Saturday, November 28, 2009

Working On A 3-Axis CNC Turning Center

Operating lathes requires exceptional skills. Years of hands-on work hones the superior machinist. I am myself a neophyte - although I admit I did use sturdy old hand-operated lathes in Mechanical Engineering lab back in my  University days to cut, trim, polish, drill and tap various prepared pieces of metal. So I'm not trying to give advice on CNC Machining here. I'm posting this so as to document what I'm picking up before I  forget it all.

A 3-Axis CNC turning center is a combination lathe and computer that gives the user freedom of working in 3-Dimensions, X, Y and Z.  The diagram below illustrates the coordinates system as related to the bed of the lathe. Being a lathe, it has a headstock with a spindle and a tailstock so that the job can be clamped securely and held that way and then spun at selected speeds to enable cutting operations. For small jobs, you can simply clamp the job to the headstock spindle. You can see a small AL 6061 job clamped to the headstock spindle below. You can also see the toolhead with multiple tools  that the machine can switch on the fly for continuous operation.

CNC (Numerical Control) allows us to control the lathe using programming statements and commands. Take a look at the picture below to see the typical interface of one such 3-Axis Turning Center. The machine is operated by a combination of entering commands into the screen and by operating the knobs and levers.

Don't let the formidable looking interface fool you. Learning it is the easy part. By far, the harder part of machining is the set up. With the aim of minimizing the number of cuts you have to make, you have to figure out the exact series of operations you need to make. Simultaneously you have figure out the set up involved in each of those operations. If you want to minimize the time you spend on it (and trust me, it always takes longer that it should, its in the nature of the beast), then you getting the set ups figured out is the most important factor that counts. A major mistake such as overestimating the clearances of the job and the reach of the tool bit can cause a huge headache. You might have to drill with a drill bit thats too long and that will cause vibration issues. Planning the order of the operations is also fairly important, especially if they build on each other and remove material that is critical for certain other operations.

Many thanks to Bob, the Master Machinist!

Wednesday, November 11, 2009


Relativistic Flyers, which are of use in the safe transportation of people and material. The Flyer is a Relativistic Machine (RelMachine) involving gyroscopic effects and the motion is achieved by a process which is the Mechanical equivalent of the generation of Electro-Magnetic Waves. In order to understand the basic operating principles of the Flyer, we need to understand the process of generation of Electro-Magnetic waves. The basic components of all circuits that generate Electro-Magnetic waves are capacitors and inductors.

Discovered first by Tesla, capacitor-inductor circuits possessed a property whereby at a unique frequency that is particular to the combination of capacitance and inductance involved, the circuit was susceptible to excitation into states involving the emission of Electro-Magnetic waves, provided this emission was supported by a source of energy that pumped AC current of that specific frequency through the circuit. The differential mathematics underlying the analysis of LC circuits is identical to that of the Relativistic Machines.

The phenomena manifests as kinetic energy flowing to the Frame of Generation (the coordinate frame in which the resonance occurs) causing its movement. In a very real sense, the Frame of Generation rides the resulting resonance wave. The wave is measurable by the physical acceleration pattern experienced by the vehicle.

When a Flyer is operated, the vehicle acquires momentum in a specific (controlled) direction – a result of the resonance that occurs when a gyroscope spinning at a specific speed is then oscillated about another axis that is at 90 degrees (to the axis denoting the gyroscope’s spin velocity vector), at a specific frequency relative to the angular velocity of the spin of the gyroscope.

What are the characteristics of the Engine producing the Flyer motion ?

Calculating from the baseline power requirements of the working prototype, the expected power consumption is in the range of 1500 Watts for an 800 kg payload. The engine will be approximately 1.5m X 1.5m X 1.8m and weigh around 35-40 kg. It will run on solar/battery energy. Current commercial battery technology leads to fair expectations of the battery life to have a range of 12-15 hours of flying.

Further efficiencies will be realized since it moves from a given point in 3-D space to another point by an optimal path without the influence of the gravitation upon the travel path.

How do you operate a Flyer?

This vehicle has 3 degrees of freedom of movement in space. The steering of the vehicle will happen primarily by adjustment of the vertical movement in conjuction with an adjustment of the direction of the horizontal movement and its magnitude. Foot pedals (integrated with cruise control) help set speed of horizontal and vertical movement. The wheel sets the direction of the horizontal movement. A joystick sets the direction of the vertical movement.

Well designed and modularized mass production could ultimately bring costs of a Flyer to less than $5000 per unit. That expected sale price makes this not only a safer, lower power-consuming and a more optimal 3-D P2P (Point-to-Point) transportation engine but also makes the Flyer cheap enough to sell it in very large quantities in the emerging markets of India as well as the mature markets of the West. Therefore those are the logical first targets of the product.