Friday, January 23, 2015

Interesting 3D printing development today.

Have been dialing in the settings and the like for my 3D printer.  Oddly the machine puts out better quality the faster I run it.

Currently printing at 200mm/second speed.  Started out at 100mm/second bumped it up to 200% federate and the print quality got better.

Most of the little consumer printers can't even hit half these speeds without serious frame flexing, lost steps etc.

Next step will be increasing the x,y axis resolution even more.  


Are you watching? Or are you acting?





8Then I heard the voice of the Lord, saying, "Whom shall I send, and who will go for Us?" Then I said, "Here am I. Send me!" 9He said, "Go, and tell this people: 'Keep on listening, but do not perceive; Keep on looking, but do not understand
Then I heard him call out in a loud voice, "Bring near those who are appointed to execute judgment on the city, each with a weapon in his hand."

Heaters.

So much of my design lately centers around heaters.

My regular gig, I build 3D printers for a living.  The printers I have spent over a year now working on utilize heaters.  

I have been using 12volt DC heaters in the form of silicone pads from China.  The downside to this arrangement is that I need a large power supply.  40 amps is a lot of juice and money adds up fast in wires, connectors, etc.

So today I started working on making my own heater.  

I purchased a length of NiChrome wire from the local heating supply company, and set to work.

First attempt turned out really bad.  

I tried to cheese it by using regular household silicone caulk.  It didn't set right and turned cuumbly.

Today's attempt was different.  

I used a sheet of Mica, taped the NiChrome wire to the sheet with kapton tape, then added silicone RTV, making a sandwich of silicone RTV, mica and heater wire, with a thermistor handling the temp reading.  

I had success...

Well kind of....

The thing works.  Draws 254 watts at 220v AC.

Heated up to 120c no problem.

Except that the silicone is not curing properly.  I think I got an old tube. It remains sticky.

So tomorrow I'll grab a tube of new silicone rtv and hope the catalyst in it will get the other stuff to cure as well with another layer on it.  

It is just a prototype and although it is the shop machine, so I do use it to make stuff.




CNC Plasma cutting for noobs.


CNC plasma cutting is the use of a CNC machine to cut metal.

It is not as accurate as laser, or water jet.  This is because of how the plasma torch works. 

It will be accurate for things like auto parts, structural steel fabrication, farm equipment etc.

However it is not accurate enough for firearms, or electronics parts requiring high levels of precision.

If you are looking for a side business or even a small cash business you can run from your garage, CNC plasma can fit the bill. Of course your individual situation will vary. You need to do careful study and all the usual business was stuff.

CNC plasma is 2D cutting, much like water jet or laser.  There are 3D plasma machines, but they are well above 100k USD and beyond the scope of this article.

First things you need some basic skills in CAD, drafting, metal fabrication, and ability to read blueprints.

Second you need a machine.  

My experience has been that you need at least 4x8 foot working area and preferably 5x10 feet.

This is because steel comes in 4x8 sheets.  Smaller machines will result in lost work, and extra headaches.  I learned this the hard way.

You need a separate plasma torch with what is called a machine torch.  For money making you really only have one choice, and that is the Hypertherm Powermax series.

This is because of the consumable parts. There are China machines and Thermal Dynamics which are cheaper initially but over the course of even a few months, the consumables cost of the cheaper machines will save you more than what the price difference was.  

You need at minimum a Powermax45 or Powermax65 with the machine torch, NOT the hand torch. 

This is for the next part of the machine you need which is the automatic height control.

Steel will flex when cutting and the torch will either crash into the steel or get too far away to make proper co tact and the flame will go out. Manual height control machines seem like a great deal but they are a 2 man operation and you need to take all sorts of extra precautions with eye wear etc.

Save yourself the headache and get it.  

You need a good air compressor.  Something big like 5hp. I used 2 smalller 1hp compressors running at the same time.  It did work.  Along with that you need a air dryer.  Some guys get obsessed about it. An ordinary harbor freight dryer for paint sprayers works ok, just run the air thru a large 1-2inch steel pipe that will act like a radiator before the water separator to let the air cool down and the water will condense easier.  Water will kill your torch tips.

You also need a water table.  The machine sits on top of the water table.  When the torch cuts it produces sparks and smoke.  The water will catch the sparks, smoke, and cool the metal reducing distortion.

Consumable parts are expensive. A typical set of tips will get you an hour of cutti g with a Hypertherm. Mostly it depends on the pierces the torch makes.  Each time it fires there is a little bit of an electrode inside made from hafnium that gets consumed. A set of torch tips for a Hypertherm will get you 3x the amount of pierces that a Thermal Dynamics torch will give you and cost the same amount for a set. A Chinese torch will cost half per set of tips and get you 1/4 the amount of pierces as a the thermal dynamics.

