D&M4 project. Gecko conversion questions.

This forum is dedicated to those Hobbyists Interested in CNC machining in their home shops. (Digital Read Outs are also topical, as is CAD/CAM as it relates to CNC)

Moderator: Harold_V

Post Reply
User avatar
Bentworker
Posts: 170
Joined: Fri Mar 02, 2012 1:29 am
Location: State of Jefferson

D&M4 project. Gecko conversion questions.

Post by Bentworker » Mon Nov 23, 2015 12:05 am

I want to make some chips by Christmas.

I bought a project D&M4 and it has collected a sufficient amount of dust. It is time for me to figure it out.

It has Vextra PK266-02A 2-phase 1.8 degree/step Dc2A 1.8ohm stepper motors.

I just bought a Gecko G540 for it.

The spindle controller is stock and functional. There is a 10k potentiometer on the front panel to control speed.

I think I have the wiring under control. I have a 48 Vdc supply. The inductance of the steppers is 2.5mh, so square root of 2.5 times 32 works out to about 48V.

There are no travel limit switches.

This is the first CNC that I have played with. I took a course at a junior college on g-code about 18 years ago and have forgotten most of it, but still have the material somewhere.

I'm looking for guidance with software. I am pretty clueless about how it all functions, what software I need, what OS is the best to run it on etc...

I'd like to be able to do engraving with it, and maybe some simple projects.

Please toss your .02 in on what software you'd suggest.

Thanks for your time,
Peter
Shop toys...
10X54" Vectrax GS20F mill with DRO & frequency drive (saved from the scrap pile).
Jet 13x40 lathe.
Powermatic 1150 drill press.
I love Craigslist!

User avatar
Bentworker
Posts: 170
Joined: Fri Mar 02, 2012 1:29 am
Location: State of Jefferson

Re: D&M4 project. Gecko conversion questions.

Post by Bentworker » Tue Nov 24, 2015 1:26 pm

I'm looking at Mach 3. Also going to take an old desktop and toss a new hard drive and video card in it. Probably going to run Windows 7.
Shop toys...
10X54" Vectrax GS20F mill with DRO & frequency drive (saved from the scrap pile).
Jet 13x40 lathe.
Powermatic 1150 drill press.
I love Craigslist!

hobgobbln
Posts: 177
Joined: Tue Apr 13, 2010 7:31 pm
Location: Palmer, Ma

Re: D&M4 project. Gecko conversion questions.

Post by hobgobbln » Tue Nov 24, 2015 5:17 pm

I'm a beginner myself but I'll try to help if I can.
Bentworker wrote:I'm looking for guidance with software. I am pretty clueless about how it all functions, what software I need, what OS is the best to run it on etc...
There are a whole lot of options/variables. I would say the biggest questions are
1) what do you want to make?
2) how much of a budget do you have?
3) how deep down the rabbit hole are you willing to go?

Right out of the gate, once configured, Mach3 or EMC (linux) will allow you to make chips. You can learn a few basic commands and type them in one at a time kind of like digitally turning the dials. Instead of turning your handwheel 3 full turns and 87 thousandths, you would type G1 X0.387 F4 and away it goes in a straight line at 4 inches per minute. For one offs and basic things this is what I do.

For more complicated parts with more operations you probably want to write out a bunch of lines ahead of time and save them as a file. This has the advantage of copy and pasting repetitive moves and changing the numbers. It also makes life much easier to make multiple parts. Once the file is written you can run the program over and over just buy pressing Cycle Start. It also allows you to pull up the same program a week, month, decade later and watch it make that same part without typing it all in again.

For even more complicated parts or to get around having to actually write out all the G-code by hand, you'll need to pick up a CAD program and a CAM program. You draw the parts in CAD and then run the drawing through your CAM program to tell it how to actually cut it. The CAM program will spit out the G-code for you after you've given it some basic info. Cutter width, max depth of cut, ball nose or regular endmill, max feed rate, etc.....

Things can get really expensive once you go the CAD/CAM route. Draftsight is a free 2d CAD program that works perfectly fine for a lot of things. If you want/need to make 3d models, hold on to your wallet. Same with CAM. There are a number of basic CAM programs for a couple hundred bucks that can do a lot of things from what I've seen people make. If you want the advanced optimized tool paths, high speed machine, etc, get your wallet back out and grit your teeth.

So, it really all depends on you. Some folks don't mind spending the money and go straight to high end CAD/CAM right away while other folks have made super curvy and mind meltingly complicated programs all written by hand.

My advise, and remember I'm fairly new to CNC myself, start out by learning the commands and hand coding. It will get you up and running faster and will also help you identify and solve program errors later on if you step up to CAD/CAM.

Good luck and don't be afraid to ask questions. The people on this board are great.
Griz

User avatar
Bentworker
Posts: 170
Joined: Fri Mar 02, 2012 1:29 am
Location: State of Jefferson

Re: D&M4 project. Gecko conversion questions.

Post by Bentworker » Wed Nov 25, 2015 1:31 pm

1) Engraving, and small RC car parts. Engraving will be it's primary use.
2) I'd like to spend less than $500 on software for starting out.
3) Not that far with this little machine. Depending on how much I end up using it I might go and buy a "real" compact machine someday.

