I recently completed my most ambitious ShopBot project to date: casting a concrete birdbath bowl in a mold that I CNC’d. This was also my first attempt at producing a video about a project as I’m working on it. Watch the video below:
Archive for the ‘CNC’Category
Here’s a summary of my coffee table project that many of you have seen me work on (or struggle with) over for the last several months.
I like furniture that can flex or modify it’s position to address different needs. I’ve seen coffee tables that raise to eating height before, but I wanted to design one that really expresses the mechanism and plays up the physics behind it. Back in October I made a 1/2 scale mock up of the design to understand the motion.
Then it was back to designing a full size mock-up.
I realized it wasn’t going to be stable enough with just one set of arms, so I decided two sets would still look good. Everything was designed in Autodesk Revit. The software allows you to figure out volume, then with a given density of materials I could get weights from the various parts. This allowed me to determine the balance. I didn’t want it to be perfectly balanced with the counter-weight, but have enough weight to assist the movement.
First I started making the frame out of aluminum. It’s fastened using a pneumatic riveter.
Painting the steel arms.
CNC cutting the concrete forms out of pink foam
Creating the concrete counter-weight form
Failed attempt to CNC cut aluminum for brackets. I’ll skip the rest of these struggles…
Casting the concrete base
Casting the counterweight (nice and sloppy)
The base assembled.
Frame is attached.
There were many tweaks after testing it. There was some wiggling around the axles, so I widened the holes in the steel arms to put nylon sleeve bearings in for a tighter smoother fit. There was still some shifting after putting some weight on the front, so I designed a locking mechanism with a latch.
Lots of struggle with this latch at the top of the photo. (FYI, learn the cold metals milling machine if you need a part like this)
And finally… a video…
By Josh Myers
I had a plan for how to blog about this project, but I’m going to step out of order and talk about the latest development since it pertains to the last Fusion 360 Meetup. So to catch up in a hurry: I’ve already constructed a control box containing an Arduino Mega 2560 and a Raspberry Pi, power supplies, relays, etc. all mounted on DIN rails. This is the “brains” of the system, and the Pi runs an open source control framework called EPICS. The control box sits on a separate stand on wheels that I welded. In keeping with the “Beer Church” theme, I suppose this is the “Beer Pulpit”.
I realized early on that the control box was out of room. I want this brewing system to be modular so that I can attach different equipment and reconfigure everything via software. To that end, each device needs to connect to the control box with its own sturdy, detachable connector. The original BrewTroller project (which isn’t online anymore) made use of XLR jacks. These are ideal. Nearly every device I’m interfacing with uses 3 or, in some cases, 2 wires. The OneWire serial bus, which is used for measuring temperatures, uses a 3 pin M12 connector; these are chained together using splitters. A few use cases need more than 3 wires: multiple pressure transducers on one board (used for fluid level sensors) and stepper motor drivers (used for controlling gas needle valves). For these, I’m using 8 pin mic connectors. But I don’t have enough panel space on the control box for all of these jacks, especially now that I’m considering adding a small touch screen. Nor do I have room inside the control box to mount a 120 V to 24 V transformer; 24 VAC is a HVAC standard, and the propane burner valves need it.
A number of commercially available and hobbyist-built computer controlled brewing systems already exist that solve many of the issues I mentioned in my previous post on this topic. They have a number of similarities, but address the problems in different ways. I’m going to describe a number of methods used for computer controlled beer brewing, which improve up0n repeatability by reducing deviations in the mash process. These systems range from simple thermostat / standalone PID controls to microcontroller-based devices. I’ll also list my own design decisions when building this system and my reasoning. Note that my design decisions aren’t necessarily best, there are plenty of valid arguments for and against many of the solutions presented here, and as I write this, I’m kicking myself for some of the mistakes I made along the way.
I’ve examined a number of systems. Our local homebrewing store operates one. I’ve paid particular attention to open source and published plans for hobbyists, given that these offer the most information. Two of my primary sources:
- Brutus Ten – Website here. Build pages here and here. This is a popular brewing system due to plans published in Brew Your Own. It consists of a welded steel frame and propane burners driven by standalone industrial temperature control modules.
- BrewTroller – The original website was oscsys.com which features an Arduino-based open software and control electronics framework for brewing. The website hosted the software, documentation, a web forum for users, and an online store where one could purchase electronics, actuated valves, switches, temperature probes, etc. It is not locked to any single brewing system design; rather, it is flexible enough to support a wide variety of brewing hardware configurations. While the original site shut down, a user took this over at this site.
A bit over a year ago, I began a project to build a computer-controlled beer brewing system that Beer Church (Pumping Station: One’s homebrew club) could use to brew all-grain beer. I had no idea when I started this project that it would lead to visiting people from multiple countries, two synchrotron radiation sources, and a nuclear research reactor, or that control systems engineers from international labs would provide assistance. While it still isn’t ready to brew beer yet, I’ve recently reached a milestone in integration testing, and I’m rapidly approaching the point where the first test batch will be possible. Unfortunately, I haven’t been blogging about it, so a lot of catching up is needed….
