Reporting from ShopBot ...

A occasional webcolumn describing things going on at ShopBot and perspectives on ... whatever.
 
     

ShopBotting for Profit - October 2007

For many ShopBotters, owning a ShopBot is a business proposition. Sure, a lot of ShopBots are used as production tools in manufacturing environments and as small components of a bigger business. At the other extreme, an increasing number of non-commercial ShopBots are being used for hobby, home, or D-I-Y projects. However, many ShopBots are purchased as the centerpiece around which a small business will be organized.

Selling ShopBot Businesses

I think this is a good thing, and it’s one of the primary reasons we developed and make ShopBots. We wanted individuals to be able to use them. And, from what I’ve been hearing at Camp ShopBots this year, ShopBot-based businesses are blossoming. More and more people are telling me about the success they are having with small enterprises based primarily on products they are producing with ShopBots – these businesses vary from doing a range of subcontract work, to manufacturing an interesting or unique product; and from selling locally through word-of-mouth, to marketing through a relatively sophisticated web-based storefront.

CNC-Business Training?

We’ve attempted to see what sorts of informational resources we could develop for ShopBotters. Early out we thought that one way we might assist ShopBot start-ups was by providing some sort of business training. We piloted the idea with a day-long training program at a ShopBot Jamboree several years ago. We called this training “ShopBotting for Profit” and organized the session around the “6-Ps to CNC-Based Business Success.” The 6 P’s were:

Product     Purchaser     Price     Process     Profit     Plan
    [Here’s a PDF of the brochure that summarizes that day of training.]

The session was led by a couple of experienced business consultants. For the group that participated in the 6P’s training at the Jamboree, it seemed to be a useful thing -- effectively reviewing a number of the primary areas that need to be attended to in developing a small business.

ShopBot Resources for CNC Businesses

Of course, many ShopBotters need to figure out how to manage their accounts or best utilize their business software package, but we’ve come to realize that we aren’t going to be the best source for generic business start-up support. Instead, the best type of help we feel we can provide is that which emphasizes the product, marketing, and pricing concerns that arise from the unique creative and productive capabilities of CNC tools. Here’s how we’re working on it:

Camps and the Jamboree. Last year’s Jamboree included numerous talks from ShopBotters with unique business stories and adventures, well captured in the name of Jillian Northrup’s and Jeffrey McGrew’s ShopBot business, “Because We Can” (Jillian and Jeffrey were last seen at the Austin Maker Faire showing off their portable “Art Golf” miniature golf course. The Jamboree also featured a session on the marketing of CNC products. The session was led by ShopBot’s own marketing maven, Dave Minella and by David McNutt, a Wisconsin ShopBotter, builder, and marketing whiz.

Even if they offered nothing else, the show-and-tell sessions at Camps and Jamborees offer a cornucopia of great business ideas and examples of entrepreneurial inventiveness. There are ideas, and more importantly there is inspiration in seeing what others have done. Also at Camps and Jamborees, there are incredible opportunities to learn about how others are approaching making money with CNC. You might think that people would keep their good ideas to themselves, but they don’t. There is an incredible openness and sharing of information and experiences, both about how they make things, and how they manage their businesses. I think this is because ShopBotters are not as interested in the specifics of what others are selling, as in the problem-solving involved in getting something efficiently produced and successfully sold.

ShopBot Trainings. As I mentioned earlier, trainings at ShopBot turn out to be a great time to learn about how other ShopBotters handle business issues. The trainings are not actually oriented to business issues, but you will meet people from all over who are engaged in many types of business. There are lots of opportunities to learn about what they are doing or what they are planning to do – people in the same boat as you, and people a little further along.

The Talk ShopBot Forum. The Forum is the place to interact over ideas and to get help with your plans or reactions to what you are trying to do with your business. It’s an online business roundtable. Go right to the business section. It’s OK to lurk for awhile. But don’t hesitate to jump in and ask your question or make your comment. It goes without saying that there are no dumb questions. This is a place where you can get a dialogue going.

ShopBot Wiki. The Forum is for interaction, but the ShopBot Wiki is the place for content and resources. We’ve just started it, but ShopBotters are helping making the best and most appropriate business information available here. Please use the Wiki, and when you get comfortable with it, contribute the information and information sources that have been most useful to you. It’s thin now, but with help we hope to make it incredibly useful. [If you aren’t familiar with the Wiki concept, read the introductory material to get the idea.]