I am curious what sort of magical interface I would use to connect a G540 to a PC if I wanted to run Mach 4. They say you should not use a parallel port, but I don't understand what other communication options are. Really I need an idiots guide.
Shop toys...
10X54" Vectrax GS20F mill with DRO & frequency drive (saved from the scrap pile).
Jet 13x40 lathe.
Powermatic 1150 drill press.
I love Craigslist!

hobgobbln
Posts: 177
Joined: Tue Apr 13, 2010 7:31 pm
Location: Palmer, Ma

Re: D&M4 project. Gecko conversion questions.

Post by hobgobbln » Sat Nov 28, 2015 8:33 am

Well, I would say to try Draftsight for drawing, Cambam for CAD and if you want to stick to Windows, Mach as a controller. That will keep you under budget and able to do quite a bit.

Check out this video. The quality isn't great but its good enough to follow along with. It gives you a basic rundown of how to make parts with basic software.
https://youtu.be/5sjYd3obtdg



I started looking into Mach4 for you and it is a little confusing as to what you need. If I'm reading everything right it looks like you need to buy one of the compatible controller interfaces to go between Mach and your Gecko. Not sure how much digging you've done, but it sounds similar to the way a SmoothStepper board is supposed to work. The basic idea is that the extra interface hardware takes the heavy lifting off of Mach which will give you faster travel speeds, cleaner pulses to the steppers etc.

Griz

User avatar
Rex
Posts: 680
Joined: Wed Apr 28, 2010 6:29 am
Location: DFW Texas

Re: D&M4 project. Gecko conversion questions.

Post by Rex » Sat Nov 28, 2015 10:01 pm

D&M4 - that's a Sherline-based teaching mill?

If you have a G540, the wiring to the PC is dead simple: A single DB25-to-DB25 straight-through parallel printer cable. Plugs into the G540, plugs into the PC. For this reason, older PCs are preferred, usually running Win XP. Seriously.
For software, the standard is Mach3. Mach3 is available to download for limited trial to get your machine up and running. The full version is just $175, and even that is discounted by CNC4PC and possibly others.
If you want free software, run Linux CNC under ubuntu. Harder to learn, but plenty of online support and info.

User avatar
Bentworker
Posts: 170
Joined: Fri Mar 02, 2012 1:29 am
Location: State of Jefferson

Re: D&M4 project. Gecko conversion questions.

Post by Bentworker » Mon Nov 30, 2015 6:32 pm

Griz,
The video was good. Friday I'm supposed to go pickup an older PC with a parallel port, hopefully over the weekend I'll try out Mach 3 and see if I can at least accomplish some forward progress. I might call up Newfangled Solutions this week and see what the deal is running a G540 with Mach 4. Seems like their website is a little over my head.

Rex,
Yes, it is a Sherline, wrapped up in a fancy enclosure.

Thanks guys,
Peter
Shop toys...
10X54" Vectrax GS20F mill with DRO & frequency drive (saved from the scrap pile).
Jet 13x40 lathe.
Powermatic 1150 drill press.
I love Craigslist!

RET
Posts: 708
Joined: Wed Jun 07, 2006 8:36 am
Location: Toronto, Canada

Re: D&M4 project. Gecko conversion questions.

Post by RET » Mon Nov 30, 2015 8:04 pm

Hi,

If its a Sherline mill, one way would be to buy their CNC computer and software and use that with your unit. I'm not sure about using the steppers you have, but that combination should do everything you want to do and more if you use the Sherline steppers.

I started out with a turnkey CNC mill package over 10 years ago from Sherline and that worked quite well. I wanted something bigger & heavier for the mill side so I built my own version but I'm still using the same computer and steppers. You can see the new setup in "Richard's Latest Project." The new CNC mill is MUCH better. It is capable of running all 4 axes simultaneously and can work to a thousandth of an inch (the software can do tenths, but accuracy of a thou or less is quite good enough for most purposes). The Sherline front end on top of EMC makes things more "user friendly" and you can prove out your code with "Backplot" before actually running it on the mill. You really need a CAD program to get line intersect coordinates that are accurate enough (at least 4 decimal places) for the code to work without errors.

Even if you don't do anything else, you should download Joe Nelson's CNC instruction book on writing "G" code from the Sherline website (its free).

Welcome to the CNC club. Don't be afraid to get your feet wet.

Richard Trounce.

RET
Posts: 708
Joined: Wed Jun 07, 2006 8:36 am
Location: Toronto, Canada

Re: D&M4 project. Gecko conversion questions.

Post by RET » Tue Dec 01, 2015 8:01 pm

Hi,

In my previous post, I forgot to mention that you can buy a CD from Sherline that contains their complete software for (used to be) $25.00 US. The software self installs on a PC. and includes EMC2, the Sherline "front end" and the Ubuntu version of Linux. It also includes English and metric versions of both the mill and the lathe software. Its hard to get a better bargain than that.

Like a lot of people, I wasn't familiar with Linux when I started out, but Linux is deliberately made to look and operate a lot like Windows so it isn't too bad. I have the Linux machine on a local area network so I have internet access with it and I can move files between the Linux machine and a Windows7 machine. Windows7 is "picky" about talking to other computers so I have to use the Ubuntu machine to move the files back and forth, but it works.

Hope this helps.

Richard Trounce.

Post Reply