The lab is also teamed up with the computational epidemiology department at the U of Iowa. Some of their research studies how often doctors and nurses wash their hands in a hospital setting. The group consists of doctors, computer programmers and engineers. The idea bases on setting up little beacons in hospitals that record (anonymously) the location of a worker and when they wash their hands. Here is a demo of one day of testing.
Many of the cases for the beacons are made locally in the shop. I saw this a good opportunity to get the PCNC 770 in on a little of the action. The final product is a polypropylene collar that hangs off a hand sanitizer bottle (as shown below). The production run was about 40 total parts.
The collar was made using a 3-part injection mold.
As a final operation there needs to be two holes drilled in the collar to hang an electronic box. The part is very odd shaped and directly clamping into a vise deformed the plastic collar too much. The fixturing setup is not the most elegant, but it is accurate enough for the job and enables quick loading/unloading of collars.
Holes were drilled. Rather impressed with the Tormach drill chuck, spins very true. Have had trouble with much more expensive drill chucks that tend to “wander” the drill bit. Look forward to getting more parts running through the Tormach mill.
Took some creative engineering to get the stand under the mill. First the mill needed to be lifted off the table it was originally setting on. The hoist was a little too big for the job and made it hard to maneuver.Once the mill was lifted the stand was placed underneath and the mill was set back down.
The mill was bolted on and the chip catchers were attached. The mill was reconnected to the computer and installation complete. Ready to make some chips!
Upon arrival to work from a glorious week of spring break, I noticed a Tormach package had arrived.
It was a stand for the PCNC 770 mill! I have completed taking it out of the crate and put on the stand legs. After lunch I need to run to the rental store to pick up an engine hoist to raise the mill onto the stand.
I have recently starting writing the introductory lesson to the PCNC 770 on programming. Many topics to cover, trying to strike a balance between elaborating on topics and staying concise. I understand the personality of many users of the 770 rather learn by experimenting rather than reading a 15-page lesson, shooting for 7 pages. To be continued…
A pen has been attached to the end effector of the robot. The pen is spring loaded to provide a constant force on the writing surface, complements of Matias Perret. Cartesian coordinates are pretty much copy and pasted into the RoboWin7 interface. Simple! Also thanks to David at ST Robotics for helping with the Roboforth code. So here is the video of the Tormach logo.
The ST Robotics R17 is up and running. While “homing” the robot I almost caught a left hook to the face, otherwise setup went smoothly.
The robot communication with the mill is pretty primitive. Basically it works as a hand-off. The robot will work on a task while the mill sits in a loop waiting for robot to hand off the task. As the mill completes a task, the robot is waiting for the hand-off. The electronic box that completes the hand-off is shown below.
I am able to click on and off all the relays with the mill. I also have no problem turning on and off the outputs from the robot. To familiarize myself with Roboforth (the language the R17 robot uses) I decided to write a code to test all the hand-offs. The code uses the mill to ensure outputs from the robot are turning on and off and the robot ensures the mill is outputting correctly. The code is designed to make sure no relays are stuck and everything is working properly. I encountered some unusual errors. The code would complete sometimes and then other times, Mach 3 would not detect a handshake from the robot. I have a few ideas to try to debug tomorrow. I connected the mill and the robot to the same computer, if all else fails I may try to split the mill and robot to separate computers.
Putting the mill together has taken a little longer than expected. I’ve tried to keep things neat while setting up because I knew once the mill was running, milling out parts would take precedence over tying back wires, enclosing the computer, etc.
I fabricated a stainless steel bracket for the manual oil pump, this keeps it from getting knocked over.
A polycarbonate box provides the protection for the computer from chips, fluid, etc. Holes were cut/drilled to run wires out of the box.
All wires (which seemed never ending) were tied back with cable ties to look as neat as possible.
The machined was turned on and software was set up. The mill is operational, having no trouble jogging the machine. I really enjoy the Shuttle Jog Controller, makes jogging the machine very easy. I would love to have one of these for the Haas Mini Mill at the U of Iowa. The arm holding the keyboard and LCD screen needs some work. Since it sits on a table instead of a stand, the keyboard is a little higher than what I would consider comfortable. The arm also tends to swing backwards, these are minor things that will be fixed in the next couple weeks.
Tormach sent along tool holders for the mill. I just ordered an 3/4″ diameter R8 collet to connect to the drawbar and sets of tools with 3/8″ and 1/2″ shanks. These were ordered from Wholesale Tool. The mill should be cutting parts at the beginning of next week.
Next step, setting up the robotic arm and interfacing it with the mill.
My name is Brian Johns. I’m a PhD student in Industrial Engineering at the University of Iowa. Tormach sent me a CNC mill (PCNC 770) and robotic arm to design educational lessons for students/instructors wanting to learn about machining. My personal goal is to excite more students about manufacturing at the U of Iowa by developing helpful and intriguing lessons. I will be keeping my progress posted on this blog.