The ABC's of CNC

Rumors of my death are largely exaggerated…..

Taylor Collins — Tue, 07 Jun 2011 03:11:31 +0000

It’s been WAY too long since I have posted anything here…. and for that, I apologize. Time is my worst enemy, and the number of projects far exceeds the hours in the day to get them done. That said, I will be posting a lot more often here, and have a lot of exciting news to share. Things like a new “hybrid” machine that just came on the market… which is a combination CNC hotwire cutter, and CNC router. It only takes up one “footprint” of space, and that footprint is HIGHLY variable, depending on your needs. All that is necessary to make a larger machine is to expand the size of the tubular rails (and these are made of inexpensive EMT electrical conduit from the home supply store.)
Another new development is the addition of a swiveling computer workstation, that serves both my CNC router and CNC foam cutter. This change was forced by an unfortunate death in the family. My old, trusty 20″ eMachine CRT style monitor just up and died. So, replacing it with a nice, slim flat screen monitor forced a re-design of the work station area. I’ll have photos and details up here soon! I promise…!! No really…. I mean it!

Is This You?

Taylor Collins — Wed, 03 Mar 2010 03:16:47 +0000

Is This You?
O.K… I’m going to climb way out on a limb, and see if I can guess who you are.
You like to build things, make things, and fix things. You’ve got a home workshop, with a few power tools, quite a few hand tools, and a stack of raw materials. You really appreciate craftsmanship. You enjoy the look and feel of precisely made parts, widgets and gadgets. Face it… You’re a Gear Head!
But appreciating and enjoying all of this precision is a far, frustrating step from being able to make things with that degree of precision in your home workshop.
You try to work accurately, but somehow that old joke about “measure with a micrometer, draw with a ruler and pencil, and cut with an axe” seems to pretty well sum up your life in your workshop.
Well, I’m here to tell you that it doesn’t have to be that way. You don’t have to settle for the accuracy that you can get with a hand drill, a hand held router, a bandsaw, or a tablesaw. You don’t have to compromise on how intricate a design can be, because it would take hours or days to cut out what you have in mind. You don’t have to put up with parts that are accurate to something like a thirty-second of inch (if you can even achieve that)…. With a CNC (Computer Numeric Controlled) machine, whether it is a router, a milling machine, a laser cutter, a plasma cutter, or a lathe, then the world of professional manufacturing is suddenly yours.
Without getting too ‘Touchy Feely…. Nanu Nanu’, let’s just say that having your own CNC machine can be truly life changing. Do you build model airplanes, or boats, or trains? Now you can cut finished parts, or make molds or patterns…. and do them with intricate cut patterns, repeatable hole patterns, straight lines that are straight, and flowing curved lines that you could never do by hand. If your part requires a grid of tiny, 1/8″ squares… no problem. Need a wheel or a gear that has a series of 24 circles, laid out on a circular pattern. It’s easy with a basic CAD program and your CNC router or mill. And if you need 2 dozen of these parts, that’s not a problem either. Once set up, the machine will happily run all day long, if necessary, to produce exactly what you need. And every part will be identical.
Sign making, plaques and trophies, engraved images made from photographs, 3 D sculpting, mold and pattern making, engraving printed circuit boards…. all of this is easy to accomplish with a CNC machine. And even if your interests are in more basic things like woodworking, just consider the possibilities. You can spend hundreds of dollars on a fancy dovetail jig… but even the largest ones can only handle a part that is something like 24 inches long. You can cut extremely accurate dovetails or box joints along a board that is as long as your CNC router (or even longer if you reposition the part between cuts). You’ve seen those fancy jig/pattern machines that hold a router, and follow some pre-made templates for cutting angled slots to make louvered shutters. You can do all of that, and much more with a CNC router. Cut the louvered slots, and then do decorative cuts derived from computer clip art. Your imagination is the only limit.
Do I get excited about CNC technology? You better believe it. And I want you to get excited too! This is something that anyone with average mechanical skills can achieve. The machine designs, the kits, the electronics, the software are ALL available “off the shelf”. If you’re apprehensive, you can start with a very small machine, and once you’ve learned the basics you can move up to a bigger one.
Or, you can just dive in and start on a larger machine. My first CNC router had a 24 x 48 inch cutting area. All that’s really necessary is a belief that you can do it!
And we’re here to help. The ABC’s of CNC video teaches you everything you need to know to get started… and our on-going educational community provides all the resources, links, and hints and tips to help you succeed. Ready for a life changing, liberating experience? Click this link and get started in the rewarding world of CNC!