ProjectWizard. This one is a little further out, but we want to share what we’ve got in development. We’ve been working on our website application for generating cutting files from parametric projects. Stretch, modify, or customize a project (a coffee table or boat) until you get it just the way you want it. Click a button and run a credit card, then download complete cutting files and detailed instructions.

Step one is to make ProjectWizard available to ShopBotters as a source of content. But as step 2, we have been planning to tie ProjectWizard to a network of ShopBotters looking for business. Anyone who wanting to design something using one of the parametric projects could do so, and then make a selection from the ShopBotter network list and download the cutting file to the nearest ShopBotter for production. ProjectWizard can work both for any individual wanting to get a project cut or made, as well as work for the growing community of ShopBotters interested in providing CNC services. There are a number of logistical difficulties that will need to be overcome to make the system work, but working with ShopBotters seems a great way to get something like this going.

ShopBot Storefronts. While I’m pondering ShopBot businesses, let me mention another kind of ShopBot business idea. We’ve been wondering whether it isn’t time for a ShopBot storefront. Imagine a sort of Kinkos for ‘making things’ -- organized around a ShopBot or two, with a laser cutter and perhaps a 3-D printer also on site. There would be computers for designing with lots of software resources, and a basic stock of sheet goods so that things could be cut immediately. You could design something and get it cut, or get help cutting it yourself. A ShopBot storefront might be a little like a Fab Lab and a little like a Tech Shop, but with an emphasis on turning sheet goods into little things or big things using digital tools. You might even sit down and use ProjectWizard at a computer to create your design, or perhaps send your design to someone at the store for reproduction.

First ShopBot storefront?

Of course we have no idea whether this is going to be a model for others or a franchise kind of thing. But, Bill Young is going to take a crack at setting up our first ShopBot storefront this spring in Exmore, Virginia. He’ll be experimenting with which tools and resources to put in it, and what kinds of activities and services to organize. And most importantly, figuring out what sort of personnel it will take to make it happen. Exmore is small (and quaint), so Bill will have lots of time to contemplate the details -- and we’re hoping to learn a lot.

Whew ... (caught up!) - May 2007

Today we loaded up the truck going to our 2007 ShopBot Jamboree in California. Bill Young and Bill Palumbo have been working incredibly hard getting a great program ready for the event May 17^th-18^th at the San Mateo Fairgrounds. We think we’ve got the logistics worked out pretty well and we expect this to be a great opportunity for us to touch base with ShopBotters on the other side of the country. ShopBot vendors and software providers will be available throughout the Jamboree. Lots of interesting sessions with ShopBotter presentations are planned, and we've allowed plenty of time for conversations and networking.

There will be an Introductory Level ShopBot CNC Training Session on Wednesday the 16th. The Women's Class on Friday will be cutting with one of the new PRS tools. Then, Saturday and Sunday the 19th and 20th the Maker Faire will be at the same site for any ShopBotters who wish to stay over (encouraged!). Recent ShopBot CNC Training at our facility here in Durham

Assembled 4x8 PRS being loaded; (far right) 5x10 PRS modules in crate ... headed for the Jamboree!

We’ll have a 4x8 PRSstandard and a 5x10 PRSalpha set up for the Jamboree and the Maker Faire. With the 4x8, we’re experimenting with shipping a fully assembled tool, which could become an option for future purchasers (though there are a lot of advantages to receiving your ShopBot in more manageable modules in our standard shipping crates).

YZ Car on X Gantry

We had done some last minute revisions to the design. These changes required producing a new round of parts. And then, we had some start-up delivery problems in getting materials as well as in getting the revised parts. All this got us off to a delayed start and left us needing to play catch-up. I’m glad it is behind us, and we now have a little more time to get focused on some of the other things we want to be doing. Yes ... like writing this blog for the website. [We are small enough, that when there is a need for help in production, we all shift our priorities and pitch in as much as we can.] Now I can at least report that we're getting ready for the Jamboree ...

By the way, at the Jamboree, we will also have a prototype of the new Benchtop version of a PRS ShopBot. (Oh no! Here I go again.) There are a number of details on the Benchtop that are not yet final (including the name), and it won't be ready to ship for a while. But we know that ShopBotters are interested to see what we are working on, and there have been a lot of questions about the Benchtop.

