Category Archives: Uncategorized

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Watch Do Teach, a practical approach to lab instruction

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I read somewhere that lazy people make the best inventors.  I’ve also heard that necessity is the mother of all invention. Well, my mother raised a lazy inventor!  I’m always looking for an easier way to do things and have in the past spent at least a day automating a data entry system when it would have only taken a few hours to enter the data manually.  I may have missed on that one, but I did learn about data entry and some automation techniques that I have used successfully and more quickly for other tasks.
Tasks that are ripe for automation are frequently simple and repetitive.  In the spring of 2006 I took over responsibility for teaching between two and three hundred engineering students per year how to program and operate CNC Machine tools to make parts and assemblies that they have designed.  Over the years lab use has increased and now over one thousand students per year are doing work in the facility about half of them use one or more of the CNC machine tools.  I’ve done this with two full time staff members plus countless student lab assistants and pear learning assistance.  Even with that help it only works because we have automated a significant amount of the instruction.
How many times can you explain that the green button turns the machine on?  For me it was about 64 times.  By the time the 2ndbatch of 64 arrived I had written a 14 page quick guide that included information about starting the machine changing tools and jogging as well as instructions for loading code and running programs.  The guide was deployed as a PDF document on computers located next to each machine tool.  This was the beginning of the automation, but far from the end.
In those early days each class had 64 students divided into sections of 16 students and the course was offered 4 times per year.  We have since expanded the enrolment to 72 students total but the overall layout remains the same.  Each student has 4 hrs of lab per week for a total of 28 hrs of lab per term.  With an average of 70 students per term times 28 hours per term times 4 terms per year that’s about 800 total hours of lab instruction and over 58,000 student hours of lab instruction that I’ve been responsible for.
In those almost 60,000 hrs, you might say I’ve learned a lot of students, but more importantly I’ve learned a lot about teaching and learning especially about lab instruction.  The most important thing I’ve learned is that the best instructor is the one who has just completed the exercise they are teaching as long as they understand what they did and why, and the worst instructor is the one who is bored with the exercise, could do it with their eyes closed, and would rather just do it for the students because it would be faster.
How do you get the best instructor in front of the students?  We did it by developing lab instructions that were simple and easy to understand (kind of like assembling furniture from IKEA) and then developing a system that allows the student who just finished the exercise to be the instructor for the student who just watched them do it.  We call it watch-do-teach, wdt.  I understand it is similar to the system used in medical schools where it is sometimes referred to as “watch one botch one.”  Since operating a machine tool isn’t brain surgery we generally avoid the “botch one” aspect with simple clear instructions, and by asking the students to show understanding of the instructions and the concepts before they even start the watch step.
Our system has evolved over the years and has produced some amazing results.  The first exposure is actually before the watch step and happens before the students arrive in lab.  Students are expected to review pre-lab materials and the lab instructions and then answer questions in a pre-lab quiz usually by the Sunday evening before we complete a given exercise
Once students complete the quiz they add themselves to a wdt list by filling out a web based form.  Once the students arrive in lab they are called to the machine tool or lab bench where the exercise is set up in the order they added themselves to the list.
To start an exercise the first two students are called up.  The first does the exercise while the second reads the instructions to them (the instructions are deployed on a computer at the machine tool.)  Once the first student has completed the exercise a third student is called up to watch, and the first student becomes the “instructor”, while the second student starts the do step of the process.
If a student is not available when they are called to the exercise a notation is made to the list indicating why they were unavailable and the next student is called.  If the bottom of the list is reached, and there are still students who have not completed the exercise we begin again at the top of the list of course skipping anyone who has completed the exercise already.
The entire process is facilitated by a group of three students who have previously completed the labs.  These three students are hired as pear learning assistants, PLAs.  The group is composed of a lead PLA, this is someone with several terms of experience teaching labs; and two les experienced PLAs.  The least experienced PLA is responsible for making sure that the students are called up in the correct order and that student are working on the correct exercises.   The third PLA is responsible for starting the exercises and helping troubleshoot student problems both at the machine tools and while working on CAM exercises.
Students not actively working on one of the exercises are expected to be present in one of the two computer classrooms in the lab working on self paced CAM exercises, learning how to program the machine tools.  When a student has a question about the CAM assignments they are encouraged to first ask their peers, and then find one of the PLAs.
This WDT system allows students who have never seen a machine tool before become safe and competent operators and programmers in just a few hours of “instruction”.  It includes constant re-exposure to key concepts and the exercises are intended to build on each other.

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Can you train a Machinist on a CNC machine tool?

