Hypothetical ShopBot MiniMe (was Re: On bravery...)
Paul D. Fernhout
>> You can probably see where I am going with this... :-)
>>
>> What if ShopBot made a toy version of its big ShopBot systems out of wood
>> (or even plastic), that was one-eight its size, and called it
>> "Mini-ShopBot"
>> system, as a toy and training tool for grownups, who might just want to get
>> a sense of what the big thing might do or who have little time or space?
>> Ideally, it would cost about $1000. Then maybe that could be a new niche?
Ted Hall wrote:
> I thought it was bad enough at ShopBot ... but now you are bugging me
> about it too!
:-)
> A favorite pastime at ShopBot is how we could build a desktop model.
> Indeed, there are a number of prototypes around the shop ... many projects
> undertaken for just the reasons and logic you describe.
:-)
> Bottom line: An under $1K additive machine is possible,
:-)
> and under $1K
> subtractive machine is not.
:-(
I'd suggest, maybe it depends what you want to subtract. :-)
When I was around six years old, I got this battery powered power tool set
that could cut balsa wood, with a jigsaw and a drill. Maybe someone could
not sell it now to kids, I don't know. :-( But the tools cut light balsa
wood and I had fun with them. And I still have all ten fingers. :-)
Maybe in part because of that early experience?
So, you're still seeing this hypothetical ShopBot MiniMe as a serious tool.
The CarveWright you mentioned looks like a serious tool, for example.
You already sell a serious tool in several versions. And as you say, it has
trouble scaling to a small scale at a desired price point.
Why compete with all that?
So, I'm still suggesting, see a ShopBot "MiniMe" as a toy or training tool.
Something that can cut stuff like balsa, wax, cardboard, and paper. And
that's it. Anything else voids the warranty. But it looks and works just as
much as possible like a miniature ShopBot, so you could also add all sorts
of things on top of it, including additive options or a marker for plotting
or an engraver for simple engraving.
Every time someone sees one of these, they think, oh, that's a ShopBot.
Granted, you'd want to do some market research that would not effect your
brand negatively, but rather positively in terms of mindshare. This would be
something to get your brand and your ShopBot configuration in front of
thousands of more people, so when they move up, they are thinking, "I know
this is a toy, but now that I want something better, let's move up to the
real thing from a company I trust." Granted, the toy has to be good enough
to be a satisfying experience within its expectations, so expectation
management is critical.
> It comes down to the cost of the motors and
> drivers. If you want to do real cutting, we're up against the cost of the
> motors ... as discussed elsewhere in OM recently. The big motors require
> current drivers. We haven't figured a way around this. We made our own
> drivers for awhile to try and get the price down, but the problem is as soon
> as you get above the size of something in a printer you get to needing
> current sources that require discrete component circuits and costs just
> mount up. We'll probably keep trying ... but, as I've described before, you
> want the thing to be able to do a decent job of cutting and that takes a
> little power and rigidity. Have a look at the Carvewright (
> www.carvewright.com), they've taken a pretty good shot at the desktop
> subtractive tool ...
Well, the size I am proposing is the size of a printer more or less. At
one-eight scale, a ShopBot PRSalpha 144-60 (168" x 91" x 68)
http://www.shopbottools.com/prSalpha.htm
would be:
21" X 11.375" X 8.5"
Here are the dimensions for an HP printer:
http://www.shopping.hp.com/product/printer/Officejet/1/storefronts/CB780A%2523ABA
"17.07 x 15.81 x 8.53 in"
I still don't see why you can't drive some steppers or servos to do at least
what you need for that smaller scale and cutting balsa or cardboard. People
do that on YouTube. Why not just use modified RC servos or small steppers?
But maybe that is because I am speaking from ignorance of not having tried
CNC with them. Or, maybe you are setting higher expectations for speed and
accuracy than what I expect from a toy?
Maybe the price point is even too high at US$1000 for expectations? Maybe
you should be thinking $500? Or $300?
More than two decades ago I made circuits with things like Sprague (now
Allegro) motor drivers to run a robotic finger controlled by a Commodore VIC
in assembler using geared motors and linear potentiometers (very unreliable
the ones I got), so I know it is doable to make simple circuits, even with
regular motors. How can it be harder now, programming in C or Forth where
you can get off-the-shelf cards and don't have to wirewrap stuff and you can
even use cheap optical encoding tricks with cheap LEDs? :-)
And, you have a ShopBot router to patiently carve optical linear encoder
parts for you, so you can even just use regular motors, if you wanted. :-)
Cheap servos and drivers abound. This is one place I was just looking at for
a cheap winch Servo (a neighbor who does RC recommended winch servos for the
Tensegrity robot design).