Prototype New PRS 'Benchtop' ready to ship to the Jamboree for its Preview.

We’re shooting for a mid-July release date of the first models. These tools will be based on the same beam and YZ Cars as the full size PRSs and use the same motors and controls. There will be an affordable ‘standard’ version and a higher performance ‘alpha’ version. We expect that, as with the current benchtop tool, it will have a moving table and be available with or without a stand. If you really can't make it to the Jamboree and still want a peak, Click Here.
 

A CNCer’s View of Robotics - January 2007

Over the holiday break, I happened to read a Scientific American [Jan., 2007, 58-65] article by Bill Gates in which he describes his views on emerging trends in consumer robotics. In the article, Gates makes the point that the field of consumer robotics is coming of age—particularly in having created around-the-house-helpers like Roomba—and that by wirelessly networking consumer robotic devices with our powerful Windows PCs we will soon find ourselves getting a lot more assistance with chores at home.  Asimo

It was an interesting enough article as far as it went. Gates argued the importance of solving robotic software issues and was promoting Microsoft’s new investment in robotics software. This software will provide a robotic operating system along with basic core functions for robotics developers (visual search, object recognition, navigation, etc). I’ll personally be interested in seeing whether the software will be of any use in operating robotic CNC tools. But more generally I wonder about his emphasis, which is on software as might be expected, as well as on the integration of increasingly sophisticated sensors with software. My perspective is a little different. For me, the major practical challenge in consumer robotics today is not with this control component of the devices but is with the output side or motion component.

Challenges: The physical

Consider, for example, the challenge of moving a powerful spindle, which is heavy and exerts vibrating side forces, through the precise 3D motion needed to create a small v-carved letter—and then doing another one with completely different shape—all while simultaneously monitoring speed, position, load on motor etc. This is to say that whether it’s putting away a wine glass or cutting plexiglas, producing effective, complex motion is challenging. Motion currently necessitates expensive, complicated, and/or heavy mechanisms. And the hardware for producing motion is the primary immediate challenge for consumer robotics. How do we produce useful movement at affordable prices?

The Roomba floor-cleaning robot that Gates mentions is actually an exception that illustrates my point. Despite the success of these well-executed little devices (and yes, I think they are neat), they don’t actually clean floors very well. The physical cleaning capabilities that can be provided at a low price is limited. Roomba shows that volume markets can get costs down for the control components. Its sensing, navigation, and robust task software are impressive (you can even get development versions of the little critters). Yet for helper robots to actually be helpful, they need to be able to really do something effective, and that is typically something very physical (like winning the DARPA Challenge, perhaps?).

To engineer systems that provide powerful, precise, flexible and general purpose motion at attractive and affordable prices is the specific challenge. Impressive, high-end, industrial systems for this kind of robotic motion do exist. It is simply that they are not practical for broader markets. The motion side of robotics has not made the volume-pricing progress that has been made in sensors, chips, processors, and software and that now offers so much practical potential on the control side of robotic devices.

There is now a Roomba “Workshop Robot” for cleaning your shop floor. Perhaps a new buddy-bot for your ShopBot?

As an interesting aside, one mobile robot that has tackled the motion issue with a bit of success is the toy, Robosapiens. These little robots make use of numerous servo motors at articulated joints. At the industrial level producing and controlling this type of motor is quite expensive, but a clever re-engineering of the mechanisms for consumer application has made these little guys available at surprisingly low prices. Unfortunately, they don’t start off doing very much, but numerous hackers have given them more interesting brains that take advantage of some of their motor capabilities (see robosapien1, and my hack below; indeed, there is lots of interesting puttering going on with robotic toys, e.g. Mindstorms, VEX). I suppose that I obsess over the motor, effecter, or output challenges in robotics because that is where we at ShopBot constantly struggle in terms of making robotic tools (CNC) that are affordable. It is not the software or electronics that makes CNC expensive, but rather the cost of the electrical and mechanical effectors that will actually do a reasonable job of cutting, milling, and machining.

It is certainly the case that solutions to these challenges exist in industrial motion systems, but these are solutions that are oriented to heavy, complex, and capital-intense machines that must be made the focus of a large part of a business operation. They are not solutions that allow putting tools to use by individuals, whether consumers or single workers in production settings.

