
Maslow CNC - MaslowCNC
http://www.maslowcnc.com
======
ChuckMcM
I've built several of the 2D plotters (two stepper motors, some string, some
math, and blam you have you have a plotter. Most fun was sticking them on
chalk boards and then using chalk in them to put some really amazing drawings
up on the chalk board.

That experience has suggested that this project is not going to be as
successful as they would hope. That is because you can't depend on gravity to
be stronger than the angular momentum of a router bit hitting a knot in the
wood. Specifically when you're routering away and you hit material that pushes
back on the router, the router may not move in a gravity planned sort of way.
I've seen that in the plotters when the drawing device catches on the material
that its drawing on. You get a line that goes horizontal when it should go
down.

These sorts of things are pretty easy to pass off when you just hang a new
sheet of paper but if it means throwing out a 4x8 sheet of plywood its going
to be a bit more painful.

As for discontinuous lines you put a wall sensor on the drawing puck (or the
router) and when you need it to move you tell the operator. Who goes over and
lifts the pen/router off the paper. The code detects the lift, adjusts to the
new position while you lightly hold the puck, and then indicates you should
let it back down on the surface. Once the wall sensor activates it goes back
to drawing.

~~~
BarSmith
Hey ChuckMcM,

I wanted to jump in here and add something. Full disclosure, It's my project.

The machine is designed to print things out of the sort of manufactured sheet
materials we use in most construction these days so things like plywood,
sheetrock, MDF..etc. Knots don't tend to be an issue because they are only in
one ply of the plywood, meaning the force is very consistent even when passing
through a knot. We've never seen an issue. Materials like drywall and MDF of
course don't have knots at all.

~~~
ChuckMcM
Awesome project btw! I'm glad you've not seen any issues. Re-reading what I
wrote, it sounds more pessimistic than it should. I am sure everyone that uses
one of these will have lots of successful "prints" and will make many
interesting things.

~~~
jacquesm
If the problem does occur you could simply make the thing heavier and run a
bit slower. Inertia is a big killer for speed but this isn't a production
machine.

~~~
tonyarkles
I wish it were that simple! On a lot of materials, going too slow will cause
problems as well. You want your "chip load" to be within a band; too slow, and
you'll start burning the wood instead of cutting it.

[http://www.pdsspindles.com/engineering-
speeds](http://www.pdsspindles.com/engineering-speeds)

I, too, do not want to come across negative about this. I'm very excited about
it. If it isn't sufficiently strong to handle some types of wood, even just
being able to drop a V-cutter into the router and having it very accurately
draw out all the cut/guide lines is a win for the target price. If my work
flow is "draw accurate cut lines, do a rough automated cut (leaving some extra
around the edges), and finish on the scroll saw and belt sander", that's
great!

~~~
jacquesm
Yes, obviously if you're moving so slow you're not longer cutting then that
won't work but that's so slow that I highly doubt it couldn't be improved on.

~~~
allannienhuis
Setting the rpm of the router is an ordinary setup/configuration step for
doing 2d machining. I used to run 2d router systems at sign shops for years.
You're always looking to optimise the speed of travel and router rpm to get
the best cut qualities - fast travel with high quality cut - too fast can
result in chips/burrs, too slow results in burning/melting and damage to bits,
etc.

I always had a list of settings to use for various combinations of materials,
thicknesses, router bit sizes/types. It was a bit of a black art actually -
sometimes the results of changes were counter-intuitive because of specific
material properties (heat retention, etc), and that cheat-sheet wound up
containing the accumulated knowledge of years of trial and error
experimentation. "The only difference between Science and screwing around is
writing it down" :)

~~~
herewulf
Such a cheat sheet sounds like the perfect thing for an Open Source project
with a (hopefully) active community to curate.

------
JaggedNZ
I'm a relatively new owner of an OX CNC (Ooznest kitset). I also researched a
bunch of other options before purchasing, including the Shapeoko 2 & 3\. I've
spent ~$1200USD (incl. shipping literally across the globe), Those in the US
could easily come in under $1000USD. The above mentioned CNC routers are
really on the low end in terms of minimum required rigidity.

While the feed rate of the machine looks OK, but they do not specify the depth
of cut per pass. Combine this with the fact they don't show a part being cut
from start to end, even speed up, is telling. I suspect a excessive number of
very shallow cuts, leading to long cut times and excessive tool wear. I also
suspect if the cut depth is to great you might find out the true meaning of
climb cutting.

0.4mm resolution is not that great and the resolution actually changes based
on how far you are from each motor!

Mounting material to cut on a vertical surface is going to be a major pain if
it's not a quarter sheet of ply or bigger. And once a part is cut loose
without tabs the router is liable to kick them out, that's going to be a nasty
learning experience for some.

The only great things about this machine are its large cutting area, small
foot print and low price. But fair warning, the limitations will start to
stack up fast I suspect, this machine would be best suited cutting flat pack
furniture designs from full sheets of ply, when delivery time is not an issue.
To his credit this does seem to be the market he is targeting.

