CNC machine update #4: material investigations, cut lists, wiki updates and funding difficulties

Added on February 29, 2012

For a couple of weeks now, my initial design of the Y axis of my machine has been complete, but I have been unable to make any real, tangible progress due to funding complications. I’ll get to that matter shortly, but first I wanted to discuss what I have been able to do without the funding.

A closer look at types of wood

The original Mantis 9.1 project that I am basing my design on utilized 1/2″ MDO for all of its structural material, which seems to raise the eyebrows of the ‘traditional’ CNC specialists I’ve talked to so far. Professionals like tool-and-die makers and seasoned industry veterans seem to cringe at the thought of using wood of any kind to build a CNC machine, and some even go so far as to claim that a CNC machine built out of wood would be exceedingly difficult for a person of my skill level to build. They all advocate using metal for the structural material, but this presents some significant hurdles to me; for one, I do not have any tools or knowledge about working with metal in this way. This would almost necessitate collaboration with a local machinist, which would drive up complexity, time and, most importantly, cost. Given the the fact that wood is cheaper and easier to machine for me than metal, I am still planning on using it. Besides, this machine is, at best, a dirt-cheap prototype that may or may not work.

To me, the type of wood is extremely important; choosing the wrong type and size will result in way too many obvious problems. However, I am not an expert craftsman or machinist (yet), so my current level of knowledge about types of wood and their properties is limited. Therefore, to me it seemed that the best thing to do would be to do some research into this topic and learn a few things about wood. I started by poking around on the web for information about types of wood and their properties, but I kept find inconsistencies between sources and didn’t feel like I was getting the intimate level of knowledge I was looking for.

To really get a good understanding of the materials, I headed down to one of my local lumber stores (we only have two here :)) and took some time to really look at the choices. This way, I can get an idea of what is actually available in my area (there’s no sense in ordering sheets and shipping them in), and get a hands-on look at the differences between each type of material. For the sake of solidifying my own understanding, I’ve taken pictures and notes about the materials that looked good to me:

MDO (medium density overlay)

Medium density overlay (MDO) is similar to the plywood that most people are familiar with in that it is made up of several layers of wood fibers pressed together. Unlike cheaper plywood, the layers of MDO sheets are bonded with resin, so that it is structural more solid than regular plywood. MDO is good for machining and painting, and can be a great choice for a CNC machine. In fact, the original Mantis 9.1 project used MDO!


Particle board

Whereas MDO is composed of fibers of wood, particle board is compose of particles of wood, meaning small, regular pieces. Similar to MDO, the particles in particle board are bonded using synthetic resin, though not in layers. Complete sheets are formed through high temperature and pressure. Particle board is useful in some cases, and might seem like it would work for a CNC machine, but I would advise against it. This is because particle board contains voids, which cause a certain amount of weakness and flaking during machining. Think of it like very strong styrofoam – if you cut a piece of styrofoam, you can get an edge, but you can easily use your fingers to break away small pieces.

More information:


MDF (medium density fiberboard)

Medium density fiberboard (MDF) is another kind of composite material that uses fibers of wood bonded together with resin and compressed under high temperature and pressure. However, MDF smaller fibers than the previous two types of wood, and is bonded using greater pressure, which results in a quite strong material. A key benefit of MDF is that it contains no voids, and is quite a bit more dense than the other kinds of plywood. More density means less compression, which means if you cut out a 2″ strip of this material, it will maintain its size and shape better. For me, MDF is the ideal material for my machine. However, there is one very important property of this type of wood that needs to be kept in mind – MDF is formed using formaldehyde resins, which are possible carcinogens. When you cut up MDF, you need to do so in a well-ventilated area and possibly with a respirator (fear the cancer dust, for your own safety). The jury is still out about how much is harmful, and how harmful it is, but for safety’s sake, take precautions.

More information about MDF:


Cut lists

Regardless of the material, it will still be cut into parts for the Y axis. The ‘correct’ way to do this is with a cut list, which is simply a list of stock sizes and cuts that need to be made. I like to draw up sketches of the sheets I am working with, and mark out the various cuts and dimensions I need. Ideally, you will want to arrange your pieces in such a way that the number of cuts is minimized, and adequate spacing is provided for the saw blade thickness. Of course, you can just do this all on paper, but I felt like creating the cut list in CAD, just to keep things consistent.