An example of the CNC mechanical challenge that comes up daily and still has us stymied is the tool changer, a device that will automatically swap out the cutter in a robotic tool. Industrial solutions to this challenge exist in the form of a well developed system of tool holders and draw bars (grabbers for holding the tool holders which hold the cutters).

Tool changer system on left, tool holder and components on right.

But for a robotic tool that is oriented to individual users this is a very expensive way to change tools. When one of these standard industrial tool-changing systems is fitted to a ShopBot, it costs more than the entire ShopBot. Certainly, our automatic tool-changer works well enough, and it is still much less expensive than the other guys’ CNC with the same changer system, but somehow it does not seem like a solution that is in the right spirit. There is a real challenge here in coming up with a new approach that works, and works for robotic tools that are oriented to use by individuals. [See my prototype here of a new approach.]

<< Here's my prototype of a new approach to CNC tool changing.

While we may be able to look to industrial automation technology for ideas on how robotic action can be produced in products designed for use by individuals, at the moment costs are prohibitive and mechanical systems they utilize are not scaled for or oriented to personal use. Other solutions to the motion/mechanical problem may lie in new smart or ‘adaptive’ materials, artificial muscle, or nanotechnology, but these technologies are still a way in the future. More than likely, the near term progress we make in being able to provide affordable motion will be based on multiple small but clever new approaches to accomplishing things in ways which incrementally leverage motion capabilities, physically and conceptually.

Opportunities: First steps in the evolution of human helper robots

Like Gates, I am excited by the prospects of the coming robotic revolution. But to my mind, one of the first and most natural steps in the evolution of human helpers will be the development of robotic tools. Tools that help individuals make and produce things should be able to earn their way into common use. Such personal robotic tools address needs of consumers (particularly of the DIY type) and may soon appeal to those just interested in “replication” in the Star Trek sense of making a needed object on demand (see Jeff Raskins comments on replication from a few years back). Imagine, going to the web for a file representing something you would like made and while online doing some variation or modification to the generic version of the item. Then you would download the file to your robotic tool, shove in a piece of raw material, and have the item come out the other side a few minutes later. [A rudimentary version of such a system is available now; see our ProjectWizard plans.] Such personal robotic tools can empower the productivity of individuals and small groups.

Neil Gershenfeld, of the MIT Media Lab, has a name for this concept of robotic tool use, he calls it ‘Personal Fab’ (from ‘fabrication’; Neil's book, FAB: The Coming Revolution on Your Desktop - From Personal Computers to Personal Fabrication, Basic Books, 2005). Gershenfeld points out the potential cultural importance of robotic tools when oriented to individual use, a use that universally empowers production. Others have similarly called attention to increased access of individuals to automation and robotics tools as a basis for a new trend in “micro-manufacturing” whereby regional production needs can be increasingly served by networks of very small shops taking advantage of locally available raw materials. Micro-manufacturing has sometimes been suggested a means for third world countries to come on-line technologically; it may just as realistically be a recipe for how American ingenuity revives a new style of American manufacturing. Micro-manufacturing and personal robotic tools also fit well with the growing American entrepreneurial trend towards ‘personal businesses’ (see Intuit Report SR-1037).

Gershenfeld looks to the day when in addition to the ‘subtractive’ capabilities of cutting tools like CNC routers (tools that whack away at a sheet or block of raw material to make something), ‘additive’ robotic tools such as practical 3D printers and will also be at hand. Indeed 3D printers exist. Today’s models are sometimes called rapid prototyping machines, and they are capable of producing 3D objects (check out the Wikipedia entry for rapid prototyping). At this point, the cost is high and because of the materials used, the usefulness of the objects is limited. But these devices certainly lead the imagination to appreciating how new capabilities in additive robotic tools will be increasingly useful – and, maybe it’s not that far off (see www.fabathome.org; or a particularly interesting example for squirting out buildings). [UPDATE 5/8/07; The New York Times just did an enthusiastic report on a new, affordable rapid prototyping product from DeskTop Factory, due out soon for ~$5K. These 3-D printing devices look pretty nifty, but their limitations still make subtractive prototyping tools attractive for their extensive size range and breadth of usable of materials.]