~~~
BarSmith
Hey JaggedNZ,

The OX CNC is awesome.

You are spot on about what we're targeting. We're looking at people who are
building big things, houses, sheds, furniture, kayaks, tree houses, geodesic
domes, huge signs etc. Basically the kind of things that get built using hand
held power tools now. The goal is to make a machine that can download and
build those type of things more accurately than a guy who's really good with a
jig saw.

As for # of passes, I'll throw some mention of that on the website tomorrow. I
usually do 1/8th inch passes so 1/4 inch ply is a 2 pass job, 1/2inch is a 4
pass thing...yada yada

~~~
ansible
Can you get good results on a single pass if you really slow down the feed
rate?

------
jacquesm
Very nice job!

An alternative for the router brand: Makita, they offer a number of router
bodies that seemingly last forever in both wood and more difficult materials
(fibreglass), I've run them for 100's of hours (and probably 1000's) without a
problem.

Beware of steppers when you're driving routers, you may lose steps along the
way ruining your workpiece (step loss is loosely related to Murphy's law, it
will happen near the end of complex workpieces).

If you build this thing out of metal with a watertable underneath it will be
slightly more expensive but you'll be able to use a plasmacutter to cut metal
as well as wood by swapping out the head.

Here is what I built:

[http://pics.camarades.com/d/11225-2/dscn3995.jpg](http://pics.camarades.com/d/11225-2/dscn3995.jpg)

(That's the first version, before making a much lighter gantry to improve
speed constancy in corners, not very important for woodworking but extremely
important when plasma-cutting.)

Some critical observations about 'Maslov':

Hanging plotters suffer from asymmetric curves when it comes to acceleration
'up' or 'down' which can lead to surprises in overshoot/undershoot of the
intended toolpath.

Cable plotters tend to have a problem with that anyway and gravity will make
this problem worse. If accuracy is important consider making it horizontal.

~~~
fest
I helped with building CNC plasma cutter as well:
[http://www.boot.lv/forums/index.php?/topic/133809-cnc-
plazma...](http://www.boot.lv/forums/index.php?/topic/133809-cnc-plazmas-
griezejs/) (beware of the latvian language but has nice pics).

How did you solve the torch height control? We ended up using "digital torch
height controller" \- basically measure the arc voltage, compare to fixed
preset and move Z axis up-down accordingly. This is a stupidly simple approach
but requires complicated lookup tables of voltage vs height vs feedrate vs
material and I'm thinking about how to improve it.

~~~
jacquesm
That's exactly how I did it, but I built the controller myself.

The arc voltage is directly proportionate to the height above the workpiece so
you don't need much in terms of lookups or feedrate, all you want to do is to
keep the voltage constant, so if the voltage is too high you need to get
closer to the material (beware of strikes!) and if it is too low you need to
back off (fast!, sometimes the material is warping towards the torch very
rapidly, especially when the material you're cutting out of is thin).

Where in Latvia are you? I go there with some regularity, I'd love to come
visit. Mail: jacques@mattheij.com

Tip: you could lose quite a bit of weight on that gantry but turning it into a
lattice.

[http://pics.camarades.com/v/jacques/renewables/windmill/09_s...](http://pics.camarades.com/v/jacques/renewables/windmill/09_sep_final.jpg.html)

Weight in a plasmacutter gantry is killing because it reduces the speed with
which you can change the direction of motion while cornering in detailed work.
That in turn causes you to have to slow down which will burn away fine detail
so any weightloss on the gantry should be pursued.

Ideally you want constant velocity relative to the workpiece while cutting.
This also helps in maintaining precision because the cone shape that the flame
has will cause it to cut thinner and thicker depending on the stand-off
distance.

