MDF CNC kits

[rodm]

I saw this on ebay and thought it might be of interest as there has been a few asking about kits.

http://cgi.ebay.com.au/CNC-Milling-Router-Engraver-Machine-Kit_W0QQitemZ150264151192QQihZ005QQcategoryZ92083QQssPageNameZWDVWQQrdZ1QQcmdZViewItem

I don't know anything about it other than the listing. What do you think of the kit and price? Looks like you have to get motors, driver board and computer/software to get it running.

[crocky]

Hi Rod,

Seems fairly complete and would be good to get a foot in the door as a first machine, specially if you wanted an easy to build first time machine :)

[rodm]

Hi Bob,
Yeah I thought it was a good starting point for somebody that didn't want to do steel or aluminum.

[jb2060]

Hi Guys,


Yep it looks like a pretty decent kit. There is a good chance he made these kits with a steel/aluminum CNC machine :2tsup:. Well priced too.

[John H]

What would be the best priced steppers and controller to suit this kit?

[WillyInBris]

I would think the following would do from http://www.xylotex.com
if you have someone to put it together you could just get the kit for $357 otherwise the drive box is ready to run then you need software I got the kit and put it together myself, just check my link in my sig it has most of the suppliers etc.
Just remember that big is not necessarily better when it comes to steppers.:2tsup:

3 Axis Drive Box (269 oz.in. motors)
======================
(1) 3 Axis Drive Box (269)(220VAC) $410.00
(1) USPS Shipping $94.00
TOTAL $504.00
======================

[John H]

hmmmm

So for around $1400-$1500 you could get a complete CNC machine + another $100-$200 for a router.

It's a fairly small table size, but that depends on what you want to use it for.

interesting.

[McDuff]

I have just ordered one.

I have been collecting stuff for a couple of years towards CNCing an X1 mill and a mid-size metal lathe and was planning to make a small router table also. So far I have miscellaneous ballscrews, linear guides, a bunch of Geckos, a 4-axis HobbyCNC system with 300 oz in steppers and a CNC Fusion kit for the X1 mill. Still quite a few gaps, but getting there. :U

I have a couple of months leave coming up and was looking forward to making some progress on this but broke my wrist and will be in plaster for another 4 weeks. I figure I can still assemble this kit and bolt the HobbyCNC gear to it and then at least start getting some experience on the software and design side by "cutting air". That way I at least make some progress during my break.

It may also allow me to bootstrap up to a larger and more rigid router table with less backlash - I hope so anyway. Any thoughts on this? I'm thinking maybe it will handle small aluminium work with light passes so I can build a heavier router - certainly I should be able to make accurate mdf torsion box elements with a bit of thought and some sort of indexing setup for the larger pieces...

I'll let you know how it looks when I get it in a few weeks.

[rodm]

Hi McDuff,
Sounds like you have done the research and have quite a collection of bits.
I don't see why this machine will not cut aluminum with light passes and approproate feed rates. Obviously it is not made to do this all the time but I'm sure it will handle a few jobs.
Interested to see your progress on the machine.

[maddog 62]

hello McDuff
i would be intersted to know how you get on with that kit
am thinking of moving into the cnc world (am a total novice) so all the info, help ect i can get would be a real advantage
cheers Tony

[John H]

Well, I didn't want to get any of that nasty sawdust in my metal mill so I ordered one of these kits. It arrived today but is missing 6 bearings and a couple of screws.

Everything else looks pretty good and it has all been cut by laser. There is a 37 page instruction book supplied in pdf format on a DVD that looks very detailed, with photos and step by step assembly instructions.

Apart from the missing parts, the kit looks like it's very well made and should be fairly easy to assemble. An excellent beginners CNC.

I have a Xylotex controller and stepper motors to go with the kit.

[McDuff]

Well done John!

I'm still waiting with 'bated breath! Should only be a few more days with luck.

Do you think it might be worth painting it before assembly?

@rodm & @maddog62: I'll certainly be letting you know how I get on - looks like we'll have a couple of these at least to compare and contrast. :U

Cheers,
Dieter.

[John H]

I guess you could paint it, but I'm not going to bother

[John H]

I've made a start on assembly. Everything fits together like a glove, although the number of included bolts and screws don't seem to match the number required.

[rodm]

Hi John,
Looks like you made some good progress in 5 hours. :2tsup:
Keep them coming as it is looking very good.

[John H]

I'm taking the family to the snow tomorrow so i'll have to wait until Sunday before I can tinker some more. :( But there has been some good snow falls yesterday and today. :)

The missing bearings should be here Monday or Tuesday and the guy should be sending me a dxf of the spindle mount so I can modify up a new part to suit my router.

I'm going to use a cheap Ozito for starters as I ordered a Milwalkie Die Grinder from Justtools two weeks ago and they still haven't sent it. :((

I'm working out how to wire up the BOB to the Xylotex controller so I can include home switches and a E-Stop.

[McDuff]

Looking good John!