Examples:
http://www.pololu.com/catalog/category/23
"Pololu Serial 8-Servo Controller (assembled)" $26.95
http://www.pololu.com/catalog/product/727
"GWS S35 STD Continuous Rotation Servo" $13.49
http://www.pololu.com/catalog/product/948
So, one hundred and fifty dollars for the electronics and motors retail,
even if you throw in an Arduino board as a controller for stand-alone
operation. That servo may be a little wimpy, but for $40 each you can get
some RC Winch Servos and modify them for continuous rotation or at least to
do ten or so turns, bringing the cost retail for the electronics up to $200
or so (half that wholesale?). Maybe $200 for wood and cutting time and
assembly? $100 for profit. $500 plus shipping if mail order direct? I know,
in practice, it would probably cost more, with returns and dealers and Q/A
and tech support and so on. So, back to $1000?
Maybe you put a small Dremel tool or some simple motor for a spindle on it.
Maybe you make a *partnership* with Dremel? And get them into Home Depot?
Just as a toy, for simple things, to learn about the technology?
> None of these problems hold for additive tools (or laser or plasma cutters)
> because the forces are so much less. Also, for additive, speed is less
> important and this allows for much more rudimentary motor drives. This is
> where the hope for really cheap desktop models is. We'd like to work on this
> at some point ... but as you and others have noted here, there's already
> some really good stuff going on. We find large-scale additive appealing, but
> haven't found the deposition system that's really sold us yet.
Maybe you've gotten so good at making quality tools that it is hard to just
make a "toy" for adults? :-) But the rest of the world (well, at least me
:-) wants a toy it can experiment with and learn from. Just to build some
confidence with the concepts. You know that's often how people learn --
trying something, building confidence, then going on to bigger things. The
ShopBot PRSalpha is a big leap for the rest of us, whereas it is a small
leap for a professional woodworker. The rest of us need to go in baby steps. :-)
But here is the thing -- it would be nice to have a cheap Cartesian robot to
play with that was open enough to build on. I have still not seen a plain
Cartesian robot for sale that was cheap (there are lots of humanoid toy
robots, but not Cartesian ones, which seem industrial). The CupCake CNC
configuration, as well as the CarveWright, are positioned (and cramped
enough) only for specific things (extrusion, woodworking). ShopBot Tools
obviously understands the idea of a general purpose Cartesian robot. I'm
just saying, take that idea and bring it to the toy level, but with an
upsell to a big system that looks much the same.
Still, the problem of holding the workpiece could be a problem for paper or
cardboard (maybe requiring some clever approach, whether a ShopVac or sticky
intermediate paper, or something).
Oh, and it would be nice if you could run a conveyor belt under it, while I
am dreaming. :-) Then I could automate a lot of my Lego sorting, even with
such a small device, adding a camera and a gripper. :-)
I see the "Bot" part, whereas it is easy to get stuck in seeing just the
"router" part. :-) So what if it is not a great router when it is small? It
is still a "bot". :-)
Well, anyway, just some ideas. But clearly, the low end space is exciting to
a lot of people.
--Paul Fernhout
Patrick Anderson
> Well, the size I am proposing is the size of a printer more or less.
On a similar note, but for paper, how about an 'Open' version of the
http://Cricut.com paper cutter allowing anyone to make, share and
upload their own patterns instead of being required to buy damned
cartridges.
Paul D. Fernhout
Yes, that whole system seems fairly proprietary, from design software
through supplied clip art to supplied cutting cartridges.
Still, one of the reasons I'm excited about any of these things (even with
proprietary aspects) is the notion of getting people involved in
understanding these technologies and feeling empowered by them rather than
feeling disempowered by technological change. That's all part of getting
people to start imagining a post-scarcity society.
While I think better gadgets are a good thing, over all, I have to put my
faith more in the notion that people will make better social and political
decisions about the future if they can gain a sense of comfort with these
emerging technologies, and a sense of understanding of them, and a sense of
control over them to some degree. That's ideally all part of the (self)
educational process continually going on in a democratic technological society.
That's why I was disappointed going to Lowe's a couple weeks ago and seeing
no CNC equipment in the small tools section. There was a router press
attachment for a Dremel tool (hand operated). I think it would be a big
thing for open manufacturing if the average GeekDad
http://www.wired.com/geekdad/
rather than plunking down a thousand dollars US for a new computer, would
instead go to Lowe's or Home Depot and plunk down a thousand dollars for a
new peripheral for their current computer, to get a peripheral that was a
Cartesian robot that could actually do something useful (however small,
sorting Legos, cutting Balsa, helping with papercraft, making small signs).
Here is a Hexapod cutting a shape:
"Hexapod Robot CNC Router - Cutting 3D face"
http://www.youtube.com/watch?v=quN37YskoaM
Hope they are wearing ear protection, cutting that foam is so noisy. Sure,
the results are small and simple, but what were the images like on the Kim-1
(LEDs) compared to a modern PC (bitmapped screen)?
I can see it now -- the cardboard box behind glass alongside the other
Dremel tool add-ons, sitting there, with a $999.98 price tag, beckoning,
"How much credit you got left on your card, big boy?" :-)
And for professionals, it is likely tax-deductible if it relates to their
business. So, that might cut the real cost by a third to a half.