Roughing and Finishing… The Easy Way

Taylor Collins — Tue, 02 Mar 2010 03:19:06 +0000

If you are doing sign making, or plaque making (or anything else that involves a lot of pocket cutting, where you want a good finish on the cut), you’ll want to follow the “professional” method and do it with a rough cutting (oversize) pass, and a final finish pass.
The easy way to do this is to “lie” to your CAM program. I use a 3/8″ diameter cutter so I set up 2 new cutters in Vectric Cut2D. I labeled the first cutter as “3/8″ Rough Out Cutter” and set the cutting diameter to .42 inches and the pass depth to .25 in. This offsets the center of the bit to .21″ away from the outline of the part being cut, which makes a cut that is “oversize” by .085 ( a little more than 1/16″).
I label the second cuttter “3/8″ finish cutter”. For this cutter, I set the diameter to the “actual” .375 and the pass depth to .80 With these cutters saved in the tool data base, the machining is simple. Select the outline to be cut, and then define the toolpath. Using a profile tool path I set my total depth to .05″ LESS than the finished cut, and choose the “3/8″ Rougt Out” cutter. Roughing is usually done with a climb cut (imagine a car sliding forward on ice, with the wheels spinning backwards. That’s a “climb cut), so that selection is made at the same time. Then generate the tool path and name it “rough out”. The code generated will cut to .70 in three passes. Then go back and change the total depth to .750 and select the “3/8″ Finish Cutter”. For the smoothest finish, select conventional cut (this time the “car” is moving forward, and the wheels are rolling forward as well). At this point I add tabs if I am using them, name this “Finish Pass” and generate tool pass. This generated code will make 1 pass at .75 inches deep and leave tabs they were added.
Don’t be put off by this long winded explanation… it is really quite simple, and the results should be great. And once you have the cutter definitions set up, you can use them repeatedly, without any more effort.

Birch Plywood Vendors

Taylor Collins — Mon, 01 Mar 2010 03:25:21 +0000

One of the trickier parts of actually going “into production” on the boat kits was finding sources for the material. This 1/6 scale Crackerbox boat is built from thin birch plywood… in 1/32″, 1/16″ and 1/8″ thicknesses. After LOTS of research, it became obvious that I was going to have to buy the material from multiple suppliers. It’s amazing how much prices vary on this stuff from different vendors, and the prices vary on the same thicknesses… not that any particular vendor has the best prices overall.
So… if you’re going to be buying a large quantity of thin plywood for your project, my best advice is “Shop Around!”. Among other things I discovered, was that it’s difficult to find sources for large sheets (like 4′ x 4′). I’m sure this is primarily due to the difficulty in handling and shipping, but for a project like the boat kits, the larger sheets can mean a big savings. The hull sheeting pieces are 30 inches long. Cutting these out of 48″ long pieces leaves a lot of 12″ x 18″ left overs. But by buying the 48″ squares, I can cut four set of hull sheeting from the width, and another set from the “left-over” length. But this is only a saving if it offsets the increased shipping cost for the large sheets.
Bottom line… let me recommend these three vendors. All provide great quality wood, and very quick delivery. The best prices will depend on your needs for thickness and sheet size.
Balsa, basswood, and birch plywood – www.nationalbalsa.com
Hardwood, birch (and other hardwood) plywood – www.sloanswoodshop.com
Spruce, birch plywood, composite materials, and everything else needed to build a full size airplane! – www.aircraftspruce.com
Hope this helps!

Ooops! I forgot to share the links….

Taylor Collins — Sun, 28 Feb 2010 03:29:51 +0000

If you’re curious about the R/C boat kitting project, you can check out what I am up to at http://www.soaringstuff.com/crackerbox.html
The Crackerbox is a popular full size racing class… Basically, it is a small (16′ or so) flat bottomed boat, with a huge V-8 engine. The rules require that there be a driver and a “mechanic” ( this is a reluctant friend of the driver, whose basic job is to hang on for dear life, and try to not look too terrified).
These particular 1/6 scale Crackerbox boats are intended for electric power. Because of the flat bottom, these boats don’t handle particularly well. Instead of tracking through waves, etc., they tend to wander a bit, so they have to be “Driven” all the time. There is a video of one of the prototype boats in action. Just go to the link above, and about 1/4 of the way down the page is the link.
I’ll have more about the production process, and the CNC part of this project here in a day or two….