I've heard from lebuyn1 that mine's been shipped now so
sometime early next week I guess... I'm in the middle of
house renos so it will be a while before I get mine all put
together though, so I'll be keeping a keen eye out for what
you find out!

Cheers, Dieter.

[John H]

I machined up a new set of mounts out of aluminium to suit the Ozito router today.

[rodm]

Hi John,
Nice work on the machining - how did we get by without CNC?

I am interested to see how the Ozito is locked into the mount. Can you give a sideways shot showing the locking mechansim?

[John H]

I just used the holes that normally connect the metal part of the spindle the the plastic body. I found four long wood screws that have the same thread as the original ones and screwed it all together.

[crocky]

That is bit different than how we made ours with the help of Greolt. Ours is just a alloy plate that takes the whole thing at the base of the Ozito.

Slightly different :)

[seafurymike]

Crocky has made his mount exactly like mine. I do find that it binds to the aluminum after a while and makes it a little difficult to unlock when you want to use the router for something else.

The only thing that i see with these tables is that the screws and guide rails will collect swarf/dust from the routing process. My suggestion is to look at protecting these with something. Otherwise, will wait with baited breath to see the progress of these units. They look to be designed well, what size are those slide rails, they look close to 1". The biggest issue i had with my unit was that I ran 1/2" slide rails on my y-axis and I had to add an extra rail on top to stop the porposing that occured when i took cuts.

/M

[John H]

The slide rails are 3/4 inch.

The missing bearings were delivered today so I can continue construction.

Just a question on limit/home switches. Can I get away with just using 3 switches for homing only and not worry about limit switches for the other end of each axis? I'm thinking that I can just use the soft limits in Mach3 to set limits.

[seafurymike]

John,

Home and limit switches have different functions. (not trying to point out the obvious here, please read on)
I would recommend using a dedicated set of switches for homing and another set for limiting.

On my setup I wired the home switches to Mach directly through the parallel port.
For my limit switches, i ran these directly to the gecko 201 drivers I had, isolating them from the computer or mach. Mach is great software, but i would never use it to limit/halt my machine.

So you can use 3 switches for homing, although 2 would be adequate for the x and y axis and I would then use some other method to deduce the Y axis, such as a plate that can be placed on the material being machined, which has a known thickness. This plate is grounded to Mach 3 and triggers when you touch it with the tool.

Of course the tool gets a wire too, which is placed on it when you complete this touching action, making a circuit which is detectable to Mach. For the exact setup of this I would ask Greg to explain it in depth as I know he has this working on his unit. I just shim the tool (paper) to the workpiece when I machine, which is good enough for me.

[John H]

Ok, I'll give the home/limit switches some more thought.

I managed to get the unit assembled and jogging on all axis tonight. Now the fun begins getting everything setup right before making some sawdust.

[rodm]

You certainly are a man of action. That is probably the fastest build I have seen.
The Z axis touchplate is an easy and time saving gadget for zeroing on the job. One of those things you wonder how you ever got on without it. The Web cams are also a good tool for setting up X and Y axis.
I would not get hung up on home and limit switches. I have found them to be more of a pain (false triggering) than a benfit. Because they gerally work on 5 volt and low watts they are very prone to EMI. I disconnected mine and have not missed them one bit. Another issue people have raised is that if you set up on home every job then you end up with uneven wear in your screws. Not sure if this is a big issue but it does make sense.
Keep the posts coming as it is very interesting to see this machine being built.

[McDuff]

Mine's finally arrived! Unfortunately I'm busy hammering holes in various brick walls around the house for the next few days - the data cabler will pay a visit on Saturday. Still, based on John's experience it should be a quick build. Still can't decide whether to give it a coat of protective paint before assembly as MDF really hates moisture...

Cheers, Dieter.

[seafurymike]

Holy crap batman, that is one quick build.
Keep up the great work John

What is the available cutting area of the machine?

/M

[John H]

No real expertise needed to build this unit as it's a pretty well put together kit.

The cutting area is X = 400mm, Y = 250mm, which is a little small but ok for what I need at the moment.

Rod: An interesting comment re the home and limit switches. I might wait and have a bit of play the unit before I look at installing them. Might save myself some time and heartache.

The Z Zero touchplate sounds like a good idea. I'll have to see where I can hook it into the Xylotex board.

Any details on the webcam setup? Is there one available that is better suited to be mounted and zeroed in?

[WillyInBris]

Yep agree on the homing switches as well took mine off will put them back on when I get a C11 Breakout board if I can be bothered lol as I had trigger problems like Rod, couldn't be bothered playing with them any further as they are really low on my to do list.

The touch-plate rocks and easy as to set up off the Xylotex board :2tsup:

[rodm]

All you need is here
http://www.cnczone.com/forums/showthread.php?t=36099 (http://www.cnczone.com/forums/showthread.php?t=36099)

Greolt originated this and has put the above thread which is very easy to follow. Touchplates are the first thing I put on all my gantry routers and mills I convert. The convenience and accuracy will impress.
I have hooked a couple up to Xylotex boards and use a 100 ohm 1/4 watt resister from Dick Smiths. Pin 15 and the rest of settings and script is in Greg's thread.