And, even for individuals, there might be some wiggle room (check with your
CPA), if you took some kind of course and they required you to buy one
through the school? :-)
http://www.irs.gov/publications/p970/ch06.html
"Student-activity fees and expenses for course-related books, supplies, and
equipment are included in qualified education expenses only if the fees and
expenses must be paid to the institution as a condition of enrollment or
attendance. ... Example 1. Jackson is a sophomore in University V's degree
program in dentistry. This year, in addition to tuition, he is required to
pay a fee to the university for the rental of the dental equipment he will
use in this program. Because the equipment rental fee must be paid to
University V for enrollment and attendance, Jackson's equipment rental fee
is a qualified expense."
I'm not sure about that last -- like if TechShop could do that? Or if it
would have to be a community college? Just trying to generate ideas here
that stay within the letter of the tax code, not to get someone in trouble
with the IRS.
Teachers could deduct some of it, if they bring it into class sometimes:
http://www.irs.gov/taxtopics/tc458.html
"If you are an eligible educator, you can deduct up to $250 of your
unreimbursed expenses [otherwise deductible trade or business expenses] you
paid or incurred for books, supplies, computer equipment (including related
software and services), other equipment, and supplementary materials that
you use in the classroom."
Here is another possible cost reduction (purchasing through and educational
savings account for K-12?):
http://fairmark.com/forum/read.php?4,18156
http://www.irs.gov/publications/p970/ch07.html
"The purchase of computer technology, equipment, or Internet access and
related services is a qualified elementary and secondary education expense
if it is to be used by the beneficiary and the beneficiary's family during
any of the years the beneficiary is in elementary or secondary school. (This
does not include expenses for computer software designed for sports, games,
or hobbies unless the software is predominantly educational in nature.)"
I don't know exactly how one decides whether learning through a hobby is a
hobby activity or educational activity?
It does suggest that the box should emphasize "learning" over "fun". :-)
Let people figure out the fun part on their own. :-)
Anyway, an educational deduction might bring down the overall real cost a
little bit (guessing 10%?). And clearly, learning these sorts of skills,
basically how to be a manager of a robot, is something that will be in
demand in the 21st century (at least until robots manage themselves. :-)
So, buying one of these devices would be like someone interested in
technology in the 1970s buying an Altair 8800 or KIM-1 (the KIM-1 was my own
first computer, beyond circuits I built myself from switches and ICs). As a
teenager, after looking at ads for computers in the back of magazines for a
time, I remember my Dad and I going to this far away computer store to buy
the KIM-1 (pretty much the cheapest computer you could get). I was inspired
in part by Tod Loofbourrow's "How to build a computer-controlled robot"
which used one of those).
http://en.wikipedia.org/wiki/KIM-1
"While the machine was originally intended to be used by engineers, it
quickly found a large audience with hobbyists. A complete system could be
constructed for under $500 with the purchase of the kit for only $245, and
then adding a used terminal and a cassette tape drive."
We had to build the power supply ourselves.
Not quite an Apple-I, but leading up to it. Here is the one that got more of
the limelight, and a family friend (my godfather, actually) had one (he
demonstrated it to us, but I never used it), from:
http://en.wikipedia.org/wiki/Altair_8800
"The MITS Altair 8800 was a microcomputer design from 1975, based on the
Intel 8080 CPU and sold as a mail-order kit through advertisements in
Popular Electronics, Radio-Electronics and other hobbyist magazines. The
designers intended to sell only a few hundred to hobbyists, and were
surprised when they sold thousands in the first month. Today the Altair is
widely recognized as the spark that led to the personal computer revolution
of the next few years: The computer bus designed for the Altair was to
become a de facto standard in the form of the S-100 bus, and the first
programming language for the machine was Microsoft's founding product,
Altair BASIC.[1][2]"
But there was more stuff earlier than that:
http://www.blinkenlights.com/pc.shtml
I'm thinking, either I'm going senile (might be some of that :-), or I'm
reminiscing so much about the 1970s because these times are feeling like
those for these digital fabrication technologies and open manufacturing.