So, why would someone want to make what could be called a CNC machine for beer? First, it’s not about eliminating humans. The goal isn’t automation to the level of “push button, get beer.” Humans will still need to load the ingredients and monitor the process. We don’t want a hose breaking, resulting in 12 gallons of beer wort on the floor and a propane burner melting the bottom of the resulting empty stainless steel keg. Rather, the primary reasons are:
- Repeatability. I want to eliminate human error. Repeatability often is the domain of commercial brewers, but for hobbyists, repeatability still is critical. Transitioning from good beer to great beer means experimentation. And that requires having good control over all the variables. How do I know if that different yeast I used made my beer taste better, or if it could be explained by sloppy temperature control in the mash process?
- Predictability. Shareware and free beer design software exists that acts like CAD for beer. You can design your grain bill based on a library of ingredients, enter a mash and hop schedule, yeast, fermentation temperature, etc. and it will simulate the process, telling you what you can expect in terms of initial and final specific gravity, percent alcohol, color, bitterness, etc. You can tune the model based on the efficiency of your brewing system. But prediction works only as well as the repeatability of your process.
- Capacity. Right now, we are limited to 5 gallon batch sizes. While we certainly can buy larger hardware, it makes sense to upgrade to automation at the same time. With a system based on 15.5 gallon beer kegs, we can produce 10 gallon batches at a time.
And, well, there are plenty of secondary reasons that can best be described as “Because hackerspace!” I’ve wanted to learn more about industrial control electronics and the EPICS software environment. It was a great excuse to learn to weld. I had acquired authentic cold war indicator lights from actual nuclear missile systems that needed to be put to an awesome new use. And I could do all that while brewing beer!
To describe the CNC beer system, I first need to explain all-grain brewing and the issues inherent with our current brewing method. To be clear, these issues affect repeatability, not quality. We are already making really good beer. Nothing is wrong with what we’re doing. This new system likely will improve beer clarity (and that is important in homebrewing competitions) but otherwise it won’t do much on its own to make the beer better. Start with a bad recipe and you’ll end up with bad beer; the new hardware just makes it repeatably bad! Rather, it will provide state of the art tools to anyone who wants to experiment, and this could be very useful to brewers wishing to be competitive in homebrewing contests.
The PS:One ShopBot is a great CNC machine that has the benefit, among other things, of being huge, allowing for a lot of cuts on large pieces of material. One of the difficulties working with the machine, however, is getting the bit at exactly 0,0,0 in the X, Y, and Z axis so that if you need something cut at exactly six inches from the edge of the material, it will be exactly six inches. There is already a built-in method for setting the Z axis, using a metal plate and clip and running a specific program on the ShopBot, but there is no such program for setting the X and Y, requiring the user to manually position the bit. This can lead to inaccuracies and wasted work.
To help everyone with accurate setting of the the X, Y, and Z axis, I made a thing:
This is an aluminum plate that is milled to be as precise as I could make it (read: probably a lot of room for improvement) where it sits on the lower left hand corner of the piece to be cut, with the corner of the work sitting directly in the middle of the circle.
With the piece placed on the work, the cable is plugged into the back (I had originally drilled two holes on the front left and bottom of the plate, forgetting that is where the bit has to touch so as to not push the plate off the work, so I drilled a new hold on the back and wrote “Do not use this hole” on the other two) and attached via the alligator clips (ToDo: make a better cable) to the Z plate.
The user should position the bit somewhere over the top part of the plate, where doesn’t matter. The user loads xyz-zero-finder.sbp (the code is available at this GitHub repository) into the ShopBot software and runs it. Assuming the bit is somewhere over the top, it will then slowly move the bit down until it touches the top, at which point it will move to the side (visually this appears to be moving towards the front of the machine, but in reality the side of the machine with the power switch is technically the bottom, or X axis). The program will move the bit inside the circle at what it believes is exactly 0,0,0 and, after displaying a message, will move the bit up two inches to allow the user to remove the plate and put it away.
The plate is in the drawer under the ShopBot in the Arduino box (ToDo: Make a real box for the plate). Feel free to use it and report back how it worked for you, so that we can make it better.
I want to thank Dean, Everett and Todd for giving me valuable advice about how to mill the plate on the Bridgeport; it was tricky because both sides of the plate are milled and getting it to sit properly in the vice was very worrying to me. I also want to thank Eric for suggesting the project in the first place.
Thursday 8/6/2015 @ 7;30pm we will be doing a Chilipeppr Presentation
Chilipeppr is full featured, web based, GCode sender. GCode senders basically send your CNC toolpath files to the micro controller running your CNC machine.
Chilipeppr takes that concept to the max. It more like a full featured front end to your CNC machine. It visualizes the GCode, shows the status of your machine, helps with work offsets and jogging. It also has some cool tricks it can do to deal leveling and Z probing. It is currently compatible with machines running Grbl and TinyG.
John Lauer, the creator will be conducting the presentation via Google Hangout. We hope to expand the presentation. I’ll tweet out a link on @buildlog and post it here when we work that out.
We will have a machine or two for a physical demo.
