Hi,
I’m looking for any information I can find about a do-it-yourself CNC machine for cutting blanks. I’m at that stage where I cannot keep up hand shaping, so its time to go to CNC, and I want to build one since budget is limited.
Does anyone know of any online plans (mechanical, electrical and programming), or other information that I could find that would help me get started?
Thanks
Corran
in montreal really?
I don’t know of any plans, though I did see a photo of a rocker cutter in I think mat kechle’s factory.
bear in mind that I don’t know all that much about it…
http://www.8linx.com/cnc/cnc.htm
Home Built Hot wire CNC Foam cutter
I’ll note that this is described as a 'smallish ’ kind of machine for wings on radio controlled model aircraft, though the thing can be modified to be a CNC router, better for 3D shapes. ;
The design can be modified to almost any size. Keep in mind that for longer travel you will need a longer lead screw.
The problem with a long lead screw is that because it its own mass, it will “wobble” in higher speeds.
One way to overcome this problem is to move to a larger diameter lead screw.
Another way is to move to a chain or belt driven design. Belt driven machines are usually 8’ and longer but require the use
of micro-stepping. An example of a machine larger then 8 foot would be a surfboard foam cutter.
Some surfboards are up to 12 feet in length, the only way to cut these boards would be a belt driven or chain driven mechanism
I will try to cover this topic in the future with a sample machine and pictures…
While there might be some loss of accuracy with a long belt drive, say like the toothed belt that runs the cartridges around, I’d think it’ll be more than close enough.
hope that’s of some use
doc…
Hi Corran,
It is possible as I’ve done it. You can look at Ken Riemers’ website, he used the ShopBot
as his basis. ShopBot is probably the biggest value you will find so far, if you are mechanically,
digitally, and electronically inclined.
KR:
http://groups.msn.com/MyKRSurf/krcomweb.msnw
ShopBot:
http://www.talkshopbot.com/forum/messages/29/14298.html?1169146577
hope this helps,
George
There are many many examples of similar machines in machineshops everywhere. You could get a used mill and CNC hookup for under $10k if you look around enough machine shops.
The hard part will be the translation stages need to be long enough to do surfboards, and you need to be good at centering in the blank on each side. That is where you see most of the design innovation. Because other than that, the CNC machine is just a set of long translation stages coupled to a mill.
Except for the Shopbot, which is a CNC router instead of a mill. It is more difficult to make work well, because the centering problems are compounded by the mount of the cutter being less secure.
More generally I think a shaping business would require tens of thousands of boards per year to make a good CNC machine cost effective. This is another reason why the CNC machines do not help most shapers - you can only afford to use them by paying part of your shaping fee on each board. Unless you use the machines to make more boards than you could finish by hand.
hi Corran,
I’m just few steps from finishing my CNC hotwire machine.
I build mine very similar to the “8-linx” one.
it’s quite easy to build , and in Israel the the total cost was about 300$.
I’m sure in America it would be half the cost.
I have a friend who has a working one for about a year now and he made
beautifull things with it.
the only problem is that it’s a 4 axis machine ( x,y on each side) ,
and you can’t make with it much more than a “blank”. ( like what “american blanks” )
we’ve been thinking a lot of building a 5 axis machine but we reached a point
where we understood that a homemade 5axis machine will be very costly
not to mention that if you have technical prob’s with it it’s a shitload task to find&fix them.
we also didn’t find any plans to a 5axis controller/interface , meaning you have to buy one ($$$$).
also we havn’t found any plans for such machine.
well , I don’t want to run the wind out of your sails but these r just few things you should think of before
you’re getting into it.
If you do find plans for such machine or interface , I would be glad to build one and share
with you building ideas along the process.
good luck
lee
Hi lee… whats your email? I’d love to talk.
Essentially, cutting our EPS blanks from a block to a plan and profile shape is enough of the “automated process” for us. After this, cutting the crown, rails and bottom concaves is fine. Just cutting the foam blocks from a square to a “blank” would already be a massive step in the right direction and cut down half the shaping time, so I’m interrested.
I’m sure its also possible to then rotate the blank a series of times on the “table” and make a series of automated cuts which create the crown… say for example from “flat” a 10 deg blank rotation (after the plan and profile are cut) and the wire makes a pass, rotate it 10 deg more and it makes another pass, and again a 3rd time… then do the same on the other side of the board, and your basic crown would be cut. Finally, the blank cut into 2 pieces so the stringer can be laminated in, and then its just up to the hand shaper to knock off the ridges in the crown, shape the rail, and of course put in the concaves, fins etc.
This should be possible to build… its what I see as an inexpensive way to make consistent “close tollerance” blanks from big blocks of foam.
So I’d love to see what you built and trade ideas.