Even in the 1970s, there were "serious" IBM and Sperry-Univac mainframes
(the ShopBots and Bridgeports and Fanucs of that day), like they had at
national laboratories or big companies. The Kim-1 or Altair 8080 or anything
else was just a toy, not for serious work. Maybe you might use one in some
application, but hardly anyone had one, or knew what to do with one. I never
put mine in a robot. And I never really understood the KIM-1 assembly
language (6502), until I sold it to get money to buy a Commodore PET. Only
later, with an assembler program on the PET, did that stuff start to sink
in, as I moved beyond typing in stuff I did not understand to writing things
myself, something that took a couple years to do. And that was also helped
along by playing with a cardboard "Cardiac" computer at school:
http://www.boingboing.net/2009/06/02/cardiac-paper-comput.html
http://www.boingboing.net/2008/03/11/newold-stock-of-bell.html
When you have gained a skill and practiced it for many years (me, writing
software, or Ted, making ShopBots), it is hard to look back and remember how
important just playing with the basics were, or how much there was to learn
that now all seem obvious. All the little stumbling blocks. All the little
assumptions. All the little habits of mind and behavior. All things that got
learned, on tiny experimental step at a time. And, at least in my case, how
many *years* it took just to get comfortable around something, and gradually
gain a feeling for ideas I take for granted now (like a sequence of
instructions telling something what to do). Basically, people need these
things in their homes so they can make a lot of mistakes with them and break
them. :-)
If you look at the 1960s Cardiac cardboard computer video, from the 1960s,
you can see what learning about computers meant back then. Such basics. What
is a computer? What can they do? What is the industry all about? What is
"Computation"? And so on...
So, papercraft systems are great. Papercraft is maybe the easiest way to get
into home CNC. But we couldn't we do more with a general purpose open-ended
Cartesian robot that was the size of a typical printer?
So, how should the ShopBot brand (or other brands) transform over time, with
changing expectations and changing possibilities?
From the book "Groundswell: Winning in a World Transformed by Social
Technologies",
http://www.amazon.com/Groundswell-Winning-Transformed-Social-Technologies/dp/1422125009
http://blogs.forrester.com/groundswell/
page 76, quote from Ricardo Guimaraes: "The value of a brand belongs to the
market, and not to the company. The company in this sense is a tool to
create value for the brand... Brand in this sense -- it lives outside the
company, not in the company. When I say that the management is not prepared
for dealing with the brand, it is because in their mind-set they are
managing a closed structure that is the company. The brand is an open
structure -- they don't know how to manage an open structure."
So, to that extent, Ted is really cutting edge, by being here and listening.
(Pun intended. :-) That book has lots of other good ideas to be involved
with customers and potential customers too.
But, I'm not sure I'd be that unhappy with a mostly open system that had
some consumables. For example, what if ShopBot Tools sold some kind of
two-sided sticky paper to hold down Balsa wood while it was being cut on the
device? (Not sure that would work, just an idea.)
Anyway, so much is happening, but that's the nature of a slow peaceful
revolution, same as with the spread of the microcomputer in the 1970s. Even
then, people predicted the potential of computer networks and democratizing
information, as well as various threats, but it took decades to see that in
a big way.
Part of the threat:
"Freedom's Edge: The Computer Threat to Society"
http://www.atariarchives.org/bcc1/showpage.php?page=66
http://www.atariarchives.org/bcc1/showpage.php?page=295
Part of the promise:
"Computer Lib: Dream Machines"
http://en.wikipedia.org/wiki/Computer_Lib
"In Computer Lib, Nelson writes passionately about the need for people to
understand computers deeply, more deeply than was generally promoted as
"computer literacy," which he considers a superficial kind of familiarity
with particular hardware and software. His rallying cry "Down with
Cybercrud" is against the centralization of computers such as that performed
by IBM at the time, as well as against what he sees as the intentional
untruths that "computer people" tell to non-computer people to keep them
from understanding computers."
So, a ShopBot MiniMe or ShopBot Mini or ShopBot Micro could perhaps best be
seen as a tool for hands-on digital fabrication literacy, as opposed to a
tool for using in a production woodshop eight hours a day like a ShopBot
PRSalpha. Granted, there are other people doing things as well, from
Makerbot's CupCake CNC, CarveWright, Fab@Home, RepRap, through TechShop and
FabLab and Maker Faires. There is room for a bunch of approaches, each
having their own strengths and weaknesses.
So, in any case, "digital fabrication literacy" might soon be a new
buzzphrase. Although it probably needs to be shorter. "Fablearning"?
"Faberacy?" :-)
Anyway, that's a marketing paradigm shift. Everyone seems to want to sell a
tool to do something. What about just selling a tool to learn something? Or
maybe the two are inseparable? Maybe a tool is not interesting to learn it
if it can't do something interesting? But, I'd suggest the bar for
meaningful functionality can be lower for cheaper learning tools (like the
Cardiac cardboard computer, where you just use an erasable marker to write
numbers on coated cardboard and move some cardboard slides around).
Dremel says not to press the tool hard into any material, and to let the
speed do the cutting. So, how much side force should a system using a Dremel
tool exert? So maybe some minor change to a design, like to have a
force-torque sensor or measure deflection of a tool or measure motor current
might be enough to make a functional subtractive machine, even within
limits, for Dremel bits?
Still, the old adage in engineering: "Fast, Cheap, Good", pick two. So, it
has to be "Cheap". So, is it more important as a learning tool that it be
fast or good? (Where fast might be taken to mean lightweight, easy to buy,
and so on.)
I think that is a mistake my father made when I wanted to get a
mini-all-in-one-mill-lathe-etc. advertised in the back of various magazines.