CNC Production Workflow

Taylor Collins — Sat, 27 Feb 2010 03:32:42 +0000

One physical disability that I have always had to deal with is my stunning inability to pronounce that “N-O” word. As a result of this severe speech impediment, I’ve found myself in the radio controlled boat kitting business. An old friend of mine, who has always been an avid boat racer talked me into cutting a couple of kits for him. He provided a link to a site that has downloadable JPEG images of a two sheet plan, which was originally drawn for building a much larger, 1/4 scale boat. Naturally, the original plans were printed out on letter size paper, taped together (not particularly in alignment), scanned, and then published on a website. So my task was to download the JPEG’s, trace them, convert the traced drawings to DXF format, import the DXF’s into Vectric Cut 2D… and make parts.
That part of the process went swimmingly well. The bad news was that between the misaligned sheets on the original drawing, and the misaligned parts and notches on the drawn parts… I wound up having to pretty much re-engineer the whole boat. I’m going to put up some photos, and videos of this project… because I learned a lot along the way, and hopefully you’ll find it interesting as well. I learned quite a bit about fixturing for production, and now find myself actually selling boat kits.
If you ever considered starting a small, home based business, based on a CNC router…. you’ll find this particularly interesting. YES… it is entirely possible and practical. I can say that, because the first eight boat kits are actually shipping tomorrow! Stay tuned for future news, hints and tips…..

CNC Workflow – Concept to Drawing to CAD to CAM to Cutting

Taylor Collins — Mon, 08 Feb 2010 03:34:42 +0000

Cutting parts with a CNC machine is a drastically simpler process than it used to be. But it is still easy to get sidetracked, confused, or downright lost if you don’t set up some standards for the organization of your workflow. Depending on your memory is just too frustrating, and even if you can dependably keep track of the CAD, CAM and cutting files, it just isn’t a good use of “psychic RAM”.
Having a consistent workflow, and a consistent filing system for your CNC projects will give you the most efficiency with the minimum investment in time and money.
One of the best tools that I have found for my CNC projects is an application called DropBox. DropBox provides online storage, that is accessible through any internet connection (either hard-wired or wireless), and allows you to access that storage from any computer that you have set up with your account information. DropBox also keeps a copy of each file “locally” on each of your computers, and it updates those files automatically to match the latest version.
So, how does this work in a “real world” situation? The computer that I actually use to control my CNC router and CNC hot-wire foam cutter is out in my workshop. And, although I could certainly do all of my designing, drawing, and programming on that machine, I just don’t find it very comfortable or accessible. I prefer to work in a quiet, comfortable chair, on my laptop computer in my home office.
So, I create the CAD drawings of the parts that I’m going to cut (using DevCadCamPro or Corel Draw). I lay out the actual parts to be cut in my CAM program of choice which is Vectric Cut2D. And then I export the actual gCode cutting files from Cut2D. I save ALL of these files in folders within DropBox. Then, when I am ready to cut parts, I can access the DropBox folders from my “cutting” computer, and if anything needs a minor tweak or modification, I can do that right at the “Cutting machine”.
I use a consistent folder structure, so that I can find anything that I am looking for very quickly. Each project gets it’s own dedicated folder. For example, I’m building a 1/3 scale radio controlled model of a Thomas-Morse S4E (a World War I biplane.) So I created a folder called “R/C Airplane Projects”. Inside that folder is a folder called “Thomas-Morse S4E”. Within that folder, I two additional sub-folders called “S4E Active” and “S4E” archive. Inside each of those folders are folders for the major categories of parts…. “Wing Ribs”, “Fuselage Bulkheads”, “Landing Gear” , etc. Click on the images below to see the DropBox interface (available from any web browser) and a graphic that shows the folder structure that I use.
This may seem to be really anal retentive, but having this well defined file structure takes all of the unnecessary thinking out of the process, and allows me to concentrate on the gamesmanship of drawing, programming, and cutting good parts.
Once I have the folders created, I can go through the process of drawing a part in DevCad or CorelDraw. I save each drawing with a descriptive name (something like “Upper Wing Ribs”) and I also put a few initials right in the file name, to indicate what type of file it is. A typical file name might be “UpperRibs_DVCD” which tells me that this file was created with DevCadCamPro. Yes… I know that the Windows operating system will create the suffixes automatically, but sometimes these can get confusing, and I want to be able to identify everything at a glance.
I also save the Vectric Cut2D files in the same folder, with a “C2D” appended into the file name. When I generate the GCode in Cut 2D, I use the same naming structure, but start the file name with “Cut”, and also enter a code that reminds me of the material thickness and the cutter diameter. So, the G Code file for my Mach3 software will look something like this…. Cut_TMS4E_UP_Ribs_18_035.
I can glance at this label and know that this is the GCode cutting file… for the Thomas-Morse S4E upper wing ribs, and that they will be cut from 1/8″ thick balsa wood, with a .035″ router bit.
Right now, you’re probably saying to yourself “this guy is some kind of a nut. I don’t have to go to all that trouble”. And then, when you are looking a sea of file names that don’t ring any bells… you’re going to change your opinion and decide that maybe I’m not so nuts after all. it’s your choice.. but I know that I can sleep better at night knowing that I can find any file that I need… months after the project was first created.
In the course of the project, if I find that I need to make a significant change to any of the files, I will move the existing files into the “Archive” sub-folder for the project, and then save the new, replacement files in the “Active” folder. This way, if I do have to go back and do some “CNC Archaelogy” and reconstruct a project, I will still have the original files available to work from.
Oh yes… I forgot to mention… DropBox is FREE (for up to 2 gigabytes of online storage.) Larger storage limits are available for very nominal charge. And, DropBox will work fine with Windows, Macintosh, and Linux operating systems. I use my DropBox account with both my Windows and Mac machines, and access and modify files between all of them.
(Disclaimer – In the interests of transparency and openness… this blog is being written on my MacBook Pro, while I am sitting in my favorite coffee shop. I’m saving the text file as I go, into my DropBox account, and will post it into the ABC’s of CNC blog when I get back into my office!)