Of course, if you are reading this you already know that consumer robotic tools of the subtractive sort are here … or at least, they are here for a few of us. Maybe as we make ShopBots even more affordable and interactive they will find their way into more basements and garages, but increasingly they are making robotic machining capabilities and production capacity available to individuals and small shops. We look forward to helping them do it more and more …

Now, if there were a C-3PO for the shop, I’d probably be the first to be interested. But despite Asimo (and the Robosapien tool-changer), the likelihood of an affordable, skilled, humanoid robot for productive work in the shop in the near future seems pretty low. Yes, our shops are human-oriented physical environments, but for the first stages of helper bots, we are more likely to benefit from mechanicals designed to handle tools or materials and that help us in simple ways to make or produce things we could not without help.

Robotic tools are the right step in getting robot helpers to individuals because they are based on mechanical systems that are within reach. CNC routers, for example, are basically just large plotters or printers -- essentially taking 3-axis motion to the next level. The mechanical challenge of producing effective cutting motion is not nearly as great as say the mechanical challenge of folding laundry.

I believe that consumers are actually ready for these kinds of helpers. It has been very encouraging in the last 10 years to see the emergence of home, computer-controlled, sewing and embroidery machines. These robotic tools leverage existing mechanical systems to get real work done. If one is looking for robots that are earning their keep, these robotic tools may be the best example. Closer to my own interest are the very affordable CNC paper cutters have become available to ‘scrapbookers’ in the last few years. And now, Sears is carrying a small, entry-level CNC carving machine. This nifty little tool really will do stuff in the shop. More importantly, it will help to introduce CNC to consumers and D-I-Yers.

Too often CNC tools are associated with industrial automation and repetitive mass production. People are simply unaware of the cutting, machining, and sculpting capabilities that a robotic tool can give them for their one-off projects. Even for industrial or manufacturing applications, it is often not appreciated that while heavy, expensive CNC centers have been the basis for mass production, new ‘lean’ approaches to manufacturing depend on more flexible robotic tools that are oriented to use by individual workers and that rely on rapid reconfiguration with the flow of production (see ShopBots in Manufacturing).

Gate’s summary point in the article that I mentioned at the start of this column was: that it is now time to get PC’s off the desktop and out into the world and moving around. I have been a believer in this general idea for quite a while -- but I would rephrase it a bit more specifically: “It’s time to get PCs off the desktop and doing something productive besides pushing paper”. Robotic tools that accomplish real work are the natural next step in making robotic helpers commonplace.

2007 ShopBot Jamboree - December 2006

Over the years we have really enjoyed the excitement of the ShopBot Jamboree and the opportunity to meet and interact with so many ShopBotters. It’s been a fun and inspiring event for us and I know from what the ShopBotters who attend tell me that they get a lot out of it. One request that we have gotten for many years from ShopBotters on the West Coast and other places far from Durham is that they would like something like the Jamboree nearer home. Yes, regional Camp ShopBots are great opportunities to meet and talk with other ShopBotters, but they don’t offer the same wealth of information and stimulation, and breadth of meeting opportunity of a larger get-together. However, at this time ShopBot’s resources only allow us to sponsor and coordinate one event a year like the Jamboree.

What we thought might be a good solution is occasionally, say every 3-4 years, to hold the Jamboree on the West Coast or in the middle of the country. These away-from-home Jamborees would create more opportunities for participation and would give us the opportunity to get out of town every once in a while, too.

So, for Shopbot Jamboree 2007 we are in the preliminary stages of planning a West Coast ShopBot Jamboree for San Mateo California.

What will help make this ShopBot Jamboree a very special event is that we have been invited to hold it in conjunction with the Maker Faire. The Maker Faire is a fascinating celebration of 21st century creativity put on by Make Magazine. Last year’s Faire had thousands of participants and featured inventive projects of hundreds of "Makers"; everything from robotic bugs, through various crafts, to a flame thrower. And, of course, there were the ShopBotters Jillian and Jeffrey showing off the clever products of upstart company "Because We Can ...".

Make Magazine is a great new magazine oriented towards a do-it-yourself, make-it-yourself, hack-it-yourself approach to integrating technology into our lives. It's not going to replace your subscription to your favorite woodworking magazine. But if you have any interest in puttering with new things or with approaching what you can do with CNC with a new attitude, you'll find this magazine an inspiring treat. It is published (quarterly at the moment) by O'Reilly Media, a company famous for their technology books ("putting the cool in geek"). We're hoping to see more and more applications for robotic tools and CNC in coming issues of Make. You can get the magazine at places like Barnes & Noble, but the one near me is always quickly sold out soon after an issue arrives.

