Meta

New Site for Mechanical Designs and Automation Ideas

I’m launching a new site to catalog mechanical designs and provide inspiration for automation equipment.

automate.engineer

I would call this a “design library” or “idea library” for mechanical equipment and automation. I’m a mechanical design engineer by trade and I haven’t found a good resource for collecting mechanical ideas or cataloging cool designs. My new site will try to fill that void.

I’m building this for myself so I’m not sure what the utility or broad appeal will be. But check it out if you’re into animated mechanical gifs.

3D Printing, Software

Importing Lattice Type Geometry into Solidworks

I’ve been daydreaming about some 3D printing projects again and have spent some time looking at the lattice style structures that are used as low density volume fillers in SLA or SLS prints. I think this is an underappreciated area of printing because these structures can only be created practically by printing and there is likely some interesting strength and stiffness optimizations you can do by tinkering with the lattice geometry. I think this will become much more interesting as flexible material prints become more popular.

 

These lattice structures are pretty simple geometrically so in theory you could create them in Solidworks but in practice I think it would be tedious and a bit of a pain. The geometry should be easy to generate with a few lines of code so I thought it would be interesting to see if I could generate some geometry programmatically and then import it into Solidworks.  After doing some research I couldn’t find an existing method of doing this.  The closest thing was a few Solidworks macros to import point clouds.

I’ve found the Solidworks API and associated VBA difficult to work with in the past.  In theory I could generate all my geometry just using some VBA in a Solidworks macro but I think that would be an exercise in frustration for myself.

I decided to do most of the heavy lifting outside Solidworks and then write a macro to import the geometry and create some simple swept cylinder features to replicate my geometry.  I’ve done some 3D work in Processing before so I expected the geometry creation to be straightforward by reusing some existing code.

Here’s a quick overview of the plan I developed:

  1. Generate line geometry in Processing
  2. Export lines as pairs of 3D points and a diameter parameter
  3. Use a Soldiworks macro to create 3D sketches based on the points, then create a swept circular profile for each

Predictably the Solidworks macro was the most difficult part for myself.  It imports data from a text file with each line defined by Diameter, X1, Y1, Z1, X2, Y2, Z2.  It creates a 3D sketch, inserts a line, then performs a circular profile sweep (SW 2017 and later).  Overall it’s pretty crude.

The macro works OK but could use some improvement.  The swept cylinders end with flat surfaces which creates gaps at intersections.  Ideally each cylinder would have a spherical end to reduce gaps.

Each cylinder is created as a separate body by design.  This allows the lattice to be easily trimmed in Solidworks without leaving any weird partial bodies.

Overall this was a fun project.  I don’t have any immediate plans for this work but I think I’ll dust off this code in the future.  If this project interests you I would suggest that you don’t go into the deep end of programming complicated geometry. Mesh Mixer has a lot of high end tools for this type of work.

Here’s the macro code:

Dim swApp As Object
Sub main()

Set swApp = Application.SldWorks
Set Part = swApp.ActiveDoc

Dim x As Integer
x = 1
Dim sketch As String

‘open file
Open “lines.txt” For Input As #1
Do While Not EOF(1)
Input #1, D, X1, Y1, Z1, X2, Y2, Z2

‘create 3d sketch
Part.SketchManager.Insert3DSketch False
‘create line
Set skSegment = Part.SketchManager.CreateLine(X1 / 1000, Y1 / 1000, Z1 / 1000, X2 / 1000, Y2 / 1000, Z2 / 1000)
Part.SketchManager.Insert3DSketch False

‘select new line
sketch = “3DSketch” & x
boolstatus = Part.Extension.SelectByID2(sketch, “SKETCH”, 0, 0, 0, True, 4, Nothing, 0)
x = x + 1

‘create sweep
Dim myFeature As Object
Set myFeature = Part.FeatureManager.InsertProtrusionSwept4(False, False, 0, False, False, 0, 0, False, 0, 0, 0, 0, False, True, True, 0, True, True, D / 1000, False)

Loop
Close #1

Set swApp = Application.SldWorks
End Sub

Software

Satellite Weather Bot

ABOUT

I’m a big fan of NOAA in general but I’ve fallen in love with the real time imagery available from their GOES-16 satellite.  Weather nerds are all over this stuff but I don’t think the general public has any idea this space imagery exists.

