Ok everyone...It's been a while, but I got my first machine up and running. I built that one with the frame of mind of it being a learning machine and I have learned alot from it. The time has come and I feel that I want to upgrade my machine and build something with a bit more cutting area.

My current machine has an 8x8x2 cutting area. Works nice for small parts and testing my skills, but it doesn't work well for alot of things I'd like to make.

My first question to you all is this (and I'm afraid I may be using an oxymoron here)...Are there plans to build a machine that would give me a fairly large cutting area (at least 2'x4' and maybe 6-8" z travel) and remain reasonably cheap? I don't have a lot of budget at this time, looking to keep it less than a few hundred if possible. I do have the electronics for it already so that will cut some of the cost.

I am looking to be able to cut woods, plastics, and possibly some small parts from alluminum. Is an MDF machine good enough for this?

Check out Joes 2006.
2' x 4' cut area.
Lots of people have built them and cut wood and plastic all the time. I think a few have tried aluminum.

Alright I've decided on a basic design and have started construction.

Here is a link to my website and build journal for this machine.

MyHomeCNC (http://www.myhomecnc.info)

Let me know what you all think either here or on the website...Or both :)

Ok everyone I posted a big update on my build log today...

Question for everyone...actually I have two.

1. What do you all think the minimum size motor to move a 24x48 MDF moving gantry style router? I am ordering the 305 oz./in motors from hobby cnc, but in the meantime while I am waiting for the arrival and whatnot I have 3 NEMA 23 motors that are somewhere around 100 oz./in (labeling on motors is poor and not exactly sure how much it is).

2. What is a good router to purchase to mount on my mill? I am looking for a good quality, easy to mount, and relatively low priced. Basically the best router I can get for the lowest price. This router is going to be dedicated to the machine as I already have a nice router for projects that just won't suit this machine well.

I've been eyeballing the Bosch Colt palm router for my machine. I was wondering if anyone had used this router and what their opinions were on it. I am working on a fairly tight budget and wanted to know if anyone had any other suggestions for routers to use for the machine.

I've got it just about built completely. I just need to mount my steppers and get a router so I can build the mount for it.

Thanks,
Kevin

joes 2006 is a 24 x 48 and I think he used 200 oz in motors on the original. I have the same 305s on mine and they work well.

The Bosch Colt is nice little router. If you want a little more power at a little more cost, the Makita RF 1101 would be my choice.

Thanks for the input BobF. Actually since I posted the previous entry, I decided I'd get the 425oz/in motors from Keling. $49 a piece before shipping.

I've also got the option for close the same price as the bosch as a craftsman palm router. Any preference on brands? both are 1hp.

Thanks

The HobbyCNC motors are rated in unipolar since all of their boards are unipolar. They will do about 425 in bipolar, but HCNC does not sell a bipolar driver. Not sure about the Kelings, but they are likely very similar motors.
I think the Craftsman may be made by Bosch. I know they sell some larger ones made by Bosch. If this is the case, I have no preferrence, otherwise Bosch.

Would 18,000-28,000 RPM's be a good range for a variable speed router?

Would the spindle speeds of 18,000 - 28,000 RPM be good for a router, sorry but I am new to this and I'm afraid that part of it is Roman to me.

Would the spindle speeds of 18,000 - 28,000 RPM be good for a router, sorry but I am new to this and I'm afraid that part of it is Roman to me.

That should do fine for wood. The only time you might want to go slower is if you cut plastics or aluminum. The ones I have used had a range of about 10-12 up to 22 - 24 thousand.

I had been reading the other thread near the top of the forum about speed controlling a router and was wondering what effect using an after market speed controller on a router with a speed control built in?

i.e. if I set the router to its minimum of 18k rpm and then use an aftermarket speed controller to lower it down even more...should that work? That way I can have more of a range with the same router?

I had been reading the other thread near the top of the forum about speed controlling a router and was wondering what effect using an after market speed controller on a router with a speed control built in?

i.e. if I set the router to its minimum of 18k rpm and then use an aftermarket speed controller to lower it down even more...should that work? That way I can have more of a range with the same router?

Don't think it will work. The aftermarket speed controls I have seen say they won't work if the router has softstart. The one I have gives less than satisfactory results. I wouldn't recommend it.

Alright everyone...ITS DONE!!!

I have finished the router and it is awesome, I do however have 2 problems I'd like to look to you for ideas on.

