TRIAC Mill Spindle Project



For a while I have been thinking of improving the performance of my mill. The controlling system is somewhat old and quite elaborate to work with. I have been forced to write a simple program that acts as a postprocessor and convert the output files of my CAM-program (CAMBAM) so that it can be interpreted by the TRIAC. I had only the energy to do the conversion of a few G-commands so it is not in any sense a real postprocessor and I still have to be careful and use some tweaking of the code in order to make it work properly.

But the most annoying feature of the TRIAC is that it cant take programs longer than 750 rows and that is really not so much when working with computer-generated G-code. I have to split the file in several smaller files and try to fit the programs together with. Its doable but not so straight forward as you want it.

So in order to get control of the TRIAC in a more production-friendly way I am now launching a long term project to retrofit the controlsystem with a completly new one and control the whole thing with Mach3. The only thing I am keeping of the old control system (that is for sale..) are the motors (at least that is the plan now).

Its a pretty standard hobby project as so many have done it by now. But judging from the great results people have had I just cant wait any more.

To make things a little more intricate I will also try to make a new spindle for the mill. It will be a R8 system that will use the Thormach Tooling System (TTS). I will also fit a bigger motor to it, some 1,5 kW instead of the 0.3 kW that is used now. Also I will run the spindle faster. Not shure about how good I will get all the parts but hopefully between 5 - 10 kRPM.

As the spindle bearings is quite delicate I will try to protect them against coolant and heat by installing a air-coolant system that will push air in between the spindle and the housing.

The system will be more compact compare to the easychange system I am using now that builds up quite much thus limiting the Z movement of the mill.

And while I am at it I will also fit a coolant system and some decent lights under the mill head. I have not yet decided on a mist type cooling system or a flood type system. Time will tell.

As base for the spindle I ordered a X3 replacement spindle from Little Machine Shop with the promise that the radial runout should me less than 0.0005 inch (0,01mm).

I also did a bargain on ebay on two sets of matched spindle bearings. The bigger ones having a bore diameter of 40 mm (Super Precision Angular Contact Spindle Bearings.. cool name).

Now, in order to have some personal influence of the design of the spindle I decided to make a new bearingshoulder on the spindle to have the bearings closer to the tooling and thus the cutting force. Hopefully this will make a more stable spindle.

The tolerances of a mill spindle with the bearings and tooling runout is something I have never done before. I really lack the proper tools for this. A common lathe is just not good enough to meet the demands form the bearingmanufactors. But I will try to do as good as possible and hopefully I can get a decent spindle. At least better than the existing one.

The pictures is commentend and the project will unfold as I go althogh I have most of it planned already.

More speed, more power, more movement, more coolant, more light..

So far I have not quit the spindle project. Tomorrow I will make the bearing distance and a nut so that I can screw it all together and measure the radial runout of the tool. Its a make or brake test, so lets hope my plan worked.

Next step would be to make the housing. For that I need to disassemble the TRIAC spindle head and figure out the final dimensions of the housing. I plan to “outsource” the housing as my machines is too small for such a piece.