~~~
fest
IIRC, the arc voltage was proportional to height only at constant velocity. I
guess it was also a function of how much material is below the arc at the
instant.

I was working on a controller which was supposed to get it's setpoint by
measuring voltage during first few seconds of a cut, but the project turned
out to be outside of my EE skills at the time (isolating analog signals, high
voltage resistive dividers that didn't blow up because I had no low-voltage
feedback signal from plasma source etc.)

About the need for rapid accelerations- that too was one of the things we
learned by building this machine. IMO it should be stressed more in
discussions about plasma cutters.

In this case the blue linear slide actuator was off-the-shelf part and
modifying it would require to cover the belt and linear guides inside with
something else and was thought to be too much of an effort.

~~~
jacquesm
You can usually tap a point in the plasma cutter power unit that will tell you
exactly what the arc voltage is, almost any slightly larger plasma cutter
power supply will have a point that's convenient.

You'll still need to use an opto-coupler, the way I built mine was the
setpoint and comparator lived on one side of the divide, then two input bits,
one for 0.1 V below the setpoint or lower, -0.1 to 0.1 was both inputs off and
one for 0.1 V or higher, the setpoint was scaled so that it would have a nice
range mapped to the inputs of two op-amps doing the comparison. The outputs of
those op-amps drove the opto couplers and the software would track the 'Z'
stepper up, down or hold depending on those two inputs. Super simple really.

------
Animats
This is kind of neat, but the rigidity is questionable. It's significant that
they only show sped-up video. You don't get to see the actual cutting speed. I
suspect they have a really low feed rate because they can't exert significant
side loads on the router. Maybe if they had four chains, so it wasn't just
gravity holding the thing in place... Wallboard, yes, MDF, probably, plywood,
if thin, hardwood, no.

A big problem is that this thing gets its Z position by riding on the material
it is cutting. So you have to cut things out of fresh big sheets. If you cut
away too much, work near the edges, or use smaller sheet stock, there's going
to be trouble. For decorative scrollwork in thin stock, though, it could be
useful. Expect stuff from this machine to appear on Etsy shortly.

I've used ShopBots for similar work. Those have enough rigidity for wood, even
hardwood. The limitation on cutting speed is damage to the router bit; the
machine has plenty of feed power.

~~~
jacquesm
My own drivetrain for something like this was simply a small gear on the shaft
of a stepper running on a long piece of gear rod. Accuracy was more than
acceptable and you could reach very high speeds with the appropriate
acceleration curves (very important too to minimize step-loss chances).

------
Dowwie
This kind of work gets me so excited. Thank you for leading the way,
@BarSmith! Open source industrial design communities such as OpenBricks [1]
and OpenDesk [2] have emerged to fuel the imaginations of users of Maslow CNC
mills.

For instance, one could now mill a vertical gardening wall-mounted planter,
with community help, by joining this project:
[http://www.openbricks.io/app#!/project/566af15e584123b4502f4...](http://www.openbricks.io/app#!/project/566af15e584123b4502f40ef/bricks)

It is a right of passage for a homeowner who DIYs to create a workbench. I
haven't created mine yet but have investigated approaches. One novel approach
is a torsion box-based workbench. The painstaking process one must undergo to
create the lattices could be replaced by a fitting together CNC milled,
continuous pieces. So cool.

I'm so ready to join this movement..

[1] [http://www.openbricks.io/](http://www.openbricks.io/) [2]
[https://www.opendesk.cc/](https://www.opendesk.cc/)

------
abetusk
This seems like a cool project but the non-commercial license in the CAD files
[1] is a no-go for me to fund their Kickstarter. It does look like the PCBs
[2] and firmware [3] are free/libre licensed.