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They say that a Swiss machinist apprentice starts with a piece of steel, a file, and a micrometer and are told to make a cube.  I don’t know the truth of this assertion but it has a sort of elegance.   It can give the apprentice insight into measurement and metal removal.  It also lets them appreciate the ease of using a milling machine later in their training to complete the same task in minutes.  It brings to mind books like Ivanho where we can almost feel what it is like to grow up in a feudal castle and go through the steps from page to squire and then knighthood or even apprentice, journeyman, and master.
When I started teaching people to program and operate machine tools I was tasked with taking engineering students and enabling them to use the equipment to make something they have designed.  I wasn’t given 7 years to take them through an apprenticeship program or even 7 months to train them I was given 7 weeks and only four hours a week of lab time.  We started on the first day making chips in a CNC lathe. 
I knew that the “old-timers” insisted that students first understand how to use a manual machine before operating a CNC tool.  They argued that you needed to have a feel for the process, with your hands on the handles controlling the feed, feeling the cutting forces, and vibrations of the process.  Since these were the “old-timers” that taught me I believed them.  The problem was I hadn’t used a manual machine tool for 10 or 15 years and could barely remember how to turn it on it wouldn’t have been safe for me to teach them with a manual machine.
In that first 7 week term the students and I taught each other how to program and use the machines.  In the seven  years since that first day I’ve had hand in the instruction of thousands of students most of them engineering students although recently we’ve been using the engineering students to help train CNC operators and setup technicians. 
The system we have developed involves the use of standalone multimedia teaching lessons that any pair of students can step through the series of lessons taking turns in the role of student and instructor.  The lessons are intended to teach safe use of the equipment and to allow the students to become familiar and comfortable with the controllers and setup procedures.  The theory is that this system enables us to use students to teach each other the simple aspects of programming and using the equipment allowing the staff to help them understand more complex and nuanced issues dealing with complex fixturing and complicated tooling and tool path selection.  The reality is the students end up handling the most complex setups with very little help as the staff members tend to be interrupted too often to concentrate on anything complex.
Through the years I’ve traveled to meetings and met with instructors from all over the world.  The training methods we’ve developed are frequently a topic of discussion.  We almost always get to the question of the missing value of our students not getting a chance to feel the cutting forces through the handles.   In the beginning I was a little defensive when taking these questions it seemed there may be some validity.  In all of these meetings we would tour the local teaching institutions and local manufacturing facilities.  I began to notice quickly that in the only places I saw row after row of manual machine tools was in the schools.  Frequently the manual machines had been donated to the school by a company that was closing or upgrading to CNC equipment.
With that realization forming in my mind I began to look critically at our teaching methods and their lack of manual machine tools.  The arguments for starting with manual always revolve around the idea that machinists need to have a feel for the process to understand the influence of changes in feed, speed, and depth of cut.  They will tell you that you need to have this feel for the process to truly understand what is going on and make good parts.  It reminds me of a story I heard about a WWI fighter pilot visiting a Messerschmitt factory at the beginning of WWII and telling the engineers that the first thing the need to do is remove the cockpit glass so the pilots can feel the wind in their faces.  If the pilots can feel the wind they will know how fast they are going.
All of the CNC machine tools I’ve used have a power meter so I quickly began to discount the wind in the face / feel the force arguments.  It is not hard to convince the students that power is directly related to cutting force.   The other argument I’ve heard returns us to the feudal system.  You will appreciate the easier methods more if you’ve done the work the hard way.  This argument even extends to the discussion of teaching G-code or CAM first.  One of my colleagues likes to point out that is like saying you need to ride a horse from Boston to Worcester before you can appreciate the Mass Pike.
If we look critically at the real need and the value we can add to our students we need to consider the types of jobs they are doing and the type of equipment they will be using.  Just because I learned it that way doesn’t mean I should teach it that way.  In my experience starting with CNC is faster, safer, and creates qualified machinists that meet the needs of today’s industry.  Auto technician training doesn’t start with the Model  T.

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Grading the blogs

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I must admit that I assigned the blogging assignment without really thinking through the fact that if I want the blogs to have any value to you (the students) or us (the instructors) someone needs to read the postings.

I’ve been reading blog postings for the last hour and a half, and I’m about half way through. I’ve come up with a grading rubric, and method.  I’ve also extracted some statements that I would like to re post below after quickly explaining the rubric.

Grading Rubric

The stated assignment was to make at least 1 blog posting per week so I will review the blogs periodically check the content and posting dates to assign points.  As I do the reviews I will add to the score in the Blog grade column. I reserve the right to give bonus points for high quality efforts.

Possible Points Due Date
Week 1 2 18-Jan
Week 2 3 25-Jan
Week 3 3 1-Feb
Week 4 3 8-Feb
Week 5 3 15-Feb
Week 6 3 22-Feb
Week 7 3 1-Mar
Total 20