I have cut over 1/4 mile of 6mm steel plate with one Hypertherm tip, and I have cut 1/4 sheet of 12mm steel and consumed a tip.  But generally the Hypertherm was consuming 5-6 sets of tips per month in my shop on average.  

Electric service.

You need good electric.  As in 20kva.  If you plan on running a generator get 30kva. The surge in power draw will wreak havoc on lower rated generators.  Or get a Miller brand all in one gen set for welders. They are rated for this type of duty cycle.

Most households in the US will have enough power to handle a CNC plasma.  Basically you need around 50-60 amps service which means you need anywhere from 4-6ga wire depending on how far you run the wire.

You also need a angle grinder.  Something good not cheap.  Cheap angle grinders vibrate.  Vibration will ruin your hands fast.  Plasma leaves slag on the back corner of the cut.  It needs to be removed with a hammer and angle grinder with a flap disc or a grinding wheel.  You will use both.

Angle grinding is a often overlooked art and skill that you will have to master.  

Metals and how they react to CNC plasma

Steel, steel cuts the best.  Does not matter if it is tool steel, armor plate, or mild steel, it all cuts the same and the settings will be in the manufacturers handbook.  Armor steel and tool steel HAVE to be cut on a water table with the water touching the bottom of the sheet of steel.  If not you will ruin the steels tempering or in the case of untempered tool steel you will flame harden it which makes it hard to impossible to machine.

Stainless steel depending on your setup can leave some really nasty slag. I have cut a lot of it, it is not fun to clean up.

Aluminum makes a funny type of slag, it can be almost removed with a hand file or a gloved hand for the most part. Sme people are paranoid about aluminum cutting and hydrogen gas buildup.  A regular open water table will not make enough gas to worry about.  It will however give you nice hot thermite sparks in the water if you are cutting both aluminum and steel into the water. The sparks are not a lot, but they will glow bright and briefly in the water.

Brass leaves slag that can be cleaned up with a file or very gentle flap disc work.

The sludge in the bottom of a water table is black iron oxide.  It has it's uses too. It can be made into thermite,  or my favorite, I used it as plant food for iron poor soil. Never made thermite with it.

Now you ask what machine to get.

It all depends on your budget and expertise.

I seriously would not buy a PlasmaCam brand.  It is made from thin sheet metal and will wear out fast, not to mention that it is not strong enough to throw heavy steel on to it for any amount of time.

Torchmate brand is good, especially if you are a noob. Great customer service.  You are going to pay for it. Torchmate occupies that market space at the bottom to middle of the CNC plasma market.  Better than China machines and strong enough to run all day every day, and they work every time you turn them on.  The same can not be said about China machines. Expect to pay around 8-10 grand for everything you need.

DiY route. You can go with the eBay kits but you really need to know your CNC. When I started out I probably would have had a disaster with one, now days, I could build a CNC plasma from scratch.

You can go for the super DIY route by buying steel, and a $350 dollar electronics/motor/power supply kit from China and drive it with motorcycle chain, hardware store bearings, and a $1000 auto height controller from that guy in Eastern Europe that sells on eBay.  It all depends on how handy you are.

CNC plasma has many uses to make money. Most noobs start off making decorative stuff with it and do the flea market thing.  

However you could make a better living by making tool parts, car parts, bead locks, knife blanks, and the like with it. 

Farm equipment is a good market as well as up armor kits.

The salesman for Torchmate told me years ago that they sold a lot of their machines to Mexican companies for vehicle up armor kits.

You can also build boats with a CNC plasma table.

Download the files online, convert to blueprints and cutting files.  Those little 2 plywood sheet boats can be made with sheet metal just as easily.  Of course you gotta know how to weld and the rest.

Billing for services.

CNC plasma typically bills $1.50 to $2 per minute for cutting.  Seems a lot, but often times you get these little 20 min jobs that take you an hour or 3 to set up.

Software.  

Torchmate CAD is a private label version of Signlab.  It is $350 for the light version.

You will need at least the lite version to prepare files for cutting.

For serious design work, it will work, but you need very good imagination and mechanical reasoning skills to draw something in 2D that will be assembled in 3D

Not to mention that  CAD does not do layouts very well. Yes you can do them, but they are a pain in the rear to draw and time waster.  

For that I prefer Sketchup Pro or DesignSpark Mechanical, both of which I have written about before.