As a machinist, then tool-maker, then manufacturing engineer, he rightfully
scoffed at them, and said the money would be better spent towards a used
Bridgeport. But, we did not have the room for a Bridgeport, or the money to
move one (how to get it down a flight of stairs into a basement?), and so
on, so, instead, we got nothing, and I just used the hand tools we had.
I only really learned machine shop skills on big mills and lathes in my
twenties is a university shop, taught by the person who ran the machine
shop. Once, I bent a centering tool using the automatic drive he warned us
about, I was so embarrassed; although he fixed it up, but I'm sure it was
never the same; I'd have much rather damaged one I owned myself in private.
Sure, maybe the resulting parts would have been junky on a cheap all-in-one,
but I would have been learning on my own.
Granted, I can wonder if safety was a concern? But would a mini-mill really
be that much more dangerous than a hand drill or a soldering iron? I can see
it might be somewhat, with the potential to get you hand caught.
Now that I have a young kid of my own, I can better see the value in
something to learn with, even if the results are not going to be commercial
quality. Still, safety (including ear protection) is a concern. That is why
I bought Lego Mindstorms (plastic) instead of Vex robotics (with metal, and
small nuts and bolts) when my kid was younger. But, we have a printer in the
house, and woodworking tools, and between the two, a mini-CNC machine would
not do much more than either, although granted, putting them together has
the potential for things to go wrong. But, that's part of learning. And it
is better to learn things like "watch where you put your hand" on small
things with motors that will give more easily than on something bigger and
stronger. And in any case, a versatile 'bot in the shop could be used in
safer ways at the start (like starting with pick and place activities, or
additive machining, or scanning, or paper cutting, or plotting, before
moving onto subtractive methods.)
In any case, another thing to add to a ShopBot MiniMe -- break away or
flexible connectors? :-) I know, that conflicts with a desire for rigidity.
--Paul Fernhout
Ted Hall
We did take some developers kits (controllers for CNC's and robotics) and little CNC toy type things to the San Mateo Maker Faire in 2008 (a CNC tool, a light show, and a beaded-chain-based drawing device modeled after a well know one whose name I'm blocking on). There was not much interest there in kits or these kinds of tool and we got a little discouraged -- but it may not have been the right place.
This year, we just did a thing for kids that turned out to be a huge hit (now open source mfg): www.linkerlogs.com
Ted Hall, ShopBot
Vitaly Mankevich
> Bottom line: An under $1K additive machine is possible,
> and under $1K
> subtractive machine is not.
There is Zenbot Mini which costs about $800. Its work area is really small though and there doesn't seem to be a lot of user feedback, either positive or negative, at least judging by a quick google search. Link: http://www.zenbotcnc.com/merchant2/merchant.mvc?Screen=CTGY&Store_Code=zenbot&Category_Code=routers
There is also a startup called Purple Crayon with a small desktop mill "Cassius" in beta. They say it will cut soft materials (no metals) and will be priced under $1000 when released. Link: http://www.purple-crayon.com/
But maybe that is because I am speaking from ignorance of not having tried
CNC with them. Or, maybe you are setting higher expectations for speed and
accuracy than what I expect from a toy?
Maybe the price point is even too high at US$1000 for expectations? Maybe
you should be thinking $500? Or $300?
I would buy a desktop mini router for $300. It would have to be reasonably accurate (0.01") and not too slow. I think the $300 price is unrealistic though, even if such a thing was mass produced. But a paper craft cutter can be had for even less: http://www.uscutter.com/Graphtec-Craft-ROBO-2--Scrapbooking-Craft-Cutter_p_126.html
But here is the thing -- it would be nice to have a cheap Cartesian robot to
play with that was open enough to build on. I have still not seen a plain
Cartesian robot for sale that was cheap (there are lots of humanoid toy
robots, but not Cartesian ones, which seem industrial).
Thanks for the opportunity to plug the project that I've been working on - an open source construction set for building Cartesian robots :) It's basically Erector/Meccano made from aluminum, but with linear motion elements. Some examples of robots assembled from it - plotter http://www.youtube.com/watch?v=vo-z0VBXkfQ and mini-router http://www.youtube.com/watch?v=oWVjI2rJ7NM Last video is sped up 16 times - as you can see it's a bit slow.
The intended uses for the set include prototyping (things like 3D printers), creating very simple and basic CNC machines - router, mill, hotwire cutter etc, and eventually bootstrapping home fabrication lab. It's still very much a work in progress - the assembled machines are more like toys at the moment (though functional toys). I'm hoping to improve the performance/usability characteristics by combining linear motion elements from the set with small T-slot profiles. The project has also been a good way to learn about CNC hands-on without buying expensive machines. The cost is under $500 in parts and materials.
Link for anyone interested: http://www.garagefab.cc/contraptor
Paul D. Fernhout
> Ok ... I give. We'll put it on the list.
