CNC Robotics: Build Your Own Shop Bot (Tab Robotics) [ペーパーバック]

The pre-pub blurbs say it shows you how to build the equivelent of a $7500 workshop bot (an intentional play on the name ShopBot I guess) for $1500, and the cover front and rear are full of promises not delivered inside...

"Great for use... on the industrial floor" NOT!

"Provides step-by-step instructions for building your own CNC machine"... "Scaling and customizing instructions for building just the robot you want"... "Sources for easily obtained parts"

There is no discussion of design rationale, bearing loads, etc. He just jumps in and, in a 12 page Chapter 1 (three of which are used for showing the explosion views of the $3000? NuArc copy camera he scrounged the entire Y-axis carriage and rails from and telling you he made the Z axis from a TV shelf slide), tells you what he used. Nothing about the pros and cons and accuracy implications of different linear motion components, ballscrews vs acme, etc. Less text in the chapter than someone would use in a web forum post breifly describing their homebuilt CNC machine.

Chapter 2 uses 51 of its 62 pages to reprint the manufacturer's documentation (probably available online) for the L297 and L298 chips he uses in his stepper motor driver... Chapter 3 is 20 pages showing how to photo etch his printed cicuit board... Chapter 4 is 13 pages showing how to drill the board and solder the components on. This information may be of use to some, but with proven 3-axis stepper driver boards readily available for $100-150, I think I'd skip the electronic components gathing, and the gloves, eye protection, respirator, and the carefully monitored heated baking dish full of of ferric chloride solution giving off "nasty and dangerous fumes."

Chapter 5 shows you how to install KellyWare KCam software and test your drives... he barely mentions that he used three PC power supplies to power the three axii (he left them out on the "Materials Needed" list that starts the chapter); no discussion at all about power supply selection issues if you happen to have stepper motors different from the surplus ones he found.

The next few chapters show how he drilled and bolted the frame and gantry, and made pillow blocks... how he crudely supported the 3/4" linear shafting on free-standing bolts (he doesn't say, but I guess he bought the shafting pre-tapped, which nearly triples the price). I just love this... "In order to assemble the Y-axis, you will need the following tools and materials: Guide rails... Slide from NuArc copy camera...". The shaft support bolts are used to "straighten" the precision rails to a constant height from the square tubing that supports them (??).

After a decent chapter on motor and leadscrew mounting (no comment on probable whipping of the very long skinny X-axis leadscrew), more about KCam, some crude router mounting, and some examples of some things he's routed, the book ends with a list of addresses and phone numbers of corporate headquarters of linear motion components manufacturers, etc.

This book isn't real impressive with its lack of technical info. Most of it is like the web pages individuals put up showing pictures of the CNC router they built, often with scrounged/E-bayed parts that the next guy may or may not be able to find. Like those websites, it's always interesting to "see how someone else did it", but don't burn your $35 on this book expecting much more. If nothing else, I suppose you can vicariously "build" your first machine in your mind by reading this book, then build your first real machine better after more web research and questions to others online who seem to be more informed on design issues than this author.