[1]
[https://github.com/MaslowCNC/CAD/blob/master/License](https://github.com/MaslowCNC/CAD/blob/master/License)

[2]
[https://github.com/MaslowCNC/PCBs/blob/master/LICENSE](https://github.com/MaslowCNC/PCBs/blob/master/LICENSE)

[3]
[https://github.com/MaslowCNC/Firmware/blob/master/LICENSE](https://github.com/MaslowCNC/Firmware/blob/master/LICENSE)

~~~
blackguardx
Why? They put a lot of work into this and are giving the plans away. They just
don't want you to compete with them. It seems fair to me.

~~~
TaylorAlexander
We all work hard on the things we make. But many of us open source those
things so that others can make them better. When we restrict commercial re-
use, we're hobbling the project in certain ways. What if someone wants to help
make it better, but they want to earn money from their improvements? You can
still license the code with attribution and share alike. That way people know
you designed it, and you get to use the improvements other people make.

It's okay that they choose a non commercial license. But it may make me less
interested in supporting it.

But I'll check out their PCBs and see if I can help make any improvements. I
like this project.

------
2sk21
This may be very well received in the model railroad community. When building
a layout, one of the techniques (called cookie cutter) for creating the
subroadbed is to cut out shapes from a sheet of 4 by 8 plywood similar to this
gadget. See this for example:
[https://www.youtube.com/watch?v=iqcUKofeElc](https://www.youtube.com/watch?v=iqcUKofeElc)

------
locusm
The Kickstarter is live
[https://www.kickstarter.com/projects/1830738289/maslow-
cnc-a...](https://www.kickstarter.com/projects/1830738289/maslow-
cnc-a-500-open-source-4-by-8-foot-cnc-machi/description)

------
kirillzubovsky
An interesting alternative to a Glowforge. This machine seems less of a "tool
for makers" of small things though, and rather an autonomous cutting machine
for big projects. It would be silly to use this to cut out a leather wallet,
for example, but totally reasonable to build a chair. Neat!

p.s. oh man, make a chair design, and then just set these babies to run day
in/out. that could be an fun factory!

~~~
wanderingjew
There's more to CNC than a hip startup like glowforge. (In the interests of
disclosure, it should be noted that Series A investors for Glowforge include
Bre Pettis and Jenny Lawton. Given their business decisions with Makerbot, I'd
consider them 'tainted' to this market).

This device is more akin to a regular 4x8 cnc router, like ShopBot, or an off
the shelf Chinese CNC machine. The innovation here is an experiment with the
drawbot mechanics popularized around 2010, but with a much heavier toolhead.
If it works, awesome - it's an order of magnitude cheaper than a shopbot. Even
if it's not ready for production, it's an interesting enough idea for a few
shops, garages, or hackerspaces to replicate the project.

This is really an awesome idea, and comparing it to a startup with
questionable investors does it a disservice.

------
abakker
2 more things:

1\. this isn't really printing, its subtracting. I think its important to make
this distinction.

2\. feed rate is REALLY important with getting good tool life as well as good
cut quality. Relying on gravity to control a 1-2 HP router is not going to
counter the cut forces well except at seriously sub-optimal cut rates.

e.g. A carbide 2 flute upcut end mill with .5" diameter cutting plywood works
nicely with a cut depth of about .5" and a feed rate of somewhere around
200-300 inches per minute. Even that may not yield the optimal chip load to
keep the bit cool. That assumes a router speed of ~20k RPMs and 3.25 peak HP
(AC motor @ 110v).

~~~
VLM
"Relying on gravity"

I have never built one of these, I wonder why they do that.

I would think 3 strong steppers would be capable of some pretty amazing forces
and would be quite well constrained. Or perhaps 4 steppers or more.

I've spec'd out NEMA 42 frame steppers that could quite easily start my car
(under the theory that a pony engine need be a tenth size to start a larger
engine and my commuter car only has 100 ft-lb torque, so 20 or so ft-lb of
torque should easily be adequate to start the engine)

Lets see a KollMorgan KM11 with 3750 in-oz of torque applied to a six inch
pulley is 40 pounds of force. That should accelerate a ten pound router with
some authority, 4 G or so. I know from experience I can push a traditional
router against a jig or fence or table much longer and more comfortably than I
can curl 40 lb barbells so 40 peak should be more than adequate.