If you are asking what a layout is, then you are probably not ready to jump into CNC plasma woot some serious study time first.









Above:

Rice mill parts, structural steel, decorative metal, and a gasifier cook stove.

I'll do an article about wood gasifiers in a future article.




Thursday, January 22, 2015

Stuff I made on the CNC plasma



Knives

Here a couple of animations of some CAD files for knives I did for a customer when I was first learning 3D CAD

Printer speed tests.

Speed tests on the shop prototype machine. 

This is the first big printer I built.  I use it for shop printing, and experiments with new part designs.

Here it is running at 500mm/second. 

Notice how it is shaking the table.  I usually keep it on the welding table made from 6mm steel plate, but that table has the mini mill on it right now.


The combustion powered weapon

Here is a little video of something I made awhile ago.

It is a alcohol powered spud gun that shoots marble potatoes.

Specs:

Caliber: 100
Barrel: Schedule 40 pipe
Combustion chamber: 300 cubic inches 2 inch schedule 20 pipe.
Ignition: Stun gun and homemade spark plug


Now the trick to get more power from these things is to disrupt the flame to induce deflagration rather than a burn.  To so this I added in some steel springs inside the chamber.

Myth Busters did an episode about exploding sewers detailing this effect.

It did shoot marble potatoes thru plywood at over 80 feet in the shop in further tests.

I had some really good video but this was all I was able to recover from crashed hard drive.

It was made for a ww2 re-enactor in the style of a M1 Bazooka



Wednesday, January 21, 2015

Micarta as a material to work with.

I have played around with micarta for awhile although not nearly as much as my buddy at the knife shop.  

It is easy to make, stronger than most plastics, does not conduct electricity and is not flammable.

It is the same stuff used in the ugly brown furniture the Soviets used on their weapons.

Micarta is essentially paper or cloth bonded with fiberglass resin.

It is easily machinable and unlike fiberglass, does not itch nor need the full moon suit to grind on it.

You can even cut it with a low power laser.

it is a great material to use as feedstock for a mini mill.

There are plenty of sites with recipes to make it, you can find with a simple google search so I won't bore you with the repetition.  

In my experience machine shops have never even heard of the stuff.  Mainly I suspect that cause it is so easy to make, very few places sell the raw blocks of it, and it has not occurred to most engineers to use it.




You need to learn this to stay relevant

I posted this before, but it bears repeating with stronger language.

In order to stay ahead of the pack, if you are to make stuff; you really need to know how to commit your designs to paper/digital format.

To,do that you absolutely need to know CAD.

For the experienced guys out there reading this, it's basic knowledge.  However for the noobs out there, cause, face it, high school shop class was something to be made fun of or eliminated from the curriculum. 

These are THE essential skills going into the next few decades.  The ability to make real things with real value. When you can do that, you do not have to depend so much on that lame ass job to get the stuff you want or need.

For the mechanical guy and electronics guy there is this:

It is FREE, yes I said FREE.

While it is not the all powerful Solidworks, it will do 90% of the stuff that Solidworks does without the $5000 price tag.  

By far it is the most powerful free program out there.  It beats Sketchup hands down.

Not saying Sketchup does not have its uses.  I still use Sketchup too for some things.

Along that lines there is also a companion electronics program that goes with this program called DesighSpark PCB. Also FREE.

Now here is the very very cool thing that DesignSpark has.

You can download standardized objects, from gears to profile aluminum, to well, all sorts of stuff.

Then you can actually 3D print the part instead of having to buy it.

Like this:


It looks a little rough cause I made it scaled it down and it needs some cleaning up with a hand file.

But you get the picture?

On a philosophical note:

We live at the cusp of greatness or darkness. It is our individual decision.  Participation is mandatory.

If someone decides to be lazy or corrupt and take the dark path, they will suffer for it and they damn well deserve it.

Embrace the abundance in the world. It is all there for the taking and the making.  

With the unlimited knowlage of the Internet, there is absolutely no excuse to be poor.  To be poor in tomorrows world only means that you are lazy and you deserve to starve, because you have chosen to not utilize the blessings bestowed upon you.


http://comeandmakeit.blogspot.com/2015/01/the-combustion-powered-weapon.html









My 3D Printer...


My 3D printer...

This is the culmination of 13 months R&D.  

This current unit looks rather rough as it has been assembled, and disassembled countless times.

Right now I have a whole shop filled with these things going together with a few mods from the photo here.

This is my industrial grade 3D printer.  It is wickedly fast.  500mm per second fast.  