There are a few accessible points for the imagery, notably NOAA’s GOES site or the RAMMB SLIDER, but I wanted something that would make the imagery a little more immediate.    I decided a Twitter bot would be the perfect tool to create animated satellite loops and then push them out to be seen by the world.

Originally built for an audience of 1 (myself), I was free to experiment and tweak the outputs to my liking.  I focused on the north east US so I could have an hourly view of clouds in my area.

The bot has exceeded my expectations and it’s become a great tool that I check multiple times a day.  It’s a great for tracking weather patterns and storms but I really just love watching clouds.  I hope that this bot provides the same wonder and curiosity that it provides me.

Thanks to  NOAA and everyone involved with GOES!

FAQ

Q:  Can you cover different regions?
A: Probably, I’m considering expanding to cover new areas.  Message me on Twitter.

Q:  Why do you use the geocolor output?
A:  I think it’s visually the most appealing and I’m targeting a broad audience here, not just weather nerds.  I don’t like the geocolor night time output though.  If you really want a different band, message me on Twitter, I’m curious to hear what you want.

Q:  Why do your animated loops have low resolution?
A:  I think the resolution is a good compromise between usability and Twitter’s video compression.  It took some tweaking to get a good output, a really high quality output  will get heavily compressed by Twitter and result in a worse animation.

Q:  How did you choose the frequency and length of outputs?
A:  I wanted something that would provide an hourly picture of the weather and I also wanted something that would provide nice long loops so you could see how the weather changed over the course of a day.  The outputs try to address both goals but are still being tweaked.

Machinery

Mechanical Design Idea Sources

Trying not to reinvent the wheel? Need a simple proven linkage, detent, clamp, or other mechanical widget?

Here are my idea sources when trying to sketch out a mechanical design.  Often the path of least resistance is reusing an existing design.

Misumi Library – Downloadable designs for automation mechanisms, fixtures and small equipment. Everything is professionally designed.  Some interesting and detailed content here.  A hidden gem.

507 Mechanical Movements – A familiar resource for simple sketches of mechanical widgets and linkages.  The animation helps in some cases but the website is a little cumbersome.  I would recommend finding a used copy of the book from Amazon, it’s easier to flip through.

Thang010146’s Videos – An impressive YouTube channel full of animated mechanisms.  A little difficult to navigate for specific ideas but the breadth and detail here makes it worthwhile.

Google Patents – Patent language is infuriatingly vague but the diagrams are often well illustrated and provide insight to the working principals of the design.  This search can cast a wide net, I have better results when targeting the portfolio of a specific company.

Used book stores are also a great way to find interesting resources. The quality of “mechanical movement” books can vary a lot so it helps to flip through a few.  If I see a textbook or other reference book recommended online I’ll often purchase a used copy through Amazon.

3D Printing

Magnetic Camera Mount

I’ve been looking to dip my toes into the 3D printing pool for a week or so now.  I really needed a project that would be a good excuse to print some parts.  I decided to start with the design of a magnetically fastened camera mount that would use a Maxwell kinematic coupling.  I love kinematic couplings and used them in some cool automation applications in the past.  They’re a great way to repeatably and accurately locate tooling or fixtures that need to be easily removed.

I started off with the design in Solidworks going through a few iterations of the magnet spacing and contact surfaces.  The V-grooves in the base part accept a roundish spherical feature in the mount for accurate location. Three magnets are located in circular pockets in both the base and mount piece.  The center of each piece has a counterbore to accommodate a socket head cap screw for the standard 1/4-20 camera thread.

I shipped the files off to Shapeways to try out their “professional plastic” material which is really HP’s Multi Fusion Jet process which I was not familiar with.  As an aside, I think I’m going to rely on printing services in the short term before I invest in a printer.  I’m really tempted to get the AnyCubic Photon but I think I would be limited by the build volume.  Services will give me a lot of flexibility for experimentation.

