Back in
Part
1, we introduced the basics and started building the electronics.
In
Part
2, we finished up the controller and started building our machine.
Today we complete our unholy marriage of cutting boards and dot matrix
printers in Part 3 of How-To: Build your own CNC machine. Good luck.
Last time we showed you the completed base, with the first axis. The
screw drive turns easily and there's very little play in the motion of
the table.
The design of the upper axis is simple, but is the most difficult to
execute. Originally we hoped to use a pair of the small sliders, but
binding was an issue so we redesigned it to use a large printer slider
at the base. Ultimately, the binding was caused by the nut and threaded
rod we were using. Swapping them out solved our problems.
A simple tower constructed of three pieces forms the basis for the rest
of the machine. The tower will be mounted to the outer edges of the
base. This allows greater side to side movement to maximize the usable
area on the table.The center piece of from the same cut as the bottom of
the base. To drill the two sides evenly, we screwed them together and
drill the mounting holes with the drill press. One the first screw was
in, we drilled the rest one at a time.
The center slider is the most complex to build. Each piece is visible
here. We used our usual trick of screwing the opposite pieces together
in order to align the holes for the slide and the threaded rod. The
brass slider and long hex nut were pressed into the plastic with our
bench vise. This technique seems to work well, but alignment is
critical!
To effectively deal with the minimum space, we had to get tricky. There
just isn't enough room in the carrier to mount bearings for the Z axis.
Instead, we pressed bushings into the plastic with our vise. Then we
added a washer and a lock nut to the threaded rod at the top and bottom
of the carrier. Careful tweaking with a pair of wrenches made for very
little play. Just how long this setup will stay tight is in question so
we'll have to keep an eye on it as we break in the machine.
This slide and carrier were salvaged from an old Okidata printer. We
decided to use it to smooth out the action for the Y axis.
We whipped out the drum sander attachment on our dremel tool and
contoured the plastic on the bottom so we could mount the printer slide
without compromising the integrity of the cast metal.
Once the slide was mounted, we marked and drilled the mounting holes for
each axis. Once the slides are set up, we'll use some screws to lock
them in place.
Once things start coming together, they'll get extra frustrating as you
begin aligning the slides and drive screws. I took us a while to narrow
down that the source of binding was the drive screw and nut combination.
We'd overlooked them initially because they worked very, very well in
the other cases.
Once each axis has been constructed, we needed a carrier for the
rotating tool. We picked up a flexible dremel shaft and created a simple
mount for it. The flexible shaft will reduce vibration. The dremel
version has the nice button for locking rotation -- far less frustrating
to use than the off-brand tools.
We used a couple of tricks to achieve a nice fit. The strips were cut
first, then screwed together with some space to spare. Then we drilled
the plastic with a starter hole and used the dremel tool to taper and
round out the holes until the fit was perfect.
Motor mounts are dependent on the motors you've ended up with. If you're
lucky, you'll salvage some motor mount brackets. Creative mounting can
be achieved by using new or salvaged pulley systems.
Limit switches are very helpful for keeping your machine from self
destructing. A switch is placed at the limit of each axis and wired in
parallel. When the carrier or table contacts one, the circuit is closed
and the controller signals the computer. Lever switches like these
are ideal, or you can salvage some of the exposed contact switches from
printers. The main danger of either switch is fouling caused by debris
from your work project. Covering the switch with a bit of latex glove or
balloon can help prevent problems later on.
Now that you've got
all the bits of information you'll need to build your machine, lets get
into some actual software to make the machine work.
KCam - Probably the easiest
software to set up and configure, KCam is great for testing out your
machine. It ran just fine on our Windows XP laptop. The drawback has to
do with the method that Windows uses to access the parallel port.
Because of this limitation, the machine won't run as smoothly as it
really can.
EMC Linux -
Some dedicated individuals maintain EMC and actually produce a stripped
down, brain dead install of Linux just for running EMC. It doesn't take
much of a machine to run, so it's great for dedicating an old machine
just to run your CNC machine. Add a network card and you can operate and
send jobs to the machine remotely. It's not too bad to install, but
expect to spend some time figuring out the quirks.
Now, what you've all been waiting for... the machine in action! The bit
is another tungsten carbide bit from
Drill Bit City. (Oh, how we love
them.)
If you've gotten this far, congratulations are an order!
