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drfish
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Re: My thoughts on the Prusa I3 MK3 3d printer kit

Sun Apr 07, 2019 7:35 pm

I regretted not going to MRRF last year and this year I found out it was happening too late and had other plans. It's only a couple hour drive. Ugh, I've got to get there next year.
TR BBQ XVI is happening 8/10/19.
 
CScottG
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Re: My thoughts on the Prusa I3 MK3 3d printer kit

Sun Apr 07, 2019 8:15 pm

-looked like there were lots of attendee's despite the cr@ppy weather. :D
 
SecretSquirrel
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Re: My thoughts on the Prusa I3 MK3 3d printer kit

Wed Apr 17, 2019 7:06 am

The print has been idle for a while due to a combination of work, other projects, and just general lack of time. However, as noted elsewhere, two different projects have intersected. The printer is busy printing rev2 of a coil winding form to help with winding a replacement width coil for my Ms Pac Man monitor. I'll also be printing the mounting hardware for the coil. As the details are quite fine, I still have the 0.25mm nozzle installed. I'm using gray Prusa PLA as a I had the tail end of a spool that was too short for anything large. Rev1 printed just fine as far as the printer was concerned. Rev2 is an adjustment of some measurements.

The above is actually the base reason I decided it was time to buy the printer. Not this project specifically, but for the ability to create my own tooling and project parts when needed.

As a related aside, I decided to take a risk and back the kickstarter for IVI: https://ivi3d.com. We shall see how that turns out. If things go well, it will be interesting to compare it to my Prusa.

--SS
 
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Re: My thoughts on the Prusa I3 MK3 3d printer kit

Wed Apr 17, 2019 7:22 am

We expect a full long form write up on the front page a week or few after you get it in

I know numerous people are clamoring that you should have done that for ms pac man, but, I always thought the Prusa would have been the better (and technically more relevant, using multiple meanings of the word technically at the same time.. efficiency!) write up for the site... GET TO IT! nopressure
 
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Re: My thoughts on the Prusa I3 MK3 3d printer kit

Wed Apr 17, 2019 11:19 am

SecretSquirrel wrote:
As a related aside, I decided to take a risk and back the kickstarter for IVI: https://ivi3d.com. We shall see how that turns out. If things go well, it will be interesting to compare it to my Prusa.

--SS


I've been seriously interested in jumping into 3d printing for a while now, and the IVI looks really interesting with being able to laser engrave and CNC in the same machine. I don't really have the time to tinker with it to get everything dialed in, and it seems to be a good option for getting into it while also having some nice to have additional features. I don't know if you're active/follow the maker community, but if you are I'm curious if this product is seen as a likely good bet? I'm not really sure where to look for trustworthy opinions in that community, and there's a lot of hype surrounding the IVI. I'd just like something reliable so I don't have to spend more time tinkering with it than using it, at least initially, but at least robust enough for some complex uses.

My primary use case was going to be parts and vents and the like for SFF computers, and parts and adapters for my work on classic cars or other electronics. Nothing in the engine bay, but inside the cabin, or the like. And whatever else I can figure out a use for it, like custom storage for small tools. Other organization helping stuff like a cradle for my wife's PS4 controllers so they stay there and have compartments for the charge cabling without having to run cables all over for the cat to chew on. Plus making parts to go with my woodworking projects would be neat.
I did know my way around Autocad and solidworks a few years ago so I'm hoping that relearning that part isn't too onerous.
 
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Re: My thoughts on the Prusa I3 MK3 3d printer kit

Tue May 07, 2019 10:28 pm

Ikepuska wrote:
SecretSquirrel wrote:
As a related aside, I decided to take a risk and back the kickstarter for IVI: https://ivi3d.com. We shall see how that turns out. If things go well, it will be interesting to compare it to my Prusa.

--SS


I've been seriously interested in jumping into 3d printing for a while now, and the IVI looks really interesting with being able to laser engrave and CNC in the same machine. I don't really have the time to tinker with it to get everything dialed in, and it seems to be a good option for getting into it while also having some nice to have additional features. I don't know if you're active/follow the maker community, but if you are I'm curious if this product is seen as a likely good bet? I'm not really sure where to look for trustworthy opinions in that community, and there's a lot of hype surrounding the IVI. I'd just like something reliable so I don't have to spend more time tinkering with it than using it, at least initially, but at least robust enough for some complex uses.