The print head is water cooled, which means that you could leave the hot end on all night with plastic in it and it will still extrude in the morning.  It is so much more reliable and gives way better quality than just about everyone else out there.

Build area is a cubic foot although I can scale this design up to 8 cubic feet fairly easily.





Sunday, January 18, 2015

Compliance

Doesn't matter how much you complain about a unjust law, if you comply with it.

Resist the thugs in Panem... Err the District of Corruption.


Knives

I don't really publish much of my work using my tools, but here is something I made about a year ago.

A buddy from the local knife shop asked me to turn some of his drawings into knife blanks.

I found a batch of armor plate at a local supplier that was exceptionally tough.  The dealer had a large amount of it in stock and was unable to sell it because it was TOO tough.  Customers could not work it with carbide bits.  

I started out with the hand drawing. traced a photo of it I  CAD, then worked the angles in Sketchup.  This was before I really learned 3D CAD very well so the renderings did not look as nice as I do now.

So I turned half a sheet of it into blanks and had a tool and die shop grind it on a surface grinder with a diamond wheel. Then the powder coat shop had their turn and the knife shop did the handles and kydex.

They are some incredibly tough knives.  The knife shop owner took it up to Subic where the US Army has a small SF unit.  They did all sorts of crazy stuff to them like shooting them on edge to split the bullet and shooting them with green tip 5.56.  The edge shoot with 9mm didn't do much except remove the powder coat.  The shooting on the side bent the blade badly  but it didn't penetrate or break.

The composite blade was for a different customer.  Really difficult to work with carbon fiber.  Itches really badly when working with it. 

If I had to do this again I would have just used cotton cloth micarta, water jetted it and ground it with a die grinder.
  

Above: Composite Karambit knife core.  Later laminated with carbon fiber.

Below: Chopping thru a tree with the small knife by customer.



Above finished knife with micarta handles, 

Below blades back from powder coating.



Above with kydex sheath 

Below after grinding and CNC cutting.





Pics of Heavy Metal Cutting

Photos of a Burny CNC table making stuff.

Armor plate fabrication?




Running the numbers on the mill.

So I'm making the mill.

And I'm working the numbers.

And I'm thinking.

We need a better way.

Not my project here.  It's still going full speed ahead.

But I'm thinking about how a few years people used to share the reprap project.

They printed these vitamin kits as they called them.  Basically a set of printed parts that along with some electronics and hardware store parts, could be used to make another machine.

Then I'm thinking about the Daemon and Freedom(tm) books.

So our movement.  We need manufacturing and 3D printing will not cut it.  I mean it has it's place but sometimes you can't beat metal.

So this is what I am thinking.

What if I made a CNC router vitamin kit?  

Something that would work with a off the shelf plunge router.

It will work in aluminum and plastic.  

A set of parts along with hardware store parts to make a 2x2 foot router for $500-$600

Leave your thoughts in the comments.

Update:

Ok here is the situation.  I can get lasered steel and CNC bent parts done cheap. Like really really cheap.

So what do we need for this thing?

So I will break it down as to my view.

We need a box, which means if we use off the shelf plumbing parts we need corners.  Plumbing parts, (threaded steel pipe) is threaded at the ends.  We really don't want that for the corners using elbows.

Why?  Because you can not make a complete square with plumbing elbows without one corner connection having a reverse thread.

But what if we go with PVC pipe?

Then you run into issues of how do you attach parts to the PVC not to mention the obvious flex issues.   It could be stiff enough but the biggest sticking point is the attachment of the steel parts without having to drill precision holes.

Flexing could be solved by filling the pipe with fiberglass resin after assembly.

What about CoreXY?  I do not know it if it can work with the torque we need.  My CoreXY runs lightning fast but I am leery of sticking anything with torque on it. (you will have to google CoreXY for an explanation)

So what do we REALLY need?

Basically we need a steel box.  

Holes for the bearings, shafts, and guides.

Corners for the gantry.

So that brings me back to the Torchmate


It is a great machine,  but the linear slide is hard to get made cheaply.

Since we are going smaller, we can ditch the ball screw and go with threaded rod if budget is an issue.

Remember we are thinking along the lines of how did they ramp up manufacturing during ww2.  

Compare making Stens vs the Thompson SMG

So we basically need the Sten version of a CNC machine.

Once we have the router, we can use it to make bigger and stronger machines.

Gotta start somewhere ya know.

Why is CNC the first choice you ask?

Because it is easier for a noob to get up to speed making chamfers, fillets, and other shapes with a CNC than the tedious method of doing it manually.