Dot to Dot

Posted on October 16, 2016 by george

We all learned to create
pictures by connecting the dots.

A simple child’s task like connecting the dots matches a computer’s capability. This was especially true in the early days when computer numeric controls had a lot less intelligence. It was a stretch for the computer to perform a simple 2 dimensional connect the dot task. Even todays CNC (Computer Numerical Control) is based on connecting dots with straight lines.
We began the computer controlled manufacturing revolution by using simple 2 dimensional dot to dot. In the very beginning there were long distances between the dots. The parts that were CNC manufactured had facets like you see on diamonds. As Moore’s law has given us more computer memory and horsepower we use ever greater numbers of dots to the point where the facets caused by straight line connecting of the dots are perceived as a smooth blend. A simple 2 dimensional approximation of a circle using a ring of dots connected by straight lines has evolved into a the chain of connected dots that has lengthened to stretch many miles.

A string of connected dots, many miles in length guides the path of a cutter used to make a mold

As we acquired more computer horsepower we wanted to expand into three dimensional objects. We again looked for the simplest way. A straight line connecting two dots was evolved into a set of three dots connected by straight lines defining a plane in three dimensions. Computer defined three dimensional objects look a lot like geodesic domes

Tyranny of numbers came to get us. Whereas we were able to manually program CNC machining G-code and moon landings by creating the travel path dot by dot, it simply was not humanly possible to define all of the little triangles needed to define an object shape. The STL (STereoLithography) data format we created for the task actually is capable of defining just about any shape that we can conceive. It was the early 90’s before any version of CAM (Computer Aided Manufacturing) software could generate a complete enough STL shape definition to be commercially useful. It was the turn of the century before any CAD (Computer Aided Drafting) software caught up to the same level. The underlying issue is that most of the part shapes that we use are not pure cubes,cylinders or spheres. In the classic example, three different radii meet at a corner. What is the shape at the corner? Turns out the computer does not know either.

The historic solution to the three different radii meeting at corner, was to instruct the pattern maker to do a blend. The digital solution started out in a very similar fashion. The STL file was manually adjusted by a person. This time consuming and costly step is one of the impediments slowing the adoption of 3D printing. The incredibly slow 3D printing speed is fast compared to the time need to clean a STL data file triangle by triangle. Moore’s Law keeps advancing. Each generation of software and 3D printing hardware opens the door for new affordable uses. Even though 3D printing theoretically has the ability to create any shape, in the near term it will have economically imposed shape limitations like any other manufacturing process

Kludge

Posted on July 4, 2015 by george

Treasure is camouflaged in the digital jungle

kludge
[klooj]
noun – Computer Slang
1. a software or hardware configuration that, while inelegant, inefficient, clumsy, or patched together, succeeds in solving a specific problem or performing a particular task.

*definition from Dictionary.com

Whoever came up with this term must have been assigned to marry legacy IoT (Internet of Things) digital controls. Lots of ones and zeros show on the logic analyzer, with obscure or forgotten protocols for interpreting what they mean. In the arms race to stay ahead of the newest start-up, many of the companies who built the previous generation equipment with embedded internet communication no longer exist. However, even the first internet connected device is still a part of our IoT infrastructure. At the blinding communication speed of two bits per week, the transmitter shuts off the water feed pump every Sunday when the water tower is full.

We take running water out of our taps for granted

I used to worry about terrorists gaining control of our infrastructure using the internet. It is theoretically possible to inflict some serious damage and injury. My concern was based on the fact that early IoT devices have very little access protection. Now that I have integrated some legacy systems I realize the lack of standardization will be our saving grace. It is next to impossible to apply experimentally the right combination of ones and zeros without a guide.
I was discussing the evolution of CNC position encoders with the technician who was upgrading the control on one of our CNC machining centers. In mold making, the cutter path software that converts 3D models (3D printing) into physical shapes, originally used a layer by layer contour line approach. We would like to use the more modern climb milling software because it eliminates the contour lines. (and the hours of hand draw polishing to remove them) The upgraded control will position X Y and Z at high speed instead of just X and Y which is all the contour line method requires. The embedded computer in each axis position encoder sends a high speed serial data stream including error correcting bits back to the control. This is a far cry from the first GE (now Fanuc) CNC control retrofitted to a Buffalo milling machine that I first programmed – yes, there is still a lot of legacy stuff in operation out there. This control also had position encoders without the local embedded computer. It only lost about 2500 count per shift (about 1/4 inch of position) and it came with a switch to shut off the Z axis so that you did not mill too deep. We evolved through resolvers and glass scales and back to a smart encoder. Don’t expect to do “big data” analysis of this type of IoT real time data stream. Bad things happen if the transmission of position is interrupted.