This month’s CNC Build Club meeting will be a demo night. Bring something to show. It can be a project you finished, something you made, a work in process or something we might think is cool.
I will be bringing several things I have recently completed.
The bipolar ORD Bot: This is a CNC machine I built for 2015 ORD Camp. It is a super simple drawing machine with some fun math behind the motion.
The DC Power Supply Interface: This is something I did for Inventables that we will be selling soon. It really cleans up the wiring when you use a DC power supply on a CNC machine.
The TB6600 Stepper Driver Shield: This is another Inventables project. The TB6600 can do a ton of cool CNC stuff. Now you can interface it to the free grbl CNC controller.
The CNC Club is a monthly meeting of Chicago area people passionate about learning, building and using digital fabrication equipment. It is held at the Pumping Station One Hackerspace. It is open to non members. We also have a Google Group called CNC Build Club.
Each meeting we talk about, build, train on and use CNC machines. We have 3D printers, laser cutters, CNC routers and vinyl cutters. Come out and join the fun.
Please RSVP on Meetup. I will have a CNC or Inventables related door prize to a random person who RSVPs and is present at the meeting.
Scotland is a place that, for the average American, provokes strong reactions. Single malt Scotch whisky. Haggis. And bagpipes. At least in America, the thought of 3D printed bagpipes may inspire fear in some people. Bagpipes were considered weapons of war, and commonly thought to be banned following the unsuccessful Jacobite Rising of 1745. (The Act of Proscription 1746 doesn’t directly mention them, though.) Personally, I’m quite a fan of pipe music, as well as other Scottish folk music, such as the Corries, and the music of Nova Scotia, especially Mary Jane Lamond.
I bought a Highland bagpipe practice chanter years ago, only to discover that the angle I had to hold it to keep my fingers in the right position was torture on my wrists. I figure it would be more comfortable to play when attached to an actual bag. But acquiring a full set of Highland bagpipes wasn’t terribly practical, and that would probably lead to my neighbors breaking down my door and coming after me with torches and pitchforks should I try to practice indoors. Or at least they’d complain to the condo association. So I forgot about that for a while.
Then in spring of 2014 I saw the Dreaming Pipes Kickstarter posted by Donald Lindsay of Glasgow. He was creating a 3D printed chanter with a customized extended range for the Scottish smallpipes, which are, as their name suggests, smaller, and designed to be played indoors. But he was also creating plans for a full set of smallpipes modeled off a 17th century design that could be 3D printed, with a laser cut bellows. And he was also designing 3D printed Highland bagpipe drones. I’ve got access to four 3D printers and a laser cutter at Pumping Station: One. It looked like fun to build. So I backed it.
My knitted-circuit artwork, Electronic Damask, was in a gallery show, NoFi, at Chicago Artists Coalition, October 24 – Nov 13. The piece was a collaborative effort, put together through the volunteer efforts of close to two dozen PS:One members. PS:One really represented at the Oct 24 opening, and I managed to drag most of us in front of the camera for a group photo with the artwork. (Thanks to Everett for the photo!)
If you missed the fun that night, you’re in luck. Electronic Damask has already been tapped for another show, and with an opening tonight in Pilsen, from 6 – 10pm.
This show should be of particular interest to PS:One members. It’s called Technologic and it “celebrates making art through technology”. It features some amazing stuff made with 3D printers, LCD screens, CNC watercolor painting, and of course a certain knitted e-textile.
The gallery, Chicago Art Department, is located at 1932 W Halsted in East Pilsen’s Chicago Art District (#8 Halsted bus runs right past it). Tonight’s opening coincides with the district’s 2nd Fridays gallery night, so there will be other openings all over the neighborhood.
You can find preview photos of the show on the facebook page. Full info is below. The show runs until December 6.
curated by Chuck Przybyl
Friday, Nov 14, 6-10pm
An exhibition that celebrates making art through technology. Work featured will include robotic drawing, 3D printing, laser cutting, textile circuitry, algorithmic art, image slicing, circuit bending, and prosthetics. Although often unsung – artists having access to new technologies has historically pushed and propelled creative endeavors. The exciting new technologies of today have been pushing the overall culture of DIY and propelling the Maker Movement. This is a participatory culture that embraces tools and empowers masses of people to innovate and create. Technologic explores and showcases not only how art is currently being produced with new tools, but how fringe technologies can be used in progressive and cutting edge ways.
Viewers also have an opportunity to “go deeper” to gain further insight through series of discussions and workshops as well information on the processes at the exhibit.
Technologic is curated by Chuck Przybyl for Chicago Art Department.
Artists: Tom Burtonwood, Christopher Furman, Harvey Moon, Luftwerk, Jesse Seay, Nathan Davis, Christopher Breedlove, Christian Oiticica, Leo Selvaggio, Antoine Kattar, and Russell Prather
Opening Reception Nov. 14 – 6-10 PM
3D Printing Workshop with Tom Burtonwood Saturday Nov – 15 – 2-5 PM
Panel Discussion Saturday Nov – 22 – 2-5 PM
Chicago Art Department – 1932 S. Halsted St. Suite 100 Chicago IL 60622 USA