I received the parts a few days later and I was impressed with the results.  The plastic had a nice smooth finish and matte appearance.  The prints were close to being dimensionally accurate but their was a weird curled lip on a few of the sharper edges.  The assembled pieces didn’t quite hold the small 0. 020″ gap I designed in between the two halves.  This indicates that the V-grooves and spherical contact features are slightly off in size.

I assembled everything including gluing the magnets into the parts.  The pockets I designed for the magnets had a lot of extra clearance because I wasn’t sure how accurate the inner diameter would print.  In the future I would like to get this to a press fit but in the short term adding some super glue is an easy assembly step.

The design worked great!  Snapping the pieces together has a nice satisfying feeling and overall the design is practical and functional.  In the next version I would like to increase the magnetic holding force because it’s at the limit when holding my 70D.

Overall I’m pleased with the project and the design of the mount.  I think there a lot of room to explore this application in the camera mounting space.  The magnetic coupling is a novel approach and I think the design could be a great solution to mounting smaller GoPros.  Stay tuned!

3D Printing

My Thoughts on 3D Printing

Hobbyist 3D printing has never made sense to me as a design engineer.  The applications always seemed limited to printing useless trinkets.  At best you could maybe print an interesting piece of geometric art.  Arguments for “functional prints” always involved a large investment of time for a small payoff.  I don’t want to take an hour to model and print a 5 cent knob.

The technology seemed limited as well.  The prints were low resolution.  Small build volumes limited prints to the desktop trinket size.  FDM printing can have issues with distortion or warping.

My mind has recently started to change.  I have been aware of the DLP SLA printers such as the Form but I was surprised by the price and capability of the AnyCubic Photon.  Although limited in build volume I can appreciate the print quality and resolution.

Inexpensive high resolution printing got my gears turning.  I could build parts that could hold tolerances that would be workable in assemblies. I could build homogeneous parts with an attractive finish.  I could flex some design muscles and build some extremely complex parts that would be impossible for traditional fabrication methods.  I saw a path for some novel design work that I haven’t seen anywhere else online.

Although I would be handcuffed by the build volume I very quickly came up with a mental list of interesting projects. I found my own use case for 3D printing that didn’t fit the traditional mold.

One of the final ideas that clicked was the ease of creating parts.  As an apartment dweller I don’t have a large shop to build or tinker in. I certainly don’t have a garage with a modest machine shop. 3D printing offers an inexpensive and low resistance path to creating and making new parts.  My day job has me working with a variety of machine shops to quote and order parts.  There is a very real cost and time investment to making the parts that I am familiar with.

3D printing offers almost the same experience in a convenient and inexpensive method.  Parts will certainly be made a material that has greatly diminished strength but this can be addressed.  Compromises will have to be made by the upside is worth it.

I’m excited about the opportunities and I’m looking into a few different projects.  I plan to cover a variety of projects and investigation in the near future.

Machinery

Mechanical Design is a Jigsaw Puzzle

I’ve been doing machine design for about 10 years and I often compare the mechanical design process to a creating a jigsaw puzzle.   The most obvious parallel is that there are many pieces for both a machine and puzzle that must fit and work together.

Even simple machines are broken down into multiple subassemblies that need to fit together like puzzle pieces. Each subassembly piece has to fit together in the process and in the context of the overall machine, both in a static and dynamic state.  If one piece needs to grow your other pieces may need to shrink.  You may have a rough idea of what the final puzzle may look like but you’re figuring out the pieces as you go along.

The puzzle process gets more challenging when you remember you’re dealing with 3D pieces and working collaboratively.  The best advice here is to divide the puzzle so you can each work a corner and have someone paint the broad strokes so you know what the completed puzzle will look like.
Machine design is complicated because in many cases you’re fitting together dynamic systems and subassemblies.  There are a few constraints or requirements that  shape the design from the start but there are many self imposed constraints that arise during the design process.  Things like part clearances, working planes, conveyor pitches, and transfer points need to be established.  These factors will greatly influence your design along with a common thread that ties everything together.
Petroleum

What is a Spoolbase?

A phenomenon adjacent to the Wikipedia rabbit hole may be Google Maps tourism.  While reading the Wired article “The Inside Story of the Great Silicon Heist” by the excellent Brendan Koerner I was curious to look at the Mitsubishi polysilicon facility described in the article on Alabama’s Theodore Industrial Canal.  While the facility wasn’t much to look at I did notice an interesting neighbor on the canal.