The web camera are these.
http://cgi.ebay.com.au/New-Mini-Protable-USB-Pinhole-Web-Camera-5-0Mega-Pixels_W0QQitemZ350028499917QQihZ022QQcategoryZ4616QQssPageNameZWDVWQQrdZ1QQcmdZViewItem

I just did a quick search for this and are not recommending you buy from this seller.
I have attached a couple of photos of the resolution so you can see the magnification. If you get a camera unscrew the cap and turn the lens about 1/3 to 1/2 turn anti-clockwise to focus the camera for about 55mm from job.You will then get the magnification in the photo. Have also attached how I mount the camera. The crosshair in the photo is from Mach3 and not the camera.

Again Greolt did the pioneering work on this concept. The only change is from a laser crosshair to a web camera.
http://www.cnczone.com/forums/showthread.php?t=48752

If you are going to take any script off the zone remember to make sure it is in metric.
Having designed the odd screen or three I can help with screens and script if you need it. Still trying to create the perfect screen set by the way.

If this post doesn't make sense then my excuse is I am trying to cut a job at the same time. :)

[rodm]

Forgot to add the camera is 15mm in diam to give you a size to work by.

[John H]

Thanks for that :)

So you don't zero the webcam to the centre of the spindle? It looks offset so I assume it's looking to the side?

Now I have another question. This one relates to setting up the motors in Mach3. Have I worked this out right

Steps per revolution: 200
Step Resolution: 8 micro steps
Screws: M12 thread 1.75 pitch

200x8 = 1600 / 1.75 = 914.28571428571428571428571428571

So I need to put the final number in the "Steps per" box of the Mach 3 Motor Tuning and Setup screen?

[rodm]

Yes the camera is offset but the button script puts the spindle dead centre of the camera crosshair when you press the button. Is a real advantage as you do not have to mount.demount the camera each time. Do the Z axis after this and you are set up and running in very short time.

Yes your calculation is spot on. Mach3 will probably only let you enter the whole number 914 first time. Do the calibration and it will set the steps to decimals. Don't get hung up on the decimal points as 1/914 of a mm is 0.001mm and better than you can measure even with a vernier. :)

Yes again, the steps go in the motor tuning screen as you say. Don't forget to set the pulse to 2 or higher in the same screen. Xylotex need a 2ms pulse.

[John H]

Ahhh ok, now I get it. I'll be back with some more questions when I get a camera ;)

I went for broke and entered in the numbers before. I just finished cuting some air (too late to start the router) and did some moves with the MDI screen and everything seemed to move the right distance. I just laid a ruler on the table and eyeballed 20mm movement on the X and Y.

Is the 2ms pulse for the "Step Pulse" or the "Dir Pulse" box? I had zero in both pulse boxes. What does the pulse do?

[rodm]

Now we are getting in the electronic technical side which I refer to as mumbo jumbo. :)
As best as I understand it is the width or duration of the pulse. It just gives a little more time for the electronics to see the pulse. Obviously 2ms is a very small time so it is not like it is holding anything from happening. If you hop on the zylotex site or maybe in the instructions there is a graphic that shows the signal as a flat top 2ms duration pulse.

Like I said all mumbo jumbo to me and I hope I have not led you astray with my explaination. You set them both to 2 or as high as 5.

Now you have it running you will be wishing away the hours until you can run the machine for real.

When you get serious about calibration I just set a verier on the table and push the jaw with a set move in MDI. Compare the vernier value and you have your calibration done. Some cut a square and measure the job for accuracy but this assumes the cutter is exactly the right diameter.

[Greolt]

Just to add to this step duration setting discussion, some more useless info. :U

The step length when set at zero is 5us. When set at 1 it becomes 6us, set at 3 it is 8us, at 5 it is 10us. etc.

That is micro seconds. A microsecond is a millionth of a second. A millisecond is a thousandth of a second.

Just set it to 2 in Mach if that is what Xylotex recommend.

I use Gecko drives and set mine to 3 as they recommend. But can see no difference if set at zero either.

Greg

[John H]

I was just giving some thought to workholding on the table and I was wondering what would be a good method.

I'm considering attaching a bit of 300mm wide MDF to the table and getting some of those T tracks from Timecon (http://www.timbecon.com.au/details/t-track-system-13712.aspx) spaced about 30mm apart (anyone know how wide the T tracks are?)

[Greolt]

Cheaper here

http://www.woodworksupplies.com.au/category73_1.htm

Greg

[John H]

It was raining today so I got a break from fence painting and finally modified the table.

Using 24mm MDF and T-Track from woodworksupplies (Thanks for the tip Greg).

This has increased the usable size of the table to 430mm x 300mm.