My primary use case was going to be parts and vents and the like for SFF computers, and parts and adapters for my work on classic cars or other electronics. Nothing in the engine bay, but inside the cabin, or the like. And whatever else I can figure out a use for it, like custom storage for small tools. Other organization helping stuff like a cradle for my wife's PS4 controllers so they stay there and have compartments for the charge cabling without having to run cables all over for the cat to chew on. Plus making parts to go with my woodworking projects would be neat.
I did know my way around Autocad and solidworks a few years ago so I'm hoping that relearning that part isn't too onerous.


I tangentially follow making, at the conceptual level, but not at the individual manufacturer or product level. I'm out of time for new expensive, time sucking hobbies. Do I think they are a good bet? Enough to risk $350 on them. Do I expect they will deliver on time? Most likely not. Do I think I will get something? Probably. Will it live up to the hype? Probably not. Will it be better than other printers you can get for $350, almost certainly. Will I get software or other updates past the initial delivery? Hard to say. It's a kickstarter. I assume it will fail, and I'll loose my money. But I hope it will succeed and I'll get something pretty nice for way less than I might otherwise.

As far as the multi-tool head, it's a neat concept, but I worry about the viability. Do you really want all the shavings created when doing CNC work to be tossed around inside the chamber where you are trying to 3d print something, where keeping a clean environment is a key ingredient to getting good prints? I also have minimal use for laser engraving. Cutting? Perhaps. But not engraving. I opted for a second print nozzle as my bonus item for being an early bird backer. The problem I see with the CNC setup, beyond the aforementioned mess is that the horizontal force available for the cutting head is very limited because of the mechanical setup. While the rotation of the tool is supposed to be the primary cutting force, rigidity perpendicular to the direction of cutting is important for things like vertical precision. So I doubt you could ever hope to do anything with metal, even soft aluminum would likely be impossible. That said, I just stumbled across something that made me consider going back and upping my backing slightly and getting the CNC head as well. Next post...
 
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Re: My thoughts on the Prusa I3 MK3 3d printer kit

Tue May 07, 2019 10:47 pm

To of my "hobby" activities continue to collide. The joystick used in Pac Man, Ms Pac Man and other games has a plastic stop spacer that goes around the joystick shaft and limits the through of the joystick, as well as limiting the joystick to four directions. Those spacers are unobtanium at this point. Enter the 3d printer again. Spent some time with OpenSCAD to create models for a complete set of replacement plastic parts to rebuild a Pac Man joystick.

The complete set, printed with a 0.25mm nozzle and 0.15mm layer height.

Image

The stop spacer is the tall cylindrical part. The exist in both black and red versions. The one on my joystick right now is black. The red one in the picture is another test print. You can't tell in the picture, but the central 14mm is solid, rather than hollow with infill. That's the wear area.

Here they are, side by side with NOS originals.

Image

Image

This is the black stop spacer I have on my joystick.

Image

The internal shaft in actuator (the ball shaped this) is not symmetric.

Image

Image

When printed with the inset side of the shaft up, it can be printed without any supports and comes out very looking quite good. The spacer (thing that looks a bit like a top) and the actuator plate (flat part) are much harder to print. I couldn't get them to print at an acceptable quality with supports. The actuator plate was especially bad because of its shape.

Image

Image

The central square is raised on both sides. I ended up printing it as two pieces. The raised square is smaller on one side than the other. The smaller part was cut out and printed separately and then press fit into the rest of the piece. Even with the actual piece in your hand, you can't tell. Same for the sleeve. The tall cylindrical piece is printed separately and press fit into the bottom part. It turned out way better than I was expecting.

All these test prints were done in PLA, which isn't really appropriate for high wear parts like these. So, I'm going to try out a new, more exotic filament. I've got both red and black nylon on order and arriving, hopefully, this weekend.

--SS
 
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Re: My thoughts on the Prusa I3 MK3 3d printer kit

Tue May 07, 2019 11:39 pm

I think it's time for a small station with a solvent bath (w/ fan-venting to filter), cleaning bath, and media-blaster. :wink:
 
drfish
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Re: My thoughts on the Prusa I3 MK3 3d printer kit

Wed May 08, 2019 7:10 am

As with your other thread, I'm still loving the updates in this one. So cool how both projects have collided.
TR BBQ XVI is happening 8/10/19.
 
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Re: My thoughts on the Prusa I3 MK3 3d printer kit

Wed May 08, 2019 9:31 am

SecretSquirrel wrote:
So, I'm going to try out a new, more exotic filament. I've got both red and black nylon on order and arriving, hopefully, this weekend.

I'm very interested to hear how that goes. I've only ever printed in PLA and TPU, although I've just received a spool of Hatchbox PETG because I'm curious as to how it will compare.
 