A stepper of that output retails qty one to end users for like $150 delivered
maybe? So figure maybe $300 for three in bulk order shipped by pallet-full?

Over the course of my life the prices of steppers and control electronics
doesn't seem to change but the torque seems to go up an order of magnitude per
decade for several decades now, so it might be a matter of waiting until 2026
to unleash something like the above.

~~~
abakker
Steppers are definitely strong enough. The NEMA 42s on my machine are geared
down 10:1 and work very well moving a 100ish pound gantry.

The issue with gravity is not really motor strength so much as it is rigidity.
There is no z axis rigidity in the setup because it only has a chain. So it
can't exert pressure against the material from the axis.

The lack of rigidity is the real problem. As mentioned in other parts of this
thread, .01" accuracy is not going to give you great tolerance for pieces
where that error can be cumulatively compounded.

------
MaslowCNC
Hey everybody! Just wanted to throw out a quick reminder that we're launching
on Kickstarter tomorrow, the 25th, at 9 AM PST. Hope to see some of you over
there!

------
penglish1
It seems like it would be worth shopping with whoever has a "normal" CNC
machine nearby, and seeing if you can get your stack of plywood machined for
less for a given project. If you make a mistake with DIY, you're potentially
out a sheet of plywood, not to mention time and effort.

Your project will involve plenty of time and effort at other stages than the
plywood cutting bit.

Still, I'd consider getting one (perhaps on v2 after the Kickstarter has
played out, and v1 gotchas figured out). It is cheap enough to get "just for
fun."

------
danellis
"We're making the choice not to patent it."

Now that the US is first-to-file, doesn't that mean someone else can patent it
and use the patent against them? Isn't the best thing to patent it and give
royalty-free licenses?

~~~
nullc
No, this is a common misunderstanding of the implications of first to file.

Publication or public practice of their work is prior art. It immediately
precludes third parties from patenting their work. (And, after a grace period
will preclude them as well)

First to file deals with interferences, when two parties try to patent the
same work at the same time-- it doesn't change how prior art works.

Of course, it is still useful to file defensively since relevant prior art is
much more likely to be discovered when it exists as a patent... if it's not
discovered a patent could be incorrectly issued. (The patent would be
invalid-- but could still be used to harass people until put out of its misery
by a court. :) )

------
beambot
Looks cool... but I'm worried about repeatability and accuracy. I've seen a
lot of similarly-designed 2-motor "drawing robots", and the precision
definitely wasn't 0.4mm (as claimed). I imagine this could be difficult given
the use of gravity to supply the lateral cutting force?

On a related note: I'm pretty excited for the ShaperTools handheld router:
[https://shapertools.com/](https://shapertools.com/) You get the benefit of
big work pieces & CAD-based routing, but in a hand-tool form factor.

------
skj
Oh, Kickstarter.

------
zxcvvcxz
Small random quote from the vid:

> More details for nerds below

I'm not knocking the person who said this fairly innocuous statement (I catch
myself saying similar things), but it goes to show our unresolved social
biases against technical people. Yes, some people care about numbers and
details and engineering. Unfortunately, that associates them with a term that
implies low social value.

If another country overtakes the US in terms of innovation and engineering,
you can be sure that they will be showing greater respect to their technical
class of peoples.

------
100ideas
The crawlbot is another hobby-friendly compact 4x8' CNC. It's $2000. It saves
space by attaching directly to the 4x8 sheet with timing belts and using it as
the frame for the long axis. The shorter axis and router are contained in a
5x1x1 ft housing that "crawls" back and forth across the workpiece.

[https://printrbot.com/shop/printrbot-
crawlbot/](https://printrbot.com/shop/printrbot-crawlbot/)

------
jessedhillon
Quick tip about your site: put up some photos, not just videos. I'm on a
mobile phone and want to see this thing, and playing video is annoying, and
sometimes unfeasible.

------
Yaggo
I don't know if the idea is unique (edit: no, they mention it's based on a
known concept of "hanging plotter"), but that's a neat way to utilize gravity
to bring down costs. It's much more accurate (.4mm) than I would expect,
enough for most hobby work with big sheets.

