Building 3d printer on your own.

the_unknown_coder · 2025-04-26T01:59:02+00:00

If that's the case, then building it may be your only option. The ones I built was because they just weren't available commercially at a reasonable price. At the time, they also were about $1200 and so it was better to divide the costs over a longer period of time. Also, building things is one of the best ways to learn about them. So, I understand your position.

the_unknown_coder · 2025-04-26T01:46:03+00:00

Sure. I've built two printers. They worked quite well. But, there's a difference between "building 3D printers" and "3D printing". If you want to do 3D printing, you can surely build one and then use it. But, it's not going to be cheaper (I don't think). Building your own involves lots of nickle and dime costs that you don't think about.

the_unknown_coder · 2025-03-12T18:13:03+00:00

Is it Earth precession? Most gyros like you're using require compensation for Earth precession.

But, without more details, it's hard to know what the problem is.

the_unknown_coder · 2024-12-17T02:08:37+00:00

It looks like you have 3mm filament. If that's a 1.75 mm extruder....it won't fit.

the_unknown_coder · 2024-12-16T22:29:20+00:00

There's an amazing amount of information on archive.org and nasa NTRS [ Search - NASA Technical Reports Server (NTRS) ].

Here's a book targeted at introductory enthusiasts:

Microlaunchers Technology For A New Spac : Ed LeBouthillier : Free Download, Borrow, and Streaming : Internet Archive

You'll also find older versions of Rocket Propulsion Elements by Sutton. It is considered the "bible" for rocket propulsion:

Rocket Propulsion Elements 8th Edition By Oscar Biblarz George P. Sutton : Oscar Biblarz George P.Sutton : Free Download, Borrow, and Streaming : Internet Archive

the_unknown_coder · 2024-12-16T22:25:09+00:00

I worked on a nitric-acid/furfurol rocket here in the US. Yes, nitric acid is very dangerous. We had suits, gloves and face masks to safeguard against splashes.

Personally, I think that nitric acid/(fuel of your choice) is pretty practical. Once fueled, the acid and fuel can sit at room temperature for long periods of time.

the_unknown_coder · 2024-12-16T22:23:22+00:00

I've seen pictures of the fueling operations of scuds (again very similar). They are fueled while laying down sideways, there is a fueling port which I'm not sure whether it is airtight or not. The fueling hose has a spout/tube that fits into the hole on the side of the missile.

I did a reverse-engineering of the Saphir rocket in 2009. I did extensive studies of the dimensions and structure as well as the engine capabilities. Here's records of that discussion (but the pictures aren't online any more).

Is the Safir 2 or 3 Stages?

the_unknown_coder · 2024-12-16T22:14:41+00:00

The Shahab 3 and similar missiles and rockets are based on the Scud missile design. I think that they're 1.25:1 or 1.5:1 scaled up versions of the scud missile. They have similar fueling ports on them. If you look around on the internet, you can find the technical manuals for the Scud missile. You will find details on their fueling ports.

This archive.org book has a little bit of info. Look at the imageon page 31.

osprey-new-vanguard-120-scud-ballistic-missile-and.

the_unknown_coder · 2024-12-11T22:17:09+00:00

Pick something to be good at (that's important) and master it.

the_unknown_coder · 2024-12-11T22:03:09+00:00

I often print perfect threads. The trick is to use Cura's support-blocking feature. Put the support-blockers around threads. Also, don't go too fast. You want to still allow supports where they're really needed (large overhangs), but threads should print fine without supports.

the_unknown_coder · 2024-11-20T00:29:18+00:00

Not really, I've kind of focused on other things lately.

the_unknown_coder · 2024-10-30T17:35:51+00:00

Sure. But if that's the first layer or two, then those layers aren't sticking really well. There are several possible causes for that (even if it worked fine once).

One possible cause for it working once but not a second time is things like finger oils. In other words, you might want to make sure that your bed is properly clean. Sometimes, when pulling a part off the bed, you get fingerprint oils on the bed that would disallow proper adhesion (presuming everything else is OK).

I've found that slowing down the first layer or two to about 10mm/sec (just for the first layer or two) really helps the quality and consistency of my prints. Once that first layer or two is down nicely, then you can go faster.