Who will bridge the genetation gap?

On the hardware side it is very convenient to connect the 10/100 port of my laptop to the ethernet switch. In my latest control I added ethernet cables so that it can be used in convenient locations without exposing it to the open internet. The generation gap became painfully obvious on the software side. The desire of the Windows operating system coders to download daily changes exceeds the ability of any custom low volume application software creator to keep up. We are finding that the latest version of custom application software is obsolete before it is sold. In the short term we will keep the systems synchronized by isolating them from the internet once we solve the inter-connectivity issues. This solution does not work for every IoT software mismatch issue. In my mileage trakker www.mileagetrakker.com IoT connected car application, it is necessary to have a staff who continuously monitors the functionality of the links and keeps up with interfacing with each model and car maker as they evolve. This becomes part of the monthly charge which enables our trakkers to obtain a couple thousand dollars in annual savings. Many of my mileage trakker competitors have gone out of business because they got caught continuously rewriting their cell phone based code in order to keep up with a rapidly changing software platform.
The IoT is evolving like the power grid. New IoT applications emerge based on the cost and performance drivers. Each implementer chooses a variation that matches the application without regard for the broader inter-connectivity issues. This will generate employment for the people with the STEM skills to link users to the vast data pool.

3D Niche

Posted on June 21, 2015 by george

Most 3D printed materials have porosity like swiss cheese
Emmentaler Switzerland PDO Cheese image by Dominik Hundhammer

The first successful applications for 3D printed materials tolerate the porosity in the part. Materials from nature such as quartz are essentially porosity free because they were formed over millions of years. This is why we like quartz for kitchen counter tops because bacteria does not have any place to hide. I suspect that man could create porosity free materials if we are willing to wait a million years or so. Given that our life span is a lot shorter than that, pretty much all man made materials contain porosity. With that as a preamble, I am not surprised that 3D printed materials have significant porosity. One of my active 3D printing projects is a two piece case for electric controls. Normally this would be made as an injection molded plastic which is reasonably water tight. I was hoping that the Stereolithography process which uses a photo catalyzed liquid plastic would also be liquid tight. It turn out that only one side has a water tight skin as my 3D printing service company discovered by making custom chocolate candy molds. This matches my experience with other materials. We all get frustrated if the porosity in the case of a transmission causes a big puddle on our driveway. Having made a multritude of transmission cases, I can report that only the skin of the case is liquid tight.

A Transmission + A Seive for a Case = A Driveway Puddle
Oil Stain picture by Christopher Sessums
Seive by DaveMontPhotography
Automatic Transmission by Vestman

When we actually need reasonably porosity free materials it is currently necessary to apply the 3D printing process to creating the mold. We successfully manufacture low volume metal parts by 3D printing a mold made from glued sand. The surface tension of the molten metal retains the metal even though the sand mold is 20% air. A similar strategy is used by Invisalign to make retainers where the high density sheet is vacuum formed over 3D printed molds.

Vacuformed orthodontics are shaped over 3D printed molds by Smikey lo

It is possible to post process a part with porosity. One of my clients makes aftermarket automotive air conditioning compressors. Freon is a gas and is very difficult to contain. Most car owners would be happy if they never had to refill freon in their car AC system. Even though zero leaks is impossible, as a manufacturer it is our goal. Freon is also used to prevent explosions in high voltages switch gear. When a switch in Downtown New York lost its freon and an killed a hundred or so people ABB enlisted my client to solve their leakage problems because the impregnation cell I set up for them is best in class. Even with that level of impregnation talent, I doubt that the anaerobic sealer we use, can fix 3D SLS (Selective Laser Sintered) metal parts because the pores are too big. Other techniques such as burnishing can be used to create a local skin.