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Re: My thoughts on the Prusa I3 MK3 3d printer kit

Wed May 08, 2019 10:04 am

drfish wrote:
As with your other thread, I'm still loving the updates in this one. So cool how both projects have collided.


Well, to be fair, I'm actually starting to use the printer for my stated reason for buying it. Not Ms Pac Man specifically, but so I could create custom parts for various projects I might be working on - cases, enclosures, mounts, etc. Secondarily, so I could model and protoype something prior to sending it off to be machined properly. Just so happens that the first project it got used for is a neat one.
 
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Re: My thoughts on the Prusa I3 MK3 3d printer kit

Wed May 08, 2019 10:07 am

Chuckaluphagus wrote:
SecretSquirrel wrote:
So, I'm going to try out a new, more exotic filament. I've got both red and black nylon on order and arriving, hopefully, this weekend.

I'm very interested to hear how that goes. I've only ever printed in PLA and TPU, although I've just received a spool of Hatchbox PETG because I'm curious as to how it will compare.


If you've been able to successfully print TPU, PETG should be pretty easy. I found that PETG had a tendency to be a bit more stringy and required a little bit of temperature and retraction tweaking and that you will need some sort of build plate adhesion assistance. At least I did, printing on the Prusa PEI coated build plate. Even with it immaculately clean any part, that didn't have massing build plate surface area, had a tendency to become unstuck during printing.

--SS
 
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Re: My thoughts on the Prusa I3 MK3 3d printer kit

Mon May 13, 2019 11:44 am

Nylon filament arrived Friday afternoon. Have been running test prints, off and on, all weekend.

I was surprised at how soft and flexible the filament is. It's obviously nothing near as flexible as TPU, but it's more like TPU than PLA or PETG in flexibility. I've had three "jams" this weekend. None of them were a blocked nozzle, but anything that makes extrusion a bit hard (like trying to extrude too cold) will almost certainly jam up the filament at the extruder gears. In one case, the gears just ate enough filament away that they couldn't get a grip. In another, it started to spit filament out the side of the extruder gear opening, like can happen with TPU. In all the cases, releasing the extruder gear spring tension and pulling the filament out (with the nozzle heated) was all the was needed.

The big take away from the weekend of printing -- glue stick for teh win! :lol:

The Prusa Mk3 has a PEI coated build plate. Nylon doesn't stick to it. Period. However, simple glue stick coat solves that problem very effectively. In fact, almost too effectively. Elmers white glue is contains PVA while sticks to the PEI. The white glue sticks use a cellulose filler and the nylon sticks very well to that. So well that if I let things cool, it will separate the PEI from the steal plate, if I'm not careful.

Moisture. Go read up on nylon and everyone talks about how hygroscopic it is, and drying, and storage. It rained all last week, and Friday and part of Saturday were overcast and definitely humid. I haven't had humidity related issues, with one exception -- oozing. For now, I'm chalking it up to printing with a 0.25mm nozzle and a fairly slow print speed. The result is that the filament feed rate is quite slow. This means that it spends a fair amount of time (relatively) above 100C. So I'm thinking that the extruder is effectively pre-drying the filament. The purge line printed right at the start of the print has a very high extrusion rate relative to normal printing, and it does show signs of moisture in the filament. I'm not seeing any surface or other print defects one would expect from moisture in the filament, especially a filament that has effectively been sitting in reasonably high humidity for three days.

Oozing... Nylon oozes like crazy. Damp nylon oozes even worse. This is the one place that I have noticed the moisture.

Image

The "mohawk" on that part it due to ooze happening as the print head moves from another part, across the build plate, to start the next layer on this. The print was of nine identical parts and this was the first in the layer cycle. The individual hairs line right up with the layer start/end points. Another example:

Image

Again, all the hairs line up with start/end points and the rest of the part surface is in pretty good shape. The photos above are the two worst parts. From the print of the cylindrical part, that was the only one that was not good enough to keep, once the hair was trimmed off with an exacto knife. I'm actually re-running a print of the ball shaped parts printing them sequentially, instead of in parallel, to see how that impacts the print quality.

I do plan to dry the roll of red nylon I've be running test prints with, and I'm also picking up a cover that I can place over the filament spools on the printer to greatly reduce the moister absorption.

I'm printing with Nylon 6, and it warps if you look at it crossways. :( Enclosed printer is a must. I'm using a 90C first layer and 95C subsequent layer setting for the build plate. Even so, I had one of the ball pieces warp badly. The other eight were fine. Trying to print larger flat surfaces requires you to pay special attention to adhesion, or you'll have a corner pull up, especially if you build plate temperature is a bit on the low side and/or particularly uneven across the surface.