>
> We did take some developers kits (controllers for CNC's and robotics) and
> little CNC toy type things to the San Mateo Maker Faire in 2008 (a CNC tool,
> a light show, and a beaded-chain-based drawing device modeled after a well
> know one whose name I'm blocking on). There was not much interest there in
> kits or these kinds of tool and we got a little discouraged -- but it may
> not have been the right place.
Ted-
When I woke up this morning, I was thinking, maybe you were right in the
first place? :-) Especially in the context of your other email, as well as
the last paragraph above?
You wrote in your previous email to the list (put for reference here):
> But, Paul, do consider more than just costs in
> conceptualizing current digital fab devices as metaphorical main frames,
> mini's, and micros. In the heyday of DEC, the system was never even
> considered for use by the non-expert (not to mention the notorious comment
> on why you'd never need a computer in the home). Even a mini was an
> enterprise tool requiring enterprise resources. A ShopBot is oriented to use
> by individuals and small shops and requires little expertise. We've always
> seen it as a micro vs mainframe. In 70's and 80's pricing it may not even be
> so bad; I bought my share of TRS-80's back then for >$3K. The price of the
> first ShopBot (that performed a bit like the edu-toy you have in mind) was
> $1800.
I'm starting to see how there are some half-truths in my understanding here.
When I read "ShopBot" as a term, with me being into robotics (at least in a
former life :-), I focus on the "Bot" part. And I think, "Wow, I'd like to
have a small version of that just for fun and learning."
But I'm really ignoring the "Shop" part. I did mention before that maybe a
mini version might be best under another brand name, and I can wonder more
about that. Anyway, this is not to question the value of a home Cartesian
robot as a fun play thing or great educational tool; this is just to muse
about how it aligns with the ShopBot brand or historical parallels. (And if
you did such a device, maybe a different brand ("HomeBot"?) would make
sense, despite what I said about upsell potential.)
Personal computers were also things people played with in the house. The
problem with the ShopBot brand from that standpoint is, a ShopBot system is
not something you can put in the kitchen or living room or den. (At least,
not realistically for most people with spouses. :-) Nor can you move one
easily if they weigh about 600 lbs. A neighbor had to go through all kinds
of gyrations to get three-phase power working for a sheet metal press (you
sell a three-phase spindle option). Even just 220v is a big inconvenience
for locating things in the home. (I'm not sure if all ShopBots require 220v
though?) Also, to use machine tools safely, they generally should have a
safety perimiter around them for easy access and jumping out of the way and
to contain sparks and debris. So the real footprint of a comfortable ShopBot
installation might be two hundred square feet, which is a lot of space in a
home to devote to one thing (about a Ping Pong table's worth).
So, in that sense, ShopBot systems really require a "Shop". So, in that
sense, a ShopBot system does require an aspect of expertise and a dedicated
enterprise, and that is why, even at a similar price point, the personal
computer parallel is awkward.
Now, it is interesting that many homes (not ours, unfortunately) have a
basement, and that can serve as a shop-like transition area for tools, where
it is climate controlled at no extra cost and spacious enough for big
things. So, a "BasementBot"? :-)
Anyway, that may be why it is harder to categorized ShopBot than I thought,
and why I am wandering into half-truths in trying to fit it into the home
computer metaphor. The "'Bot" part is what I want to see in the home. But
the "Shop" part is what is expensive and requires dedication and a lot of
resources.
But in any case, that's why 3D printers in small boxes end up looking more
appealing for the home market. I've been having a problem with a complex
bracket in my treadmill that holds the optical encoder detection circuitry
(it is plastic and sagging and dragging), and I was just thinking this
morning that if I had a V-Flash, and a 3D scanner, and the right software, I
could scan the bracket, morph it slightly, and print out a new one.
http://www.modelin3d.com/vflash_benefits
I can see devoting a corner of a room somewhere to that sort of thing, for
fun and toys, but not a room way bigger that my (tiny) office. :-)
What I want for my own circumstances (young kid, wife's office in the
woodshop which is small anyway, unheated garage bays in a very cold climate)
is something I can play with in the house. We've got a ShopBot's worth of
Lego (almost literally, and just bought some more yesterday as to fufill a
promised reward for bravery at the dentist :-) and we've got two Mindstorms
NXTs and several other animal-form and humaniod robots, so it would be nice
if it played nice with them too (so, ideally, a frame that could sit on the
floor and reach the floor). And I doubt we are that unusual in that respect.
(Or at least, there are many like us. :-)
We also just bought a tool/toy yesterday I'd love to drive by a Cartesian
robot: a "Crayola Cutter" (US$15) that can do paper cutting but it is hard
to make it go in fancy patters by hand:
http://www.crayola.com/canwehelp/products/cutter/index.cfm
"The Crayola Cutter makes cutting as easy as tracing a picture. The safe,
easy-to-use cutting wand handles like a pen, so you can cut out intricate
shapes anywhere on the page. Designed with safety in mind, the punch-tip
action cuts paper by perforating it, not slicing, and the tip retracts when
not in use. The Crayola Cutter comes with stencils, decorative paper,
acetate sheets, and an idea booklet."