(Off topic, but a hanging plotter (for drawing) would be rewarding project to
build with a kid!)

~~~
DannyBee
Errr, .4mm is not very accurate. It's about 5-15x less accurate than basic
wood cnc machines, which do 0.001-0.005 (they could easily do better, it's
just not necessary for wood). If each part was off by 1/64th, you can't even
form a 4 sided box that is guaranteed less than +-1/16, which is a lot.

I'm pretty sure they are also not including the router runout (since it uses a
router and not a spindle, add about 0.005-0.010, or, rather, halve their
precision again)

Now, don't get me wrong, it's a neat idea.

It may be really cool for construction (though drywall/etc guys are a lot
faster than this machine is), but ...

But you actually could not likely use this for real cabinet parts, etc.

To give you some idea:

Their specs:

Encoder Resolution: 8148 steps/rev

Real World Precision: +- 1/64th inch (.4 mm) or better

Max feed rate 48 inches/minute

Specs on my pretty basic 36x36 wood CNC router:

Encoder Resolution: 4 million steps/rev (22bit). Electronically gearable to
whatever (they are servo motors)

Real world precision: +-0.001 (1/1000) inch

Max feed rate 1200 inches/minute

Now, obviously, there is a range of costs and other machines between these two
machines :)

But building precision CNC routers, even with good closed loop servo motors
and ball screws, is not anywhere near as expensive as it used to be.

~~~
swimfar
He said, "It's much more accurate than I would expect." He's referring to how
accurate it is based on how it is designed. And I disagree that it's not very
accurate, given the use case. 0.4mm or 1/64" is way more accurate than almost
anyone can do with traditional power tools.

Sure, other more expensive machines have better precision. But how many people
actually need that much? Even plywood is going to experience changes in length
due to temperature/humidity greater than 0.001" (0.025mm). Solid wood (which I
guess this machine isn't really designed to cut) is going to be even more.

~~~
DannyBee
"And I disagree that it's not very accurate, given the use case. "

What use case?

"construction" is mentioned, but plywood guys and drywall guys can make
cutouts and curves far faster and more accurately than this machine can cut.

So seriously, what is the real use case other than "fun toy"?

" 0.4mm or 1/64" is way more accurate than almost anyone can do with
traditional power tools."

This is just flat out false.

With a simple track saw, i can easily get within 1/128th without even trying.

Hell, i can do that with a circular saw and a straight edge without a track.

You can get to within 0.005 pretty easily if you have bothered to tune your
tools at all and don't beat them up.

You can definitely get 0.005 if "traditional power tools" includes routers.

Of course, if you go to hand tools, getting within 0.001 is utterly trivial
with good hand planes.

"But how many people actually need that much? "

Wood certainly moves, but 0.005 is about being able to make nice fitting
joinery repeatably.

[https://woodgears.ca/mortise/accuracy.html](https://woodgears.ca/mortise/accuracy.html)

"With a mortise of 0.503", here's how the tenons fit: ...

Realistically, the total range of latitude is about 0.005" for a good fit. And
this is using spruce, which is a very forgiving soft wood. For mortise and
tenon joints in hardwoods, accuracy is even more critical. "

~~~
Yaggo
For a wood-cutting system supported by two chains and gravity, .4mm is
surprisingly good tolerance. Sure, it is possible to get far more stricter
tolerance with tradiotional power tools (for skilled person) but first you
need to somehow draw a line to follow, a challenging task in itself for
complex shapes. This tool can do CAD, a big benefit.

~~~
DannyBee
"For a wood-cutting system supported by two chains and gravity, .4mm is
surprisingly good tolerance."

Remember that this is jut the 'precision'. It says nothing about the
repeatability.

I have strong doubts it's repeatable to even that level.

"but first you need to somehow draw a line to follow, a challenging task in
itself for complex shapes"

????

It's really just not that hard. In the absolute worst case, you use graph
paper and cut it out. Most of the time, you just use a protractor or a bow and
cut it nearly perfect anyway. Given the tolerances pretty much restrict this
to "construction work", you can get the same result quite easily.

"This tool can do CAD, a big benefit."

I'm also going to assume you've not used much cad/cam software, because for
most people, it's _infinitely_ faster for a one off to draw it by hand than it
is to draw it in a cad program and generate gcode for it using cam software.

People have enough trouble using sketchup, let alone something real :)

The advantage for most people for CNC is the ability to repeatedly do the same
thing.

Unless you invest 100k in automated workflows, you aren't ever going to get to
the point where it's simply "draw in cad, click button, have machine cut it".
It's just never that simple, from workholding to what have you.

Which is another reason why i think it's neat, but has no real use case.

