was the arch over the door of the rook that the Rep 2 built had a little dangly artifact, which was quickly scraped off with an Xacto knife.