Some excerpts from the blogs

If you don’t find yourself quoted here it’s possible that your name is from the 2nd half of the alphabet, or perhaps I thought something I copied from another post was redundant with your comment.
“would be nice to have some sort of direction on when things are due and what order they should be completed in”
  • I’ll try to address this in on the web site — people have also been having difficulty figuring out were to upload finished CAM files
“So far I’ve been in two lab periods and haven’t had a chance to complete any labs yet. It’s a little frustrating but understandable since there aren’t many lab TAs and they can’t be expected to give everyone perfect instructions.”
  • You should have had a chance to work on CAM exercises.  The intent is that several different activities are going on at the same time to allow us to use more of the labs resources at the same time.
“The directions for the lab seemed unclear until the PLAs helped with setting up the template along with using the machine”
  • I think we need more pre-lab prep activity.  I’m glad the PLA was helpful.
“I think I might have to go do the CAM exercises on my own outside of lab time because I feel we do not have enough time to do that and the directions seemed unclear at first but now I understand them.”
  • This is encouraged if you feel that you are getting behind.
“it was quite frustrating at times, between the confusing instructions (which are apparently worse than they were last term, according to a PLA)”
  • If you have a comment like this please indicate what was confusing (if you can) I’ll speak with the PLAs to see if I can figure out the problem
  • The instructions this term are almost identical to last term for most of the exercises.
“THe lab was very confusing and could have used any explanation or some introduction to how it was going to work.  I found my self wasting alot of time simply because I did not know what I was supposed to do or how to start the process.  Overall, it was very frustrating.”
  • For comments like this please include information about which lab section you are in so I don’t have to look you up in the class list to figure out if the problem is specific to your section, or systemic. 
“Something I think could be approved upon for the labs – have the lab assistants be available, but not hovering over the groups working. Not only did this make us uncomfortabe while working, but it also resulted in the unecessary stopping of the machining process, because he wasnt fully aware of what we were doing, and jumped in.”
  • This is my intent.  I will make sure that the PLAs are reminded.
“It would good if there was a greater degree of organization, however, because it was confusing at times whether we were supposed to be working at a machine or on CAM.”
  • This is the intended function of the Watch Do Teach lists.  There is supposed tobe one PLA in eash section who’s job is to maitaint he list and make srure people kow what they are supposed to do.
“TA’s couldn’t fix the problems fast enough. I stood there for a long time just doing nothing and felt that it was an extreme waste of my time, especially because I still need to do the measurement lab and the CAM labs”
  • This is a good point.  if there is a problem that will take some time to correct something broken.  We need to be able to quickly determine that the problem exists and sen people back to the computers or to some other task while it is being fixed.  Alternately rather than fixing the problem the PLA could have instructed you how to fix it so you could learn something new…
“I feel like there are a lot of overlapping labs in this class, and it stresses me out because I never know if Ill get the good grade or not because of how much stuff there actually is to do.”
  • I’ll do my best to address the organization and make sure that feedback is prompt.
“don’t like how the lecture is getting rushed near the end. I am not getting a grasp on the lecture side of class as much as the lab, because I always feel rushed in the lecture”
  • This is a common problem.  I’ll see if I can stick to the agenda better, and try to reduce my expectations about what I can include in a given lecture to avoid rushing at the end.
“Today was my first time in Washburn!  It’s taken me three years to discover this grimy wonderland”
  • It’s not supposed to be grimy
 “While I’m learning some things, I’m still a little confused by the course organization”
  • Me too! I once vowed to appear more organized to my students. I quickly determined that I would actually need to become organized, and would probably never appear organized.
  • I’ll revisit the Syllabus page and update a weekly reminder of the coming activities for the next week
“I warn anyone new to this software not to overestimate it’s user-friendliness.”
  • it gets better as you get used to it.
 “The instructions were….detailed, but missing steps”
  • Please include specifics.  Don’t struggle too long before asking for help.
see you in class

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Worst Lecture Ever

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The title may be exsessive, but that was how I felt as i walked away from the classroom. I think part of the problem was high expectations. I spent a good part of the weekend thinking about the lecture and preparing figures.

The first time you use any figure you notice the mistakes… The pen input in the classroom not working as expected didn’t help.

The real problem with the lecture though was my drawing the wrong angle and not noticing my mistake even when pointed out to me. That is why I try to avoid doing math on the fly in front of the class.

I feel that I need to fix a few things as a result of the lecture today.
In order of increasing importance.
-  reduce the value of the quiz questions to reduce the impact of my poor lecture.
-  post corrected slides
     -  rt=t1/t2
     -  Phi and Theta used interchangeably
-  create and post a camtasia video of the feed to t1 derivation
-  create and pose a camtasia video of force transformations

I would simply change the due date of the quiz  andtry the lecture over but that would disturb the schedule significantly.

You laugh I’ve done it before when I was unhappy with a lecture.

Monday lectures suck. Especially when the happen on Tuesday (I saw you sleeping! People aren’t supposed to be falling asleap until next week)

Stay tuned for anouncements about the items listed above.

See you in class
torbjorn


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Perfect is the enemy of good enough

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I have to admit that this first blog posting has been a little bit hard to start.  It is the first one after all it seems that it needs to be exceptional to set the tone for the class and the site.  You know the exceptional tone that I think it should have.

I sat and made notes about what I wanted to write.  I made plans and outlines even sketches.  I was going to film a video intro with embedded screen capture.

It was going to be perfect!  You know, like the first time should be.

It dawned on me though that while worrying about making it perfect I wasn’t doing anything useful.  Nothing that the class could use, or decide to ignore, was flowing out.  The realization that that was much worse than a little less than perfect made me decide to type this stream of conciousness this morning and if all goes well I’ll click publish and stop procrastinating.

see you in class