So, there are more and more hand tools and toys that the system could work
with. We saw another toy for placing beads and making them solid with water.
So, that's why I'm thinking I wand a "HomeBot" and not a "ShopBot". (I'm not
saying HomeBot is a good name, I'm just looking at a parallel.)
Now, another way to look at this is simply that, if a ShopBot system was
like a microcomputer, then maybe the nature of the home should change? :-)
Maybe everyone needs a big "Shop" to put their ShopBot system in? :-)
But, a Shop is still out of reach for most people. But, with creative
financing, mobile trailers, and such (people talked here about factories in
trailers), no doubt one could expand the ShopBot line to putting in Shops
for people's 'Bots. Which as creative real estate deals go, is not without
precedent. :-)
But short of that, I can see the original argument, that as far as the
ShopBot brand goes, it is a tool for a "Shop". And linking that with the
notion of manufacturing systems at different scales, it might be wise to
focus on that niche, as long as their are "Shops".
So, maybe I am just wrong about there being a good link of home use and the
"ShopBot" brand?
Anyway, just more ideas to support your own lukewarm feelings about it. And
add to the confusion. :-)
--Paul Fernhout
Ted Hall
When I woke up this morning, I was thinking, maybe you were right in the
first place? :-) Especially in the context of your other email, as well as
the last paragraph above?
I'm starting to see how there are some half-truths in my understanding here.
Well, if I really responded to this one it would just be spam ... I like that this group is not just patter, either. So I won't indulge.
We also just bought a tool/toy yesterday I'd love to drive by a Cartesian
robot: a "Crayola Cutter" (US$15) that can do paper cutting but it is hard
to make it go in fancy patters by hand:
http://www.crayola.com/canwehelp/products/cutter/index.cfm
But I did get one of these the other day probably -- from the same curiosity. It was disappointing. It only worked for about 5 min, and I'm not sure that it even worked right at all. I may have to try another because I did not get close to getting it on an XY gantry.
Ted Hall, ShopBot
Paul D. Fernhout
> On Wed, Jun 17, 2009 at 10:29 AM, Paul D. Fernhout <
> pdfer...@kurtz-fernhout.com> wrote:
>> When I woke up this morning, I was thinking, maybe you were right in the
>> first place? :-) Especially in the context of your other email, as well as
>> the last paragraph above?
>>
>> I'm starting to see how there are some half-truths in my understanding
>> here.
>
> Well, if I really responded to this one it would just be spam ... I like
> that this group is not just patter, either. So I won't indulge.
Understood.
This morning, I had another design idea, obvious in retrospect. :-)
This is not a design I want myself (because I want a table model for
pick-and-place things), but many others might like it who do mostly cutting.
Imagine a ShopBot table upended and sitting on its narrowest end. And then
put in in a large enclosure (well, the enclosure would be integrated into
the design of course), that stood up like a shallow refrigerator. Maybe it
would be bolted to the wall if it was top heavy, to keep from falling over,
and to give it extra rigidity. It might be shaped like and armoire or
standing closet.
http://images.google.com/images?hl=en&um=1&sa=1&q=armoire
Plywood (or other large sheet material) could perhaps be more easily loaded
into it with less risk to the back? I know at least I don't like laying
plywood flat as one person (but I've only worked near the ground on it, so
maybe it is easier at table height). So, this might have ergonomic
advantages for the one person shop?
The plywood is initially held in place by some clamps at the edges. That is
not going to work after parts are cut of course, and the plywood may also be
warped to begin with, so it is also help by either by a vacuum system as
now, or perhaps by a *pressure* system.
I'm not sure how this pressure system would work for sure, but imagine a
rear panel that had holes in it, where either every hole had a computer
controlled valve with a pressure sensor (yes, thousands of them), or maybe,
more cheaply, a flexible but tough membrane (perhaps even an entire surface
that was flexible). The cabinet is closed and pressurized, and the pressure
holds the material against the rear side which is open to the room
atmospheric pressure. The valves would have a sensor to close if a cut part
fell away from the area, but the membrane approach could do that too if it
had a maximum distension, so, the membrane would give up to a point and then
stop. You might want to use a vaccuum first in the cabinet to bring the
membrane in, before pressurizing the system after internally seating the
board (maybe there might even be a roller inside for flattening?).
Presumably, the parts either fall to the bottom onto a soft material, or are
carefully removed as cut (maybe controlling those valves) and placed gently
to the bottom of the enclosure or elsewhere by a suction-cup on the arm.