A perfectly straight, mile-long piece of construction that butted up against the water.  What was this?  An airport runway? Rail yard?  Pipeline? Things got more interesting as I zoomed in.

First, I noticed there was an adjacent rail yard that was dwarfed in comparison.  Second, there were two parallel lines here.

As I zoomed in on the end of the line I noticed rough edges which indicated I was looking at individual pieces of extrusion or pipe.

Time to do some internet detective work.

Google has the site labeled as TechnipFMC.  A quick search yields that this is their Mobile Spoolbase facility with the following information:

Technip’s spoolbase in Theodore, Alabama (close to Mobile) serves the nearby Gulf of Mexico market. The facility consists of a pipe receipt and storage area, a fabrication building, a welded pipe stalk storage area, and a quayside. Since its inception in 2001, this spoolbase has fabricated more than 2,000 km of pipe.

Now we’re on the right track and my interest has been piqued. This falls right at the intersection of maritime engineering, petroleum, and logistics – all fascinating areas to your correspondent.  But what is a spoolbase?

This is where the searching is easy.  We have the correct keyword so we can find the Wikipedia article, photos, and anything else we want.

A spoolbase is a facility that allows long lengths of pipe to be welded together before the pipe is reeled onto a pipe laying vessel.  A facility that has the unique requirements of allowing mile long lengths of pipe to be handled and that is located along the water to accept ships that will pull the pipe on board and spool it.

The real center of the process here is the welding and I found some great information from CRC-Evans that details the process.

Short sections of pipe are transferred into the weld shack.  The pipe ends are beveled and prepared for welding.  The sections are welded together to form the mile-long pipe string.  Each weld is then cleaned, inspected, and coated before it exits the shack into the long yard to wait.

The pipe handling, welding, and inspection processes are all automated to some degree and feature some very interesting equipment similar to pipeline welding equipment I’ve covered before.

I recommend the following video:

When a ship arrives to receive pipe it will pull in a mile-long section and then stop to have another mile-long section welded to the end for a much longer continuous reel.

The pipelaying vessels themselves are extremely interesting and deserving of their own separate article!

Gadgets

Compatible Android OTG Devices

Android has a little known feature that provides built-in support for USB hardware devices.  Provided you have the right adapter, you can plug in a keyboard, mouse, gaming controller, or USB drive and it will just work.  This is due to a USB specification called USB On-The-Go (OTG) and it’s an amazing piece of functionality.

My Frankenstein tablet project generated a lot of interest for OTG with Android and I wanted to explore the idea further.  I couldn’t find an official  list of hardware that would work with Android via OTG beyond some details on the InputDevice class so I figured I should make my own list.

After rummaging through my box of computer hardware and with a little bit of testing I have generated the following list of USB devices compatible with Android.

Tests performed with a Nexus 9 and a Micro USB adapter.

Device Compatible Notes
Android Phone Yes Select "Transfer Files" from the slave phone
Borescope Yes Requires app
Card Reader – SD Yes Format card with Android
DVD Drive No Tried a few apps that claimed support
Flash Drive Yes Format with Android
Game Controller – N64 Yes
Game Controller – SNES Yes
Game Controller – xBox "S" Yes
Hard Drive Yes Format disk with Android
Keyboard Yes
Mouse Yes
Printer Yes Requires app
Webcam Yes Requires app

Stay tuned, I’ll update this list with new devices! I would like to test more output devices including a USB monitor.

Overall it seems like most mass storage devices, cameras, and game controllers are compatible. I was surprised at the extent of native support and the prevalence of apps offering third party support.

Android has a ton of functionality when you consider the full list of both Bluetooth and USB devices.  Some of the tested USB devices have some questionable usability when there’s a Bluetooth alternative but I’m still amazed that there’s any USB support available.