Back to the Jamboree; the preliminary dates are May 17-18 (this is two days in advance of the 2007 Maker Faire, which will be May 19-20) and the site will be the same as for Maker Faire, the San Mateo Fairground. We'll be arranging a room deal for ShopBotters at a nearby 'headquarters' hotel. After the Jamboree, you'll be welcome to stick around and participate in the Maker Faire. The organization of this ShopBot Jamboree will be similar to what you've come to expect: Lots of information about putting a ShopBot to use, with talks and demos on cutting and production techniques; booths, presentations, and consultations with our favorite CNC vendors (software and hardware); and most importantly, the Jamboree as always will be an event to meet and exchange info with other ShopBotters and to hear about what they are up to. For those who are interested, there will also be a ShopBot: Basic Training session.

Having a Jamboree on the West Coast is a bit of a logistic challenge for us. When we're here at home in Durham, opening up the factory works well because we already have tools, space, and ShopBot people in place (and we're able to mostly keep our business and support services going at the same time). For California, to maintain the character of the Jamboree, we're planning to get several of our new PRS ShopBots out to San Mateo along with a lot of our ShopBot crew. The facilities for running tools and doing a little cutting look excellent at the fairgrounds. Nonetheless, we're going to be especially dependent on active participation of West Coast ShopBotters to make this a great Jamboree. In particular, we're hoping as many ShopBotters as possible will bring show-and-tell projects with them. Whether you're just getting started or an old CNC pro, other ShopBotters really enjoy seeing and hearing about your experiences. If you are uncomfortable standing up in the group, bring your stuff anyway to show people casually - or pictures and .jpg's if you can't carry your project. We'd also like to hear from West Coasters who have suggestions for presenters (ShopBotters or vendors) and/or any kind of "local knowledge" that would be helpful in making the event interesting or fun.

So this is your preliminary notice: ShopBot Jamboree 2007, May 17-18, San Mateo Fairgrounds, San Mateo, California. There will shortly be a Forum section set up for the Jamboree [and/or email questions about the Jamboree].
 

Circle Smoothness 'beta' - November 2006

I'll talk a bit more about development at ShopBot and expand the 'resolution' theme from last month, more broadly taking up the issue of smoothness in cutting with ShopBots, and specifically reporting on some progress we are making. For a number of months now, we have focused software development on creating strategies for smoother tool motion by making improvements to both PC and Control Box software. Using a new algorithm that borrows somewhat from the anti-aliasing system of computer graphics, we've now improved on how ShopBots cut circles, arcs, and diagonals -- providing motion that is more vibration free with an edge that is considerably smoother.

The improvement will be available for existing PRTalpha tools and PRTstandard tools that have been upgraded to the new Version 4g control board. The new software capabilities rely on the speed of the PRTalpha micro-controller and outboard software (also now used in the PRT V4g control boards) -- which means, that at least for the moment, it will not work on older PRTs that have not been upgraded.

Because the software has been significantly modified in the process of implementing this new contouring system, it represents a major revision number change (now Sb3.5.xx) and needs more extensive testing than a minor revision or maintenance upgrade. For this reason, before we make an official release of the software, we are going to make it available for 'beta' testing by those who have an interest in trying it out and hopefully providing us a little feedback on what is working well and what is not. [Link for Downloading Beta Software]

Our expectation is that after a few weeks of thorough testing here at ShopBot and testing by those who try the beta version, this new upgrade in cutting performance will be ready for production use on all PRTalpha and PRT V4g ShopBots. Beta testers will notice that there are also several other enhancements in the new version of the software, including more efficient buffering of the streamed motion commands which allows high-resolution tools (and V4g boards) to attain higher speeds in cases where PC capabilities may have been limiting. We'll detail all these changes when we release the official version. Nonetheless, our primary focus in this recent work has been on cutting smoothness improvements that can be achieved with software and made broadly available to existing ShopBotters.

So let me put this software improvement in the context of the earlier resolution discussion and with reference to specific tools:

PRTstandard. Upgrading to the Version 4g control board will improve cutting smoothness by increasing the resolution of stepping (as provided by the higher resolution stepping of the Gecko drivers and higher speed of the controller; you'll also get 2-3 times greater speeds). The new Sb3.5 version of the software will provide further enhancement to cutting smoothness (and in some cases higher speeds) because of the improved strategy for contouring.

