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#1 michaelghammer Jan 15, 2010 05:08 AM

DIY CNC Router for modelers
 
Hi all

Like many other modelers Iīve wanted a CNC Router for years, but the cost and complexcity of the machines have kept me from getting one. But then about six months ago I stumbled upon Tom Mcwireīs ultra simple desktop CNC router/mill built from water pipes and aluminium L-profiles. The machine was so simple and easy to build that it convinced me that even I could build one.

So I started to collect stepper motors and other parts from old matrix printers while searching the internet for info on DIY CNC stuff. The last bit provided me with an overwhelming amount of info. I spent MANY hours sorting through some of that info, and came to the conclusion that I might as well build a bigger, stronger and more precise machine than the small Mcwire CNC.

So I looked at kits, plans and parts. But all the kits that I liked were too expensive and most of the machines built from plans I didnīt like. Parts could be purchased at reasonable prices, so I decided to design my own CNC Router.

My design goals were: Keep it simple. Keep the costs below $1000. Use standard tools to make the machine. Keep it simple. Make it a size fit for modeling purposes. Keep it simple.

One of the main differences between my design and most of the other designs are the use of concrete in the base of the machine!!! But more on that later...

In the following posts Iīll explain how the machine was designed and built. I will provide free plans and a shopping list.

Just to whet your appetite hereīs a video of my machine:
DIY CNC Router.WMV (2 min 45 sec)


http://www.youtube.com/watch?v=DdaoQPjeZdk

- Michael Hammer, Hammer Models

#2 michaelghammer Jan 15, 2010 07:46 AM

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The work area of the machine is 625x330mm and max z-axis is 110mm. I use a Dremel 300 but plan to upgrade to a 800w Kress router. All motors are Nema 23 with 1.85Nm holding torque.

In order to keep things simple I opted to buy all linear bearings, rails, ball screws and couplers as a set from a chinese guy on Ebay. He was recommended by several people and he didnīt disappoint me - on the contrary. Here are the things I got. Quality was excellent and ball screws were end machined to fit bearing blocks. Just the thing you want when most of your workshop is aimed at balsa and plywood :D

Many DIY CNC designs use gas pipes and roller skate bearings, but it seems like an awful lot of work getting it to run smoothly. With the set I purchased you donīt have to worry about adjusting roller skate bearings. It just works and you can concentrate on building the machine.

Of course $417 + $145 shipping is a lot of money, but youīre building a tool that will probably serve you for many years to come.

- Michael Hammer

#3 18DFlyr Jan 15, 2010 09:21 PM

Michael,

This looks very interesting! Thanks for sharing. I just subscribed - looking forward to learning more.

Bill

#4 michaelghammer Jan 18, 2010 06:09 AM

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One of the things I found really hard to do was getting the base of the machine to be completely straight. The base of a CNC Router is critical for the succes/precision of the whole machine and if you make a base that rocks when placed on a straight surface like a table top you will not be able to get the machine running in a precise way. A wooden frame is difficult to make completely straight and will probably distort a bit when exposed to heat/cold humidity etc. An aluminium frame can be great but depends on the tools that cut it.

So hereīs what I did:

Because I used most of my budget on rails, bearings and ball screws I had to come up with an inexpensive solution. So I bought an aluminium step ladder from the local DIY store. Cut it up and made a frame held together with threaded rods and nuts. Then I attached a temporary bottom which also helped keep the corners at a 90 degree angle. I placed a steel net inside the frame and tied it to some screws that had previously been inserted into the sides of the frame. The frame was placed on a completely straight surface and concrete was poured in and vibrated until all air bubbles were gone. A heavy load was placed on top of the frame and then left to cure for a week.

The result was a very heavy, sturdy and completely straight base ready for the x-axis supported rails.