~~~
abakker
Thank you for these detailed responses. They track very well with my
experience using a 4x8' CNCrouterparts machine. There are so many things
acting against precision that I spent my first year of CNC ownership finding
out what was really practical. Inlays on machines with >.005" accuracy don't
work. Guitar necks do NOT fit. Puzzle joints don't glue up.

The sources of problems are endless, even in a rigid machine: 1\. spindle
runout. 2\. bit diameter changes (its is labeled at .25", but its really .246
3\. climb vs conventional milling yields different characteristics in
different materials. 4\. bit deflection in certain cutting actions (plunge,
tight corners, etc) 5\. bit wear during the job. 6\. dust removal / chip
recutting 7\. lost steps 8\. dust in the ways of the machine 9\. linear motion
system misalignment. 10\. workpiece slippage/hold down. 11\. material not
being flat/level (especially with cheap plywood, which often varies in
thickness by >.005")(try making accurate box joints with that...)(also, it is
never flat, it always has some twist/warp because of the way the plys are cut
out of the tree).

This machine seems to be a great thing, and I very well may build one for an
outdoor plasma cutter, but, I find the accuracy claims very difficult to
believe. All of these sources of precision loss will effect the end result.

------
roel_v
How would this thing lift up the router to go between spots that aren't
connected? Or can't it, and is that the reason the logo's circle was open?

And what would be the precision on this thing? It's a bit suspicious they'd
leave that out... Would it be able to work at 1 mm precision?

~~~
lostapathy
They say 1/64in/0.4mm precision or better.

I'm sure they can lift it up. This kind of mechanism isn't exactly new - but
using it on a router is fairly new. There's a lot of projects with pen
plotters built in this general pattern, see
[http://hackaday.com/2011/11/17/polar-pen-plotter-draws-
huge-...](http://hackaday.com/2011/11/17/polar-pen-plotter-draws-huge-images-
very-slowly/)

~~~
iheartmemcache
I remember seeing that pen plotter before, guess I wasn't creative enough to
put 2 and 2 together, haha.

Even for just 2D, this is really clever for the form-
factor/capabilities/price. It's in 'impulse buy' pricing territory for most
people (I mean, posting here at least). It takes up basically no space. If the
steppers are well-engineered, I can't foresee a failure mode other than just
normal tool wear.

I was considering buying a Shaper[1] (which is really cool in it's own right)
after seeing Ben from Applied Science mess around it. With the Shaper, "you're
only limited by the surface on which you can place those encoding stickers"[2]
while with this, you can build out effectively until the elasticity point of
your support structure (or, I suppose, the chain has a fatigue failure). 15
thou isn't bad at all, especially if you know where the run-out is going to be
(i.e. if it's gearing backlash, you can design your features around that with
that in mind / build your software to compensate for it / incorporate active
air cylinder brakes / etc). Edit: On second thought, they said the steppers
were closed loop. So if it's any worse than 15 thou, shame on them, really.

My only concern is if the slop/run-out goes up as a function of the material
you cut. The Shaper has what seems to be using some sort of active delta
compensation[3] Aluminium and a standard house-hold router can accurately mill
your 6061 aluminum that's good for up to like 30k tensile with it. The
collet/chuck/gantry/whatever will just actively re-orient your bit for the
micro-tuning. (Though, for the $1500 they want, you can pick up one of the
thousands of Bridgeports Series 1 CNC's out there, throw another 500 for your
carbide cutting tools + retro-fit kit and you've got a home machine shop and
come out way ahead only a few hundred behind with the ability to actually mill
something structurally sound like steel.)

Either way, this is super cool - I'll wait for a few reviews, but I think I
know where my money's going even if it's limited to wood.