Automation Getting Automated!

Taylor Collins — Sun, 29 Nov 2009 03:39:12 +0000

I’ve fallen a bit behind on blog entries….. partially because of the Thanksgiving Holiday, and partially because I’ve been really busy in the workshop and studio. I’ve moved up a level in sophistication with the CNC router, and now have semi-automated tool positioning. Gone is the setting of the Z axis tool height with little pieces of cash register tape from Lowe’s….. Edge finding, and even center finding over a dot marked on the work-piece is now automated…. and we’ll be sharing the details of all of these cool functions in a series of free videos here (and on the main website at http://www.abcsofcnc.com) of course…. Stay tuned!

Look Out Lockheed… Here We Come!

Taylor Collins — Tue, 27 Oct 2009 03:47:55 +0000

I’ve started experimenting with some exciting new software from the amazing Stefano Duranti, in Italy. We’ve been using Stefano’s Profili2 program for a long time… to design model airplane wings, plot out wing ribs, and even generate cutting paths for CNC router cut wing parts. But the latest thing from Stefano is DevFus … a complete CNC design package that will work from a side view and top view of an aircraft fuselage design, and create all of the formers or bulkheads … and even generates building jig patterns so that you can be assured of a straight fuselage when you are done.
The program is pretty complex, but it comes with a library of sample designs… including a scale Spitfire, a Fafnir sailplane, a 3D aerobatic plane, and more… and you can walk through the work flow, using these pre-done samples to help in learning how to create your own masterpiece. When the design process is finished, there are four different 3D preview modes that you can access, that will show just the outer “skin” surface of your fuselage, the inner bulkhead and stringer structure, or combinations of these views. It is just TOO cool to be able to rotate these 3D views around in space. The big aerospace companies don’t have a whole lot on us modelers…when we’re armed with technology like this.
Oh yes…. the output from DevFusCAM can be input directly into your CNC controller software (something like Mach3) and you can cut all of those incredibly detailed fuselage bulkheads on your CNC router or laser cutter!
Stay tuned for further developments. I’ve got a lot to learn with this package, but the potential is pretty much unlimited!
The DevFus software is available at http://www.profili2.com

CNC Information

Taylor Collins — Tue, 20 Oct 2009 03:50:11 +0000

As we’ve said repeatedly, one of the big problems in getting started in the CNC hobby isn’t the lack of information… it is the Tsunami of information that is available on the web. A simple Google search for “CNC” turns up a paltry 34 million pages that you might want to browse!
As you’ve probably discovered, we’ve got a more manageable collection of links on our newly rebuilt website (at http://www.abcsofcnc.com/cncvendorlinks.html
These fine folks have a range of products for your CNC adventure… but more important, they’re all HOBBY CNC oriented. There are a number of large, corporate manufacturing CNC companies out there, who frankly, could care less about us hobbyists. That’s fine… but just be forewarned. You’re going to be a happier camper dealing with the smaller companies, that actually WANT your business.
One great resource for additional information, tutorials, and categorized links to CNC suppliers is at http://www.cncinformation.com
The proprietor, Ivan Irons, has compiled a remarkable collection of YouTube videos (showing a range of CNC machines, cutting operations, etc.) as well as a number of written tutorials, articles, etc. Right now, he’s offering two free, downloadable eBooks on CNC… one on G code, and the other is a 1066 page book of general CNC information. The only catch is that you have to sign up as a member on the CNCInformation.com website. Considering that it is free, and is a wealth of great information, WHY wouldn’t you want to do it?
Check out our totally renovated site at http://www.abcsofcnc.com if you haven’t already….. and check out our 2 hour instructional DVD on all of the basics of CNC… including CNC routers, CNC lathes, CNC laser cutters, CNC plasma cutters, and CNC milling machines. We can get you started successfully on this fascinating hobby… and maybe you can even turn it into a business. CNC machines usually show up for work on time, they don’t take coffee breaks, and for the most part… they don’t complain. Figure out some sort of product that you can sell… and there’s probably a fairly inexpensive solution for a CNC machine that will make those products for you!