Thursday, July 20, 2017

Not In a Long Time Has These Words Been So Relevent

Think about these words.  Think about the NDAA and think about the lack of legit moral authority from DC

Preamble
1
When in the course of human events, it becomes necessary for one people to dissolve the political bands which have connected them with another, and to assume among the powers of the earth, the separate and equal station to which the Laws of Nature and of Nature's God entitle them, a decent respect to the opinions of mankind requires that they should declare the causes which impel them to the separation.
2.1We hold these truths to be self-evident, that all men are created equal, that they are endowed by their Creator with certain inalienable rights, that among these are life, liberty and the pursuit of happiness.
2.2That to secure these rights, governments are instituted among men, deriving their just powers from the consent of the governed. That whenever any form of government becomes destructive of these ends, it is the right of the people to alter or abolish it, and to institute new government, laying its foundation on such principles and organizing its powers in such form, as to them shall seem most likely to effect their safety and happiness.
2.3Prudence, indeed, will dictate that governments long established should not be changed for light and transient causes; and accordingly all experience hath shown, that mankind are more disposed to suffer, while evils are sufferable, than to right themselves by abolishing the forms to which they are accustomed.


Friday, June 30, 2017

MarkForged 3D Printers Special Sauce

I see the Markforged printer and was wondering how it did what it does, and why is it worth the $5000-$10000 price tag?

Finally found a video explaining it, and well the only secret sauce is the advertising.

The filament they sell is basically a regular plastic CF filled filament with proper engineering data sheets.  Wether the data sheet is real or just copy and paste from the manufacturers spec sheet is unknown.

The strands of fiber are essentially the same thing that you can buy on eBay as Kevlar thread. It's quite cheap.  It prints a layer then basically irons the fiber into the surface and has a cutter in the head of the printer.  That's it.

I am surprised no one has released a DIY version of this already, patents be damned.

Yeah it's a nice machine and the custom slicer software, I would pay maybe $500-$1000 for, but the printer itself?  It's a $1500 printer being sold for $10000.  Add another $200 if they are using Euro or Japanese linear guides vs China parts.

The metal sintering idea isn't that new.  It has been speculated and debated in the industry for several years.  

Looks basically a guy like myself with more cash than I got spent some experimenting time.  I was thinking about this process a couple years ago.

The microwave crucibles are a common ceramic pottery crafts item. Metal filled filament can be purchased from Protopasta, or even no name China stuff now. If I need a really high metal content filament, I'll give a guy in China that I know a call and order a batch.

This reminds me of the big marketing push last year about the supposed new high strength high temp PLA plastic.

It gets annealed in a oven at 100c for a hour which raises the melt point and increases strength.  It was a big thing... Until people discovered that ALL PLA plastics have the same qualities, not just the magic stuff from Protopasta.  

If you want to do laser metal sintering 3D printing.. It isn't hard..  I can build one for probably around $10,000 counting my experimentation costs for the first unit and bring it in at maybe $2000 per unit production price for a co2 laser based model and if you want something really fast, a fiber laser based model for probably around $25,000 development and $9500 per unit production costs.

Most of the software is already released open source, the hardware is open source, it's basically just putting the bits together and tuning it.


Wednesday, June 14, 2017

The Beauty of Carbon Fiber Parts



For holding a 65mm spindle in a MPCNC

Coincidence that a cheap trim router and the good inverter spindle are the same 65mm size.

Solid plastic with 15% carbon fiber by weight

Tuesday, June 6, 2017

Tuesday, May 30, 2017

Carbon Fiber 3D Printing 2

I have so far done roughly 60 hours of printing with the carbon fiber PLA filament.

I have gone thru about a kilo at this point.

Observations:

It does not warp like the usual PLA plastic can tend to and it is much stronger.  How much stronger I do not know, but it took quite a lot of effort to break a item I was hammering on with a rubber mallet.

I had a set of files that for whatever reason the designer made the separate pieces fit together exactly and no tolerances.  53mm inside hole, meet 53mm part.  Of course it ended up being a couple tenths of a mm too tight.  The reason for that lies in the way the gcode is created and too complicated to go into here.

So it being 3am, tired and in a hurry I thought I would not check the parts with calipers first, rather fit together and hammer into place.  Of course I broke the part,  Not the part A that took 30 hours to print, rather just the part B that took 8 hours.

Interestingly it did not break at the layers, rather in a jagged line across the layers and in a very thin section of the part.  The part is still usable as it is cracked in a non critical area, however it is a commission job, so it goes into the sample bin and a new part was re-drawn with tolerances and is re-printing.

I am quite impressed with this stuff.

The finish is pretty much as advertised.  It is matte and smooth.  Stringing was about the same as regular PLA.  I am using a bowden print head on this one and it is pretty much par for the course to have to clean up the part in post processing.

It does require printing at a much slower rate than regular filament.  That is a downside.

It does clean up easier with sandpaper and wet sands better than regular PLA.  It does not really work with the wire brush cleanup trick that regular PLA works with.

I am now looking for Aramid fiber filled and higher percentage fill carbon fiber filament.  I found a 30% filled filament in China for around $50 with free shipping.

The Aramid fiber is still very exotic and not available from China.  So far I can only find 2 manufacturers of it, and they are all out of stock.

Reviews of the stuff show that it is slightly more giving than the carbon fiber and not as abrasive on the insides of the machine.

I am also searching for nylon carbon fiber filament and will be placing a order of that soon as I find someone willing to answer emails back about shipping and is not making me jump thru a series of hoops.

Note to those of you in the former USA.  The Chinese are rapidly catching up to you on customer service and reliability.

Friday I placed a order of carbon fiber filament from China, and it arrived Monday afternoon at a price less than buying from a local supplier.  $40 with shipping and 5 spare nozzles.

My latest batch of China orders was a little over $800 and shipped via various methods.  All the express shipping orders arrived within 10 days and the postal orders are all ready to pick up at the registered mail clerk with the exception of 2 small items coming from Singapore as of today.

This is from China to a turd world country, with a corrupt postal system full of thieves.