I'm using Kodak nylon 6 filament, which is listed at having 240-270C print temperatures. I have found the higher end of that range to work best for me. I've settled on 260C as working well. I imaging the higher temperature helps contribute to the oozing problem, on top of moisture, but the layer adhesion, bed adhesion, and surface finish are much better and printing sequentially, rather than in parallel stops the oozing from being a factor.

My replicated parts on the left. Originals on the right. The stop spacer (tall cylinder), I don't have an original for.

Image

--SS
 
drfish
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Re: My thoughts on the Prusa I3 MK3 3d printer kit

Wed May 15, 2019 6:18 am

I have a bit of experience sonic welding nylon webbing. When you sew it, anything goes, but man, welding it could be infuriating. We bought it in bulk, cardboard boxes and thousands of yards. It wasn't practical to control the humidity, so we had to fine tune the settings on the welder for each run, especially as the weather changed. A little bit more energy, a little bit less, all because of the moisture content varying, ugh.
TR BBQ XVI is happening 8/10/19.
 
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Re: My thoughts on the Prusa I3 MK3 3d printer kit

Thu May 16, 2019 7:47 am

I woke up to this mess this morning.

Image

This is what happens when you are printing with a sticky filament that has bed adhesion problems. I was printing Pac Man joystick spacers and started a print before going to bed. One of the spacers separated from the build plate. Because nylon is very gooey, it pulled the piece along and extruded a blob. Quite annoying.

Now, the good news is, if you are going to print a blob, nylon is a great filament in which to do it. While it is very gooey and sticky, it doesn't actually stick well to anything else. I was able to heat the extruder and simply pull off most of the blob.

Image

It took about a half an hour, with a pair of needle nose pliers and a fine wire brush, to clean the remaining bits off the extruder. Luckily, there was no collateral damage. It does make me think that I should probably print a set of plastic parts for the print head, and order a spare heater cartridge and thermistor. That way, when it happens and there is collateral damage, I can tear down the hot end and fix it immediately.

--SS
 
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Re: My thoughts on the Prusa I3 MK3 3d printer kit

Thu May 16, 2019 5:23 pm

This black nylon has been nothing but a frustration. The red had the normal, expected problems associated with nylon. The black? Well, its just being strange. Trying to run sequential prints of spacers, effectively a 35mm long tube with 14mm OD and 8mm ID, works great for the first part. Sometime after it moves to the second part, it will jam. I have to stop the print, bring the extruder back to temp, pull out the jammed filament and reload. Even printing at the upper range of the suggested temperature for the filament, it doesn't seem to want to melt well. :-?

Might try switching back to the red and see if the problem really is the filament, or if it is some weird side effect of last night's blob.

--SS
 
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Re: My thoughts on the Prusa I3 MK3 3d printer kit

Sun May 19, 2019 6:38 pm

So, this isn't so much about the Prusa I3MK3 as much as it is about 3d printing in general. I spent most of my spare time Friday fighting with the black Nylon. I was acting like it was possessed. On a multi-part print, printing in parallel, I'd get the first part come out perfect....

Image

And then the second would crash and burn (not literally). The printer would simply stop extruding and I'd get something like this....

Image

No stop between parts, just moving the print head from one location to the next. Doubly strange is that it might print the first few layers of the second part just fine, before it stopped.

Image

Tried slowing down the print. Disabled retracting. Everything I could think of and nothing helped. So finally i opted to go ahead and dry the filament, even though the print itself wasn't showing any signs of moisture problems and the red had printed just fine, even after two days of printing in relatively high humidity weather.

Whadya know...

Image

Mind you, I had trouble with the black from the moment I took it out of the manufacturers vacuum bag. So, the moral of this story? Dry you nylon before you do any printing with it, period, the end. i suspect the 0.25mm nozzle and smaller layer height exacerbated the problem.

My theory is that slow print speed and the 0.25mm nozzle allows any moisture to completely vaporize well before it reached the nozzle tip. The filament reaches 100C well before the melt zone. This steam will generate an internal pressure that would force the filament in every direction. The 0.25mm nozzle creates enough of a restriction that the steam presses the filament out and back as much as down through the filament. As the filament becomes softer, the pressure will cause it to expand and generate extra resistance against the nozzle walls, acting like oversized filament. Combined with the normal back pressure of printing, this may be enough to keep the filament from moving smoothly through the nozzle. Since its such a soft filament and the heat of the enclosure, plus the heat from the extruder motor conducted through the gears means that the gears will slip with very little back pressure from the extruder.

Not sure it that's really it, but it sounds good. :D

--SS

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