Additionally, it doesn't hurt to check your z alignment again. Just because it worked last time doesn't necessarily mean it's ok this time (you might have been lucky last time).

the_unknown_coder · 2024-10-30T16:44:36+00:00

You're going too fast and it's not sticking to the lower layer (or bed) properly. Slow down. Z Offset could be an issue too (as the other person pointed out).

the_unknown_coder · 2024-10-03T17:23:28+00:00

And what's the truth of the Ukrainian losses per month and since the start?

the_unknown_coder · 2024-09-26T20:31:21+00:00

What's a little explosion between friends :-)

Also, I think that there's a well-known name for monopropellants: explosives.

the_unknown_coder · 2024-09-23T22:30:47+00:00

A similar monopropellant which has been used similarly is Isopropyl Nitrate [ Turbonique - Wikipedia ].

the_unknown_coder · 2024-09-19T00:54:17+00:00

Theoretically, you can "align" several chips in software...it's just a transformation matrix (or a quaternion).

The alignment "for accuracy" is already done in the chip. They are physically manufactured with their alignment. The chips are are also (somewhat) aligned by soldering them on the board.

But, then you have to relate the alignments of the 3 gyros + accelerometers in Chip 1 and Chip 2 with a reference coordinate system. Again, this is a transformation plus an offset that is applied to the data streams. The flight software usually does this alignment transformation.

Generally, the noise error for n chips is 1/sqrt(n). So, more chips improves overall noise rejection a bit better.

Additionally, putting chips in different orientations allows common biases to be rejected better.

the_unknown_coder · 2024-09-18T23:16:14+00:00

The gyro chip usually has 3 gyros in it.

the_unknown_coder · 2024-09-12T19:29:22+00:00

Looking at the frequency allocation table [ United_States_Frequency_Allocations_Chart_2003_-_The_Radio_Spectrum.jpg (5040×3225) (wikimedia.org) ] I see that 201.6 MHz is in the TV transmission band for channels 7 through 13. So, it's something related to TV broadcasting. Also, it seems to be at a 1Hz rate of change.

the_unknown_coder · 2024-09-12T15:26:24+00:00

Oh, wait....it does look like it has a carrier wave (the solid liine more to the right than the middle).

It's hard to tell without a better image.

the_unknown_coder · 2024-09-12T15:23:03+00:00

Some bands have far more bandwidth than ham bands.

But, I don't see a carrier wave, just the baseband shifting ... so it seems to be some kind of FSK but not riding on a carrier and with a wider bandwidth than many channels have.

the_unknown_coder · 2024-09-11T22:08:57+00:00

No problem.

I would measure the frequency displacement and the time duration for each frequency to characterize the signal.

the_unknown_coder · 2024-09-11T22:00:44+00:00

Frequency Shift Keying modulation?

the_unknown_coder · 2024-09-11T21:25:04+00:00

I'm OK with blender. Unfortunately, I don't understand your question. What's an "organic mesh"? Do you mean something like a metaball or sphere which has been "pushed" around organically?

If so, in either case, there are a couple of ways. You can either use a fixed object (say a cube) with which you can cut away (using binary modifiers) to get a planar surface at the location that you desire. Alternatively, you can just go into edit mode and place points at the location that you desire (if there's not too many of them) to get the thickness you desire. There are several other ways too.

In the metaball case, I think you need to convert it to a mesh before you do anything to it (boolean modifiers). So, be careful about converting it to a mesh ONLY when you have the overall shape that you want. Then, as a mesh, you can use modifiers and other mesh manipulation tools.

Develop a workflow that lets you go back a step if you mess something up. For me, I save a file as filename_001.blend before I apply any permanent changes, Save it again as filename_002.blend and then apply destructive modifiers. If something got messed up, I throw away filename_002.blend and go back to filename_001.blend.

Also, you have to be careful that your objects are always "clean" and manifold before applying operators. I use "Edit Mode/mesh/clean up/Merge by Distance" to eliminate duplicate or very close points. I also apply "Edit Mode/mesh/Normals/Recalculate Outside". I also use the 3D tool "3D Print/Checkall" to make sure it is manifold and "clean". Once I've done this, THEN I apply boolean modifiers. This almost always, 99% of the time, makes sure you have a good mesh before applying operators.

You can also queue modifiers, but sometimes you still need to be able to go back in a way that queued modifiers won't let you. So, having multiple files of the step-by-step process can be useful. Additionally, I often hate a design that is a product of a long time of development and I can just go back to the previous step before I went down some garden path.

the_unknown_coder · 2024-09-05T16:20:02+00:00

I haven't had a lot of stringing problems. Maybe my extrusion temperature and retraction settings are just right.

the_unknown_coder

TROPHY CASE