Hey, Slab!

Today, I decided it was time to reduce the noise of my printer.

First I did some measurements. I created a single-layer print of pure infill, increased first layer speed, and adjusted infill angle to make the printer move X, Y, or diagonally. Sure, I could have done a custom gcode sequence to just move the axis, but I didn't feel like digging into that. The first print was quite difficult to get off, so I moved Z adjustment from -0.8 to -0.6.

For each test, I used the Sound Meter app, first right in front of the printer, then on a separate table across from the printer, taking the average after about half a print. 

Y movement: Near printer 56 dB, other table 46 dB

X movement: Near printer 54.3db, other table 37.2 dB

Diag movement: Near printer 57 dB, other table 45 dB

Y movement is far noisier than X movement. There's some suggestions in this thread: Lubricate bearings, oil axis, add motor dampers. Oiling is an easy step, let's try that. After oiling, Y axis movement is 56.7 dB near the printer, 46.7 dB on the other table. Louder. Huh. Could be a measurement error.

I don't feel like taking the printer apart today, but I did get a slab of granite, and I have plenty of foam. So let's do some tests with them.

First step: Put pieces of simple camping foam under the feet of the printer. This reduced the noise level of the Y movement to 48.3 dB near the printer, 35 dB on the other table. Already noticeable! And this foam is pretty stable, so shouldn't make the printer too wobbly.

There's also a sound coming from the power supply, probably the fan there. Slightly irregular, not that loud yet.

I took the opportunity to fasten what bolts I could get to. I tried to open the power supply, but wasn't able to without taking more apart than I felt like. I did however notice a small piece underneath it that wasn't fastened correctly, so I fixed that. After that and putting the printer on a slab with soft foam underneath, the test print measures 40.4 dB near the printer, 31.5 dB on the other table. So this shaved off in total 15 dB, impressive! Even the power supply fan seems quieter.

Of course, I should have measured between fastening bolts and putting it on a slab, but I didn't. Maybe another day.

Luckily, the filament spool just fits under the cabinet above

I might want to have the filament spool mounted separately, possible between the two edges on the sides (you can see one in the picture). I would need a setup where the holder was easy to remove, though. I suspect some of the noise from fast moves is from the filament spool.

Clearly, this merits printing a really nice McBenchy!

There's a smidgeon stringing (that I have cleaned off), and the Z level is not quite perfect, but overall it's super smooth.

The first layer of the McBenchy had an average noise level of 34.9 dB (measured in front of the printer), the second one where the usually noisy bed fan started got up to 39.5 dB - that's not just the fan, though there were also some fast zig-zag moves that were somewhat noisy. Apparently moving the printer about has at least temporarily fixed what was wrong with the fan. Later layers averaged 37.7 dB, though there were places that were somewhat louder, it seems to occasionally hit a resonant frequency. Measured on my chair arm, so at normal distance for me, it's 29 dB, at the other table 28.2 dB.

All in all, I am satisfied with this noise improvement. In fact the power supply is not responsible for a fair amount of the noise, maybe I could dampen that by adding some rubber washers to the various screws.

Obligatory Borderlands 2 reference:

An upgrade

The last post showed the broken foot pedal on our bio garbage can. I managed to epoxy it back on, but because it was so cold where I did it, the epoxy didn't fully set (and ran over the support so I had to cut through it), and within a month of further stepping, it broke off again. No saving it this time.

My printer has mostly been standing still, partly due to my own carelessness, partly due to parts failure. I neglected to level properly before a big print and ended up with so much backpush that the filament stripped, then the rest of the filament in the hotend oozed out. This resulted in stuckness that couldn't be resolved with a cold pull, because there just wasn't enough heating up going on. In the end I took the cooling part of the hotend off and placed it on a toaster (flatbed style, known as "Deathtrap" to non-Danes) until the filament became soft enough to pull. This bought me a bit more printing time before the aforementioned cracks reappeared, and I'm not going to try to re-glue that piece. Fortunately, I had printed another extruder block, which I'm now cleaning of excessive elephant's foot before mounting. I also tried, for extra reinforcement, to apply some contact cement to the side of the block. I imagine it can seep in through tiny cracks and bind it together a bit. Would be interesting to compare epoxy and various glues not for bonding two parts, but for reinforcing one.

In the meanwhile, I have turned 50 (who'd have thunk?), and in that connection my wife arranged a Christmas and birthday gift conspiracy to get me a new printer. Enough money came in to get me a Prusa i3 mk3s, and maybe also the MMU. It should just barely fit in my workbench. While the Mendel90 has been good, it has also suffered from some build problems and limited upgradability. The rest of the world has moved on, and getting proper bed levelling, motor feedback, a large print volume, a better plate, and many more improvements will allow me to focus more on the design part than on maintaining the printer. I will probably still keep the old one around (somewhere) for when I need more printing done quickly, but my day-to-day printing should be easier with the Prusa.

Blast from the Past: The Monster

As part of preparing an OpenSCAD class, I wanted to show what my old printer (nicknamed "The Monster" in FabLab) looked like. Apparently I had never posted that on this blog, so it's about time. Here's the amazing almost-but-never-quite-working McWire "The Monster" printer:

The $200 usable ARM-based printer

We interrupt our (ir-)regular post of trials and tribulations with my Mendel90 to bring a short commercial:

There is a usable, open $200 3D printer on the market. The Monoprice MP Select Mini sounds like quite the coup if you're looking at getting started. This Hackaday review finds few issues with it, mainly poor temperature control, and also points out that it is the first cheap open 3D printer with a 32-bit processor. The time of Arduino-variations might be over. That's probably what's most exciting about if, apart from being a good cheap printer. There are new developments to be made.

The fact that unlike numerous other commercially-made printers this is compatible with all the standard 3D tools makes it extra interesting for hackers on a budget. The 120 x 120 x 120mm build volume is not huge, but frankly almost all my prints so far have fit within that.

Ok, so this is news about a year out of date, but only now saw it, and I frequently get asked about what a decent printer costs. Now I have a good answer: $199. And watch out for those ARM-based accelerations.

Note: I didn't get anything for this commercial. Monoprice doesn't even know I exist.