Corran
hey coarran,
my email is:
.
you can cut the foil ,
also possible to attach several wires on the Y-axis
alowing you to cut several blanks at once. ( from a big eps chunk offcourse)
then roll the whole bunch on the side (future rails…),
using only one wire! and cutting the template (outline) and
a straight stringer line ( if desired)
at this stage you can use your homebuilt 2axis (X,Y) cnc machine with a trimer , cutting you matching stringers… 
glue them up and you got yourself a blank.
if you want to be more soficticated, you can program the machine
to make you the crown but as I se it it’s going to be one hell of
a headache. because you need to design\understand how each side of the machine has to move to create this wanted deck crown.
each side has it’s own path which is not even paralell to anything argggghhh…
( was I clear enough or should I draw it somehow and upload it?)
now lets say you overcome this hard task for a specific board design,
now you have to do the same for each board size and design and it’s
gonna take you decads to complete.
so if I were you, I would stop at the stage of the blank without crown…
I would seek for the website showing how to assemble the interface board and post it soon.
the machine’s construction time is very short ( by hours…!)
finding the right materials is the time consumer of this project.
and also the calibration and overcoming the usual problems that usually appear at the end of such project
( wire temp, motors speed etc.)
hmmm…what else???
ohh yes! don’t forget you need to be a bit creative ( which I’m sure you are!) and find a long enough X-axis and a long enough threaded rod ( or a creative replacment for it)… this is a surfboard ! not a 20cm airfoil…
any Q 'till now?
soon I’ll post all the websites and info that I thinck might help you.
Lee
Great info so far… Any more is appreciated of course.
I’m going to see if I can wrap my head around cutting the crown and foil (basic cuts only). I’m sure there is a simple way 
Have any photo’s of your machine?
Corran
Can you cut the rail bands with a 4 axis? Seems like you should be able to and that the 5 axis would only be needed for the bottom contours. The big problem with any of the cnc machines is the initial lining up of the blank. Even with the current systems used by production shapers there is a lot of variation depending on how good the operator is.
Hi Corran,
How you been?
In one of my past jobs I used to design and build 3 axis pick & place machines which are essentially CNC machines w/o a cutter. Let me just say you’re better off buying a used CNC machine if you decide you want one. With the time and money it will take to actually build it - and build it correctly - you’d be way better off sticking with shaping by hand.
But you don’t even need a CNC machine. Since you’re doing EPS you can easily step up production with a simple hotwire bow and a bunch of rocker and outline templates. Old school style.
Take it easy,
~Brian
Hey Brian,
Thats what we’re doing right now… with the hot wire bow… but we’re getting ready to scale up production to way beyond what I can shape… so I need to automate this to some degree so I can concentrate on making custom boards by hand, and “models” by machine
I’m starting to think buy a turnkey machine too… new or used… but I want to keep looking at my options.
How are things with you right now? I need to email you about getting some Bio plugs from you…I’ll do that later.
Corran
the only problem is that it’s a 4 axis machine ( x,y on each side) ,
and you can’t make with it much more than a “blank”. ( like what “american blanks” )
A four axis hotwire machine would be able to do rail bands if there is a spring on the hotwire. Hard to do the outline, but you should get really close depending on the height of both sides can go, how steep an angle you can get the wire to. However I doubt there is any of the shelf software for this so it would have to be custom software.
regards,
Håvard
How about making the board rotate (4th axis) and making the wire do the other 3 axis?
chico
That would work, it would actually work with a 3 axis controller machine providing you could slave one motor and had a good hold down system. I’d see that as the main problem. It would be limited to convex cross sections though, no concaves.
regards,
Håvard
Why go through all the trouble of building a Hot Wire CNC when the technology is so basic and there so cheap?
Just buy one that will cut in your rocker, rail bands and outline.
That will save you a lot of steps. They cost under $25,000 (high Production) and your done.
Tell the engineers the length you need and how wide? The required Z clearance.
Some machines will cut two or more blocks at a time. You can make your whole weeks production
in less than one day. I even seen some single machines for less than $10,000 including software for low production.
Spend your time making surfboards. I don’t thing it pays to be cheap when it comes to equipement.
In general, 3 controlled axis are enough to chamfer a board, one to move (machine or blank) forth and back, one to move the wire up and down and one to rotate the blank.
This is very similar to the shaping machine sold by John Gillis as he used a wide sanding drum as a cutter (26"+).
Hotwire machines are mechanically quite simple and there is no dust either to worrie about. As cutting is quite slow and without resistance, a simple stepper setup would do. Plan for enough power as you may need slave motors on all three axis.
You could go from very simple to quite technical depending on knowledge and budget. Get some inspiration at YouTube as there are many movies of home made CNC machines. Very inspirational.
The software could be a bit of a challenge and as with most of these projects, they grow while you move.
that’s the site:
http://gm.cnc.free.fr/en/interfaces.html
some discussions on r/c model forum - there’s a guy selling the interface kit at about 60$
check with him if it’s still available
http://www.rcgroups.com/forums/showthread.php?t=31724
the software my friend uses is called “GMFC…”
it’s the best software out there since it has so many variables to play with,
but it’s not a user friendly one.
my friend is a computer-software_somthing engineer and he had a really hard time
to understand it and make complicated cuts with the machine.
Just cutting the foam blocks from a square to a “blank” would already be a massive step in the right direction and cut down half the shaping time, so I’m interrested.
GULP!
You shape a board from blank in the time it takes to hotwire a blank??? sheesh you’r the fastest shaper I have ever heard of…
have you considered getting an apprentice Corran?
maybe a couple apprentice/ghost shapers…