Anyway, for all the extra difficulties here, the big advantage is
floorspace. Rather than take up 8 feet by 4 feet (32 square feet) for the
table, plus a working open perimeter for loading and safety which might be
significantly larger (so, approaching 100 square feet or even much more),
though maybe I exagerate that based on this which looks a little cramped to me:
http://www.nelsonsdesignssp.com/Nelsons%20Designs%20shop.htm
you just have perhaps four or five feet wide by one or two feet deep for the
standing design, so around four to ten feet of floor space, but it would be
eight to ten or more feet tall. For places with low ceilings, you might want
to have the long side down.
A hybrid design might have a slight backward slope to the back, maybe for
easier loading or initial holding?
If the pressure system could be made to work, I'd point out the vacuum can
only produce at most one atmosphere of pressure on the material, but you
could have any amount of pressure by high pressure systems. Of course, high
pressure systems might be more dangerous, (explosively opening doors, for
example), so a vacuum system might be better from that standpoint. Somehow,
it seems to me like a pressure system might be quieter? And more energy
efficient? It would pressurize once and hold that. But a vacuum system
working against a sealed cabinet might also be quieter? Like if it just
maintained a vacuum on the far side of the rear wall, again, perhaps with
thousands of these valves, or such a membraned that might act like thousands
of suction cups if a vacuum was on the other side? I don't know if any of
this would really work, I'm just trying to suggest alternatives because you
said earlier the holding system would ideally be even better, because the
current approach uses a lot of power.
All the removed material presumably would just fall to the bottom of the
cabinet by gravity and be contained. So, this is a system that might be
cleaner to have in the home and use less floor space. It would also be safer
to have around children, since the cabinet would be closed while in
operation. Now that you have a lot of confidence in building reliable
ShopBot systems, there is little need to poke at them while running.
Whether this approach really makes sense or is feasible (given falling cut
pieces which might break or entangle) is a different story. :-)
And for me, I'd rather have a version that I could place over a section of
the floor. But, if I were going to have a ShopBot system in a small house
that could handle big pieces of plywood, this might be the type, because of
the floor space issue and the dust and debris containment issue.
Anyway, I've been looking at more and more enclosed manufacturing cells (big
things), so maybe having a small one for a ShopBot router makes sense too?
But maybe the cost of metal walls would be prohibitive? Could be something
else for the walls perhaps, like even wood with calking or rubber seals for
pressure issues. But refrigerators for a few hundred dollars have metal
walls, but they don't plan to take pressure differentials of much
significance. Of course, maybe a tenth of a PSI might be enough to hold well?
Anyway, chances are you've thought about and rejected this idea already for
whatever limitations and difficulties it might have. Just putting it out there.
>> We also just bought a tool/toy yesterday I'd love to drive by a Cartesian
>> robot: a "Crayola Cutter" (US$15) that can do paper cutting but it is hard
>> to make it go in fancy patters by hand:
>> http://www.crayola.com/canwehelp/products/cutter/index.cfm
>>
>
> But I did get one of these the other day probably -- from the same
> curiosity. It was disappointing. It only worked for about 5 min, and I'm not
> sure that it even worked right at all. I may have to try another because I
> did not get close to getting it on an XY gantry.
We'll see how long ours works. But as a proof-of-concept, it is at least
very interesting. :-) The flexible pad underneath (like a foam mouse pad) is
part of the innovation. But, difficulties in practice, that might also
explain why they were on "sale" as clearance items where I got one. It's
really hard to make stuff that works all the time in a robust way --
especially if you also expect kids to use it and for it to be cheap.
Maybe you can re-engineer the mechanism? :-)
--Paul Fernhout
Ted Hall
Anyway, I've been looking at more and more enclosed manufacturing cells (big
things), so maybe having a small one for a ShopBot router makes sense too?
But maybe the cost of metal walls would be prohibitive? Could be something
else for the walls perhaps, like even wood with calking or rubber seals for
pressure issues. But refrigerators for a few hundred dollars have metal
walls, but they don't plan to take pressure differentials of much
significance. Of course, maybe a tenth of a PSI might be enough to hold well?
Anyway, chances are you've thought about and rejected this idea already for
whatever limitations and difficulties it might have. Just putting it out there.
>> We also just bought a tool/toy yesterday I'd love to drive by a Cartesian
>> robot: a "Crayola Cutter" (US$15) that can do paper cutting but it is hard
>> to make it go in fancy patters by hand:
>> http://www.crayola.com/canwehelp/products/cutter/index.cfm
>>
>
> But I did get one of these the other day probably -- from the same
> curiosity. It was disappointing. It only worked for about 5 min, and I'm not
> sure that it even worked right at all. I may have to try another because I
> did not get close to getting it on an XY gantry.
We'll see how long ours works. But as a proof-of-concept, it is at least
very interesting. :-) The flexible pad underneath (like a foam mouse pad) is
part of the innovation. But, difficulties in practice, that might also
explain why they were on "sale" as clearance items where I got one. It's
really hard to make stuff that works all the time in a robust way --
especially if you also expect kids to use it and for it to be cheap.