This week we are going to play with the rotary axis on the little CNC mill. We are going to assemble it and calibrate it. We will use a demo of DeskProto to run a job on it. We will of course start with the CNC Ninja Squirrel, then try some other projects. It you have something cool to try, bring a file in STL format and a round piece of material to mill it out of.
This week at the CNC Build Club we are going to do a CNC router class, training and certification. If you want to learn a lot about CNC routers come to the class. We will start out with a little class room training that is open to all including non-members, then move to the shop where we will do hands on training and certifications. This will be limited to 8 people and they must be PS:One members. If you want to be one of those 8 people, please be one of the first 8 to RSVP the meeting at Meetup.com.
Frank Hammer, a retired scientist from Monsanto, will be giving a talk tonight on Genetics and Epigenetics. The session is divided into two parts:
1. General genetics, which would include the structure of DNA,
2. How the four bases or nucleotides, adenine, thymine, guanine and cytosine are paired,
3. What is a gene,
4. What is messenger RNA (mRNA)
5. How mRNA codes for proteins,
6. What is a codon,
7. How proteins are manufactured in the ribosome,
8. Answering questions.
1. The polymerase chain reaction (PCR), which is how we multiply DNA millions of times so it can be forensically and biologically analyzed,
2. Epigenetics, its causes and effects,
3. Answering questions.
Frank has been involved in the life sciences for about sixty years. Has written two book chapters, many reports, including one about antisense which was published by Frost & Sullivan. Frank has eight patents, in the fields of food technology and diagnostic biochemistry. His avocations are reading and writing poetry.
And that’s all Frank wants to say about himself… Find out more at the meeting 🙂
See you all soon!
Tue, August 27, 9:00pm – 10:00pm
PS:One, 2nd Floor
3519 N. Elston Chicago, IL 60618
by eastein posted in Class/Workshop, Events Comments Off on Frank Hammer Genetics & Epigenetics talk tonight!
The project was to build a “single axis” drawing machine in one night. This machine uses two independently controlled carriages on a single piece of MakerSlide rail to control a pen at the tip of two linkages. The primary purpose of the project was a fun group build and a learning exercise in setting up a non-Cartesian machine using inverse kinematics. Kinematics in this case means mathematically describing the machine to the CAM controller. The One Axis DrawBot is a very simple non Cartesian machine.
The equations used are shown above. The ends of the linkages on the carriages end are at joint and joint. The pen is at pos->tran.x and pos->tran.y. The first two equations convert the desired pen location back to actual machine locations. They were plugged into the CAM program. The last two equations do the opposite and convert machine locations to the pen location.
We had one team assemble the machine, one team wire the electronics and one team setup the controller. It took about two hours to complete that phase. We try to use newbies wherever possible, so adding solder training into the mix usually adds a little time. The next step was to setup the CAM controller.
We borrowed the CNC router computer and control box to run the machine. This has Mach3 CAM controller software on it. Mach3 has a “formulas” feature that we used to enter the kinematics. We quickly had the machine running, but it was soon clear that Mach3 was not completely up to the task. In the formulas mode, it appears to disable the DROs (digital read outs) which tell you exactly where the machine is. It was also difficult to home or tell the machine the current location. Moves in the Y axis are non linear and need to know the current location. This resulted in Y axis moves that were not 100% accurate.
The other problem was coordination. If you tell a CNC machine to move from X0, Y0 to X1, Y0, it accelerates up to the desired speed then decelerates to the end point. If you tell it to move from X0,Y0 to X1 Y10, the two axes are moving different distances, so it needs to coordinate the different axes speeds and accelerations. The X axis would move quite a bit slower to coordinate with the longer Y distance to get a straight line. Mach3 was coordinating the two machine axes, but it was not coordinating the pen axes. Moves in only X or only in Y were nice and straight, but moves in both X and Y had a bit of a curve to them, but they did accurately arrive at the end point. A graphic with a lot of short moves would not show any on the problems above so we ran a quick “PS:One” graphic. Watch the video and be sure to wait for the applause.
We will switch to using EMC2 (LinuxCNC). This has a true inverse kinematics feature that should fix the problems.
There is some discussion on the EMC user mail list to help us with this project.
Update 6/23/2013: Here is the latest (untested) version of our LinuxCNC kinematics file mykins.c
About 4 people certified on the vinyl cutter by me. I started adding tips to the wiki page for the vinyl cutter because there was a little struggling to get good results. I think it was due to not setting the orientation of the plot (worked for me)
I saw some certification on the LulzBot. We need the linux computer for that fixed or replaced!
Ryan and Liz Certified on the CNC router and they cut a complete project on their own (cool little circle/star thing)
Acetone Smoothing….So it appears to make good prints look great and bad prints to worse. You can’t polish a turd.
The Quantum Delta was slowly cranking out angry ducks and squirrels all night.
We did some experimenting with ABS Smoothing. Donald J brought in most of the equipment which consisted of a heating pad, glass cookie jar and a little stand to put the parts on. We put a small amount of acetone in the jar, then put 3D printed ABS parts on the stand. When the acetone heats up it forms a cloud in the bottom of the jar, enveloping the ABS part. Most of the acetone condenses back near the top of the jar.
It worked pretty well on finely layered parts. It made some parts actually look little worse by highlighting flaws. It took quite a while to heat up and could be optimized. Donald is looking for volunteer ABS parts to practice with.
We have a temperature controller for it we can wire up. It can only drive about 3amp @ 110V. Does anyone have an SSR? The mechanical relay probably won’t last long in this application. The heater is probably 5-7 amps (guess)
Good news! Instructables have started sponsoring monthly build nights. And the more tutorials we make, the more supplies and equipment they’ll send us.
This month, we received a whole bunch of Bare Conductive Paint Pens. Tomorrow night at 7pm, we’ll spend a few hours playing around with them. Come experiment with the wonders and dangers of paper circuitry!
Express your inner mathnerd! Come join us for an evening of learning: algebra, calculus, word problems, finding x, and much, much more. We’re open to anyone looking to brush up on basic skills and to those who want to learn about more advanced topics. We can even stray into set theory, topology, and fourier analysis…. it’s all up to you!
If you’re feeling intimidated, don’t be. Any level of math experience is welcome. We will be happy to discuss any topic that falls under “math”. No question is too basic. Got a homework question? We can help! Trying to solve a tricky equation for a problem? We’ll think it through with you. Want to learn the basics of what math is all about? We’ve got you covered!
Math should be a common language to all, and we will be more than happy to help you take the first steps towards a lifelong appreciation of this beautiful subject!
Whos, Whens, and Wheres
Who – Anyone who wants to learn about math
Where – PS:One, second floor, in the electronics area