Lith0phane

First I want to say again, "The Taig Micro-mill is a great machine when converted to CNC." I have worked this machine to the extremes and it keeps begging for more. I have been running this machine constantly at 10,600 RPM for hours on end. Look at the first picture below and note where the belt in located. The motor gets HOT after hours of constant spinning under load so the TEFC is necessary. The Taig spindle when brand new didn't like this high speed and would get a little warm, but after an hour or so (a long, long time ago) it proved it was built for that RPM. Now the spindle runs cool and is stable as a rock. This is the ER16 spindle and worth the upgrade. The mist assembly is an add on and looks like it belongs there, not just tacked on. Just using air for this run.

You can see why I added the wider bed. This is the full "Y" axis travel and eliminates any "hangover" problems. No, not the kind from too many Heinekens. The edge give a perfect alignment to square the material and as you can see the material can be clamped far outside the range of the standard bed. This is not a detractor of the stock mill. Any machine should have options like this. I can go back to the narrow bed in about one minute.

I have discovered good CNC machines are not low cost. I have several $K invested here and it shows in the work it can do. The shame would be putting that kind of investment into a machine and not getting good use from it. For its size, the Taig is a sweet machine.


Now! On to making a lithophane. That is a 0.250 piece of "Bone color" Corian material. About $2.00 worth. The image produced in it will be 4" x 6". Note the "X marks the spot" on the corner of the material. I could have set the in offset in the code, but I like to avoid setting zero on a corner when possible.	Here is the full shot of the milling getting started. The cutter has just moved to the right front corner and will be cutting at 45 degree bias. After setting zero in the first picture, I added +0.080 to the Z axis. That makes the cutter go -0.080 into the material when executing the code instructions. 1/4" Corian is actually too thick for the lithophane!

Let the snow storm begin! Click for an enlargement. This is a 1/8" two flute ball nose end mill. It has no problem or wear going 0.80 to 0.180 deep at 40 IPM, 40% step over and 10,600 RPM. The flash stopped the action but there is a snow storm going on. The air removes chips and may help keep the tool cool. This is a roughing pass.	Not quite mid way through. There is a slight static to the chips but they fall away easily. This is late Spring so static may be more of a problem in Winter. When vacuuming I noticed a static discharge in the plastic hose. This could be hazardous in a volatile atmosphere. (Don't vacuum up any spilled gasoline in the garage.)

Almost complete with the roughing pass and you can see there has been a blizzard occurring. The vacuum does pick this up quite easily and it just falls off clothing. If you looked at the enlargement above you can see that it resembles Ivory Snow laundry detergent (for those of us who remember the non liquid detergents.)	I actually made two of these lithophanes This finish pass is using a 1/16" (0.0625) ball end mill. Again using 10,600 RPM and 40 IPM. The step over is a mere 15% (about 0.009") and a little over 1000 passes. This will take about 1:45:00 to run. The depth of cut is 0.020" more than the rough pass. There is a great How-To on the Vectric web site.

In this shot I am using the 3/64" (0.046879) Ball nose mill. I'll just call it a 0.047 mill. Step over of 15% makes each pass 0.007" and over 1500 passes	The chips are much smaller off these micro-mills so I have named them "micro-chips". There is some Corian dust in both the rough and the finish milling. I advocate "safe milling" and don't breath the dust. A particle filter mask should be sufficient or arrange ventilation to move dust away from the operator. Or just stay away. Yeah, I'm guilty. I just liked to stare at this this thing running to and fro. It will get old someday :)

This is the lithophane cut with the 1/16" ball mill. Note the Corian lettering on the border. It is hard to see in photos of this size. The detail is with a depth of 0.100 and is recessed into the Corian by 0.100" the back (white) areas are minimum 0.050 thick. Add 'em up and you get the 0.250 total thickness.	This is the 3/64" version. If you could look very close you can see a bit of a difference. The benefit is the smaller the tool in the finish pass and more line, the more detail can be seen and it is sharper. This was a hard subject with a lot of black, but it turned out well. The 3/64" is better.

This is the smaller end mill lithophane with back lighting. Great detail. I can recognize my face in the car. The location is Boardman, Ohio, USA. The snow is typical of winters and that much is not any concern.	This is the original B&W photo. It was taken about 1964 or 65. The car is a 1946 English Ford Anglia. My brother Jim and I restored it to running condition. Jim later bought a second Anglia about a 1948 vintage.

A few of the pictures above have links to a larger blowup so you can see the detail. Some browsers show a colored (red or blue) border and/or the pointer changes to a hand. Use the Browser back arrow to return to the normal page.

I took some tiny and short video's of the machining in process. I will set up my professional camera and take some larger video if there is interest in seeing the chips fly. These low resolution postage stamps videos will give you a chance to see and hear the machining process. The milling is set for 40 IPM and the plunge is 30 IPM. With all the Z axis activity it is nearly impossible to run the full 40 IPM except for large areas of the same color. All shade information is in the space of 0.100" of Z movement. All position information is in the X and Y axis

Snow Job - 1/8" Ball Mill	1/16" Ball Mill
3/64" Ball Mill	Near End

The travel looks like it is moving quite fast and it is. I haven't done (but should) do the chip load calculations. I think it could run possibly faster but I don't see a need right now. I have the rapid set on the Taig at 50 IPM which is quite reliable with my controller and doesn't loose steps. The faster a stepper is pushed the less torque from the motor. The screw on the Taig is 20 TPI so it is turning quite fast. I use eighth micro stepping. That's a lot of steps!

My controller is the Hobby CNC with my home built case and power supply. The machine software is MACH 3. The finish pass using the 3/64" ball end mill was nearly a quarter MILLION lines of G-Code. Perfect runs every time. There are no problems with anything in the system except for the human operator. He does screw up occasionally...

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