[1] [https://youtu.be/Kg2HOk1XHsA](https://youtu.be/Kg2HOk1XHsA) [2] And those
stickers smell of vendor lock-in. It's got the opposite 'feel' to it than this
product. [3]
[https://en.wikipedia.org/wiki/Delta_robot](https://en.wikipedia.org/wiki/Delta_robot)

------
alexissantos
When can I get my hands on this?!

I was just looking for something like this yesterday! I pre-ordered a Shaper
Origin ([https://shapertools.com](https://shapertools.com)), which ships in
September 2017, but I need something to use now.

------
mdorazio
This is interesting in that it is somewhat similar to the "delta" style 3d
printers in concept, just in 2-axis instead of 3.

------
aidenn0
This is a 2-axis router it looks like; though if you used the recommended
router, you could adjust the depth between runs.

~~~
lostapathy
Most of the work done on CNC routers is 2-axis anyway. Or 2-axis with just a
couple z-heights, which can be accommodated by changing the router depth by
hand. Ultimately it's made to cut up plywood, not sculpt things. Like a sized-
up version of small scale laser cutters.

Once you accept the constraints of a 2-axis CNC router, you can design in a
way that maximizes it and build incredible things. See
[https://www.opendesk.cc/](https://www.opendesk.cc/) for examples of a lot of
furniture that can be built this way.

~~~
aidenn0
Okay, that makes sense; this is for replacing a woodworker with a jigsaw, not
for fine work. Seems like a really good solution in this space (though I'm
biased, since I suck with a jigsaw).

------
Yenrabbit
Nice concept, and I love their philosophy about openness. I'm interested to
see how well it works!

------
callumprentice
Looks brilliant - if I could make one suggestion for the video - more examples
of what it can do.

------
awinter-py
plywood is peachy but aluminum is awesome. have a robot glue a line of
thermite to horizontal sheet metal. Light a match and you have your part.

(Tolerances may not be exact).

~~~
tantalor
You can't light thermite with a match (source: tried).

~~~
awinter-py
sparklers apparently work

------
tunichtgut
I like the low cost idea and approach. rly neat!

------
erikb
I'm no expert in hardware and software that is developed close to hardware.
Can someone explain to me where the achievement is, before the Kickstarter
even starts?

~~~
nzjrs
Kickerstarter doesn't require any achievement, innovation or novelty - success
there depends only on your ratio of marketing folks to engineering folks (the
higher the better). Oh, you also need a bunch of bay area hipsters saying how
this product transformed their life.

------
JumpCrisscross
How does this do splines?

------
Hasz
The chains are pretty neat! Any idea on backlash?

~~~
foobarian
Author made a comment in the last video; the weight of the cutter keeps the
motors under constant tension one way, so there is no play caused by changing
direction.

~~~
lostapathy
Mostly true but not quite. The forces on the chains are actually higher when
the chains are "shorter" and the router is higher up. The farther from
vertical the chains are, the more horizontal tension there is on top of the
vertical component.

The same basic principle shows up in rigging - [http://www.fdlake.com/rig-
slng.html](http://www.fdlake.com/rig-slng.html) \- the illustration where the
straps are at 90 degrees is rated higher than 45 degrees.

~~~
grogenaut
Also there is slack in any gear/chain train when switching directions as they
never fit perfectly. Same with gears. Even tiny amounts will throw you past .4
mm quickly

~~~
lostapathy
Actually that kind of backlash isn't a problem in a machine built like this.
The tension of the chain against the sprocket is always pulling in the same
direction around the sprocket. Even when the sprocket reverses direction, the
chain is pulling the same way and staying tight to the same side of the teeth
it was on.

~~~
grogenaut
That would be correct until you figure in momentum as long as you stay under
that threshold your hypothesis holds, if you get the device moving or swaying
it won't. Of course this can be compensated for in software. So Point taken.

------
GigabyteCoin
The title should be changed as this product is not currently available for
purchase.

~~~
rock_hard
The sources are available...so you are free to start building yours

~~~
GigabyteCoin
Which is great!

I only mentioned it because the original title read something along the lines
of "4 x 8 foot CNC available for purchase for under $500".

