Wolincircus.com

Dust Collector Hood

Finally got a decent solution down for dust collecting. The hood slides up and down on the surface of the router housing. It is a little wobbly at its extreme ends but overall works very, very well!

Precious Metal

Here’s a shot of a sweet machine I picked up from a guy downtown who scraps out machinery from Micron. I was pretty stoked to pick it up thinking I could make a little money on it and also get some killer parts. But as it turns out the market has taken a “significant” nose dive since last time I checked. I don’t think I will loose any money, but I won’t make a killing either.
Here is the machine in the back of the truck

A close up of the driver bank.

Here is the machine stripped down so you can see a lot of the linear components. Basically it’s a heap of coolness.

4th Axis Setup

I am working on getting a 4th Axis for my CNC machine. It has been a long time project. Here is what I have so far. Nate and I adapted this rotary axis to a couple of pieces of 3/4 inch hardrock maple cut to size on the CNC machine. My dad donated his chuck from his lathe. You can see the completed headstock here.

The tailstock was simply a threaded rod run through a nut sandwhiched in some maple. The hand crank on the back was a CNC operation and the nose cone was a milling operation. It spins on some skateboard bearings so it acts as a live center.

Still need to get the software side of things dialed in and I still need a stepper motor driver. Just a little more time and money. Increasingly valuable these days!

CNC Machine Progress

My documentation pretty much reeks on this CNC machine, but I thought I would at least throw up what I have in terms of progress. This picture gives you a good idea of the table adjuster system. The entire table moves up and down on 4 THK linear bearings sliding on 1.25” hardened rods tapped on both ends.

Here is a top view of the table assembly prior to installation of the table top and the table adjustment ballscrew.

This is a picture of the gearbox and large spider coupling that drives the table ballscrew. The gearbox is a 60:1 ratio which is just about perfect. I can stand on the table as it moves up and down and yet the table moves at a decent speed.

Here you can see some of the machine work that went into making the adapter that mated the ball screw together with the table. It was quite the time sink. My dad polished it nicely on his lathe with some aluminum polish just for fun!

Here is the Y Axis Nema 23 mount to hold the stepper motors. I wish I could brag about machining that piece, but I just bought it off ebay for 10 bucks.

This photo shows the Z axis without the faceplate installed. You can see the positive and negative limit switches as well as the THK bearings which carry the load. The ballscrew is directly attached to the stepper motor above.

This is a detailed shot of the electronics. Pictured in the photo are four stepper drivers, a power supply for the logic, an optical isolated DB25 breakout board and a “charge pump” for the Mach 3 Software.

The power supply which drives the steppers is is housed in this box along with a 5th stepper motor driver. The laptop was designed to sit on top of this little computer arm support.

The X axis ballscrews were supported on each end with regular old roller skate bearings from KMart. They pretty much just float around in there. All the precision work is done on the other end.

Here is the X axis motor mounts. I had a lot of trouble eliminating slippage until I just bit the bullet and purchased some of those really nice spider couplings ($22 a piece. Owch!). Even though they are expensive, they really do the job well. Haven’t had one problem since!

Still got a long way to go, but here is what she looks like today after hours of use. Dusty and faithful!

Steel Frame Solution

My third and final steel framed solution all started with an ebay kill… Ebay is the CNC hobbiest dream resource. There is absolutely no way anyone could create high quality industrial strength machinary at hobbiest pricing without ebay!

The unit that I picked up from the best of my research came off of a CNC machine similar to this one. The rigidity of this assembly is what impressed me the most. the y-axis crossmember was a solid piece of aluminum measuring 28 inches accross 7 inches high and two inches thick and weiging close to 100 pounds. The aluminum alone at scrap metal pricing was worth 150 bucks. Igus cabling, a stout z axis aseembly complete with stepper motor and various other misc items, made this the perfect starter kit for my final CNC project. The cost? A mere 190 dollars including shipping. I sold of the linear motor and controller that came with the unit making the total cost of ownership about 100 bucks. Can’t complain about that!

The unit I purchased came with a linear magnetic motor instead of the traditional ballscrew for the y axis. This is a picture of the controller that came with the linear motor that I pawned off on ebay. Although very cool concept in real life, I had now way of controlling it with my software.

Here is a close up of the Z axis assembly as I received it. The Z axis rides on some THK linear slides and then is driven by a Pacific Scientific stepper motor/ballscrew comination unit. The entire z axis rides on second set of larger y axis THK slides. Overall the assembly is quite rigid and about a 1000 more industrial than my previous wooden version.

Homebrew CNC Wooden Prototype

Unfortunately, I don’t have many pictures of this machine. In fact, I have no photographs. What you see here on the site is frames extracted from a video clip. It is hard to stop a project, pull out the camera and document what’s going on, but I’m working on it. Anyone who has tried to build a CNC machine knows that there is a pretty large learning curve. For me this was more like a learning wall. Not only was there the intellectual challenge of understanding all the systems, but I had no decent tools to manufacture anything precision. This was the primary reason for building a machine out of wood. Wood seems to be about 1000 times more forgiving than steel or aluminum and so it was a great place to start. The machine was built around a THK linear actuator that I aquired on eBay. Any homemade CNC machine should be built around the linear components since these are by far the most expensive part of any machine.

From the side view here you can see the gantry offset designed to maximize table usage. The gantry setup proved to be quite rigid despite its wooden construction. The weak spot would prove to be the Z axis.

The Z axis was pretty flimsy at first. In fact, what you see here, is the second attempt at making something “decently rigid.” Decently rigid is a title this machine never earned. Slight pressure could easily deflect the axis 1/4 inch or more. While not rigid, it did serve the purpose of a prototype, namely, identify the need for much more rigidity in future models.

The clamping table was nothing more than 1/4 – 20 nuts countersunk into a piece of 3/4 inch MDF in a one inch grid pattern. It actually worked quite well.

The CNC machine housed a 12vdc power supply imbedded in the table which powered some stepper motor chopper drivers from camtronics. These in turn drove my 1.4V 3.8A Vextra stepper motors. These proved to be plenty powerful. The startup torque was enough to really get the machine shaking during a cutting cycle. The speed was anything but steller. The poor performance was due to overly tight pitched ball screws and the low voltage power supply. After building this machine, I was hooked. It was time to move on to bigger and better.

My Experience with CNC

There are few things that I enjoy more than working on CNC machines! There is something about precision, repeatability and automation that really gets my creative juices flowing. Like pretty much every hobby of mine, CNC for me started with a Google search. I was cruising the internet trying to find some gift idea to make my wife for Christmas and ran across some plans for a wooden clock. I thought that was really neat, but the thought of cutting out all those gears by hand really was a turn off. My dad who is an engineer at Hewlett Packard, had told me at one point about these machines that were able to cut things out based on computer input. So, I went searching for an “XYZ cutting machine.” As soon as I stumbled across the keyword CNC I was hooked. That is what started it all!
The History

My design experience led me through three basic models:

1. Wood Prototype
2. Aluminum Frame Prototype (scrapped halfway through)
3. Final Steel Frame Solution

The three designs will be documented on this site.