Upgrading Ubuntu & EMC2

This weekend I upgraded from Ubuntu 8.0.4 to Ubuntu 10.04 & EMC2_2.4.4 Release.  The install went without a problem.  However, I couldn't get the steppers to move.  I recall having parallel port configuration issues the first time.  I wasted 4 good hours of shop-time with no success.  Then the proper information turned-on the light for me, and all is working well.  This page on HAL drivers did it for me.  I mistakenly thought the "in" and "out" parallel port settings meant the parallel port was installed (in) or not (out).  Since I was using an add-in parallel port, I was attempting to set parallel port 2 as the port to drive the steppers.  Wrong.

The "in" and "out" refer to the signal directions of the parallel port (I wanted "out").   Here's a hint how to find the address for your parallel port setting (the 'stuff' after the "0x").

The cable track

Moved to my website

WoodWorkerB.com

New Router Table as-is

Here's how the stand looks so far. Only two drawers, but it covers the basics. I've got the keyboard/mouse tray and computer/control electronics. I left room around the router table for an eventual plastic cover to control dust and noise.

A large challenge was mounting the monitor - I wanted it convenient, but not in the way of the plastic dust cover. I decided to mount the monitor on top of an extra length of steel pole I had around. Consider using a heavy-duty closet pole from Home Depot. You need to make sure that the power and video cables will fit through the tube first!

Monitor Mount: I made the monitor mount from a couple of scraps of plywood. The bottom and middle parts are bored-through with a 1.5 inch hole (the same diameter as the support tube). The top hole is a 1/4 inch smaller. This design allows the cables to be fed through the center of the tube and for the monitor to spin 90 degrees so it's out of the way during storage. There is a similar block under the surface of the table to support the tube.

Electronics Drawer: The drawer is roomy enough to hold the computer, power supply for the steppers and the stepper electronics. I added a master "mains" switch and a switch to control the router to the front panel. Also a big "stop" switch (Rockler) at knee height - for those times when things don't go as planned.
Hitting "stop" kills power to the router and to the stepper motors. A pair of filtered, computer case fans provide positive pressure to (hopefully) keep dust out of the drawer. An aluminum cover sits over the drawer.

New CNC Router table

I need to re-build my CNC router from scratch - taking into account all I learned during the first build. I decided to start with a stable, portable stand that would house the computer and electronics in a clean, safe space. I went with a simple MDF carcass with drawers. The computer drawer would contain all the electronics and would be positive-pressurized via two filtered case fans.

I can provide the sketchup drawings for the stand and the cutting guide if you're interested. Just drop me an email at woodworkerb [at] gmail [dot] com. The core case is built and the electronics installed. Not all the drawers are made yet, but that's coming - I am tired of leaving tools & such laying on the router table - just begging for trouble.

I noticed a problem when I tried to machine two "mirror image" parts, and when I tried to match-up the parts, they would not align. It seems my router was built out-of-square. I have decided to completely re-build the router, taking my time, and making sure all the parts are square. Before I make the new router, I needed a solid, mobile table on which to hold the router, PC, power supply keyboard and some extra storage. I will provide the plans and images of the table.

Fifth time is the charm!

My 5th attempt at isolation milling the PCB was finally a success. After experiencing just about every failure mode, here's what I learned.

First, be sure you've calibrated your milling tool. See "Calibrating PCB isolation routing with Eagle/pcb-gcode" by Poul-Henning Kam. He created a simple PCB design that mills traces of a particular width across from isolation paths of the same width. Compare the two - if they are the same width, you are good to go. If they are differing widths, then your bit is either too deep or too shallow.

Second, is your table surface 'flat' in comparison to your milling tool? Mine was out by just under 2 mils, which is a lot, considering 1 oz copper is only 1.4 mils thick. To test, I took one of my mill bits and inserted it upside-down in the Dremel. I moved the tool to each of the four corners and found the highest corner. I use an axillary 9 x 12 inch "sacrificial" board to which I attach my PCB stock to - with double-sided tape - so that any drill-through would not damage my router table. To the underside of each corner of the sacrificial board I added 10-32 tee nuts, countersunk slightly. Into each I used 10-32 x 1/2" set screws with a hex-head.  Update - a machinist friend of mine advised me to have have two set screws on one side and only one setscrew in the center of the other side - forming a tripod.  This makes adjustment super-easy and much faster than one adjustment screw in each corner.

I repeated the leveling exercise, again starting at the highest corner, and using a feeler gauge - update:  I have since converted to a dial indicator - about 10x faster - I lowered the set-screws until each corner was lifted to the proper height. I kept gentle clamping pressure on the board so it wouldn't move during the leveling process. The thickness of the feeler gauge is not important, just use the same thickness gauge everywhere.

Finally, align the PCB square on the routing table and test by moving the X or Y axis along one edge of the board - I use the point of the router bit as my reference. Adjust the PCB (carefully) into square.  Update - it is important to adjust the PCB to be 'square' against the path of the router, not square to the table as shown here.

Now we're ready to route.

Next post I'll cover what I learned on the Eagle CADsoft PCB design software.

PCB isolation routing - attempt 2

Much better results this time. Milled-and-drilled with excellent results. I decided to switch from my 1/4" router to a Dremel tool - this required a new mounting bracket. Naturally, I used the router table to make the new parts. The process is starting to get easier. I routed two brackets from 3/4" MDF and glued together.

I carefully added the mounting holes so I can easily switch from the router mount to the Dremel mount with only 4 bolts. Works great. Another benefit is the Dremel is considerably less noisy than the router, and the Dremel runs cool the whole time. Running a homeowner-quality router for an hour gets scary - you can smell the varnish on the motor windings getting hot.

Added a saw kerf and a bolt to "pinch" the Dremel into place. Like a rock.

Here's the Dremel mounted.




I secured special 1/8" milling bits from DrewTronics. It was the 1/8" shaft that made the Dremel the easy choice. I ordered 30, 45 and 60 degree bits with the idea to play with them all over time. I had to throw 'em under the microscope - here is a 45 degree bit at 20x magnification.

Routing went perfectly. Tooling still a bit to deep. Milling time was shortened considerably by using the gcode optimizer.

After routing, I decided to try drilling too. Snapped the first bit after drilling the 4th hole. Checking the setting of the gcode converter - I found one setting at zero inches - this caused the tool to move to the "home" position for a tool change, but didn't lift the drill out of the PCB first! Changed the number to one inch, and it worked fine, returned the router to the 0,0 position, raised an inch for easy drill changes.

Drill bits are from Jameco and seemed to do an excellent job.

Here's some of the traces at 20x magnification. I did nothing but scrub the board a little with a Scotch scrubbing sponge - no abrasives, no sanding. Was able to get a trace between two 0.100 inch IC pads.

Next I'll ring it with a volt meter, and if all is good, actually build the circuit.