I thought about my own historical use of my Nexus tablet and I do extend it with external devices quite frequently.  My top use cases are as follows:

  1. Flash drive – I have a USB drive filled with movies and TV shows that makes the tablet perfect for travel.  Nothing like having a full 128 GB media library for long flights or hotel stays.  I highly recommend MX Player, it has better codec support than VLC.
  2. Bluetooth mouse – I hate the mobile version of most websites but my fat fingers can’t click the tiny links when I request the desktop version.  Having a mouse input provides so much more precision when web browsing, it’s like night and day.  Perfect for web surfing while watching football or a movie.
  3. N64 controller – 99% of my tablet gaming is through the Mega N64 emulator.  I’m still amazed at the performance, playing these games on a tablet really makes me feel like we’re living in the future.  Nothing like a quick round of Super Smash for some fun!
Gadgets

Building a Frankenstein Tablet

Lately I have been fascinated with Android’s built-in support for USB hardware devices.  Provided you have the right adapter, you can plug in a keyboard, mouse, gaming controller, or USB drive and it will just work.  This is due to a USB specification called USB On-The-Go (OTG) and it’s pretty amazing.

I had an older Nexus 9 tablet laying around and I wanted to see if I could extend its functionality with some bolt-on upgrades.  This is a small project that I had been thinking about for awhile and I thought adding a USB hub to a tablet would be the key to its upgrade potential.

First and foremost, I think many tablets are limited in their hand free usability – you either have to hold them or prop them up in some sort of folding case, a tenuous solution that provides limited viewing angles.  Adding a proper tripod base is a little unorthodox but provides a very stable base with a lot of flexibility.

The tripod will be the legs of this project but a silicone case will be the backbone.  An inexpensive case will allow me to easily attach things to the tablet without ruining it.  I can always remove the tablet and switch it to another case if I need to travel with it.

A USB hub glued to the back will be the key to extending usability and will support all sorts of USB devices.  At a minimum I planned to use a USB drive, a mouse, and a USB microscope with the tablet on a regular basis.

I went searching on Amazon and found all of my key ingredients.

Started off with a nice silicone case.  I like the blue color, it’s nice and grippy, and seemed rugged enough to take some tumbles off the work bench.

Next was the tripod.  This was a cheap bendy tripod made for phones.  The selling point here was the orientation of the phone mount, it was a perfect match for the layout I had planned.

There were plenty of USB hubs to choose from.  This one was inexpensive and I liked the yellow color to contrast with the case.

Last was this right angle USB adapter I found.  This would allow for a low profile connection between the hub and tablet.  I’m amazed I found the exact adapter I wanted, I guess the market for USB connectivity is pretty saturated.

Once I had all of the parts in hand the next step was to lay everything out on the case.  The tripod mounting piece was slated for the lower-center of the case and I wanted to make sure the USB hub could reach the adapter on the side.  Everything seemed to fit well.

Used some silicone adhesive on the back of the USB hub and tripod mount.  A little bit goes a long way.  The grooves on the case did a good job of meshing with the adhesive.  I let everything cure overnight.

The moment of truth!  I attached the tripod and it held the tablet well.  The legs took some adjustment to support the tablet’s center of gravity but worked very well.  I was pleasantly surprised with the stability and the flexibility of the tablet’s viewing angle.

I then rushed to plug in as many USB devices as possible!

A nice shot of the populated USB hub.  Of the all of the devices plugged in, the Lexar USB drive and the mouse are by far the most useful.  It’s a little strange to use a mouse with Android to start but it provides so much more precision than my fat fingers.  Web browsing is so much easier when you can finely locate and click links.

I’m a little concerned long term about the USB connection with the right angle connector.  I would love to find a better way to protect the adapter so the tablet port doesn’t take the full brunt of a fall.  The adapter is nice and low profile but it is a weak part of the layout.

The best use case for the tablet will be in the workshop.  The tripod base frees up table space and improves screen viewing angles substantially.  Perfect for viewing manuals, diagrams, or other reference material.

Add a USB borescope or microscope and you have a multi-functional shop tool!

Overall I’m happy with this project.  The concept seems sound and I’m pleased with the execution.

If I had to do it again I would pick a better tripod, the bendy one I selected is just OK.  I also need to find a better way to protect or strain relief the USB connection to the tablet.

At worst I now have a more stable platform for watching Netflix.  At best I have a very utilitarian computer for use in the workshop!