The Burnishing process can increase density
and make a pressure tight skin
Burnished bearing race picture by Jean-Jacques Milan

Burnishing is a cold working process. We use other cold worked materials like cold rolled steel because this process closes the gaps between the grain boundaries to make them pressure tight. The CNC machining centers ability to burnish in addition to cutting is not widely known, but that does not stop me from using this very useful technique.
Invisalign, SpaceX, and GE have discovered that there are niche 3D printing applications. Engineering the product as match to 3D printing, combined with choosing an application that is not affected by material properties such as density, has enabled their marketplace success

Additive Manufacturing

Posted on June 19, 2015 by george

Your morning coffee delivered in a cup made using additive manufacturing

The value of additive manufacturing has long been known to the human race. Early civilization discovered the benefits of layering clay to create the pottery containers that we use for every day life. Most of us do not give a second thought to the pottery cups that deliver our morning coffee. Linking a coffee cup to additive manufacturing might not be obvious even if you work in the factory that makes coffee cups. A coffee cup factory is all about making an identical copy for everyone. After a coffee cup is designed using additive manufacturing, it is given to the pattern makers. Their precision wood patterns capture the shapes and serve to guide the creation of molds and tooling. This became the backbone of industrial manufacturing until the 1990s when the mathematics within the CAD and CAM programs evolved to replace wood patterns.

Wood patterns have been replaced by 3D CAD models.

Some of the bits of craftsmanship such as the “S” shaped gear spokes that keep the gear round during casting cooling have been lost from modern designs. The STEM skills required for the shape definition task are unchanged even though the practitioners are now called CAD modelers instead of pattern makers. The commercially useful shapes still require corner radii and fillets. Fits, blends, dimensional accuracy and finishes are even more important. As we evolve to a mass customization marketplace more people with this skill will be required.
Convergence is a term used to describe the effect that advancements in computer technology is having on the communications industry. The line between telephone, television broadcast, radio, paging, security, satellite, cable, and internet companies is blurring. The same is happening in additive manufacturing. A robot arc welder heats material fed as a wire and fuses it in a predetermined position controlled by a multiaxis CNC control. Interestingly enough, this is the exact description of what happens in filament style 3D printing.

ROBCAD Offline teaching welding
001 by KOMATSU Ltd
Airwolf 3D printer by Neon Tommy

As we evolve away from one size fits all, it will become possible to manufacture locally the items that we want. Computer controls will add the necessary flexibility to the production equipment that we own and recognize.

Packaged 3D

Posted on May 31, 2015 by george

A chocolate assortment in a vacuformed tray by Evan-Amos

Life could be a box of chocolates. The challenge in this era of mass customization is that the assortment of flavors that we want to buy changes with the wind. If you look at the picture carefully you will discover that the pockets match the shape of the chocolates. This means that if you want to change the assortment you require a new mold. The associates filling the box also find it hard to adapt to continuously and randomly changing customer order. It would also be helpful if the vacuum molded tray had some visual management labels to guide in the fulfillment activity.
Enter 3D printing. Invisalign pioneered the use of 3D printed molds to shape plastic sheet.

Vacuformed orthodontics are shaped over 3D printed molds by Smikey lo

Since every retainer created is different, the 3D printing process also molds into each item identification information. Why did Invisalign choose plastic sheet?
From the earliest blacksmiths shaping swords, the engineering community has discovered that it is possible to increase material strength if the application does not need the high strength in all directions. The bio-compatible plastic used by Invisalign actually works as a retainer, whereas the 3D printed plastic used to make the mold is too brittle and you would not catch me sticking it in my mouth because it still contains active plastic precursors. Other plastic composite sheet can be even stronger because reinforcing fibers can be laminated into the mix

Fibers add strength to plastics and rubber by PerOX

For example pneumatic car tires must have embedded fiber reinforcement to withstand the applied forces. Airplane manufacture is a logistic nightmare. About 100,000 parts must be manufactured and gathered together in the right order to make a plane come together. The Boeing engineers joke that FISH (first in still here) has replaced FIFO (first in first out) as their accounting system. Boeing in their Moonshine Project determined that staged delivery to the assembly floor is more that sending the parts. The parts themselves are useless without the matching tools to install them. In their historic system workers spent much of their working day traveling back and forth to the tool cabinets around the working area. As we gain engineering control, the implementation of molded tool trays on 3d printed molds is an effective shadow board so that it becomes possible visually to determine in the warehouse that all of the required tools are sent with each cart of parts.

747 airplane parts and tools are delivered together by Jeff McNeill from Chiang Mai, Thailand

Some of the solution for the shortage in transportation capacity has to come from efficiency. It would be easier if the marketplace didn’t want mass customization at the same time. I can picture us evolving to 3D print to order shipping trays so that full density skid size loads can be assembled upstream enabling fast loading and less unprofitable empty space in transit.

3D Printing – An Invisible Revolution

Gallery

Posted on September 10, 2013 by george

This gallery contains 5 photos.

3D PRINTING, a current hot news item, is actually the result of a gradual, almost invisible revolution in mold making which has finally reached a transformative point. The point where it can revolutionize the manufacture of equipment, like stock chasers, … Continue reading →

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