It seemed to me that it would be most cost-effective for me to use two sheets of 2×4′ MDF, at a thickness of 1/2″. Here is how I plan to cut them up:

Wiki updates

In an effort to generate as much quality documentation as I possibly can, I have been maintaining a small wiki to provide some high-level organization of my on-going projects, including this one. While these blog updates are meant to provide a low-level, day-to-day look at the progress I make in real-time, the wiki articles are meant to provide a complete, clear look at all of the information for the entire project in one location. In addition to making obvious updates to my blog, I will be making periodic updates to the wiki from time to time. Feel free to check it out!

View the CNC machine wiki article

Funding difficulties

When talking to other makers in other parts of the country, there don’t seem to be many individuals who seem to have great difficulty finding funding, and I find it somewhat difficult to explain my own situation simply. At my university, finding funding has been exceedingly difficult, to the point that I am spending a great deal of time wondering ‘Why?’ and how to acquire funding effectively. It seems that many prominent makers on the web come from specialized private schools such as NYU, MIT and Parson’s, but this is not reflective of the majority of students, in my opinion. There is a wealth of information on the web about how to physically create projects and even more ‘after-the-fact’ documentation about cool projects, but there seems to be very little information about where in the world the money comes for some of these projects. For this reason, I feel that sharing my own personal experiences in this area would be helpful to others who are curious about what higher education looks like from my perspective. Specifically, why this project (and others) take me much longer than others, due to funding hurdles.

Finding funding within departments and colleges
So far, I have asked both my mentor and ‘client’ for funding, and have been denied. Since some money was acquired last fall for my Artist in Residence show, the Chair of the Fine Arts department is not willing to give any more money to myself or my mentor (because other programs may complain). However, I am technically a student of the College of Education, which has a great deal of money. Unfortunately, our education college is not project-based, and has no support for projects such as this. I am involved in the college’s Instructional Technology program, which is nearly completely online-based (~98% of students only take classes online). One might think that Instructional Technology would be strongly supportive of technology-based projects, but the program is extremely small (only one or two faculty members) and has no history of any student projects. So far, no one in the College of Education (that I have met) has been willing to work with me or offer any advice about viable funding opportunities.

Finding funding through administrative bodies
UNK does have an official administrative office related to graduate studies and academic work, which might seem like a good place to start. However, funding amounts are low, tightly controlled and subject to a great deal of political forces (personal opinions of the office towards a student, mentor, department or college can, and have, affect decisions). The deadline for applying for funding (maximum amount of $500) for this semester was January 12th, while the first day of the Spring semester is 9th. This means that students have approximately 3 days to identify, research and plan their project, discuss and refine it with their mentor, then have several physical copies of the application form approved and signed by their mentor and department chair. In my experience, during this time, all respective parties are more interested in preparing for and adjusting to the semester as it begins.

A message to the Maker’s Movement
My intention in discussing these difficulties is not to whine or complain, or to make excuses. Instead, what I am trying to do is share, realistically, my own experience as a maker in an environment that is not currently conducive for makers. As I mentioned, the Maker’s Movement (prominently led by MAKE Magazine and a strong community in NYC) appears to put a great deal of emphasis on the work created by students and faculty of private universities, and does not seem to acknowledge realistic funding challenges. To me, this is an incomplete picture of the true situation that many makers face, and is not wholly representative of the challenges makers face in many parts of the country. I would personally love to see more honest dialogue about how one can take local action towards meaningful reform in situations such as mine. Many cities are too small for hackerspaces, engineering programs or niche communities, and therefore have communities which are somewhat unaware of the Maker’s Movement and its potential.

The reason this section is particularly long is that not all progress in this CNC machine project is physical and tangible. Some progress is qualitative, and has everything to do with the practical reality of my academic environment. I did not have a great deal of pictures and videos to share with you this week, so I thought I could take some time to share with you my experiences and the thoughts that have been on my mind quite a bit recently. If you’d like to join in the discussion, and maybe offer some constructive advice about what a maker in my environment may be able to try, leave a comment, send me an e-mail, or contact me through the social network of your choice (links at the top of the site)!