DIY MDF CNC Machine 36x22

The design I'm gonna present is a DIY CNC machine made with MDF board.
This design has been made by one of my friend and I have built one exactly like his. So we currently have 2 machines like this one.

This is my first instructable so maybe there will be a couple of things missing, please feel free to ask or post comments.

If you are planning to make one like that, please send me picture of the final results so I can add it to this page.

**This machine is a derivative of the machine you can find on**
http://www.buildyourcnc.com/cnckitintro.aspx



*** NEW FILES JUST ARRIVED ***
I've done all the drawing with METRIC measurement and more precise parts identification. I Had some request for metric measurements.
I will probably upgrade the imperial one soon, so you're gonna have the exact same drawings and with more accurate information.

I have postes new pics on step 9 =)

Enjoy

Step 1: Having the Plans

The machine was entirely built on the computer before it has been made, so here's the render of both versions i have

Step 2: Cutting MDF

First, get a sheet of 3/4 inch MDF board, it's enough for all the project, even if you miss a part or 2. You can get it for 35$

After that, print the CAD of all the parts and cut/drill them.
The Drawing.Rar contains all the MDF main parts.

16 Dec 2011 - New Drawings !!!  I had some times this morning and it took me 3 hours to redraw every parts with IMP and METRIC measurements, hope you will enjoy it.

Merry Christmas to all of you

Step 3: Getting Hardware

Get the cross dowels and the 1/4-20 bolts.
I took mine from

www.leevalley.com , i guess you can get them from almost all woodworking shop on the net.

The aluminium angles are 3/4 X 1/8 angles from RONA or any suppliers near your home. You'll need

2X 36" for the X axe
2X 22" for the Y axe
and 2  11" angle for the Z axe

And ONE aluminium angle 1"X1" x 1/8 for the linear bearings.

You'll need 30 bearings  Bearing Size: 8mm x 22mm x 7mm
( I took skateboard bearings from ebay )
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=400073167540&ssPageName=STRK:MEWNX:IT

The lead screws are the length of : 36" , 24" , 9"
I took them from http://myworld.ebay.com/precisiontechmachining/

Step 4: Mechanism

Here I will post picture and drawing of the mechanism. For the moment i only posted a render of the back of the machine ( the Y axis ), it's easy to figure out all the other axis ( it's exactly the same principle )

Step 5: Assembling

Step 6: The Electronic Part

I took an old computer and opened the power supply to solder 3 wire on the primary side of it. I took the wires to a switch so i can turn on or off the second powersupply and the drive.
I added 2 fans because the drive become REALLY hot so if you don't want to kill it, cool it !

Step 7: Adding the T-Slot

I just made a 1/2 mdf part to protect the table and I grooved 2  3/4 slot with the router bench.

I got each t-slot for 11$ ea.

After that, you just have to put a 1/4" hex bolt upside down and make some support for your pieces. I'll add more pics later

Step 8: Total Cost

MDF Board : 35$
Bearings : about 30$
Lead Screw and antibacklash nut : 135$
Power supply : 50
Steppers : 49$ each ( 150$ )
Gecko drive : roughly 250$
Bolt and cross dowel : 50$
Aluminium angles : 55$

Rough total : 755$

Step 9: UPGRADE

Since I had some issues with stability and wobble and I wanted to use my 1/2 carbide end mill. I had to modify the machine to  remove some flex .  I'll show you some pictures, this is optional but REALLY help the machine's stiffness.

Special thanks to my friend Max for the idea.

-- NEW PICTURES

Comments

[Brian_vz]

Hi, I may built this, How many cross dowel nuts are needed?

[australlus]

Can you make me one of these?

[Eriobis]

The whole assembly or a specific part ?

[fly-fast]

I had to take a break from this project for real life events, but, want to get started again. So, all of my parts are cut out and everything tangible is now in my possession - about $850 with beefed up motors... Where I'm struggling is how to line up holes for the cross dowels between the ribs and the cutting deck. I can't get the holes perfect. Any advice would be appreciated. I even bought a woodpeckers cross dowel jig - just don't know how to use it yet.

[fly-fast]

Thanks for the help Spiky. I'm having a hard time getting all of the cross cut dowels perfectly lined up. If you have any tips, please feel free to share.