Oh, and then you should already expect to spend some time
troubleshooting your creation. Don't be upset if everything doesn't work
perfectly! (Or if you end up ripping all apart and starting all
over...)
posted Jul 11th 2006 9:45PM
I am fascinated by this project! I purchased two cutting boards from Sam's to get started but I need the dimensions and patterns for cutting. Have you made any drawings or documents showing the part's dimensions? I would like to get started cutting but I need the data --- any chance that you could provide it?
Thanks for your time.
Fred.
Could it be possible that someone else may have duplicated this project and might have a template or dimensions of the necessary parts?
I would appreciate any suggestions or help in recreating this project. Thanks to anyone that can respond.
Fred.
Tons more CNC related Information here if you are interested:
http://www.cncinformation.com
Ivan
ok so can I do this project with 5 wire steppers from a scanner???
Btw this is an awesome! Project
I would like to build this project myself on a little bit larger scale the control board you build i can't seem to get the schematics that i need to print on the transfer paper it would be a great help if you could email me the file i need or even the pictures also since i am building this project on a larger scale is there any other 3 axis control schematics you would recommend that would work better for my project very new to all this hope you can help thank mike and by the way very impressive project my email address is [email protected] thanks for the time
I found this article kinda late but it is an excellent how-to. Just wanted to say this is a good resource if you are planning to buy a CNC Machine:http://www.ez-router.com
This looks pretty good... I just wish they picked up a set of real ball screaws. Large ones are expensive, but ebay or keeping it to 10-14 inches can keep the sent under $150, its not cheap, but the results should be worth it.
Sorry, no video of this machine in action just yet. It actually impressed me with just how well it worked.
Wow, what timing,
I just started work on my CNC machine, and it's great to see the way you guys did it, I used shower curtain railing to do the slides and had bearings running on them, it's surprisingly smooth, I would love some more info on coupling the threaded rod to the motors though, I believe that's the hardest part.
thanks for the article!
ya where is the video we want to see this baby in action!!!!
Videos please =D
will a 5 wire stepper motor work with the board?
i kinda notice one of the pictures of the motor in this lesson have 5 wires. how did you guys hocked it up to the control board?
I'll wating video. it's look like very useful
Great job! I would like to see better shots of the cutting plans and dimensions of each piece. Willing to post those?
I had a talk with a mechanical engineer about threaded rods. The angle of the grooves on threaded rod you buy at home depot is specifically made to bind. Acme threaded rod has steeper grooves, which means more force goes to pushing the nuts forward and back, instead of outwards which makes them stick in place. It's cheap and easily available. (Check McMaster.com, catalog page 3019, parts are on the next 2 pages (I can't find a direct link))
Ball screws are great, but cost about 10 times as much. BTW, ball screws are about 90% efficient, acme threaded rods about 30%, and bolt-type threaded rod is probably a bit less.
Would like to see clearer or more detailed pictures. It's hard to get a grasp of how the two axis fit together, for example.
how to build cnc lirg machin . i wuold lika to see moer detailed
Here is s CNC mill my friend made. I see it work all the time and is an excellent homemade version. He used and existing mill to create it. Here are some step-by-step (day-by-day?:)) picture illustrations on how to make your own. Video at the end. Check out the other projects also. www.sci-spot.com
"I had a talk with a mechanical engineer about threaded rods. The angle of the grooves on threaded rod you buy at home depot is specifically made to bind. Acme threaded rod has steeper grooves, which means more force goes to pushing the nuts forward and back, instead of outwards which makes them stick in place. It's cheap and easily available. (Check McMaster.com, catalog page 3019, parts are on the next 2 pages (I can't find a direct link))"
That exactly what I am talking about. For those who don't want to wait for the book to ship (it weights like 15 pounds but its free!) then head on over to mcmaster.com, I can't give you a direct link to them because the way they designed their site sucks, but you can find htem on the front page, press control+f and search for 'ball screw' and it will pop up.
I'll see if I can redraw the cutting sheets for you guys with notes on the measurements.
EMC is a pain in the royal butt. A nightmare to setup and not that fun in general. Two best options are TurboCNC under DOS and Mach (http://www.artofcnc.com) Mach has its own drivers for the parallel port so you dont encounter the problems with other software running under windows and they have free version limited to running something like 1000 lines of code.