PRTalpha. Upgrading to the new Sb3.5 software will provide smoother cutting for all PRTalpha tools. Even greater enhancement to smoothness can be gained with higher resolution gearing on PRTalpha tools. As discussed in the previous installment, we are now optionally offering 7.2 gearhead motors and drives on PRTalpha tools (for $750). We are making this same option and pricing available as a retrofit for any existing PRTalpha owner interested in upgrading. Our new PRSalpha tools, available next year, will come standard with the 7.2 gearheads.

Here's what I'd suggest if you are interested in upgrading the smoothness of your PRTalpha cutting:

• 1. Try the new software, either the current beta version, or in a few weeks the official release version.

• 2. Switching to higher resolution drives may offer some additional enhancement.

• 3. And going even further with smoothing, higher resolution stepping and increased power is available if you decide on the optional 7.2 gearheads.

My First Post - October 2006

Ever since we upgraded our website this Spring, I've wanted a space to write about the things that are going on at ShopBot. It's a bit of a busy place, but also exciting. And, we are certainly hard at work developing new CNC stuff. I'll try to make a contribution every month or so and will also recruit some commentary from others here at ShopBot. This first column is a bit on the technical side, but expect the themes to be pretty wide-ranging.

Recent suggestions on the Talk ShopBot Forum that we could do a better job of communicating actually provided the impetus to get me started here. Hopefully this webcolumn will help serve to keep everyone up to speed on some of the things going on here at ShopBot, as well as provide an opportunity to reflect on issues that are hot topics on the Forum or in the CNC business in general.

Gearing and Resolution

The question of how to improve ShopBots and the cutting they do is probably something we spend 85% of our time thinking about, so I'll comment on some of the specific related issues that have recently come up on the Forum. The first of these is gearing and resolution. Gearing and higher resolution are good things, and assuming that the motor can keep up and the backlash is minimal, the more the better.

But, if we could get a tight, robust belt-box, we would definitely consider it. Here's the spec: We would want a double reduction (so the pulleys did not get so big they are in the way) gear box with something between 5 and 10:1 reduction (7.2:1 is good). The box needs to be able to handle overhung and thrust loads (the latter to allow the option of helical rack and pinion). Output capability should be to about 600 RPM. Oh yes, and at a reasonable price because for our typical motor/gearhead, the gearhead cost is already well over half the cost of the unit.)

That said about gearheads, there is also an advantage to straight-drives. They are simple, straightforward, and cost-effective with few parts to wear. To a degree, resolution can be achieved with good microstepping, and the microstepping certainly does reduce/eliminate the tendency that steppers have to resonate. On our PRTalphas, we believe that for many standard woodworking applications the ~1200 steps/inch resolution provides pretty smooth motion, while benefiting from the advantages of a straight-drive, and from the significant robustness of the closed-loop drive system.

The down side of microstepping is that as the load on the motor is increased, the microstepping motion can become less and less linear, even though it sounds smooth. Aggressive cutting of hard materials can certainly benefit from higher mechanical gearing. It provides more mechanical resolution so that there is less reliance on microstepping for positioning, at the same time it provides more power so the motor is not as heavily loaded. This works for smoothness in cuts and against chatter. We did not initially offer gearheads as an option with PRTalphas, but for customers who can benefit from additional power and resolution we now offer PRTalpha tools with a 7.2:1 tapered-hob, gearheads (and similar upgrades for existing PRTalphas).

Motor Amps

The Geckodrive stepper drivers that are used in the new PRT Version 4g Control Board provide 2.5 times more resolution and significantly more speed (6-8 in/sec cut speed; 12-14 in/sec positioning speeds) than the old version of the PRT Control Board (v3). This improvement was made possible for us by the higher speed controller that we developed for the PRTalpha. Because these drivers are also capable of handling more current and voltage than the present PRT Control Box, it has been suggested that we switch to higher current motors and higher voltages. While it is certainly the case that we could get somewhat more performance with these additional changes, for the moment we aren't doing it. Here's why:

1. By using the existing motors at ~ 2amps we have a solution that works well for existing PRTs. The present board is a straight-forward, drop-in replacement for existing ShopBots. It requires no additional power supply or heat sinking and works well with existing motors. The simplicity of the Control Board and driver mounting allows us to provide it at a very low cost. The performance improvement is very impressive.