1. Everything works great electrically, however occasionally my Z Axis will go the wrong way than what the input is telling it to... i.e. I may be jogging down with the Z manually, stop, and start to jog back up and it will go down again. When it does this if I stop, and try again it will go the right way. This also does it during automated operations while running code. This is bad as I've had it try to raise the Z to "safe at 1" above the peice and go straight down instead... Any ideas?

2. I have lots of ideas for items to cut, however I am VERY new to this aspect of it and I am completely lost when it comes to actually going from idea to G-Code...I have access to AutoCAD and Solid Works for design through my school and I have a few demos of Cam programs and haven't locked into one I can figure out just yet. I have a good background with AutoCAD and as new as it gets with solidworks. My basic question is...what do I have to do to draw the item in cad, then what do i need to do to import into CAM and export the G-Code? Any tutorials out there? I do have access to mastercam and I have lazycam that came with mach3 on my laptop.

Thanks a million!
-Kevin

1) noise somewhere.

2) I wrote an AutoCAD macro that will export g0code direct from AutoCAD, 2002 or newer.
http://home.comcast.net/~cncwoodworker/acad/downloads/AC2GCv039.zip

Gerry,

Thanks for the quick response...Now my rebuttle questions lol...

1. You'll have to excuse my ignorance, but the electronics are probably my weakest point when it comes to this CNC thing...I understand noise, but how do I break it down to where and what is going on?

2. No questions here, just a big thank you...Any specific way I have to make my design? Just a 2d drawing, 3d viewed from the top? (I guess I did have a couple questions lol)

Just lost a big post. :(

Anyway, it may not be noise, that was a guess. check the voltage on the direction pin when it's acting up. Should be 0V in one direction, 5V in the other. Also, try increasing the direction pulse width.


There's a simple .pdf manual included in the download that explains the features. If you have any questions, there's a thread on it here, http://www.cnczone.com/forums/showthread.php?t=8226 , or PM me.

Basically 2d polylines and circles, but it will also follow a 3D polyline as well. View shouldn't matter, but if objects are dran at a Z location other than 0, then the Z location will be the depth of cut. Explained in the .pdf. Check it out and see if it answers your questions.

Another CAM program you may want to try is VCarve Pro from Vectric. You can download a free trial version at Vectric.com. It works with dxf files as well as others.

Good news and bad news...

Good news is I think I had an "Ah Ha" moment when it comes to generating the gcode from my cad designs...

Bad news.....My Z axis is still going through its terrible two's and doing as it pleases. I tried checking the Z Dir output, but the problem is that it is spuradic when it does this and I have now way to test it unless I monitor the z dir during an entire program. I can't go on with this just ramming itself down into my table as it pleases so this is my top priority now... :(

Good news and bad news...

Good news is I think I had an "Ah Ha" moment when it comes to generating the gcode from my cad designs...

Bad news.....My Z axis is still going through its terrible two's and doing as it pleases. I tried checking the Z Dir output, but the problem is that it is spuradic when it does this and I have now way to test it unless I monitor the z dir during an entire program. I can't go on with this just ramming itself down into my table as it pleases so this is my top priority now... Have you checked the voltages yet? It could be that your parallel port isn't outputting a high enough voltage and may be on the hairy edge of the signal being a 1 or a 0. Or, on the contrary, the board may have an unusually high threshold voltage for it to be considered as a 1, the opposite for 0.

Checked that and all seems to be within normal limits...Also if it was a voltage problem with my parallel port, wouldn't I have problems on all 3 axis rather than just my Z?

Ok, I fixed the problem on accident I think, I haven't been able to get the machine to recreate the issue so...we'll see how it goes.

Next problem and it's probably a simple one. I am using EMC to control the router, and Mastercam to create the toolpaths. For some reason when I post the .nc code file it throws errors up in EMC stating that there is an unrecognized g-code...the whole .nc file is using n codes not g codes...did I do something wrong?

If the first letter of each line is an "n", those are probably line numbers.

Ok, I fixed the problem on accident I think, I haven't been able to get the machine to recreate the issue so...we'll see how it goes.

Next problem and it's probably a simple one. I am using EMC to control the router, and Mastercam to create the toolpaths. For some reason when I post the .nc code file it throws errors up in EMC stating that there is an unrecognized g-code...the whole .nc file is using n codes not g codes...did I do something wrong?

Plus you have to find out if there is a post processor written for MC to EMC,
and if so, what version of mastercam it was written for. If older than the version
you're using, then MC has a utility that will automatically upgrade it.

You'll get all sorts of problems if that's the case.