In regard to your 'upgrade', would you mind taking a picture of yours installed? It was a tough piece to get perfectly cut, and I'm not sure where / how it is installed.

Servo motors are way to expensive for me, so, I'm sticking with the NEMA 23 stepper motors!

[Eriobis]

I don't remember if I had any trick. I had the plans and I drew on the wood all my measurements. I was in metrics I think ( maybe more precise ? )
The fit won't be 100% perfect since there's human manipulation. You will have to use your skills to tweak the parts a bit.

For the upgrade, there's no plan. I just drilled holes in the side of the machine and fixed the ribs with floor screw. I needed something quick and strong. It really help the stability of the machine.

[fly-fast]

Hi again Spiky.

Do you still physically posses this CNC? If so, can you please take additional pictures? It would be very helpful!

[fly-fast]

Hi Spiky!

I've got all of my MDF cutouts completed! I hope to have the whole thing assembled and tested within 2/3 weeks. I too have ordered the NEMA 23 motors. Do you have any information you can share about how you wired this? I'm comfortable building, but, am concerned about my lack of experience when it comes to wiring everything together? Is there a less expensive option of the GECKO controller? If you had to do everything all over, are there any changes that you would make knowing what you know now? I'm taking lots of pictures as I go!

[Eriobis]

If I had to do it again I would probably use servo motors, as they are in closed loop so they wont miss any step. With open loop motors like steppers, you have to watch your print and be ready to press the e-stop in case something bad happen ... or maybe I was just trying to cut too deep for each layer ... anyway .. The servo alternative is quite more expensive, I would say around 1200$ for the electronics. At that price you better buy a DIY already made CNC

The gecko driver are well engineered drives and they will allow the current the motor needs. It's been a while since I havent shopped for stepper drive for nema 23 ... I use smaller motors with my 3d printers.
You need a drive that can handle 3 - 4 amps per axis if my memory is good.

Unfortunatly I don't have time to make a complete schematic right now, you can take a look at http://www.geckodrive.com/images/cms_files/images/G540%20REV8%20Manual.pdf

Even 3d printers schematics can help you. To drive a stepper you need 2 signals, 1 for the steps and 1 for the direction

The drive needs +Vcc ( 24 volts - 50 volts ) and a Ground

Motors have 2 phases ( 4 wires ) and it's quite easy to get the info on their wiring.

With the gecko drive, you need to supply a resistor to the drive, so the drive can "know" what's the maximum current your motor need.

Good luck with your project. Let me know if you have any other questions, i'll do my best to give you an answer !

[fly-fast]

In regards to the holes shown on the top of the bed, are ALL of those holes for cross-cut dowels? I believe so, but, just want some verification before drilling them out.

[Eriobis]

Yes, there are 2 long rib underneath the bed and you need to fasten the bed to those parts.

[sobeskinator71]

What all would I have to expand to make a working envelope of 24*36 inches?

[fly-fast]

Can anyone please verify the diameter of the lead screws called for in 36" , 24" , 9"?

[Eriobis]

1/2 if I remember well

[TimF30]

I would like to try this based on an old ping pong table. That way I could cut/engrave large items like full sheets of plywood/mdf, doors, sliding glass doors...

[larystoy]

I don't know if you will get this or not. But I have to make two remarks.

1. Thanks for all of your effort.

2. Tell the others to use the gray stuff between their ears and a bit of common logic and figure out the details themselves.

[Eriobis]

Yes I know, that's what I always say to myself. If you want to build a complex project like that you need some skills. Then you need to know how cnc works, how not to crash the machine.
Some ppl may be able to run it but they've never built something like it. Personnaly, I only ask question on forums when I'm having a HAARRRDDD time figuring out something, otherwise I do it by my own.
The goal here is not to discriminate anyone, but to tell ppl to be a little bit more resourceful.

[planecrazyman]

Hi please could you tell me two things. First thing the lead screws you give the length but not the diamater and pitch . Second thing how do you install the skate bearings and are they adjustablei can't find any info on this . Thanks Dave.

[doppiej]

How are the alu angles attached to the wood? So both at the ends of the wood and on the sides of the wood.

[aryder-durrett]

Sorry tslots