2. Keeping the current demands on the Geckos relatively low means we do not have to worry about heat from the Geckos or heat-sinking them. This allows a simple, low-cost, connection scheme. The Geckos snap easily in and out of the PRT 4g Board.

3. By not increasing the voltage or current requirements for the power supply, we can stick with an enclosed, commonly available, UL/CE compliant power supply.

4. We are not pushing the capabilities of the drivers. As drivers are the most vulnerable component of a stepper system, this seems prudent.

5. Additionally, over the years we have come to appreciate that the power of these PRT motors is about right for the tool and the cutting that ShopBotters are doing. The primary difference is that now, rather than cutting at 1-2 inches/sec, they will be able to cut at 4in/sec with nearly full power and at 6-8 in/sec with pretty good power.

In short, the current motors still seem to us a good, conservative, and practical choice. Yes, we could get a little better performance by beefing up the board, motors, and power supply; but it does not seem to be a good tradeoff at the moment or for the typical uses of our tools. But we'll remain open on this one.

After-Market Control Boxes

The above topic leads into another -- the potential usefulness of the after-market control boxes for PRT tools such as the one developed by Dirk Hazelenger.

Dirk was interested in exploring Geckos and other drivers to run various of his CNC projects. After talking with us about how the PRTalpha controller could be used to operate other drivers, Dirk experimented and found that the Geckodrives worked well for him (actually, he was very excited about how well the combination worked) and put together a full control box to take advantage of them. [See: www.botrods.com]

Dirk's box is different than the Version 4g board. In concept, it is more like the Version 4 board described in the system layout on our developer's page in offering a universal interface. More importantly, it is a direct response to the interest of several ShopBotters in using higher voltage power supplies and higher current motors. Unlike the 4g, in Dirk's box the drivers are individually wired, mounted, and heat-sunk. This means that the box is ready to run a much wider range of motors, including the 4amp OM motors that have attracted attention. You could buy an interface board from us for this type of project, but you would have to do everything else yourself. Dirk's board is ready to go. It seems to me to be an excellent option if you are interested in pushing capabilities to the max with your present PRT. Dirk's board is also a great option for people looking to retrofit existing CNC tools or to add CNC capabilities to milling machines or other equipment and begin with a full motion and control system. For this latter application, because of the way the controller is sold to Dirk, he will also be able to provide a good CAD/CAM design system at a reasonable price.

In making his system market ready, Dirk has had one glitch. That was the initial choice of the Geckodrive 212 as the driver. I wanted to make it clear here that that choice was totally my error. Based on a quick look at the specs and some experience with other Geckos, it looked to me like the 212 would be the easiest way to connect to existing PRTalpha electronics and so I suggested it. It turns out that because of the way the 212 step-multiplier works the 212 is simply not suited to any kind of CNC action in which there are a lot of very short back-and-forth moves as there will be in a 3d carving file. The 202s don't have this problem, and Dirk quickly converted to them (which is probably what he would have used originally if I hadn't pushed the 212s). I think the control boxes are working great now, and there is some sample work elsewhere on the Forum.

There are other products as well. I know less about them so won't comment here. However, I do want to emphasize our general support of all the variations of ShopBots that ShopBotters want to explore. There is nothing I find more interesting than visiting a ShopBot shop and see the incredibly inventive and creative use that our tools have been put to and the clever ways in which they have been modified. In many ways ShopBots are the 'erector sets' of robotic tools and we find all the new twists, inspiring and exciting.

Back to Cutting

Here's an applied example of the upgrade discussion. Chris Burns, here at ShopBot, has a home shop with an old PRT. At the moment, this tool is his "Tech Ed Dept" for schooling his kids. He and son Bryan (6) recently became fascinated by 3D carving, partly stimulated by James Booth's 3D clip-art files, but also encouraged because of how much faster 3D goes now that he is using a PRT with Gecko drives. Chris finds he can cut 3D at 8 in/sec in XY and 8 in/sec in Z. The higher resolution stepping of the Geckos helps, but so does being able to maintain a good full speed in both the XY and Z for contouring.

Here's one of Chris' and Bryan's new bread boards on which they have put one of James' carvings (cut bread on one side; have a pretty image when the other side is facing). This one took about 40 min to cut, ash was from a tree cut in his yard I think ...   [Bryan ran the tool and finish-sanded the part.]

Coming next ...

I'll plan to report on several development projects ongoing here at ShopBot.