I have a harbor freight micro mill that I converted to CNC and am now working a a 4'x8'x16"Z mill.
http://i65.photobucket.com/albums/h228/macona/micromillcnc.jpg
You should put a "spoil board" or "waste board" on the CNC bed. That way you tear up the board and not the bed when you cut through material. On my CNC router (Techno-Isel), I use 0.25" MDO, but with something this size, you could us any rigid substrate like polystyrene (free scraps from sign shops) or some thin wood.
You guys are nuts.
I love it.
This is a really neat project! Thanks, Will!
It got me thinking: how hard would it be to modify it, changing it from a CNC machine to a solder paste applicator?
What I'm thinking is that if it were reasonably easy, then this would be a great solution to the problem of assembling PCBs with modern SM ICs (e.g. BGAs and TQ144's); the proposed machine would read your Gerber file and put dabs of solder paste in the right places. Then you'd just place your parts on the PCB, put the PCB on a hot plate and you're done.
Thoughts?
No 5 wire motors guys. I only used 6. If it did have five, the two common leads are probably wired together. All mine are 6 wire. (except this pile of bipolar motors I have)
As far as making a solder paste machine, it's completely doable. you just need to mechanize a syringe. Just make a mount that's similar to the dremel version.
If you want to make the syringe go up and down, you can add a fourth axis. There are enough pins on the parallel port to do it (if I remember).
If you can stand using a constant height, it's even easier. Just mount the syringe statically and use the z-axis to actuate it.
Also, The controller is compatible with TTL level inputs if you want to put a microcontroller in front of it for smarter controls or serial/usb interfacing.
Hi
I am from INDIA working on PCB Soldering ROBOT.Could you please tell me how to convert Gerber files into G codes for Pads only and how to use that G code for controlling Motion.Is Mach and UCN58048 Controller will be able to solve our purpose.
Is there any other alternative to do this
Kindly reaply at [email protected]
+1 for a video, on youtube or similar...
I was wondering just how accurate this machine is... Did you mill all of the gaps between traces on the board in the picture, or just the "E"? Some of the gaps appear to be less than the diameter of the bit...
Could you get some measurements with calipers and compare them to the inputs to let us know about accuracy? I am mainly wondering how small a trace you could cut with this.
Also, one final request, please put up a video so we can see this in action!
Thanks!
If you lap the threaded rod and nuts with lapping compound (available from auto places or optical suppliers) you'll get much smoother motion. Just spread some on the rod, chuck it in a drill and run the nut up and down a few dozen times, then clean the abrasive off. I've made some decent linear slides for optical components that way.
Great CNC, im adding one to my build list now...I have to get parts.
@Joel Pigdon
Joel, to couple the threaded rod to the motor use a 0.25" I.D. rubber hose with two worm-gear hose clamps. I used air hose from TSC.
My company is training toolmakers and millwrights please post more of that kind of infomation! Would you be interested in an CNC machining project from our side?!
First off, I have to say that this is a formidable example of a DIY CNC machine. After browsing cnczone.com for plans, I managed to find some technical drawings of a machine capable of holding and milling a 24" x 48" x 6" piece of material, the only setback being that another CNC machine would be needed to build it. With that being said:
Are there any plans/schematics/technical drawings for this project? It looks to be a decent starter mill.
i whan to make pc mouse whit this mashine
does this mashine can do pc mouse
I have made my own jewellery vacume casting machine and very very interested to make a cnc milling machine for carving wax models for jewellery after seeing this project . Is it possible to make? I have not seen these type of machine used for this purpose but I think this will work. Kindly mail me at [email protected]
Hello. Mr Brein, Nice work. I am new to this and a jeweller from India. I want to make a cnc for my work . Apart from yous it needs another axis to revolve the wax to be cut for rings. Any help? Bye padma
hello sir,
i like to make different kind of cnc machine.
where can i buy all equipment for cnc machine before buy i would like to see those equipments. like motors etc.
awaiting your reply
Thankyou
haw i can make cnc machine
Thank you for such a simple kickin' design
I am a CNC machinist and toolmaker/designer.
Commercial machines are large and expensive and
for years I've wanted a tiny desktop machine to play
with. this looks like it....I love the idea of all the salvaged parts. too cool
Awesome work Will! I have been looking for ages for a way to machine epoxy molds for plastic injection molding of custom Lego parts. Thanks a million!
Just wondering, with regards to the parallel port interface and the controller, how do you wire the dremel to turn on/off as required?