- Michael Hammer

#5 kram242 Jan 18, 2010 08:07 AM

The concrete base is a great idea Michael! That is going to be a great machine.
I remember when a few guys at cnczone were doing concrete y gantry's! that was pretty cool. Noe there is a guy working on a epoxy/granite machine it looks so nice and solid. Here's a link for you http://www.cnczone.com/forums/showthread.php?t=30155
Keep up the good work Michael looks great!
Mark

#6 michaelghammer Jan 18, 2010 08:25 AM

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Thanks Mark :)

After I did my concrete base I googled concrete and CNC and found some interesting stuff. But most of them are VERY HEAVY!!! Mine can still be handled by two persons if one should desire to do so. And itīs dead cheap :D

The epoxy/granite stuff could produce some very nice machines, but it doesnīt fit my Keep it Simple mantra ;)

- Michael Hammer

#7 SteveC68 Jan 18, 2010 01:56 PM

That concrete gantry is pretty cool. Notice it doesn't move, but instead the table/work piece moves underneath. Probably heavy though.

#8 ptxman Jan 18, 2010 04:17 PM

I often wondered... when people are framing up those nice homebuilt cnc structures for casting concrete into, could you integrate a series of nuts or matching threaded bolt-plate plates so that the individual elements could be bolted together? ie partition the machine into chunks so you could at knock it down to lift, move, assemble at reduced weight etc? I can see the base would probably need to be solid, but even heavy duty metal cutting Bridgeport type mill, the head is attached & removable to the main cast iron body. Do cnc routers & such demand more rigidity & vibration deadening etc because of longer surfacing strokes or more z-axis action & so needs to be a unified solid?

#9 michaelghammer Jan 21, 2010 03:50 AM

You could make a CNC router that can be split into chunks. But every time you make such a split you complicate things and run the risk of bad precision.

My CNC router design can be split into two groups. The whole gantry can be removed from the base and that leaves you with parts that can be handled by one person.

- Michael Hammer

#10 michaelghammer Jan 21, 2010 04:07 AM

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The rest of the CNC router was mostly made from 16mm plywood. Part drawings were printed on normal paper and glued onto the plywood. I used a band saw, a table saw and a drill press. Similar parts were screwed together before being cut. For example the four pieces that make the two gantry sides were all cut as one part and then separated.

The parts were glued and bolted together. Rails and linear bearings were mounted and checked for smooth motion. Stepper motors were mounted with threaded rods and nuts.

- Michael Hammer

#11 DeadTom Jan 21, 2010 11:30 AM

Quality work Michael, keep it up. Nice choice of linear guides and bearings btw.
Dt

#12 michaelghammer Jan 22, 2010 03:29 AM

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Thanks Dt :)

The work surface is made from two pieces of 8mm plywood glued together on a flat surface and weighted down for 24 hours. Further more three square 20x20mm aluminium profiles are screwed to the back side of the work surface. The resulting surface is very straight and resists bending very well.

So thatīs about it. The mecanical part of the CNC router is done. Next comes the driver board, limit switches and power supply...

#13 Steve85 Feb 04, 2010 09:22 PM

Very interesting, Michael. I've got a set of plans from John Kleinbauer and have started collecting components, and am very interested in your work. Show us more!

Steve

#14 michaelghammer Feb 05, 2010 04:41 AM

Thanks Steve

Iīll post more photos of the powersupply, limit switches etc. soon.

Building my own CNC Router has been great fun and quite challenging too. But Iīm very happy with the results and Iīm thrilled about all the things I can make with this new tool. So go for it, Steve.

BTW. donīt you have a Fw-189 to finish? I thought the Owl photos that I posted in your thread would kick start the build again... ;)

- Michael Hammer

#15 QUIKSILVER Feb 05, 2010 05:01 AM

Hey Michael!

Nice build, mine loosk the same!

First thing you want to do is get rid of that dremel router! i Brought a Kress router purposly built for CNC work Ģ100 but, it has soft start and loads of other things that keep the head spinning true and is a worthy upgrade!


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