CNC Routers - Insights

3D printing is giving the router a little run for its money in the education arena, since it looks more like engineering than a router. Sorry, that's politics. Tech. influences would be mainly the software to run the CNC router and the material used to construct the CNC router itself. I see more and more low-end routers entering the school and home woodworker market.

CAD Drafting and file manipulation. Composite design. Green Energy application technology requiring new materials cut to tight tolerance.

For me, it is the software. With good software you can pay more attention to design of the piece you want to produce and less time writing G-Code.

Shopbot and Techno

HM CNC HM 145X - they look most interesting for the money, Town Labs -my favorite CNC mill, but too small for my application. Smithy CNC is good but too expensive, their manual mills have great prices, but not their CNC machine. Looking at Bolton - they have a nice manual mill but the CNC mill I do not know much about it. We plan on buying a mill soon, hopefully CNC mill.

Haas

Personally, I used mine to engrave photos into plexiglas and lexan. I've also cut pieces needed for my projects. I use D.O.S software, "Turbo CNC," and other support software to generate most of my G-Code. Where needed I will write my G-Code, but thanks to my other programs, I rely heavily on that software to generate the bulk of the G-Code needed for my projects. Once the Machine is calibrated and running, it's mesmerizing to set and watch it do its magic.

I have used CNC Routers with high school students and teachers for a variety of projects ranging from the ever popular student name and artwork on a project to projects requiring 5 or 6 from pieces cut from different materials to fit together.

Shaping, profiling timber component parts for the manufacture of bespoke doors and joinery. Engraving doors, cutting non symmetrical apertures and machining glazing beads to suit. Creating programs to house locks and hinges.

We have CAD/Drafting students enter cartesian coordinates taken from an actual leaf and then connect them with splines in AutoCAD LT. This is exported to MasterCAM, assigned a tool path, and cut as a decoration on a cutting board. This project really gives students a lot of learning in many areas, and they get to take it home.

Occasionally, I will use my CNC as a plotter or drawing machine on large paper or drawing boards. I've made a spring loaded drawing pen that installs in place of the cutting spindle. It is more handy then one would initially consider.

Peck drilling of stretched acrylic holes. Machining of mating surfaces to specific thickness. Elimination of hand fit (secondary operations) due to precise accuracy and repeatability of trimming and drilling.

None have happened to me. However, I made a service call to "Xxxxxxx Electric". They manufacture and rebuild the large electric motors used in mining. Their old "Fanuc" Laser CNC needed attention---I repaired the electronics and the laser driver circuitry and they then proceeded to adjust the 4 lasers that are combined to act as one high power laser for the cutting task. Each laser goes through a setup to assure proper beam size. This involved using a 1/2' metal plate as a "STOP" for the beam--it was usually 10 ft away from the individual laser tube that was being adjusted. A white piece of paper was used as the actual "Target" and the hole burned by the laser was proof of proper tube setup. A short 250 ms pulse was used for the burn. Someone moved the "STOP" plate and when the laser tube was fired, the result was a solid burn on a wood wall some 30 ft away. This was only one of the tubes (~250 Watts). If all 4 of the tubes were columinated and the test burn made, it would have been something to see.

It is not "if" you crash the bit, but "when." Having said that, No, we have a very, very good safety program and great teachers who have done a great job preventing anything beyond a ruined part or bit.

Do -NOT- plunge into wood thicker than 3/4". It doesn't matter the kind of wood/plywood/composite; don't do it. It's not worth the risk of burning down your machine.

(In regard to a Flatbed CNC) Vacuum table--dust / particle collection--homing sensors to aid in setup--ability to use and control a low power laser as a cutting / etching option. A 24" x 48" cutting surface (small format) and a 5' x 10' cutting surface (Large Format).

1- More possibilities with the same machine. 2- Good motion control easy to use. 3- Small but robust machine. 4- Automatic change of tools. 5- Cooling system of tools and materials. 6- Control panel easy to use for end users.

Ability to hold a very tight thickness tolerance on a large dimension sheet in a very short amount of time. This would mean control of the top and bottom surfaces of the sheet.

For high schools, they might want to investigate local business and industry installations and try to match the basic router design and the CAM software. They can then get some professionals on their Career and Technical Education (CTE) advisory committees who can really help the school out, and grow some talented and qualified students into the most valuable employees.

Make sure the the router is built rigid enough to ensure proper accuracy and the table surface has ample substructure to support and maintain proper alignment of the tooling fixtures.

Compare and compare again---there are some very good machines available for a reasonable price and there are some expensive machines that are very much overpriced.

Read--read--read. Talk to someone that operates a CNC Machine --- Talk to someone who writes G-Code -- talk to someone who uses software to aid in writing the G-Code. Learning it all on your own is fun, but can keep you from trying things because of your fear and caution as to not wanting to break anything---Breaking things is all too easily done if you are not a cautious operator and then there is the DANGER that exists when things break while the machine is running.

Make sure you choose a manufacturer that will support your product now and in the future. The tech support they offer is invaluable not only pertaining to the machine, but of the possible processes that will go on the machine.

Purchase easy to use and broadly applicable software. Use in conjunction with a vacuum table. Shop for price and value......there is a very broad range. Look at used equipment.